JP7730711B2 - Curable composition, method for producing composite particles, thermally conductive material, thermally conductive sheet, and device with thermally conductive layer - Google Patents

Description

The present invention relates to a curable composition, a method for producing composite particles, a thermally conductive material, a thermally conductive sheet, and a device with a thermally conductive layer.

Power semiconductor devices used in various electrical equipment such as personal computers, general home appliances, and automobiles have been rapidly becoming smaller in size in recent years. As the size of these devices has increased, it has become more difficult to control the heat generated by these devices.
To address this issue, thermally conductive materials are used to promote heat dissipation from power semiconductor devices.
For example, Patent Document 1 discloses a curable composition for forming a thermally conductive material, which contains a specific spherical boron nitride fine powder.

International Publication No. 2018/074077

Thermal conductive materials formed using curable compositions are required to have both excellent thermal conductivity and peel strength. Peel strength means that the peel strength is sufficiently high when the thermal conductive material is adhered to an object (adherend) to which heat is to be transferred. Hereinafter, high peel strength is also referred to as excellent adhesion.

The inventors of the present invention have studied the curable composition described in Patent Document 1 and have found that it is difficult to achieve both thermal conductivity and adhesion in the resulting thermally conductive material.

In view of the above, an object of the present invention is to provide a curable composition that can form a thermally conductive material that has excellent thermal conductivity and adhesion.
Another object of the present invention is to provide a method for producing composite particles, a thermally conductive material, a thermally conductive sheet, and a device with a thermally conductive layer, which are related to the curable composition.

As a result of extensive research into resolving the above-mentioned issues, the inventors have discovered that the following configuration can resolve the above-mentioned issues.

[1]
A curable composition comprising a curable compound and composite particles,
the composite particle includes a particle X and a polymer compound Y that covers at least a part of the surface of the particle X,
The particles X comprise particles selected from boron nitride and agglomerates thereof, having a particle size _D50 of more than 10 μm;
The curable composition, wherein the polymer compound Y has a weight average molecular weight of 1,000 or more.
[2]
The curable composition according to [1], wherein the polymer compound Y has at least one repeating unit derived from a compound selected from the group consisting of styrene, (meth)acrylic acid, (meth)acrylamide, a vinyl ester compound, a vinyl amide compound, and derivatives thereof.
[3]
The curable composition according to [1] or [2], wherein the polymer compound Y has at least one group selected from the group consisting of an epoxy group, a primary amino group, a secondary amino group, an amide group, an ether group, and a hydroxyl group.
[4]
The curable composition according to any one of [1] to [3], wherein the particles X comprise aggregates of boron nitride.
[5]
The curable composition according to any one of [1] to [4], wherein the curable compound includes an epoxy compound.
[6]
The curable composition according to any one of [1] to [5], wherein the curable compound includes a phenol compound.
[7]
the curable compound includes an epoxy compound and a phenol compound,
The curable composition according to any one of [1] to [6], which satisfies at least one of the following requirements: the epoxy compound includes an epoxy compound having a triazine skeleton; and the phenol compound includes a phenol compound having a triazine skeleton.
[8]
[8] The curable composition according to any one of [1] to [7], further comprising a curing accelerator.
[9]
The curable composition according to [8], wherein the curing accelerator comprises a compound containing a phosphorus atom.
[10]
A method for producing composite particles comprising particles X and a polymer compound Y covering at least a portion of the surface of the particles X, wherein the particles X comprise particles selected from boron nitride and aggregates thereof, and the polymer compound Y has a particle size _D50 of more than 10 μm, and the weight average molecular weight of the polymer compound Y is 1,000 or more,
a surface modification step of contacting the particles X with a compound represented by formula (1) described below to obtain surface-modified particles X;
and a production step of polymerizing a monomer in the presence of the surface-modified particles X to produce the composite particles.
[11]
A method for producing composite particles comprising particles X and a polymer compound Y covering at least a portion of the surface of the particles X, wherein the particles X comprise particles selected from boron nitride and aggregates thereof, and the polymer compound Y has a particle size _D50 of more than 10 μm, and the weight average molecular weight of the polymer compound Y is 1,000 or more,
a synthesis step of synthesizing a polymer compound Z by polymerizing a monomer in the presence of a compound represented by formula (1) described below;
a contacting step of contacting the polymer compound Z with the particle X to produce the composite particle.
[12]
The method for producing composite particles according to [10] or [11], wherein the compound represented by formula (1) includes a compound represented by formula (2) described below.
[13]
A thermally conductive material obtained by curing the curable composition according to any one of [1] to [9].
[14]
A thermally conductive sheet comprising the thermally conductive material according to [13].
[15]
A device with a thermally conductive layer, comprising: a device; and a thermally conductive layer including the thermally conductive sheet according to [14], disposed on the device.

According to the present invention, it is possible to provide a curable composition that can form a thermally conductive material that has excellent thermal conductivity and adhesion.
Furthermore, according to the present invention, there can be provided a method for producing composite particles, a thermally conductive material, a thermally conductive sheet, and a device with a thermally conductive layer, all of which relate to the curable composition.

The curable composition, the method for producing the composite particles, the thermally conductive material, the thermally conductive sheet, and the device with a thermally conductive layer of the present invention will be described in detail below.
The following description of the components may be based on a representative embodiment of the present invention, but the present invention is not limited to such an embodiment.

In this specification, a numerical range expressed using "~" means a range that includes the numerical values written before and after "~" as the lower and upper limits.

In this specification, the number average molecular weight and weight average molecular weight are weight average molecular weights determined by gel permeation chromatography (GPC) in terms of polystyrene.

In this specification, "solids" refers to the components that form the thermally conductive material and does not include solvents. The components that form the thermally conductive material may be components that undergo a reaction (polymerization) and change their chemical structure when forming the thermally conductive material. Furthermore, any component that forms the thermally conductive material is considered to be a solid, even if it is in liquid form.

In this specification, "(meth)acrylamide" means "either one or both of acrylamide and methacrylamide." "(meth)acrylic" means "either one or both of acrylic and methacrylic."

In this specification, the acid anhydride group may be either a monovalent group or a divalent group.
When the acid anhydride group is a monovalent group, examples thereof include substituents formed by removing any hydrogen atom from acid anhydrides such as maleic anhydride, phthalic anhydride, pyromellitic anhydride, trimellitic anhydride, etc. When the acid anhydride group is a divalent group, it means a group represented by *-CO-O-CO-* (* represents the bonding position).

In this specification, a substituent or the like that is not specified as substituted or unsubstituted may, if possible, further have a substituent (for example, the substituent group Y described below) in the range that does not impair the intended effect. For example, the expression "alkyl group" means a substituted or unsubstituted alkyl group (an alkyl group that may have a substituent) in the range that does not impair the intended effect.
In addition, in the present specification, when it is stated that "may have a substituent", the type, position and number of the substituent are not particularly limited. The number of the substituents may be, for example, one or two or more. The substituent may be, for example, a monovalent non-metallic atomic group excluding a hydrogen atom, and a group selected from the following substituent group Y is preferred.
In this specification, examples of halogen atoms include chlorine atoms, fluorine atoms, bromine atoms, and iodine atoms.

Substituent group Y:
Halogen atoms (such as -F, -Br, -Cl, and -I), hydroxy groups, amino groups, carboxylic acid groups and their conjugate base groups, carboxylic anhydride groups, cyanate ester groups, unsaturated polymerizable groups, epoxy groups, oxetanyl groups, aziridinyl groups, thiol groups, isocyanate groups, thioisocyanate groups, aldehyde groups, alkoxy groups, aryloxy groups, alkylthio groups, arylthio groups, alkyldithio groups, aryldithio groups, N-alkylamino groups, N,N-dialkylamino groups, N-arylamino groups, N,N-diarylamino groups, N-alkyl-N-arylamino groups, acyloxy groups, carbamoyloxy groups, N -Alkylcarbamoyloxy group, N-arylcarbamoyloxy group, N,N-dialkylcarbamoyloxy group, N,N-diarylcarbamoyloxy group, N-alkyl-N-arylcarbamoyloxy group, alkylsulfoxy group, arylsulfoxy group, acylthio group, acylamino group, N-alkylacylamino group, N-arylacylamino group, ureido group, N'-alkylureido group, N',N'-dialkylureido group, N'-arylureido group, N',N'-diarylureido group, N'-alkyl-N'-arylureido group, N-alkylureido group, N-arylureido group , N'-alkyl-N-alkylureido group, N'-alkyl-N-arylureido group, N',N'-dialkyl-N-alkylureido group, N',N'-dialkyl-N-arylureido group, N'-aryl-N-alkylureido group, N'-aryl-N-arylureido group, N',N'-diaryl-N-alkylureido group, N',N'-diaryl-N-arylureido group, N'-alkyl-N'-aryl-N-alkylureido group, N'-alkyl-N'-aryl-N-arylureido group, alkoxycarbonylamino group, aryloxycarbonylamino group, N-alkyl- N-alkoxycarbonylamino group, N-alkyl-N-aryloxycarbonylamino group, N-aryl-N-alkoxycarbonylamino group, N-aryl-N-aryloxycarbonylamino group, formyl group, acyl group, alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, N-alkylcarbamoyl group, N,N-dialkylcarbamoyl group, N-arylcarbamoyl group, N,N-diarylcarbamoyl group, N-alkyl-N-arylcarbamoyl group, alkylsulfinyl group, arylsulfinyl group, alkylsulfonyl group, arylsulfonyl group, sulfo group (-SO _3H ) and their conjugate base groups, alkoxysulfonyl groups, aryloxysulfonyl groups, sulfinamoyl groups, N-alkylsulfinamoyl groups, N,N-dialkylsulfinamoyl groups, N-arylsulfinamoyl groups, N,N-diarylsulfinamoyl groups, N-alkyl-N-arylsulfinamoyl groups, sulfamoyl groups, N-alkylsulfamoyl groups, N,N-dialkylsulfamoyl groups, N-arylsulfamoyl groups, N,N-diarylsulfamoyl groups, N-alkyl-N-arylsulfamoyl groups, N-acylsulfamoyl groups and their conjugate base groups, N-alkylsulfonylsulfamoyl groups (-SO ₂ NHSO ₂ (alkyl)) and their conjugate base groups, N-arylsulfonylsulfamoyl groups (-SO ₂ NHSO ₂ (aryl)) and its conjugate base group, N-alkylsulfonylcarbamoyl group (-CONHSO ₂ (alkyl)) and its conjugate base group, N-arylsulfonylcarbamoyl group (-CONHSO ₂ (aryl)) and its conjugate base group, alkoxysilyl group (-Si(Oalkyl) ₃ ), aryloxysilyl group (-Si(Oaryl) ₃ ), hydroxysilyl group (-Si(OH) ₃ ) and its conjugate base group, phosphono group (-PO ₃ H ₂ ) and its conjugate base group, dialkylphosphono group (-PO ₃ (alkyl) ₂ ), diarylphosphono group (-PO ₃ (aryl) ₂ ), alkylarylphosphono group (-PO ₃ (alkyl)(aryl)), monoalkylphosphono group (-PO ₃ and its conjugate base group, monoarylphosphono group (-PO ₃ H(aryl)) and its conjugate base group, phosphonooxy group (-OPO ₃ H ₂ ) and its conjugate base group, dialkylphosphonooxy group (-OPO ₃ (alkyl) ₂ ), diarylphosphonooxy group (-OPO ₃ (aryl) ₂ ), alkylarylphosphonooxy group (-OPO ₃ (alkyl)(aryl)), monoalkylphosphonooxy group (-OPO ₃ H(alkyl)) and its conjugate base group, monoarylphosphonooxy group (-OPO ₃ H(aryl)) and its conjugate base group, cyano group, nitro group, aryl group, alkenyl group, alkynyl group, and alkyl group. Furthermore, each of the above groups may further have a substituent (for example, one or more of the above groups) if possible. For example, optionally substituted aryl groups are also included as groups that can be selected from the substituent group Y.
When the group selected from the substituent group Y has a carbon atom, the group has, for example, 1 to 20 carbon atoms.
The number of atoms other than hydrogen atoms contained in the group selected from the substituent group Y is, for example, 1 to 30.
Furthermore, these substituents may or may not bond to each other or to the group they substitute, if possible, to form a ring. For example, an alkyl group (or an alkyl group portion in a group containing an alkyl group as a partial structure, such as an alkoxy group) may be a cyclic alkyl group (cycloalkyl group) or an alkyl group having one or more cyclic structures as a partial structure.

[Curable composition]
The curable composition of the present invention (hereinafter also referred to as "composition") is a curable composition containing a curable compound and composite particles,
The composite particle includes a particle X and a polymer compound Y that covers at least a part of the surface of the particle X,
Particles X comprise particles selected from boron nitride and agglomerates thereof, having a particle size _D50 of more than 10 μm;
The polymer compound Y has a weight average molecular weight of 1,000 or more.

The mechanism by which the composition of the present invention, having the above-mentioned structure, solves the problems of the present invention is not entirely clear, but the present inventors speculate as follows.
The composition of the present invention contains composite particles containing particles X having excellent thermal conductivity. The composite particles also contain a polymer compound Y that covers at least a portion of the surface of the particles X. It is presumed that the polymer compound Y easily interacts with the curable compound in the composition and the cured product thereof when the composition is cured, and therefore the formed thermally conductive material has excellent thermal conductivity and adhesion.
Hereinafter, when the thermal conductive material formed using the composition of the present invention has excellent effects in at least one of thermal conductivity and adhesion, it is also referred to as "excellent effects of the present invention."

The ingredients contained in the composition are described in detail below.

[Composite particles]
The composition includes composite particles.
The composite particle includes a particle X and a polymer compound Y that covers at least a part of the surface of the particle X.

<Particle X>
Particles X comprise particles selected from boron nitride and agglomerates thereof, having a particle size D ₅₀ of more than 10 μm.

The particle size _D50 means the median diameter _D50 .
The particle size _D50 of the particles X is more than 10 μm, often 11 μm or more, preferably 20 μm or more, and more preferably 30 μm or more. The upper limit is preferably 500 μm or less, more preferably 300 μm or less, even more preferably 200 μm or less, and particularly preferably 100 μm or less.
The particle size _D50 of particle X can be measured using, for example, a Mastersizer 2000 (manufactured by Malvern Panalytical). When commercially available particle X is used, the catalog value can be used. Furthermore, the particle size _D50 of particle X in the composite particle can be determined by measuring the particle size of each of 100 particles selected arbitrarily using an electron microscope (e.g., a scanning electron microscope or a transmission electron microscope) and obtaining a frequency distribution. When particle X is not spherical, the particle size D50 can be determined using the longest diameter of particle X.

The shape of particles X can be, for example, rice grain-like, spherical, cubic, spindle-like, scale-like, aggregated (agglomerated), or irregular, with aggregates being preferred.

The particles X are preferably surface-treated.
The surface treatment means a treatment different from the coating of at least a part of the particles X with a polymer compound Y, which will be described later.
By carrying out such a treatment, functional groups are introduced onto the surface of the particles X, which makes it easier for the particles X to interact with the curable compound and/or the polymer compound Y, etc., and it is thought that the thermal conductivity and adhesion of the formed thermally conductive material will be superior.
Examples of surface treatments include plasma treatments (e.g., vacuum plasma treatment, atmospheric pressure plasma treatment, and aqua plasma treatment), ultraviolet irradiation treatment, corona treatment, electron beam irradiation treatment, ozone treatment, baking treatment, flame treatment, and oxidizing agent treatment. The oxidizing agent treatment may be carried out under either acidic or basic conditions (e.g., pH 12 to 14).
As the surface treatment, the modification step in the other steps is preferred.

<Polymer compound Y>
The polymer compound Y covers at least a part of the surface of the particle X and has a weight average molecular weight of 1,000 or more.

The weight average molecular weight of the polymer compound Y is 1,000 or more, preferably 3,000 or more, more preferably 5,000 or more, even more preferably 10,000 or more, particularly preferably 15,000 or more, and most preferably 20,000 or more. The upper limit is preferably 100,000 or less, more preferably 50,000 or less.
When the weight average molecular weight is within the above range, it is presumed that the polymer compound Y has a longer chain skeleton, and therefore, when the curable composition is cured, stress is relieved between the polymer compound Y and the cured product of the curable compound, thereby improving peel strength.

The polymer compound Y preferably has a reactive group.
When the polymer compound Y has a reactive group, the interaction with the particles X is improved, and/or a crosslinking reaction with the curable compound proceeds when the composition is cured, thereby providing better effects of the present invention.
The reactive group preferably has at least one group selected from the group consisting of an epoxy group, a primary amino group, a secondary amino group, an amide group, an ether group, and a hydroxyl group (hereinafter also referred to as "reactive group Y"), and more preferably has at least one group selected from the group consisting of an epoxy group, an amide group, an ether group, and a hydroxyl group.
The reactive groups may be partially or entirely protected with protecting groups, and some or all of the protecting groups may be reactive groups generated by a deprotection reaction. The protecting groups are not particularly limited as long as they are groups capable of protecting the respective reactive groups. For example, the description that polymer compound Y has a silanol group (-Si-OH) may mean that polymer compound Y has a silanol group as "-Si-OH," or that polymer compound Y has a silanol group as "-Si-OMe" and then has "-Si-OH" generated by deprotection of the protecting group by adding an acid or the like.
The number of reactive groups that the polymer compound Y can have is preferably 1 or 2 or more, and more preferably 2 or more.

It is also preferable that the polymer compound Y has a silicon atom and a group containing a silicon atom.
Examples of the silicon atom-containing group include a partial structure containing a silicon atom in the compound represented by formula (1) described below, and a silanol group or a siloxy group is preferred.

The polymer compound Y preferably has at least one repeating unit (hereinafter also referred to as "repeating unit Y") derived from a compound selected from the group consisting of styrene, (meth)acrylic acid, (meth)acrylamide, vinyl ester compounds, vinylamide compounds, and derivatives thereof, and more preferably has at least one repeating unit derived from a compound selected from the group consisting of (meth)acrylic acid, (meth)acrylamide, and derivatives thereof.
The above compounds and their derivatives also include compounds having the above reactive groups.

Examples of styrene and its derivatives include styrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2,4,6-trimethylstyrene, 4-butylstyrene, 4-phenylstyrene, 4-fluorostyrene, 2,3,4,5,6-pentafluorostyrene, 4-chlorostyrene, 4-bromostyrene, 4-iodostyrene, 4-hydroxystyrene, 4-aminostyrene, 4-carboxystyrene, 4-acetoxystyrene, 4-cyanomethylstyrene, 4-chloromethylstyrene, 4-methoxystyrene, 4-nitrostyrene, sodium 4-styrenesulfonate, 4-styrenesulfonic acid chloride, α-methylstyrene, trans-β-methylstyrene, 2-methyl-1-phenylpropene, 1-phenyl-1-cyclohexene, β-bromostyrene, sodium β-styrenesulfonate, 2-isopropenylnaphthalene, vinyltoluene, tert-butoxystyrene, acetoxystyrene, 4-vinylbenzoic acid, styrene dimer, and styrene trimer.

Examples of (meth)acrylic acid and derivatives thereof include (meth)acrylic acid, (meth)acrylic acid esters, and (meth)acrylonitrile.
Examples of (meth)acrylic acid esters include (meth)acrylic acid alkyl esters such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, t-butyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, and cyclohexyl (meth)acrylate; (meth)acrylic acid esters having an ether group such as methoxyethyl methacrylate and ethoxyethyl methacrylate; (meth)acrylic acid esters having an epoxy group such as tetrahydrofurfuryl (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, and glycidyl (meth)acrylate; 2-hydroxyethyl (meth)acrylate, benzyl (meth)acrylate, 2,2,2-trifluoroethyl (meth)acrylate, and 2,2,3,3-tetrafluoropropyl (meth)acrylate.

Examples of (meth)acrylamide and its derivatives include diacetone acrylamide, N,N-dimethylacrylamide, (meth)acrylamide, N-methyl(meth)acrylamide, N-(t-butyl)(meth)acrylamide, N-methylol(meth)acrylamide, and N-(3-dimethylaminopropyl)(meth)acrylamide.

Examples of vinyl ester compounds and their derivatives include vinyl (meth)acrylate, vinyl acetate, vinyl propionate, vinyl pivalate, vinyl benzoate, and vinyl cinnamate.

Examples of vinylamide compounds and their derivatives include N-vinylpyrrolidone, N-vinylcaprolactam, and N-vinylcarbazole.

The repeating unit Y may be used alone or in combination of two or more kinds.
The content of the repeating unit Y is preferably from 1 to 100% by mass, more preferably from 30 to 100% by mass, and even more preferably from 50 to 100% by mass, based on the total repeating units of the polymer compound Y.

The polymer compound Y may contain known repeating units in addition to the repeating unit Y.

The polymer compound Y covers at least a part of the surface of the particle X.
The polymer compound Y covering at least a part of the surface of the particle X means that the polymer compound Y covers a part or the whole of the surface of the particle X.
The polymer compound Y preferably covers at least a part of the surface of the particle X via various bonds.
Examples of the bonding mode include covalent bonding, coordinate bonding, ionic bonding, hydrogen bonding, van der Waals bonding, and metallic bonding, with covalent bonding being preferred.
The group that forms the covalent bond is preferably the reactive group, more preferably a silanol group.
Furthermore, the polymer compound Y is preferably bonded to the surface of the particle X at at least one of the ends of the main chain and the side chain, and more preferably bonded to the surface of the particle X at the end of the main chain. The end may be either both ends or one end. Furthermore, when bonded at both ends, the particle X bonded to both ends may be one particle X or two particles X. When bonded at both ends, it is preferable that the polymer compound Y has two or more reactive groups.
When the polymer compound Y is bonded to the surface of the particle X at the end of the main chain, the particle X may be bonded to the extension of the main chain of the polymer compound Y. In this case, it is presumed that the cured product of the curable compound and the polymer compound Y interact appropriately, resulting in better adhesion.
Furthermore, the polymer compound Y may form a film (e.g., a monolayer) on a part or all of the surface of the particle X. Examples of the monolayer include monolayers formed by chemical adsorption of organic molecules (e.g., a self-assembled monolayer).

The content of polymer compound Y is preferably from 0.005 to 5% by mass, more preferably from 0.05 to 3% by mass, based on the total solid content of the composition.
The content of polymer compound Y is preferably more than 0% by mass and less than 10% by mass, more preferably more than 0% by mass and less than 1% by mass, based on the total mass of all composite particles.

The composite particles may be used alone or in combination of two or more kinds.
The content of the composite particles is preferably 20% by mass or more, more preferably 50% by mass or more, even more preferably 60% by mass or more, and particularly preferably 70% by mass or more, based on the total solid content of the composition. The upper limit is preferably less than 100% by mass, more preferably 95% by mass or less, and even more preferably 85% by mass or less.
The content of the composite particles is preferably 10 to 100% by mass, more preferably 40 to 100% by mass, still more preferably 60 to 100% by mass, and particularly preferably 80 to 100% by mass, based on the total mass of all inorganic particles.

[Curable compound]
The composition includes a curable compound.
The curable compound is a compound different from the polymer compound Y.
Examples of the curable compound include a phenol compound, an epoxy compound, and a maleimide compound.
It is also preferred that the curable compound does not contain silicon atoms or groups containing silicon atoms.

<Phenol compounds>
The phenol compound is a compound having one or more (preferably two or more, more preferably 2 to 10) phenolic hydroxyl groups.
The phenol compound preferably has a triazine skeleton.
The phenol compound "having a triazine skeleton" means that the phenol compound has one or more (preferably 1 to 5) triazine ring groups.

The phenol compound is preferably a compound represented by formula (Z).

In the above formula (Z), when there are multiple groups represented by the same symbol, unless otherwise specified, the multiple groups represented by the same symbol may be the same or different.

In formula (Z), E ¹ to E ⁶ each independently represent a single bond, —NH— or —NR—.
R represents a substituent, such as a linear or branched alkyl group having 1 to 5 carbon atoms.
E ¹ to E ⁶ each independently represent preferably —NH— or —NR—, more preferably —NH—.

In formula (Z), ^B1 represents a single bond or a (k+1)-valent organic group.
^B2 represents a single bond or a l+1-valent organic group.
^B3 represents a single bond or an (m+1)-valent organic group.
^B4 represents a single bond or an (n+1)-valent organic group.
The values of k, l, m, and n in the k+1-valent organic group, the l+1-valent organic group, the m+1-valent organic group, and the n+1-valent organic group are the same as the values of k, l, m, and n specified in formula (Z).
When r is 2 or more and the values of m are different, the value of m in the (m+1)-valent organic group represented by ^B3 is the same as the value of m indicating the number of ^X3 to which ^B3 is bonded.

Examples of the organic group represented by B ¹ to B ⁴ include groups in which j hydrogen atoms have been removed from a hydrocarbon having 1 to 20 carbon atoms and which may have a heteroatom, where j refers to k+1, l+1, m+1, or n+1.
Here, examples of the hydrocarbon before removing the j hydrogen atoms include one or more hydrocarbons selected from the group consisting of an aliphatic hydrocarbon having 1 to 20 carbon atoms which may have a substituent, an aliphatic ring having 3 to 20 carbon atoms which may have a substituent, and an aromatic ring having 3 to 20 carbon atoms which may have a substituent. Furthermore, the one or more hydrocarbons may be further combined with one or more divalent linking groups selected from the group consisting of -O-, -S-, -CO-, -NR ^N - (R ^N represents a hydrogen atom or a substituent), and -SO ₂ -.
Examples of aliphatic hydrocarbons having 1 to 20 carbon atoms include methane, ethane, propane, butane, pentane, hexane, and heptane.
Examples of the aliphatic ring having 3 to 20 carbon atoms include a cyclohexane ring, a cycloheptane ring, a norbornane ring, and an adamantane ring.
Examples of aromatic rings having 3 to 20 carbon atoms include aromatic hydrocarbons having 6 to 20 carbon atoms and aromatic heterocycles having 3 to 20 carbon atoms.
Examples of aromatic hydrocarbons having 6 to 20 carbon atoms include a benzene ring, a naphthalene ring, and an anthracene ring. Examples of aromatic heterocycles having 3 to 20 carbon atoms include a furan ring, a pyrrole ring, a thiophene ring, a pyridine ring, a thiazole ring, a carbazole ring, an indole ring, and a benzothiazole ring.

In formula (Z), k, l, m, and n each independently represent an integer of 0 or greater, provided that the sum of k, l, r×m, and n is an integer of 2 or greater, preferably an integer of 2 to 12, and more preferably an integer of 4 to 8.
The value of m in "r x m" is the average value of multiple possible m's.
k, l, m and n each independently represent preferably an integer of 0 to 5, more preferably an integer of 1 or 2.
For example, k is preferably an integer of 1 or more (for example, an integer of 1 or 2, etc.), l is preferably an integer of 1 or more (for example, an integer of 1 or 2, etc.), m is preferably an integer of 1 or more (for example, an integer of 1 or 2, etc.), and n is preferably an integer of 1 or more (for example, an integer of 1 or 2, etc.).
When k is 0, ^B1 does not have ^X1 . When l is 0, ^B2 does not have ^X2 . When m is 0, ^B3 does not have ^X3 . When n is 0, ^B4 does not have ^X4 .
Furthermore, when ^B1 is a single bond, k is 1. When ^B2 is a single bond, l is 1. When ^B3 is a single bond, m is 1. When ^B4 is a single bond, n is 1.

L represents a divalent organic group.
Examples of divalent organic groups include divalent aromatic ring groups which may have a substituent, divalent aliphatic hydrocarbon groups which may have a substituent, divalent aliphatic ring groups which may have a substituent, -N(R ^NA )-, -CO-, and groups combining these. R ^NA represents an organic group. The groups exemplified as the above divalent organic groups may further have -O-, -S-, -N(R ^N )-, and groups combining these.
R 1 ^N represents a substituent. Examples of the substituent represented by R ^{1 N} include a linear or branched alkyl group having 1 to 5 carbon atoms.
Furthermore, examples of the substituent that the aromatic ring group, the aliphatic hydrocarbon group, and the aliphatic ring group may have include linear or branched alkyl groups having 1 to 5 carbon atoms.

Examples of the divalent aromatic ring group include a divalent aromatic hydrocarbon group having 6 to 20 carbon atoms and a divalent aromatic heterocyclic group having 3 to 20 carbon atoms.
Examples of aromatic rings constituting a divalent aromatic hydrocarbon group having 6 to 20 carbon atoms include monocyclic aromatic rings such as a benzene ring; and polycyclic aromatic ring groups such as a naphthalene ring and an anthracene ring. Examples of aromatic heterocycles constituting a divalent aromatic heterocyclic group having 3 to 20 carbon atoms include monocyclic aromatic rings such as a furan ring, a pyrrole ring, a thiophene ring, a pyridine ring, and a thiazole ring; and polycyclic aromatic rings such as a benzothiazole ring, a carbazole ring, and an indole ring.
The divalent aromatic ring group represented by L may be any of the above-exemplified groups in which two hydrogen atoms have been removed.

Examples of divalent aliphatic hydrocarbon groups include alkylene groups having 1 to 12 carbon atoms, such as methylene, ethylene, propylene, butylene, pentylene, hexylene, methylhexylene, and heptylene groups.

Examples of the aliphatic ring constituting the divalent aliphatic ring group include a cyclohexane ring, a cycloheptane ring, a norbornane ring, and an adamantane ring.
The aliphatic cyclic group represented by L may be any of the above-listed groups in which two hydrogen atoms have been removed.

The divalent aromatic ring group which may have a substituent, the divalent aliphatic hydrocarbon group which may have a substituent, the divalent aliphatic ring group which may have a substituent, or the group combining -O-, -S-, -NR ^N - or -CO- may be not only a divalent linking group consisting of a combination of two or more of these, but also a divalent linking group consisting of a combination of two or more of the same type of groups (for example, aromatic ring groups, etc.) via a single bond.

In the present invention, it is preferable that both ends of L are carbon atoms, in order to obtain a thermally conductive material with better thermal conductivity. The terminal carbon atoms may be part of a cyclic structure.
In addition, in the present invention, in order to obtain a thermally conductive material with better thermal conductivity, it is preferable that L in the above formula (P2) is a divalent organic group having at least one selected from the group consisting of a divalent aromatic ring group which may have a substituent, a divalent aliphatic ring group which may have a substituent, and an alkylene group which has two or more carbon atoms and may have a branch, and a divalent organic group having a divalent aromatic ring group which may have a substituent is more preferable in order to obtain better thermal conductivity.

In formula (Z), r is an integer of 0 or more.
r is preferably an integer of 0 to 20, and more preferably an integer of 0 to 10.

In formula (Z), X ¹ to X ⁴ each independently represent an aromatic ring group having a phenolic hydroxyl group.
The "aromatic ring group having a phenolic hydroxyl group" may be an aromatic ring group having one or more (e.g., 1 to 4) hydroxyl groups (phenolic hydroxyl groups) directly bonded to the aromatic ring. The aromatic ring group may or may not have a substituent other than the hydroxyl group. The aromatic ring group may be monocyclic or polycyclic, and may have a heteroatom as a ring member atom. The number of ring member atoms in the aromatic ring group is preferably 5 to 15, more preferably 6 to 10, and even more preferably 6.
The aromatic ring group is preferably a benzene ring group.
The substituent that the aromatic ring group may have other than the hydroxyl group is preferably a substituent having 1 to 6 carbon atoms, more preferably a hydrocarbon group having 1 to 6 carbon atoms, and still more preferably a linear or branched alkyl group having 1 to 6 carbon atoms.

In formula (Z), at least one of the k ^X1s , l ^X2s , r×m ^X3s , and n ^X4s is preferably an aromatic ring group having a phenolic hydroxyl group and a substituent located at the ortho-position of the phenolic hydroxyl group. The substituent may be located at only one or both of the ortho-positions of the phenolic hydroxyl group.
The value of m in "r x m" is the average value of multiple possible m's.
Furthermore, the "substituent located at the ortho position" is preferably a substituent having 1 to 6 carbon atoms, more preferably a hydrocarbon group having 1 to 6 carbon atoms, and even more preferably a linear or branched alkyl group having 1 to 6 carbon atoms.
In other words, of the (k+l+r×m+n) "aromatic ring groups having a phenolic hydroxyl group" represented by any one of X ¹ to X ⁴ , at least one (preferably 30% or more, more preferably 50% or more, even more preferably 65% or more; preferably 100% or less, more preferably 90% or less, even more preferably 80% or less) may represent an "aromatic ring group having a phenolic hydroxyl group and a substituent arranged at the ortho-position of the phenolic hydroxyl group".

In the aromatic ring groups having a phenolic hydroxyl group represented by X ¹ to X ⁴ , the aromatic ring groups other than "aromatic ring groups having a phenolic hydroxyl group and a substituent arranged at the ortho-position of the phenolic hydroxyl group" may or may not have a substituent other than a hydroxyl group (phenolic hydroxyl group).
Examples of aromatic ring groups other than "aromatic ring groups having a phenolic hydroxyl group and a substituent positioned at the ortho-position of the phenolic hydroxyl group" include hydroxyphenyl groups.
It is also preferred that at least one (e.g., one or two) of the (k+l+r×m+n) "aromatic ring groups having a phenolic hydroxyl group" represented by any one of X ¹ to X ⁴ is an aromatic ring group other than an "aromatic ring group having a phenolic hydroxyl group and a substituent positioned at the ortho-position of the phenolic hydroxyl group".
In the aromatic ring groups having a phenolic hydroxyl group represented by X ¹ to X ⁴ , the presence of aromatic ring groups other than "an aromatic ring group having a phenolic hydroxyl group and a substituent arranged at the ortho-position of the phenolic hydroxyl group" is thought to disrupt the symmetry of the compound as a whole, lower the melting point of the compound, and improve the handleability of the semi-cured film formed from the composition.

The phenol compound is also preferably a compound represented by formula (Z1).
The phenol compound preferably contains a compound represented by formula (Z1), or may be the compound represented by formula (Z1) itself. The content of the compound represented by formula (Z1) is preferably 10 to 100 mass%, more preferably 25 to 100 mass%, and even more preferably 50 to 100 mass%, based on the total mass of the phenol compound.

In formula (Z1), r represents an integer of 0 or greater. r is preferably an integer of 0 to 20, and more preferably an integer of 0 to 10.
L represents a divalent organic group. The divalent organic group represented by L in formula (Z1) is, for example, the same as the divalent organic group represented by L in formula (Z1).
R 1 and ^Z represent a hydrogen atom or a substituent.
The substituent represented by R 1 ^Z is preferably a substituent having 1 to 6 carbon atoms, more preferably a hydrocarbon group having 1 to 6 carbon atoms, and even more preferably a linear or branched alkyl group having 1 to 6 carbon atoms.
At least one of the (3+r) R ^Z's (preferably 30% or more, more preferably 50% or more, even more preferably 65% or more; preferably 90% or less, more preferably 80% or less) present in formula (Z1) may represent a substituent.
At least one (for example, one or two) of the (3+r) R 1 ^Z's in formula (Z1) may represent a hydrogen atom.
In the benzene ring group to which R ^z (preferably R ^z as a substituent) and OH are bonded in formula (Z1), it is also preferable that the R ^z (preferably R ^z as a substituent) is located at the para position relative to the NH to which the benzene ring group is bonded.

The phenol compound is also preferably a compound represented by formula (Z2).
The phenol compound preferably contains a compound represented by formula (Z2), or may be the compound represented by formula (Z2) itself. The content of the compound represented by formula (Z2) is preferably 10 to 100 mass%, more preferably 25 to 100 mass%, and even more preferably 50 to 100 mass%, based on the total mass of the phenol compound.

In formula (Z2), R 1 ^Z represents a hydrogen atom or a substituent.
At least one of the two R 1 ^Z's preferably represents a substituent, and both of them preferably represent a substituent.
The substituent represented by R 1 ^Z is preferably a substituent having 1 to 6 carbon atoms, more preferably a hydrocarbon group having 1 to 6 carbon atoms, and even more preferably an alkyl group having 1 to 6 carbon atoms.
The alkyl group may be linear or branched, and is preferably unsubstituted.
In formula (Z2), two ^Rz 's may be the same or different.

Examples of phenolic compounds include benzene polyols such as bisphenol A, F, S, AD, benzenediol, and benzenetriol, biphenyl aralkyl phenolic resins, phenol novolac resins, cresol novolac resins, aromatic hydrocarbon formaldehyde resin-modified phenolic resins, dicyclopentadiene phenol adduct resins, phenol aralkyl resins, polyhydric phenol novolac resins synthesized from polyhydric hydroxy compounds and formaldehyde, naphthol aralkyl resins, trimethylolmethane resins, tetraphenylolethane resins, naphthol novolac resins, naphtholphenol co-condensed novolac resins, naphthol-cresol co-condensed novolac resins, biphenyl-modified phenolic resins, biphenyl-modified naphthol resins, aminotriazine-modified phenolic resins, and alkoxy group-containing aromatic ring-modified novolac resins.

The molecular weight of the phenol compound is preferably 225 to 2,000, more preferably 225 to 1,000.
When the molecular weight has a molecular weight distribution, the molecular weight is a weight average molecular weight.

The hydroxyl group content of the phenol compound is preferably 2.0 mmol/g or more, more preferably 4.0 mmol/g or more, and the upper limit is preferably 25.0 mmol/g or less, more preferably 10.0 mmol/g or less.
The hydroxyl group content means the number of hydroxyl groups (preferably phenolic hydroxyl groups) contained in 1 g of the phenol compound.
In addition to hydroxyl groups, the phenolic compound may or may not have an active hydrogen-containing group (e.g., carboxyl group) capable of polymerizing with an epoxy compound. The lower limit of the active hydrogen content of the phenolic compound (total content of hydrogen atoms in hydroxyl groups, carboxylic acid groups, etc.) is preferably 2.0 mmol/g or more, more preferably 4.0 mmol/g or more. The upper limit is preferably 25.0 mmol/g or less, more preferably 10.0 mmol/g or less.

The composition of the present invention may contain, in addition to the phenol compound, a compound having a group capable of reacting with an epoxy compound (also referred to as "other active hydrogen-containing compounds").
However, in the composition of the present invention, the mass ratio of the content of the other active hydrogen-containing compound to the content of the phenol compound is preferably 0 to 1, more preferably 0 to 0.1, and even more preferably 0 to 0.05.

The content of the phenol compound in the composition is preferably from 3 to 90 mass %, more preferably from 5 to 50 mass %, and even more preferably from 7 to 40 mass %, based on the total solid content of the composition.
The term "solid content" refers to components that form the thermally conductive material and does not include solvents. The components that form the thermally conductive material may be components that undergo a reaction (polymerization) to change their chemical structure when forming the thermally conductive material. Furthermore, components that form the thermally conductive material are considered to be solid content even if they are liquid.

<Epoxy Compound>
An epoxy compound is a compound having at least one epoxy group (oxiranyl group) in one molecule.
The epoxy group is a group obtained by removing one or more hydrogen atoms (preferably one hydrogen atom) from an oxirane ring. If possible, the epoxy group may further have a substituent (for example, a linear or branched alkyl group having 1 to 5 carbon atoms).

The number of epoxy groups contained in the epoxy compound is preferably 2 or more, more preferably 2 to 1,000, and even more preferably 2 to 40, per molecule.

The molecular weight of the epoxy compound is preferably 150 or more, more preferably 300 or more, and the upper limit is preferably 100,000 or less, more preferably 10,000 or less.
When the molecular weight has a molecular weight distribution, the molecular weight is a weight average molecular weight.
In this specification, the number average molecular weight and weight average molecular weight are weight average molecular weights determined by gel permeation chromatography (GPC) in terms of polystyrene.

The epoxy group content of the epoxy compound is preferably from 2.0 to 20.0 mmol/g, more preferably from 5.0 to 15.0 mmol/g.
The epoxy group content means the number of epoxy groups contained in 1 g of the epoxy compound.
The epoxy compound also preferably has an aromatic ring group (preferably an aromatic hydrocarbon ring group).
The content of the epoxy compound having an aromatic ring group is preferably 5 to 100 mass %, more preferably 50 to 100 mass %, and even more preferably 70 to 100 mass %, based on the total amount of epoxy compounds.

The epoxy compound may or may not exhibit liquid crystallinity.
That is, the epoxy compound may be a liquid crystal compound, or in other words, a liquid crystal compound having an epoxy group.
Examples of the epoxy compound (which may be a liquid crystalline epoxy compound) include a compound having at least a partial rod-like structure (rod-like compound) and a compound having at least a partial discotic structure (discotic compound).
The rod-shaped compounds and discotic compounds will be described in detail below.

(rod-shaped compound)
Examples of epoxy compounds that are rod-shaped compounds include azomethines, azoxys, cyanobiphenyls, cyanophenyl esters, benzoic acid esters, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes, cyano-substituted phenylpyrimidines, alkoxy-substituted phenylpyrimidines, phenyldioxanes, tolanes, and alkenylcyclohexylbenzonitriles. In addition to the low molecular weight compounds described above, high molecular weight compounds can also be used. The high molecular weight compounds are polymerized low molecular weight rod-shaped compounds having reactive groups.
A preferred rod-shaped compound is a rod-shaped compound represented by the following formula (XXI).
Formula (XXI): Q ¹ -L ¹¹¹ -A ¹¹¹ -L ¹¹³ -ML ¹¹⁴ -A ¹¹² -L ¹¹² -Q ²

In formula (XXI), ^Q1 and ^Q2 each independently represent an epoxy group, ^L111 , ^L112 , ^L113 , and ^L114 each independently represent a single bond or a divalent linking group, ^A111 and ^A112 each independently represent a divalent linking group (spacer group) having 1 to 20 carbon atoms, and M represents a mesogenic group.
The epoxy groups of ^Q1 and ^Q2 may or may not have a substituent.

In formula (XXI), L ¹¹¹ , L ¹¹² , L ¹¹³ and L ¹¹⁴ each independently represent a single bond or a divalent linking group.
The divalent linking groups represented by L ¹¹¹ , L ¹¹² , L ¹¹³ and L ¹¹⁴ are preferably each independently a divalent linking group selected from the group consisting of -O-, -S-, -CO-, -NR ¹¹² -, -CO-O-, -O-CO-O-, -CO-NR ¹¹² -, -NR ¹¹² -CO-, -O-CO-, -CH ₂ -O-, -O-CH ₂ -, -O-CO-NR ¹¹² -, -NR ¹¹² -CO-O- and -NR ¹¹² -CO-NR ¹¹² -. R ¹¹² is an alkyl group having 1 to 7 carbon atoms or a hydrogen atom.
It is preferable that L ¹¹³ and L ¹¹⁴ each independently represent —O—.
It is preferable that L ¹¹¹ and L ¹¹² each independently represent a single bond.

In formula (XXI), A ¹¹¹ and A ¹¹² each independently represent a divalent linking group having 1 to 20 carbon atoms.
The divalent linking group may contain heteroatoms such as non-adjacent oxygen atoms and sulfur atoms. An alkylene group, alkenylene group, or alkynylene group having 1 to 12 carbon atoms is preferred. The alkylene group, alkenylene group, or alkynylene group may or may not have an ester group.
The divalent linking group is preferably linear and may or may not have a substituent, such as a halogen atom (a fluorine atom, a chlorine atom, or a bromine atom), a cyano group, a methyl group, or an ethyl group.
A ¹¹¹ and A ¹¹² are each independently preferably an alkylene group having 1 to 12 carbon atoms, more preferably a methylene group.

In formula (XXI), M represents a mesogenic group, and examples of the mesogenic group include known mesogenic groups. A group represented by the following formula (XXII) is preferred.
Formula (XXII): -(W ¹ -L ¹¹⁵ ) _n -W ² -

In formula (XXII), ^W1 and ^W2 each independently represent a cyclic alkylene group, a cyclic alkenylene group, an arylene group, or a divalent heterocyclic group. ^L115 represents a single bond or a divalent linking group. n represents an integer of 1 to 4.

Examples of ^W1 and ^W2 include 1,4-cyclohexenediyl, 1,4-cyclohexanediyl, 1,4-phenylene, pyrimidine-2,5-diyl, pyridine-2,5-diyl, 1,3,4-thiadiazole-2,5-diyl, 1,3,4-oxadiazole-2,5-diyl, naphthalene-2,6-diyl, naphthalene-1,5-diyl, thiophene-2,5-diyl, and pyridazine-3,6-diyl. In the case of 1,4-cyclohexanediyl, either the trans or cis structural isomer may be used, or a mixture in any ratio may be used. The trans isomer is preferred.
W ¹ and W ² may each have a substituent. Examples of the substituent include the groups exemplified in the above-mentioned substituent group Y, more specifically, a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom), a cyano group, an alkyl group having 1 to 10 carbon atoms (e.g., a methyl group, an ethyl group, and a propyl group), an alkoxy group having 1 to 10 carbon atoms (e.g., a methoxy group and an ethoxy group), an acyl group having 1 to 10 carbon atoms (e.g., a formyl group and an acetyl group), an alkoxycarbonyl group having 1 to 10 carbon atoms (e.g., a methoxycarbonyl group and an ethoxycarbonyl group), an acyloxy group having 1 to 10 carbon atoms (e.g., an acetyloxy group and a propionyloxy group), a nitro group, a trifluoromethyl group, and a difluoromethyl group.
When a plurality of W ¹ 's are present, the plurality of W ¹ 's may be the same or different.

In formula (XXII), L ¹¹⁵ represents a single bond or a divalent linking group. Examples of the divalent linking group represented by L ¹¹⁵ include the specific examples of the divalent linking groups represented by L ¹¹¹ to L ¹¹⁴ described above, such as —CO—O—, —O—CO—, —CH ₂ —O—, and —O—CH ₂ —.
When a plurality of L ¹¹⁵ are present, the plurality of L ¹¹⁵ may be the same or different.

Preferred basic skeletons of the mesogenic group represented by formula (XXII) are exemplified below. The mesogenic group may have a substituent substituted on these skeletons.

Among the above skeletons, the biphenyl skeleton is preferred in that the resulting thermally conductive material has better thermal conductivity.
The compound represented by formula (XXI) can be synthesized by referring to the method described in JP-A-11-513019 (WO97/00600).
The rod-like compound may be a monomer having a mesogen group as described in JP-A-11-323162 and Japanese Patent No. 4,118,691.

Also preferred are compounds represented by formula (XXI) in which one or both of "Q ¹ -L ¹¹¹ -" and "-L ¹¹² -Q ² " are replaced with a diglycidylamino group.

The rod-shaped compound is preferably a compound represented by formula (E1).

In formula (E1), L ^E1 each independently represents a single bond or a divalent linking group.
L ^E1 is preferably a divalent linking group.
The divalent linking group is preferably -O-, -S-, -CO-, -NH-, -CH=CH-, -C≡C-, -CH=N-, -N=CH-, -N=N-, an optionally substituted alkylene group, or a group consisting of a combination of two or more thereof, and more preferably -O-alkylene group- or -alkylene group-O-.
The alkylene group may be straight-chain, branched-chain or cyclic, but is preferably a straight-chain alkylene group having 1 to 2 carbon atoms.
A plurality of L ^E1 's may be the same or different.

In formula (E1), L ^E2 each independently represent a single bond, -CH=CH-, -CO-O-, -O-CO-, -C(-CH ₃ )=CH-, -CH=C(-CH ₃ )-, -CH=N-, -N=CH-, -N=N-, -C≡C-, -N=N ⁺ (-O ^- )-, -N ⁺ (-O ^- )=N-, -CH=N ⁺ (-O ^- )-, -N ⁺ (-O ^- )=CH-, -CH=CH-CO-, -CO-CH=CH-, -CH=C(-CN)- or -C(-CN)=CH-.
Each L ^E2 is preferably independently a single bond, —CO—O— or —O—CO—.
When a plurality of L ^E2s are present, the plurality of L ^E2s may be the same or different.

In formula (E1), L ^{and E3} each independently represent a single bond, a 5- or 6-membered aromatic ring group, a 5- or 6-membered non-aromatic ring group, or a polycyclic group consisting of these rings, each of which may have a substituent.
Examples of aromatic and non-aromatic ring groups represented by L ^E3 include optionally substituted 1,4-cyclohexanediyl, 1,4-cyclohexenediyl, 1,4-phenylene, pyrimidine-2,5-diyl, pyridine-2,5-diyl, 1,3,4-thiadiazole-2,5-diyl, 1,3,4-oxadiazole-2,5-diyl, naphthalene-2,6-diyl, naphthalene-1,5-diyl, thiophene-2,5-diyl, and pyridazine-3,6-diyl groups. In the case of the 1,4-cyclohexanediyl group, it may be either a trans or cis structural isomer, or a mixture in any proportion. The trans isomer is preferred.
L ^E3 is preferably a single bond, a 1,4-phenylene group or a 1,4-cyclohexenediyl group.
The substituents possessed by the group represented by L ^E3 are each independently preferably an alkyl group, an alkoxy group, a halogen atom, a cyano group, a nitro group or an acetyl group, more preferably an alkyl group (preferably having 1 carbon atom).
When a plurality of substituents are present, the substituents may be the same or different.
When a plurality of L ^E3s are present, the plurality of L ^E3s may be the same or different.

In formula (E1), pe represents an integer of 0 or more.
When pe is an integer of 2 or more, a plurality of (-L ^E3 -L ^E2 -) may be the same or different.
pe is preferably 0 to 2, more preferably 0 or 1, and even more preferably 0.

In formula (E1), L ^{and E4} each independently represent a substituent.
The substituents are each independently preferably an alkyl group, an alkoxy group, a halogen atom, a cyano group, a nitro group or an acetyl group, more preferably an alkyl group (preferably having one carbon atom).
A plurality of L ^E4 's may be the same or different from each other. When l e described below is an integer of 2 or more, a plurality of L ^E4's present in the same (L ^E4 ) _l e may be the same or different from each other.

In formula (E1), each le independently represents an integer of 0 to 4.
Each le is preferably 0 to 2.
A plurality of le's may be the same or different.

Also preferred are compounds represented by formula (E1) in which one or both of the two "epoxy groups -L ^E1 -" are replaced with a diglycidylaminoalkylene group (preferably a diglycidylaminomethylene group).

The rod-like compound preferably has a biphenyl skeleton, since the resulting thermally conductive material has better thermal conductivity.
In other words, the epoxy compound preferably has a biphenyl skeleton, and in this case, the epoxy compound is preferably a rod-like compound.

(Disco-like compounds)
The discotic epoxy compound has at least a partial discotic structure.
The discotic structure has at least an alicyclic or aromatic ring. In particular, when the discotic structure has an aromatic ring, the discotic compound can form a columnar structure by forming a stacking structure due to intermolecular π-π interactions.
Specific examples of the discotic structure include the triphenylene structure described in Angew. Chem. Int. Ed. 2012, 51, 7990-7993 or JP-A-7-306317, and the tri-substituted benzene structures described in JP-A-2007-002220 and JP-A-2010-244038.

When a discotic compound is used as the epoxy compound, a thermally conductive material with high thermal conductivity can be obtained. The reason for this is thought to be that while rod-shaped compounds can only conduct heat linearly (one-dimensionally), discotic compounds can conduct heat planarly (two-dimensionally) in the normal direction, which increases the number of heat conduction paths and improves thermal conductivity.

The discotic compound preferably has three or more epoxy groups. A cured product of a composition containing a discotic compound having three or more epoxy groups tends to have a high glass transition temperature and high heat resistance.
The number of epoxy groups contained in the discotic compound is preferably 8 or less, more preferably 6 or less.

Examples of discotic compounds include those described in C. Destrade et al., Mol. Crysr. Liq. Cryst., vol. 71, page 111 (1981); Quarterly Review of Chemistry, No. 22, Chemistry of Liquid Crystals, edited by the Chemical Society of Japan, Chapter 5, Chapter 10, Section 2 (1994); B. Kohne et al., Angew. Chem. Soc. Chem. Comm., page 1794 (1985); and J. Zhang et al., J. Am. Chem. Soc., vol. 116, page 2655 (1994) and Japanese Patent No. 4592225, in which at least one (preferably three or more) of the terminals is an epoxy group.
Examples of the discotic compound include the triphenylene structure described in Angew. Chem. Int. Ed. 2012, 51, 7990-7993 and JP-A-7-306317, and the trisubstituted benzene structure described in JP-A-2007-002220 and JP-A-2010-244038 in which at least one (preferably three or more) of the terminals is an epoxy group.

As the discotic compound, a compound represented by any one of the following formulas (D1) to (D16) is preferred, since the thermal conductivity of the thermal conductive material is superior.
First, formulas (D1) to (D15) will be explained, and then formula (D16) will be described in detail.
In the following formulas, "-LQ" represents "-LQ" and "QL-" represents "QL-".

In formulas (D1) to (D15), L represents a divalent linking group.
In order to obtain a thermally conductive material with better thermal conductivity, it is preferable that L's are each independently a group selected from the group consisting of an alkylene group, an alkenylene group, an arylene group, -CO-, -NH-, -O-, -S-, and combinations thereof, and it is more preferable that L's are a group combining two or more groups selected from the group consisting of an alkylene group, an alkenylene group, an arylene group, -CO-, -NH-, -O-, and -S-.
The alkylene group preferably has 1 to 12 carbon atoms. The alkenylene group preferably has 2 to 12 carbon atoms. The arylene group preferably has 10 or less carbon atoms.
The alkylene group, alkenylene group and arylene group may have a substituent (preferably an alkyl group, a halogen atom, a cyano group, an alkoxy group, an acyloxy group, or the like).

Examples of L are shown below. In the following examples, the left bond is bonded to the central structure (hereinafter also simply referred to as "central ring") of the compound represented by any one of formulas (D1) to (D15), and the right bond is bonded to Q.
AL represents an alkylene group or an alkenylene group, and AR represents an arylene group.
The alkylene group represented by AL may be linear or branched and has, for example, 1 to 12 carbon atoms. The alkenylene group represented by AL may be linear or branched and has, for example, 2 to 12 carbon atoms. The arylene group represented by AR may be monocyclic or polycyclic and preferably has 6 to 12 ring atoms.

L101:-AL-CO-O-AL-
L102:-AL-CO-O-AL-O-
L103:-AL-CO-O-AL-O-AL-
L104:-AL-CO-O-AL-O-CO-
L105:-CO-AR-O-AL-
L106:-CO-AR-O-AL-O-
L107:-CO-AR-O-AL-O-CO-
L108:-CO-NH-AL-
L109:-NH-AL-O-
L110:-NH-AL-O-CO-
L111:-O-AL-
L112:-O-AL-O-
L113:-O-AL-O-CO-

L114:-O-AL-O-CO-NH-AL-
L115:-O-AL-S-AL-
L116:-O-CO-AL-AR-O-AL-O-CO-
L117:-O-CO-AR-O-AL-CO-
L118:-O-CO-AR-O-AL-O-CO-
L119: -O-CO-AR-O-AL-O-AL-O-CO-
L120: -O-CO-AR-O-AL-O-AL-O-AL-O-CO-
L121:-S-AL-
L122:-S-AL-O-
L123:-S-AL-O-CO-
L124:-S-AL-S-AL-
L125:-S-AR-AL-
L126:-O-CO-AL-
L127:-O-CO-AL-O-
L128:-O-CO-AR-O-AL-
L129:-O-CO-
L130: -O-CO-AR-O-AL-O-CO-AL-S-AR-
L131:-O-CO-AL-S-AR-
L132: -O-CO-AR-O-AL-O-CO-AL-S-AL-
L133:-O-CO-AL-S-AR-
L134:-O-AL-S-AR-
L135:-AL-CO-O-AL-O-CO-AL-S-AR-
L136:-AL-CO-O-AL-O-CO-AL-S-AL-
L137:-O-AL-O-AR-
L138:-O-AL-O-CO-AR-
L139:-O-AL-NH-AR-
L140:-O-CO-AL-O-AR-
L141: -O-CO-AR-O-AL-O-AR-
L142:-AL-CO-O-AR-
L143:-AL-CO-O-AL-O-AR-

In formulae (D1) to (D15), each Q independently represents a hydrogen atom or a substituent.
Examples of the substituent include the groups exemplified in the above-mentioned substituent group Y. More specifically, examples of the substituent include the above-mentioned reactive functional groups, halogen atoms, isocyanate groups, cyano groups, unsaturated polymerizable groups, epoxy groups, oxetanyl groups, aziridinyl groups, thioisocyanate groups, aldehyde groups, and sulfo groups.
However, when Q is a group other than an epoxy group, Q is preferably stable against the epoxy group.
In formulas (D1) to (D15), one or more (preferably two or more) Q's represent an epoxy group. In order to obtain a thermally conductive material with superior thermal conductivity, it is preferable that all Q's represent an epoxy group.
From the viewpoint of the stability of the epoxy group, it is preferable that the compounds represented by formulae (D1) to (D15) do not have —NH—.

The compound represented by formula (D4) is preferred because the thermal conductivity of the thermal conductive materials of the compounds represented by formulas (D1) to (D15) is superior. In other words, the central ring of the discotic compound is preferably a triphenylene ring.
As the compound represented by formula (D4), a compound represented by formula (XI) is preferred in terms of providing a thermally conductive material with better thermal conductivity.

In formula (XI), R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ and R ¹⁶ each independently represent *-X ¹¹ -L ¹¹ -P ¹¹ or *-X ¹² -L ¹² -Y ¹² .
The symbol * indicates the bonding position to the triphenylene ring.
It is preferred that two or more of R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ and R ¹⁶ are *-X ¹¹ -L ¹¹ -P ¹¹ , and three or more are *-X ¹¹ -L ¹¹ -P ¹¹ .
In order to obtain a thermally conductive material with better thermal conductivity, it is preferable that one or more of R ¹¹ and R ¹² , one or more of R ¹³ and R ¹⁴ , and one or more of R ¹⁵ and R ¹⁶ are *-X ¹¹ -L ¹¹ -P ¹¹ .
It is more preferable that R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ and R ¹⁶ are all *-X ¹¹ -L ¹¹ -P ^11. In addition, it is even more preferable that R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ and R ¹⁶ are all the same.

^X11 each independently represents a single bond, -O-, -CO-, -NH-, -O-CO-, -O-CO-O-, -O-CO-NH-, -O-CO-S-, -CO-O-, -CO-NH-, -CO-S-, -NH-CO-, -NH-CO-O-, -NH-CO-NH-, -NH-CO-S-, -S-, -S-CO-, -S-CO-O-, -S-CO-NH- or -S-CO-S-.
^X11 is preferably each independently -O-, -O-CO-, -O-CO-O-, -O-CO-NH-, -CO-O-, -CO-NH-, -NH-CO- or -NH-CO-O-, more preferably -O-, -O-CO-, -CO-O-, -O-CO-NH- or -CO-NH-, and still more preferably -O-CO- or -CO-O-.

Each L ¹¹ independently represents a single bond or a divalent linking group.
Examples of the divalent linking group include -O-, -O-CO-, -CO-O-, -S-, -NH-, an alkylene group (preferably having 1 to 10 carbon atoms, more preferably having 1 to 8 carbon atoms, and still more preferably having 1 to 7 carbon atoms), an arylene group (preferably having 6 to 20 carbon atoms, more preferably having 6 to 14 carbon atoms, and still more preferably having 6 to 10 carbon atoms), and a group formed by combining these groups.
Examples of the alkylene group include a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group, a hexylene group, and a heptylene group.
Examples of the arylene group include a 1,4-phenylene group, a 1,3-phenylene group, a 1,4-naphthylene group, a 1,5-naphthylene group, and an anthracenylene group, with a 1,4-phenylene group being preferred.

The alkylene group and the arylene group may each have a substituent. The number of substituents is preferably 1 to 3, and more preferably 1. The substitution position of the substituent is not particularly limited. The substituent is preferably a halogen atom or an alkyl group having 1 to 3 carbon atoms, and more preferably a methyl group.
The alkylene group and the arylene group are preferably unsubstituted. The alkylene group is preferably unsubstituted.

Examples of -X ¹¹ -L ¹¹ - include L101 to L143, which are the examples of L mentioned above.

^P11 represents an epoxy group, which may or may not have a substituent.

X ¹² is the same as X ¹¹ , and the preferred conditions are also the same.
L ¹² is similar to L ¹¹ , and the preferred conditions are also similar.
Examples of -X ¹² -L ¹² - include L101 to L143, which are the examples of L described above.

Y ¹² represents a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, or a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms in which one or more methylene groups have been substituted with —O—, —S—, —NH—, —N(CH ₃ )—, —CO—, —O—CO— or —CO—O—.
When Y ¹² is a linear, branched, or cyclic alkyl group having 1 to 20 carbon atoms or a linear, branched, or cyclic alkyl group having 1 to 20 carbon atoms in which one or more methylene groups have been substituted with —O—, —S—, —NH—, —N(CH ₃ )—, —CO—, —O—CO—, or —CO—O—, one or more hydrogen atoms contained in Y ¹² may be substituted with a halogen atom.

Specific examples of compounds represented by formula (XI) include compounds described in JP-A No. 7-281028, paragraphs [0028] to [0036], JP-A No. 7-306317, JP-A No. 2005-156822, paragraphs [0016] to [0018], JP-A No. 2006-301614, paragraphs [0067] to [0072], and the Liquid Crystal Handbook (published by Maruzen Co., Ltd. in 2000), pages 330 to 333, in which at least one (preferably three or more) of the terminal groups is an epoxy group.

The compound represented by formula (XI) can be synthesized according to the methods described in JP-A-7-306317, JP-A-7-281028, JP-A-2005-156822, and JP-A-2006-301614.

Furthermore, compounds represented by formula (D16) are also preferred as discotic compounds, as they provide superior thermal conductivity to the thermally conductive material.

In formula (D16), A ^2X , A ^3X and A ^4X each independently represent -CH= or -N=. It is preferable that A ^2X , A ^3X and A ^4X are all -CH= or all -N=. In other words, it is preferable that the 6-membered ring (central ring) containing A ^2X , A ^3X and A ^4X is a benzene ring or a triazine ring.
R ^17X , R ^18X and R ^19X each independently represent *-X ^211X -(Z ^21X -X ^212X ) _n21X -L ^21X -Q, where * represents the bonding position to the central ring.
X ^211X and X ^212X each independently represent a single bond, -O-, -CO-, -NH-, -O-CO-, -O-CO-O-, -O-CO-NH-, -O-CO-S-, -CO-O-, -CO-NH-, -CO-S-, -NH-CO-, -NH-CO-O-, -NH-CO-NH-, -NH-CO-S-, -S-, -S-CO-, -S-CO-O-, -S-CO-NH- or -S-CO-S-.
Z ^21X each independently represents a 5- or 6-membered aromatic ring group or a 5- or 6-membered non-aromatic ring group.
L ^21X represents a single bond or a divalent linking group.
Q has the same definition as Q in formulas (D1) to (D15), and the preferred conditions are also the same. In formula (D16), of the multiple Qs, at least one (preferably all) Qs represent an epoxy group.
n21X represents an integer of 0 to 3. When n21X is 2 or greater, the multiple (Z ^21X -X ^212X ) may be the same or different.

The compound represented by formula (D16) is preferably a compound represented by formula (XII).

In formula (XII), A ² , A ³ and A ⁴ each independently represent -CH= or -N=. It is preferable that ^{A 2} , A ³ and A ⁴ are all -CH= or all -N=. In other words, it is preferable that the 6-membered ring (central ring) containing A ² , A ³ and A ⁴ is a benzene ring or a triazine ring.

R ¹⁷ , R ¹⁸ and R ¹⁹ each independently represent *-X ²¹¹ -(Z ²¹ -X ²¹² ) _n21 -L ²¹ -P ²¹ or *-X ²²¹ -(Z ²² -X ²²² ) _n22 -Y ^22. * represents the bonding position to the central ring.
Two or more of R ¹⁷ , R ¹⁸ and R ¹⁹ are *-X ²¹¹ -(Z ²¹ -X ²¹² ) _n21 -L ²¹ -P ^21. In order to obtain a thermally conductive material with better thermal conductivity, it is preferable that all of R ¹⁷ , R ¹⁸ and R ¹⁹ are *-X ²¹¹ -(Z ²¹ -X ²¹² ) _n21 -L ²¹ -P ²¹ .
In addition, it is preferred that R ¹⁷ , R ¹⁸ and R ¹⁹ are all the same.

X ²¹¹ , X ²¹² , X ²²¹ and X ²²² each independently represent a single bond, -O-, -CO-, -NH-, -O-CO-, -O-CO-O-, -O-CO-NH-, -O-CO-S-, -CO-O-, -CO-NH-, -CO-S-, -NH-CO-, -NH-CO-O-, -NH-CO-NH-, -NH-CO-S-, -S-, -S-CO-, -S-CO-O-, -S-CO-NH- or -S-CO-S-.
X ²¹¹ , X ²¹² , X ²²¹ and X ²²² are each preferably independently a single bond, —NH—, —O—, —CO—O— or —O—CO—.

Z ²¹ and Z ²² each independently represent a 5- or 6-membered aromatic ring group or a 5- or 6-membered non-aromatic ring group, examples of which include a benzene ring group (such as a 1,4-phenylene group or a 1,3-phenylene group) and an aromatic heterocyclic group.

The aromatic ring group and the non-aromatic ring group may have a substituent. When they have a substituent, the number of the substituents is preferably 1 to 4, more preferably 1 or 2, and even more preferably 1. The substitution position of the substituent is not particularly limited. The substituent is preferably a halogen atom or a methyl group. It is also preferable that the aromatic ring group and the non-aromatic ring group are unsubstituted. Furthermore, they may further have a group represented by "-X ²¹² -L ²¹ -P ²¹ " as a substituent.

Examples of the aromatic heterocyclic group include the following aromatic heterocyclic groups.

In the formula, * represents a site bonding to ^X211 or ^X221 . ** represents a site bonding to ^X212 or ^X222 . ^A41 and ^A42 each independently represent a methine group or a nitrogen atom. ^X4 represents an oxygen atom, a sulfur atom or an imino group.
At least one of A ⁴¹ and A ⁴² is preferably a nitrogen atom, and more preferably both are nitrogen atoms. X ⁴ is preferably an oxygen atom.

When n21 and n22 described below are 2 or greater, a plurality of (Z ²¹ -X ²¹² ) and a plurality of (Z ²² -X ²²² ) may be the same or different.

L ²¹ each independently represents a single bond or a divalent linking group and has the same meaning as L ¹¹ in formula (XI) above. L ²¹ is preferably -O-, -O-CO-, -CO-O-, -S-, -NH-, an alkylene group (preferably having 1 to 10 carbon atoms, more preferably having 1 to 8 carbon atoms, and even more preferably having 1 to 7 carbon atoms), an arylene group (preferably having 6 to 20 carbon atoms, more preferably having 6 to 14 carbon atoms, and even more preferably having 6 to 10 carbon atoms), or a group formed by combining these groups.

When n22 described below is 1 or greater, examples of -X ²¹² -L ²¹ - include L101 to L143, which are examples of L in the above formulae (D1) to (D15), except that in this case, the left bond in L101 to L143 is bonded to the central structure of the compound (hereinafter also simply referred to as the "central ring"), and the right bond is bonded to ^P21 .

^P21 represents an epoxy group, which may or may not have a substituent.

Y ²² each independently represents a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, or a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms in which one or more methylene groups have been substituted with -O-, -S-, -NH-, -N(CH ₃ )-, -CO-, -O-CO- or -CO-O-, and has the same meaning as Y ¹² in formula (XI), and preferred embodiments are also the same.

n21 and n22 each independently represent an integer of 0 to 3, and from the viewpoint of more excellent thermal conductivity, an integer of 1 to 3 is preferable. When ^{A 2} , A ³ and A ⁴ are all -CH=, it is more preferable that n21 and n22 each independently represent an integer of 2 to 3, and when A ² , A ³ and A ⁴ are all -N=, it is more preferable that n21 and n22 each independently represent 1.

For details and specific examples of the compound represented by formula (XII), see the compounds described in paragraphs 0013 to 0077 of JP 2010-244038 A in which at least one (preferably three or more) terminal groups are epoxy groups, the contents of which are incorporated herein by reference.

The compound represented by formula (XII) can be synthesized according to the methods described in JP-A-2010-244038, JP-A-2006-076992, and JP-A-2007-002220.

In addition, from the viewpoint of reducing electron density, strengthening stacking, and facilitating the formation of columnar aggregates, it is also preferable that the discotic compound is a compound having a hydrogen-bonding functional group. Examples of hydrogen-bonding functional groups include -O-CO-NH-, -CO-NH-, -NH-CO-, -NH-CO-O-, -NH-CO-NH-, -NH-CO-S-, and -S-CO-NH-.

(Other epoxy compounds)
In addition to the above-mentioned epoxy compounds, compounds represented by the formula (Z), formula (Z1), or formula (Z2) described in the description of the phenolic compounds in which the phenolic hydroxy group is replaced with an epoxy-containing group can also be used as the epoxy compound.
The epoxy-containing group is a group that is an epoxy group itself or a monovalent group that partially contains an epoxy group.
The monovalent group partially containing an epoxy group is a group having one or more (preferably 1 to 8) epoxy groups within the entire group.
The monovalent group partially containing an epoxy group is preferably a group represented by "-(divalent hydrocarbon group) _M1 -(-O-divalent hydrocarbon group-) _M2 -epoxy group". In the above group, M1 represents 0 or 1. M2 represents an integer of 1 or more (preferably 1 to 10). Examples of the divalent hydrocarbon group in the above group include alkylene groups (preferably having 1 to 6 carbon atoms), alkenylene groups (-CH=CH-, etc., preferably having 2 to 6 carbon atoms), alkynylene groups (-C≡C-, etc., preferably having 2 to 6 carbon atoms), arylene groups (phenylene group, etc., preferably having 6 to 15 carbon atoms), and combinations thereof. The divalent hydrocarbon group may or may not have a substituent, and the divalent hydrocarbon group may further have an epoxy-containing group as a substituent. A plurality of the divalent hydrocarbon groups may be present, and may be the same or different.

Other epoxy compounds include, for example, epoxy compounds represented by formula (DN):

In formula (DN), n ^DN represents an integer of 0 or more, preferably 0 to 5, and more preferably 1.
R ^DN represents a single bond or a divalent linking group. The divalent linking group is preferably —O—, —O—CO—, —CO—O—, —S—, an alkylene group (preferably having 1 to 10 carbon atoms), an arylene group (preferably having 6 to 20 carbon atoms), or a combination thereof, more preferably an alkylene group, and more preferably a methylene group.

Other examples of the epoxy compound include an epoxy compound represented by formula (E2).
(V-) _4-U C(-W) _U (E2)

In formula (E2), C represents a carbon atom.

In formula (E2), U represents an integer of 3 or 4.
In formula (E2), the "U" in "4-U" indicating the number of Vs and the "U" indicating the number of Ws have the same value. In other words, formula (E2) is "VC(-W) ₃ " or "C(-W) ₄ ".

In formula (E2), V represents a substituent not having an epoxy group or a hydrogen atom.
The substituent not having an epoxy group is a substituent other than an epoxy group, and does not contain an epoxy group even as a part of the substituent.
Examples of the substituent not having an epoxy group include groups selected from the substituent group Y, excluding epoxy groups and groups partially containing an epoxy group.
The substituent not having an epoxy group is preferably an alkyl group, more preferably a linear or branched alkyl group, and preferably has 1 to 5 carbon atoms.

In formula (E2), W represents an epoxy-containing group.
The epoxy-containing group is a group which is an epoxy group itself or a monovalent group which partially contains an epoxy group.
The monovalent group partially containing an epoxy group is a group having one or more (preferably 1 to 8) epoxy groups within the entire group.
The monovalent group partially containing an epoxy group is preferably a group represented by "-(divalent hydrocarbon group) _M1 -(-O-divalent hydrocarbon group-) _M2 -epoxy group". In the above group, M1 represents 0 or 1. M2 represents an integer of 1 or more (preferably 1 to 10). Examples of the divalent hydrocarbon group in the above group include alkylene groups (preferably having 1 to 6 carbon atoms), alkenylene groups (-CH=CH-, etc., preferably having 2 to 6 carbon atoms), alkynylene groups (-C≡C-, etc., preferably having 2 to 6 carbon atoms), arylene groups (phenylene group, etc., preferably having 6 to 15 carbon atoms), and combinations thereof. The divalent hydrocarbon group may or may not have a substituent, and the divalent hydrocarbon group may further have an epoxy-containing group as a substituent. A plurality of the divalent hydrocarbon groups may be present, and may be the same or different.
A plurality of Ws present in formula (E2) may be the same or different.

Other epoxy compounds include compounds in which the epoxy group is fused to a ring. An example of such a compound is 3,4:8,9-diepoxybicyclo[4.3.0]nonane.

Other examples of the epoxy compound include an epoxy compound represented by formula (E3).
Epoxy group —CH ₂ —O—(alkylene group —O) _X —CH ₂ -epoxy group (E3)
In formula (E3), X represents an integer of 1 or more, preferably an integer of 1 to 50, more preferably an integer of 1 to 15, and even more preferably an integer of 1 to 3.
The alkylene group in formula (E3) may be linear or branched. The number of carbon atoms in the alkylene group is preferably 1 to 10, more preferably 2 to 3, and even more preferably 2. When a plurality of alkylene groups are present in formula (E3), the plurality of alkylene groups may be the same or different.

Other epoxy compounds include, for example, bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, bisphenol S type epoxy compounds, bisphenol AD type epoxy compounds, etc., which are glycidyl ethers of bisphenol A, F, S, AD, etc.; hydrogenated bisphenol A type epoxy compounds, hydrogenated bisphenol AD type epoxy compounds, etc.; phenol novolac type glycidyl ethers (phenol novolac type epoxy compounds), cresol novolac type glycidyl ethers (cresol novolac type epoxy compounds), bisphenol A novolac type glycidyl ethers (cresol novolac type epoxy compounds), ethers, etc.; dicyclopentadiene-type glycidyl ethers (dicyclopentadiene-type epoxy compounds); dihydroxypentadiene-type glycidyl ethers (dihydroxypentadiene-type epoxy compounds); polyhydroxybenzene-type glycidyl ethers (polyhydroxybenzene-type epoxy compounds) such as glycidyl ethers of dihydroxybenzenes such as resorcinol; benzenepolycarboxylic acid-type glycidyl esters (benzenepolycarboxylic acid-type epoxy compounds); trisphenolmethane-type epoxy compounds; phenoxy resins, etc.; and acrylic resins having epoxy groups in their side chains. Compounds in which one or more of the glycidyl ether groups and/or glycidyl ester groups in the above-mentioned compounds are replaced with diglycidylamino groups or diglycidylaminoalkylene groups (diglycidylaminomethylene groups, etc.) may also be used as the epoxy compound.
Each of the above-mentioned compounds may have a substituent. For example, the aromatic ring group, cycloalkane ring group, and/or alkylene group contained in each of the above-mentioned compounds may have a substituent other than a glycidyl ether group, a glycidyl ester group, a diglycidylamino group, and/or a diglycidylaminoalkylene group.

The epoxy compound preferably comprises at least one selected from the group consisting of polyhydroxybenzene-type glycidyl ethers, bisphenol F-type glycidyl ethers, epoxy compounds represented by formula (DN), rod-shaped compounds (preferably rod-shaped compounds having a biphenyl skeleton), discotic compounds (preferably discotic compounds having a biphenylene ring as a central ring, discotic compounds having a triazine ring as a central ring, or discotic compounds having a benzene ring as a central ring), phenol novolac-type glycidyl ethers, phenoxy resins, epoxy compounds represented by formula (E2), and epoxy compounds represented by formula (E3).
When the epoxy compound contains these compounds, the content thereof is preferably more than 0 mass % and 100 mass % or less, more preferably 30 to 100 mass %, still more preferably 60 to 100 mass %, and particularly preferably 90 to 100 mass %, based on the total mass of the epoxy compound.

It is also preferable that the epoxy compound includes an epoxy compound having a viscosity of less than 1000 mPa·s at 25° C. (also referred to as a “low-viscosity epoxy compound”).
In particular, when the composition contains a maleimide compound described below, the epoxy compound preferably contains the low-viscosity epoxy compound.
When the epoxy compound contains a low-viscosity epoxy compound, flexibility is introduced into the semi-cured film formed from the composition, improving storage stability and improving the handleability of the semi-cured film after a certain period of time has elapsed since its formation. Such an improvement effect is particularly remarkable when the composition contains a maleimide compound described below.
The viscosity of the low-viscosity epoxy compound at 25° C. is less than 1000 mPa·s, preferably 500 mPa·s or less, and more preferably 300 mPa·s or less. The lower limit of the viscosity is, for example, 1 mPa·s or more.
The viscosity of the epoxy compound is measured at 25°C using a RheoStress RS6000 (manufactured by Eiko Seiki Co., Ltd.) and is the value obtained by reading the value 1 minute after the start of the measurement. The shear rate is 10 (1/s).

When the epoxy compound contains a low-viscosity epoxy compound, the content of the low-viscosity epoxy compound is preferably 5 to 100 mass%, more preferably 20 to 100 mass%, and even more preferably 60 to 100 mass%, based on the total amount of the epoxy compounds.
As the low-viscosity epoxy compound, for example, an epoxy compound having a predetermined viscosity among the above-mentioned epoxy compounds can be used. More specific examples include bisphenol F-type glycidyl ethers, epoxy compounds represented by formula (E3) in which X is an integer of 1 to 13, and dihydroxybenzene-type glycidyl ethers.

<Maleimide Compound>
A maleimide compound is a compound having one or more maleimide groups.
The number of maleimide groups contained in the maleimide compound is preferably 1 to 100, more preferably 2 to 10, and even more preferably 2.
The maleimide compound may be either a high molecular weight compound or a low molecular weight compound. For example, the molecular weight of the maleimide compound is preferably 100 to 3,000, more preferably 200 to 2,000, and even more preferably 300 to 1,000.

The maleimide group possessed by the maleimide compound is preferably a group represented by the following formula (M):

In formula (M), * represents a bonding position.
X and Y each independently represent a hydrogen atom or a substituent.
X and Y are each preferably a hydrogen atom.

The maleimide compound is also preferably a compound having one or more (preferably 1 to 10) aromatic ring groups (such as benzene ring groups). The maleimide compound is also preferably a compound having a mesogenic group. Examples of the mesogenic group include the mesogenic group represented by M in formula (XXI) and the mesogenic group represented by formula (XXII).
The maleimide compound is preferably a compound represented by the following formula (1):

In formula (1), m represents 0 or 1. Preferably, m is 1.
n represents 0 or 1. n is preferably 1.

In formula (1), R ¹ and R ² each independently represent a hydrogen atom or a substituent.
The substituent is preferably an alkyl group, which may be linear or branched and preferably has 1 to 10 carbon atoms.
When R ¹ and/or R ² are substituents, they are preferably located adjacent to the maleimide group on the benzene ring group, for example.
When R ¹ and R ² are both substituents, it is also preferable that R ¹ and R ² are different substituents. For example, it is also preferable that R ¹ is a methyl group and R ² is an ethyl group.

In formula (1), L ¹ represents a divalent linking group.
Examples of the divalent linking group include an ether group (-O-), a carbonyl group (-CO-), an ester group (-COO-), a thioether group (-S-), -SO ₂ -, -NR- (R is a hydrogen atom or an alkyl group), a divalent aliphatic hydrocarbon group (for example, an alkylene group, a cycloalkylene group, an alkenylene group (-CH=CH-, etc.), an alkynylene group (-C≡C-, etc.)), a divalent aromatic ring group (an arylene group and a heteroarylene group), and a group formed by combining these.
In formula (1), L ¹ preferably has 1 or more carbon atoms, more preferably 1 to 100 carbon atoms, and even more preferably 3 to 15 carbon atoms.

^L1 is preferably a mesogenic group.
Examples of the mesogenic group include a mesogenic group represented by M in formula (XXI) and a mesogenic group represented by formula (XXII).

L ¹ is preferably a group represented by "* ^p- (L ² -Ar) _k- * ^q" .
* ^q represents the bonding position on the side directly bonded to the maleimide group, and * ^p represents the bonding position on the opposite side.
k represents an integer of 1 or more, preferably 1 to 10, and more preferably 1.
^L2 represents a single bond, —C(R ³ )(R ⁴ )—, —O— or —CO—, and —C(R ³ )(R ⁴ )— is preferred.
^R3 and ^R4 each independently represent a hydrogen atom or a substituent, and are preferably an alkyl group (which may be linear or branched and has, for example, 1 to 10 carbon atoms).
Ar represents an arylene group. The number of ring atoms in the arylene group is preferably 6 to 15, and more preferably 6. When the arylene group has a substituent, the number of the ring atoms is preferably 1 to 4, and more preferably 1 or 2. The substituent that the arylene group may have is preferably an alkyl group (which may be linear or branched, and has, for example, 1 to 10 carbon atoms). Examples of structures that Ar can have include structures that can be formed by the benzene ring group bonded to ^R1 and ^R2 , as specified in formula (1).
When a plurality ^{of L2s} and a plurality of Ars are present, the plurality of ^L2s and the plurality of Ars may be the same or different.

In formula (1) when n is 1, on the benzene ring group bonding to ^R1 and ^R2 , the two groups, the maleimide group and the group represented by "-( ^L1 ) _m -maleimide group", may be located at the ortho position, meta position, or para position relative to each other. The two groups are preferably located at the meta position or para position.

In the compound represented by formula (1), m is preferably 1, n is preferably 1, and the divalent linking group represented by L ¹ preferably has 3 to 15 carbon atoms.

The maleimide compounds may be used alone or in combination of two or more.
The content of the maleimide compound is preferably 0.1 to 40 mass%, more preferably 1 to 15 mass%, and even more preferably 3.5 to 8 mass%, relative to the total solid content of the composition, and from the viewpoint of better handleability of a semi-cured film formed from the composition, it is still more preferably 3.5 to 8 mass%.
In addition, from the viewpoint of obtaining a thermally conductive material having better thermal conductivity and/or insulating properties, it is also preferable that the content of the maleimide compound is 6% by mass or more (for example, 6 to 12% by mass) relative to the total solid content of the composition.
When the composition contains an epoxy compound, the content of the maleimide compound is, for example, 1 to 200 mass%, preferably 5 to 100 mass%, more preferably 10 to 70 mass%, and still more preferably 20 to 60 mass%, relative to the total content of the epoxy compound and the phenol compound.
The content of the maleimide compound is, for example, 1 to 500% by mass, preferably 20 to 300% by mass, more preferably 50 to 200% by mass, and even more preferably 70 to 130% by mass, relative to the content of the phenol compound.

<Relationship between phenolic compounds and epoxy compounds>
When the composition contains an epoxy compound and a phenolic compound, it is preferable that the composition satisfies at least one of the following requirements: the phenolic compound contains a phenolic compound having a triazine skeleton (requirement 1) and the epoxy compound contains an epoxy compound having a triazine skeleton (requirement 2).
The composition may satisfy only requirement 1, may satisfy only requirement 2, or may satisfy both requirements 1 and 2.

The phenol compound and epoxy compound "having a triazine skeleton" means that the compound has one or more (for example, 1 to 5) triazine ring groups.
Examples of the phenol compound having a triazine skeleton include the compounds represented by formula (Z), formula (Z1), and formula (Z2) described above.
Examples of epoxy compounds having a triazine skeleton include the above-mentioned compounds represented by formula (D16) in which A ^2X , A ^3X and A ^4X are all -N=, compounds represented by formula (XII) in which A ² , A ³ and A ⁴ are all -N=, compounds represented by formula (Z) in which the phenolic hydroxyl group is replaced with an epoxy-containing group, compounds represented by formula (Z1) in which the phenolic hydroxyl group is replaced with an epoxy-containing group, and compounds represented by formula (Z2) in which the phenolic hydroxyl group is replaced with an epoxy-containing group.

When the phenol compound contains a phenol compound having a triazine skeleton (for example, when requirement 1 is satisfied), the content thereof is more than 0 mass % and not more than 100 mass %, preferably 30 to 100 mass %, more preferably 60 to 100 mass %, and even more preferably 90 to 100 mass %, relative to the total mass of the phenol compounds. Note that when the composition contains an epoxy compound, and the epoxy compound contains an epoxy compound having a triazine skeleton (when requirement 2 is satisfied), it is also preferable that the content of the phenol compound having a triazine skeleton is outside the above-mentioned preferred range.
When the composition contains an epoxy compound, and the epoxy compound contains an epoxy compound having a triazine skeleton (when requirement 2 is satisfied), the content thereof is more than 0 mass % and not more than 100 mass %, preferably 30 to 100 mass %, more preferably 60 to 100 mass %, and even more preferably 90 to 100 mass %, relative to the total mass of the epoxy compounds. Note that when the phenol compound contains a phenol compound having a triazine skeleton (i.e., when requirement 1 is satisfied), the content of the epoxy compound having a triazine skeleton may be outside the above-mentioned preferred range.

When the composition contains an epoxy compound, it is also preferred that at least a part of the phenol compound and the epoxy compound is a compound other than a compound having a triazine skeleton.
All or part of the phenol compounds may be compounds other than those having a triazine skeleton, and all or part of the epoxy compounds may be compounds other than those having a triazine skeleton.
When the composition contains an epoxy compound, from the viewpoint of adjusting the crosslink density and further improving the effects of the present invention, the total content of the phenol compound having a triazine skeleton and the epoxy compound having a triazine skeleton is preferably more than 0 mass% and less than 100 mass%, more preferably 1 to 90 mass%, and still more preferably 5 to 80 mass%, based on the total content of all phenol compounds and all epoxy compounds.

In addition, the total content of the epoxy compound and phenol compound in the composition is preferably 3 to 90 mass%, more preferably 5 to 50 mass%, and even more preferably 7 to 40 mass%, based on the total solids content of the composition.

The ratio of the total number of epoxy groups contained in the epoxy compound to the total number of hydroxyl groups (preferably phenolic hydroxyl groups) contained in the phenol compound (number of epoxy groups/number of hydroxyl groups) is often 0.03 to 33, preferably 0.4 to 2.5, more preferably 0.6 to 1.5, and even more preferably 0.8 to 1.3.
In other words, the ratio of the contents of the phenol compound and the epoxy compound in the composition is preferably such that the "number of epoxy groups/number of phenolic hydroxyl groups" falls within the above range.

The equivalent ratio of epoxy groups to active hydrogens in the epoxy compound (number of epoxy groups/number of active hydrogens) is often 0.03 to 33, preferably 0.4 to 2.5, more preferably 0.6 to 1.5, and even more preferably 0.8 to 1.3.
The active hydrogen may be an active hydrogen derived from a phenolic hydroxyl group, or may be an active hydrogen of another active hydrogen-containing compound.

The ratio of the total number of epoxy groups contained in the epoxy compound to the total number of hydroxyl groups (preferably phenolic hydroxyl groups) contained in the phenol compound (number of epoxy groups/number of hydroxyl groups) is preferably 1.1 to 3.0, more preferably 1.2 to 2.0, and even more preferably 1.3 to 1.8.
In particular, when the composition contains the maleimide compound, it is preferable that the ratio falls within the above range.
When the ratio is equal to or greater than a predetermined value, flexibility is introduced into the semi-cured film formed from the composition, improving storage stability, and the semi-cured film has good handleability even after a certain period of time has passed since its formation. When the ratio is equal to or less than a predetermined value, the heat resistance of the thermal conductive material formed from the composition is superior. Such an improvement effect is particularly significant when the composition contains a maleimide compound described below.

The composition may contain little or no epoxy compounds. In this case, the ratio of the total number of epoxy groups contained in the epoxy compounds to the number of hydroxyl groups (preferably phenolic hydroxyl groups) contained in the phenol compounds in the composition (number of epoxy groups/number of hydroxyl groups) is preferably 0 to 0.031, more preferably 0 to 0.010.

[Curing accelerator]
The composition also preferably includes a cure accelerator.
The curing accelerator preferably contains at least one selected from the group consisting of compounds represented by formula (P1) and compounds represented by formula (P2), and more preferably contains a compound represented by formula (P3).
When the compound contained in the curing accelerator has optical isomers, any of the optical isomers may be used. Furthermore, one optical isomer may be used alone, or multiple optical isomers may be used in combination. When one optical isomer is primarily used, its optical purity (ee) is preferably 90 or more, more preferably 95 or more. Similarly, when optical isomers are present in the formulae (P1) to (P3) shown below, any of the optical isomers may be included.

In formula (P1), ^Lp represents a single bond or a divalent linking group.
Examples of the divalent linking group include an ether group (-O-), a carbonyl group (-CO-), an ester group (-COO-), a thioether group (-S-), -SO ₂ -, -NR- (wherein R represents a hydrogen atom or an alkyl group), a divalent aliphatic hydrocarbon group (for example, an alkylene group, a cycloalkylene group, an alkenylene group (-CH=CH-, etc.), an alkynylene group (-C≡C-, etc.)), a divalent aromatic ring group (for example, an arylene group and a heteroarylene group), and a group formed by combining these. The divalent linking group may further have a substituent. Examples of the substituent include the substituents exemplified in the substituent group Y above.
The arylene group may be monocyclic or polycyclic and preferably has 6 to 25 carbon atoms.
The arylene group is preferably a phenylene group, a naphthylene group, an anthracenylene group or a binaphthylene group, and more preferably a binaphthylene group.
^Lp is preferably a divalent aliphatic hydrocarbon group or a divalent aromatic ring group, more preferably an alkylene group or an arylene group.

R ^p11 to R ^p14 each independently represent a phenyl group which may have a substituent.
Examples of the substituent include the substituents exemplified in the above-mentioned group Y of substituents, and an alkyl group is preferable, and a linear or branched alkyl group having 1 to 3 carbon atoms is more preferable.

_np represents 0 or 1. _np is preferably 1.

In formula (P2), R ^p21 to R ^p24 each independently represent a phenyl group which may have a substituent.
Examples of the substituent include the substituents exemplified in the above-mentioned group Y of substituents, and an alkyl group is preferable, and a linear or branched alkyl group having 1 to 3 carbon atoms is more preferable.

X ⁻ represents an anion.
Examples of the anion include hydroxide ion, fluoride ion, chloride ion, bromide ion, iodide ion, hexafluorophosphate ion, tetrafluoroborate ion, tetraphenylborate ion, dicyanamide ion, alkylphosphate ion (e.g., diethylphosphate ion, etc.), hydrogen sulfate ion, dihydrogenphosphate ion, hydrogenphosphate ion, sulfamate ion, perchlorate ion, benzotriazolide anion, and tetratolylborate anion (e.g., tetra-p-tolylborate anion, etc.).
The anion is preferably a tetratolylborate anion.

In formula (P3), R ^p31 to R ^p34 each independently represent a phenyl group which may have a substituent.
Examples of the substituent include the substituents exemplified in the above-mentioned group Y of substituents, and an alkyl group is preferable, and a linear or branched alkyl group having 1 to 3 carbon atoms is more preferable.

Examples of curing accelerators include tris-orthotolylphosphine, triphenylphosphine, tris-para-tolylphosphine, tri-t-butylphosphine, tri-i-butylphosphine, tricyclohexylphosphine, tri-2-furylphosphine, dicyclohexylphenylphosphine, di-t-butylphenylphosphine, 1,2-bis(diphenylphosphino)ethane, cis-1,2-bis(diphenylphosphino)ethylene, 1,3-bis(diphenylphosphino)propane, 1,4-bis(diphenylphosphino)butane, 1,5-bis(diphenylphosphino)pentane, 4-(diphenylphosphino)styrene, 2-(diphenylphosphino)benzoic acid, 4-(diphenylphosphino)benzoic acid, 1,2-bis(diphenylphosphino)benzene, Bis[2-(diphenylphosphino)phenyl]ether, 1,1'-bis(diphenylphosphino)ferrocene (dppf), BINAP (2,2'-bis(diphenylphosphino)-1,1'-binaphthyl), TolBINAP (2,2'-bis[(4-methylphenyl)phosphino]-1,1'-binaphthyl), XylBINAP (2,2'-bis[(3,5-dimethylphenyl)phosphino]-1,1'-binaphthyl), tBuBINAP (2,2'-bis(di-p-t-butylphenylphosphino)-1,1'-binaphthyl), 2,2'-bis[(4-t-butylphenyl)phosphino]-1,1'-binaphthyl, 2,2'-bis[(4-isopropylphenyl)phosphino]-1,1'-binaphthyl, 2,2'-bis[(naphthalen-1-yl)phosphino]- bis[(diphenylphosphino)ferrocenyl]-1,1'-binaphthyl, 2,2'-bis[(naphthalen-2-yl)phosphino]-1,1'-binaphthyl, BICHEMP (2,2'-bis(dicyclohexylphosphino)-6,6'-dimethyl-1,1'-biphenyl), BPPFA (1-[1,2-bis-(diphenylphosphino)ferrocenyl]ethylamine), CHIRAPHOS (2,3-bis(diphenylphosphino)-1,1'-binaphthyl), ...), 2,2'-bis[(naphthalen-2-yl)phosphino]-1,1'-binaphthyl, BICHEMP (2,2'-bis(dicyclohexylphosphino)-6,6'-dimethyl-1,1'-biphenyl), BPPFA (1-[1,2-bis-(diphenylphosphino)ferrocenyl]ethylamine), CHIRAPHOS (2,3-bis(diphenylphosphino)-1,1'-binaphthyl), 2,2'-bis[(diphenylphosphino)-1,1'-binaphthyl] cyclohexyl-1,2-bis(diphenylphosphino)butane), CYCPHOS (1-cyclohexyl-1,2-bis(diphenylphosphino)ethane), DEGPHOS (1-substituted-3,4-bis(diphenylphosphino)pyrrolidine), DIOP (2,3-isopropylidene-2,3-dihydroxy-1,4-bis(diphenylphosphino)butane), SKEWPHOS (2,4-bis(diphenylphosphino)pentane) Examples of compounds containing phosphorus atoms include benzene (DuPHOS), substituted 1,2-bis(phosphorano)benzene (DIPAMP), 1,2-bis[(o-methoxyphenyl)phenylphosphino]ethane (NORPHOS), 5,6-bis(diphenylphosphino)-2-norbornene (PROPHOS), 1,2-bis(diphenylphosphino)propane (PHANEPHOS), 4,12-bis(diphenylphosphino)-[2,2']-paracyclophane (PHANEPHOS), substituted 2,2'-bis(diphenylphosphino)-1,1'-bipyridines (SEGPHOS), 4,4'-bis-1,3-benzodioxole)-5,5'-diyl-bis(diphenylphosphino) (SEGPHOS), and BIFAP (2,2'-bis(diphenylphosphanyl)-1,1'-bisbenzofuranyl).

Cure accelerators include onium salt-based cure accelerators such as quaternary phosphonium compounds (phosphonium salts) such as tetraphenylphosphonium tetraphenylborate (TPP-K), tetraphenylphosphonium tetra-p-tolylborate (TPP-MK), tetra-n-butylphosphonium laurate (TBP-LA), bis(tetra-n-butylphosphonium)pyromellitate, and tetraphenylphosphonium bis(naphthalene-2,3-dioxy)phenylsilicate adducts.

Further examples include boron trifluoride amine complexes and the compounds described in paragraph 0052 of JP-A No. 2012-067225.
In addition to the above, 2-methylimidazole (trade name: 2MZ), 2-undecylimidazole (trade name: C11-Z), 2-heptadecylimidazole (trade name: C17Z), 1,2-dimethylimidazole (trade name: 1.2DMZ), 2-ethyl-4-methylimidazole (trade name: 2E4MZ), 2-phenylimidazole (trade name: 2PZ), 2-phenyl-4-methylimidazole (trade name: 2P4MZ), 1-benzyl-2-methylimidazole (trade name: 1B2MZ), 1-benzyl-2-methylimidazole (trade name: 1B2MZ), 1-benzyl-4-methylimidazole (trade name: 1B4 ... 1-cyanoethyl-2-phenylimidazole (trade name: 1B2PZ), 1-cyanoethyl-2-methylimidazole (trade name: 2MZ-CN), 1-cyanoethyl-2-undecylimidazole (trade name: C11Z-CN), 1-cyanoethyl-2-phenylimidazolium trimellitate (trade name: 2PZCNS-PW), 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine (trade name: 2MZ-A), 2,4-diamino-6-[2'-undecylimidazole] 2,4-Diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-s-triazine (trade name: C11Z-A), 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-s-triazine (trade name: 2E4MZ-A), 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine isocyanuric acid adduct (trade name: 2MA-OK), 2-phenyl-4,5-dihydroxymethylimidazole (trade name: 2PHZ-PW), 2-phenyl-4-methyl-5-hydroxyimidazole (trade name: 2PHZ-PW ... isocyanuric acid adduct (trade name: 2MA-OK), 2-phenyl-4,5-dihydroxymethylimidazole (trade name: 2PHZ-PW), 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-s-triazine isocyanuric acid adduct (trade name: 2PHZ-PW), 2,4 Examples of imidazole-based curing accelerators include 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine (trade name: 2MZA-PW), 1-cyanoethyl-2-phenylimidazole (trade name: 2PZ-CN), 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine isocyanuric acid adduct (trade name: 2MAOK-PW) (all manufactured by Shikoku Chemical Industry Co., Ltd.). Furthermore, examples of triarylphosphine-based curing accelerators include the compounds described in paragraph 0052 of JP-A No. 2004-043405. Examples of phosphorus-based curing accelerators in which triphenylborane is added to triarylphosphine include the compounds described in paragraph 0024 of JP-A No. 2014-005382.

The molecular weight of the curing accelerator is often 200 or more, preferably 250 or more, more preferably 400 or more, even more preferably 430 or more, and particularly preferably 600 or more. The upper limit is preferably 10,000 or less, more preferably 1,000 or less, and even more preferably 800 or less.
When the molecular weight of the curing accelerator is 250 or more, the vaporization of the curing accelerator itself and/or its thermal decomposition products can be more effectively suppressed when subjected to heat treatment at high temperatures, resulting in better solder heat resistance. Also, when the molecular weight of the curing accelerator is 10,000 or less, it is easy to function as a curing accelerator.

In order to obtain better effects of the present invention, the curing accelerator preferably contains a compound containing a phosphorus atom, and also preferably contains a phosphonium salt. The curing accelerator may be a compound containing a phosphorus atom or a phosphonium salt itself. When a phosphonium salt is used as the curing accelerator, the storage stability of the semi-cured film formed from the composition is also improved.
The content of the phosphorus atom-containing compound or phosphonium salt is preferably from 10 to 100 mass %, more preferably from 50 to 100 mass %, and even more preferably from 80 to 100 mass %, based on the total mass of the curing accelerator.

The curing accelerators may be used alone or in combination of two or more.
The content of the curing accelerator is preferably 0.002% by mass or more, more preferably 0.02% by mass or more, and even more preferably 0.07% by mass or more, based on the total solid content of the composition, and the upper limit is preferably 5% by mass or less, more preferably 2% by mass or less, and even more preferably 1% by mass or less, based on the total solid content of the composition.
The content of the curing accelerator is preferably 0.01% by mass or more, more preferably 0.10% by mass or more, and even more preferably 0.55% by mass or more, based on the total amount of epoxy compounds. The upper limit is preferably 40% by mass or less, more preferably 12% by mass or less, even more preferably 10% by mass or less, and particularly preferably 5% by mass or less, based on the total amount of epoxy compounds.

[Ion scavenger]
The composition may also include an ion scavenger.
The ion scavenger adsorbs ionic impurities in the composition or in a thermally conductive material formed using the composition, thereby enabling the insulating properties of the thermally conductive material to be better maintained even when the composition or the thermally conductive material absorbs moisture.
Examples of the ion scavenger include the inorganic ion scavenger and organic ion scavenger as described above.
Examples of organic ion scavengers include triazine thiol compounds, triazine amine compounds, benzimidazole compounds, benzotriazole compounds, aminotriazole compounds, and bisphenol reducing agents.
All or part of the inorganic substances described above may also function as ion scavengers.

An example of the triazine thiol compound is 2-dibutylamino-4,6-dimercapto-s-triazine.
The benzimidazole compound includes, for example, benzimidazole.
Examples of benzotriazole compounds include 1H-benzotriazole, carboxybenzotriazole, 2-(2'-hydroxy-5'-tert-octylphenyl)benzotriazole, 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, and 2,2'-methylenebis[6-(2H-benzotriazol-2-yl)-4-tert-octylphenol].
Examples of aminotriazole compounds include 3-amino-1,2,4-triazole and 3,5-diamino-1,2,4-triazole.
Examples of bisphenol reducing agents include 2,2'-methylenebis-(4-ethyl-6-t-butylphenol) and 4,4'-butylidenebis-(6-t-butyl-3-methylphenol).

Commercially available ion scavengers may be used, such as DHF-4A, DHT-4A, DHT-4A-2, DHT-4C, Kyoward 500, KW-2000, and KW-2100 (trade names, manufactured by Kyowa Chemical Industry Co., Ltd.); IXE-100, IXE-500, IXE-600, IXE-700F, IXE-800, IXE-6107, IXEPLAS-A1, IXEPLAS-A2, and IXEPLAS-B1 (trade names, manufactured by Toagosei Co., Ltd.); Jisnet DB (trade name, manufactured by Sankyo Pharmaceutical Co., Ltd.); VD-3 and VD-5 (trade names, manufactured by Shikoku Chemical Industry Co., Ltd.); and Yoshinox BB (trade name, manufactured by Yoshitomi Pharmaceutical Co., Ltd.).

The ion trapping agent may be used alone or in combination of two or more kinds.
When the composition contains an ion scavenger, the content of the ion scavenger (inorganic ion scavenger and/or organic ion scavenger) is preferably 0.01 to 10 mass%, more preferably 0.1 to 20 mass%, and still more preferably 0.2 to 10 mass%, based on the total solid content of the composition.
When the ion scavenger contains an inorganic ion scavenger, part or all of the ion scavenger may also be an inorganic substance.

[Other ingredients]
The composition may contain other components in addition to the above components.
Examples of other components include particles X to which polymer compound Y is not adsorbed, polymer compound Y not adsorbed to particles X, and inorganic particles other than particles X and composite particles.

<Acid anhydride>
The composition may include an acid anhydride.
An acid anhydride is a compound having one or more acid anhydride groups (groups represented by --CO--O--CO--).

The number of acid anhydride groups in the acid anhydride is 1 or more, preferably 2 or more, and more preferably 3 or more. The upper limit of the number is, for example, 1,000 or less.
The molecular weight of the acid anhydride (weight average molecular weight when there is a molecular weight distribution) is preferably 100 or more, more preferably 2,000 or more, and even more preferably 6,000 or more. The upper limit of the molecular weight is preferably 100,000 or less, more preferably 30,000 or less, and even more preferably 17,000 or less.
The acid anhydride may be a low molecular weight compound or a high molecular weight compound.
Examples of acid anhydrides that are low molecular weight compounds include maleic anhydride, phthalic anhydride, pyromellitic anhydride, and trimellitic anhydride.
In the acid anhydride polymer compound, the acid anhydride group may be incorporated into the main chain or may be present in a side chain. For example, when the polymer compound has a repeating unit based on maleic acid, the acid anhydride group contained in the repeating unit is considered to be incorporated into the main chain.

The acid anhydride group may or may not form a ring together with atoms other than the atoms contained in the acid anhydride group. Among these, the acid anhydride group preferably forms a ring. The ring may be monocyclic or polycyclic, and the number of ring atoms may be, for example, 5 to 15.
For example, the acid anhydride preferably has a group represented by general formula (A).

In the general formula (A), * ^S and * ^T represent the bonding positions to the carbon atoms.
However, the carbon atom bonded at * ^S and the carbon atom bonded at * ^T are adjacent atoms that are directly bonded to each other.
That is, the group represented by general formula (A), the carbon atom bonded at * ^S , and the carbon atom bonded at * ^T together form a five-membered ring.
Furthermore, there is no limitation on the type of bond between the carbon atom bonded at * ^S and the carbon atom bonded at * ^T , and for example, it may be a single bond (single bond) or a double bond. Furthermore, a five-membered ring formed by the group represented by general formula (A), the carbon atom bonded at * ^S , and the carbon atom bonded at * ^T may be condensed with an aromatic ring (such as a benzene ring), and the carbon atom bonded at * ^S and the carbon atom bonded at * ^T may be adjacent ring atoms in the same aromatic ring.
The aromatic ring may be monocyclic or polycyclic, may or may not contain heteroatoms, and may have 5 to 15 ring atoms, for example.

The acid anhydride preferably has a group selected from the group consisting of a group represented by general formula (B), a group represented by general formula (C), and a group represented by general formula (D).

In formula (B), one or two of R ^A1 to R ^A4 represent a bonding position, and the others each independently represent a hydrogen atom or a substituent.
When two of R ^A1 to R ^A4 are bonding positions, for example, R ^A1 and R ^A2 may be bonding positions, or either one of R ^A1 and R ^A2 and either one of R ^A3 and R ^A4 may be bonding positions, respectively.
Examples of the substituents that can be represented by R ^A1 to R ^A4 include groups selected from the above-mentioned substituent group Y. The total number of atoms other than hydrogen atoms in the above-mentioned substituents is, for example, 1 to 20.

In formula (C), R ^B1 and R ^B2 each independently represent a hydrogen atom, a substituent, or a bonding position, provided that one or both of R ^B1 and R ^B2 are bonding positions.
Examples of the substituents that can be represented by R ^B1 and R ^B2 include groups selected from the above-mentioned substituent group Y. The total number of atoms other than hydrogen atoms in the above-mentioned substituents is, for example, 1 to 20.

In formula (D), * represents a bonding position, which may be a bonding position to a hydrogen atom.
In formula (D), m represents 1 or 2.
In general formula (D), Ar represents an aromatic ring which may have a substituent. The aromatic ring may be monocyclic or polycyclic, may or may not have a heteroatom, and has, for example, 5 to 15 ring atoms. Among these, the aromatic ring is preferably a benzene ring.
In formula (D), n represents an integer of 0 or more, preferably an integer of 0 to 2, and more preferably 0 or 1.
In general formula (D), there are (n+1) five-membered rings having a group represented by —CO—O—CO—, and the (n+1) five-membered rings are condensed with an aromatic ring represented by Ar.
For example, when n is 0, the group represented by general formula (D) is a group represented by the following general formula (D0), and when n is 1, the group represented by general formula (D) is a group represented by the following general formula (D1).
*, m, and Ar in the following general formula (D0) and the following general formula (D1) are the same as *, m, and Ar in the general formula (D), respectively.

The number of groups represented by general formula (A) that the acid anhydride has is preferably 1 or more, and more preferably 2 or more. The upper limit of the number is, for example, 1,000 or less.
The number of groups selected from the group consisting of the group represented by general formula (B) and the group represented by general formula (C) contained in the acid anhydride is preferably 1 or more, more preferably 2 or more, and even more preferably 3 or more. The upper limit of the number is, for example, 1,000 or less.
The number of groups represented by general formula (D) in the acid anhydride is preferably 1 or more. The upper limit of the number is, for example, 1,000 or less.

Among these, the acid anhydride is preferably a polymer compound.
Furthermore, the acid anhydride preferably has a repeating unit represented by the following general formula (X), and more preferably has a repeating unit represented by general formula (X) and a repeating unit represented by general formula (Y).

In formula (Y), R ^{1 Y} represents an aromatic ring group which may have a substituent.
The aromatic ring group may be monocyclic or polycyclic, and may be an aromatic hydrocarbon ring group or an aromatic heterocyclic group. Examples of heteroatoms in the aromatic heterocyclic group include oxygen, sulfur, and nitrogen atoms.
The aromatic ring group preferably has 5 to 15 ring atoms.
Examples of the substituent that the aromatic ring group may have include groups selected from the above-mentioned substituent group Y. The total number of atoms other than hydrogen atoms in the substituent is, for example, 1 to 20.
The aromatic ring group may have, for example, 0 to 5 substituents.
Among these, R 1 ^Y is preferably an unsubstituted benzene ring group.
The repeating unit represented by formula (Y) may be used alone or in combination of two or more.

[0122] When the acid anhydride has a repeating unit represented by general formula (X), the content thereof is preferably 1 to 70 mass%, more preferably 5 to 60 mass%, and still more preferably 10 to 50 mass%, based on all repeating units of the acid anhydride.
When the acid anhydride has a repeating unit represented by formula (Y), the content thereof is preferably 10 to 90% by mass based on the total repeating units of the acid anhydride.

The acid anhydride may have a repeating unit other than the repeating unit represented by general formula (X) or general formula (Y), for example, it may have a repeating unit represented by the following general formula (Z):

In formula (Z), R ^Z1 to R ^Z4 each independently represent a hydrogen atom or a substituent, and it is also preferred that 0 to 2 of R ^Z1 to R ^Z4 are the above-mentioned substituents.
Examples of the substituent include groups selected from the above-mentioned substituent group Y. The total number of atoms other than hydrogen atoms in the substituent is, for example, 1 to 20.
Among these, the substituents are each independently preferably -COOH, -O-CO-R, -CO-O-R, or a linear or branched alkyl group. R in -O-CO-R and -CO-O-R represents an organic group, preferably a linear or branched alkyl group, more preferably a linear or branched alkyl group having 1 to 4 carbon atoms.
Examples of the repeating unit represented by general formula (Z) include a repeating unit in which R ^Z1 to R ^Z4 are all hydrogen atoms, a repeating unit in which R ^Z1 and R ^Z3 are hydrogen atoms and R ^Z2 and R ^Z4 are —COOH, and a repeating unit in which R ^Z1 to R ^Z3 are hydrogen atoms and R ^Z4 is —O—CO—R.
However, the repeating unit represented by general formula (Z) is a repeating unit different from the repeating unit represented by general formula (Y). Specifically, the repeating unit represented by general formula (Z) does not include a configuration in which three of R ^Z1 to R ^Z4 are hydrogen atoms and one is an aromatic ring group.
The repeating unit represented by formula (Z) may be used alone or in combination of two or more.
[0122] When the acid anhydride has a repeating unit represented by general formula (Z), the content thereof is preferably 1 to 70 mass%, more preferably 5 to 60 mass%, and still more preferably 10 to 50 mass%, based on all repeating units of the acid anhydride.

Commercially available acid anhydrides may be used. Examples of commercially available acid anhydrides include the SMA series manufactured by Tomoe Engineering Co., Ltd., the OREVAC T series manufactured by Arkema, and the Arastar series manufactured by Arakawa Chemical Industries, Ltd.

The acid anhydrides may be used alone or in combination of two or more.
The content of the acid anhydride is preferably from 0.01 to 40% by mass, more preferably from 0.1 to 10% by mass, and even more preferably from 0.6 to 5% by mass, based on the total solid content of the composition.
The content of the acid anhydride is preferably from 0.1 to 100% by mass, more preferably from 1 to 70% by mass, and even more preferably from 5 to 60% by mass, based on the total content of the epoxy compound and the phenol compound.

<Other inorganic particles>
Examples of other inorganic particles include inorganic nitrides and inorganic oxides other than the particles X and the composite particles.
The inorganic particles may be subjected to the above-mentioned surface treatment, and at least a part of the surface may be covered with the above-mentioned polymer compound Y and/or a known surface modifier.

Examples of inorganic nitrides include _boron nitride (BN), carbon nitride ( _C3N4 ), silicon nitride _{( Si3N4} ), gallium nitride (GaN), indium nitride (InN), aluminum nitride (AlN), chromium nitride ( _Cr2N ), copper nitride ( _Cu3N ), iron nitride ( _Fe4N ), iron nitride ( _Fe3N ), lanthanum nitride (LaN), _lithium nitride (Li3N), magnesium nitride ( _Mg3N2 ), molybdenum nitride ( _Mo2N ), niobium nitride ( _NbN ), tantalum nitride (TaN), titanium nitride (TiN), tungsten nitride ( _W2N ), tungsten nitride ( _WN2 ), yttrium nitride (YN), and zirconium nitride (ZrN).

Examples of inorganic oxides include zirconium oxide (ZrO ₂ ), titanium oxide (TiO ₂ ), silicon oxide (SiO ₂ ), aluminum oxide (Al ₂ O ₃ ), iron oxide (Fe ₂ O ₃ , FeO, Fe ₃ O ₄ ), copper oxide (CuO, Cu ₂ O), zinc oxide (ZnO), yttrium oxide (Y ₂ O ₃ ), niobium oxide (Nb ₂ O ₅ ), molybdenum oxide (MoO ₃ ), indium oxide (In ₂ O ₃ , In ₂ O), tin oxide (SnO ₂ ), tantalum oxide (Ta ₂ O ₅ ), tungsten oxide (WO ₃ , W ₂ O ₅ ), lead oxide (PbO, PbO ₂ ), bismuth oxide (Bi ₂ O ₃ ), cerium oxide (CeO ₂ , Ce 2 O ₅ ), and the like. _Examples of _inorganic oxides include antimony oxide ( _Sb2O3 , _{Sb2O5 )} , germanium oxide ( _GeO2 , GeO), lanthanum oxide ( _La2O3 ), and ruthenium oxide ( _RuO2 ). The inorganic oxide _may be an oxide produced by oxidizing a metal prepared as a non-oxide under environmental conditions.

〔solvent〕
The composition may further comprise a solvent.
The solvent is preferably an organic solvent, such as cyclopentanone, cyclohexanone, ethyl acetate, methyl ethyl ketone, dichloromethane, and tetrahydrofuran.
When the composition contains a solvent, the content of the solvent is preferably an amount that makes the solids concentration of the composition 20 to 90 mass %, more preferably an amount that makes the solids concentration of the composition 30 to 85 mass %, and even more preferably an amount that makes the solids concentration of the composition 50 to 80 mass %.
The content of the solvent is preferably from 10 to 80% by mass, more preferably from 15 to 70% by mass, and even more preferably from 20 to 50% by mass, based on the total mass of the composition.

[Method of manufacturing composite particles]
Examples of methods for producing the composite particles include known production methods.
As a method for producing the composite particles, production method A or production method B is preferred, and production method A is more preferred.

[Manufacturing method A]
The production method A includes a synthesis step of synthesizing a polymer compound Z by polymerizing a monomer in the presence of a compound represented by formula (1);
and a contacting step of contacting the polymer compound Z with the particles X to produce composite particles.
Polymer compound Z is a compound that can become polymer compound Y when it comes into contact with particle X. A group represented by -Si(R) ₃ that can be covalently bonded to particle X is located at the end of polymer compound Z, and when polymer compound Z comes into contact with particle X, a reaction occurs at the -Si(R) ₃ moiety, resulting in polymer compound Y. R represents any of the groups ^R1 to ^R3 and ^R5 to ^R7 described below.
The monomers used in the synthesis of polymer compound Z include the monomers exemplified as the monomers that form the repeating units of polymer compound Y. The various properties of polymer compound Z, such as the content of the repeating units and the weight-average molecular weight, are the same as those described for polymer compound Y.

<Synthesis process>
The synthesis step is a step of synthesizing a polymer compound Z by polymerizing a monomer in the presence of a compound represented by formula (1).

Examples of methods for polymerizing the monomer include known polymerization reactions.
Specifically, step-growth polymerization and chain polymerization are mentioned, and radical polymerization, cationic polymerization, anionic polymerization, or coordination polymerization is preferred, with radical polymerization being more preferred.
The polymerization method may be living polymerization.
As the living polymerization, reversible addition-fragmentation chain transfer polymerization (RAFT) or atom transfer radical polymerization (ATRP) is preferred, with RAFT being more preferred.
The RAFT method is preferable because it can control the molecular structure of the polymer compound Z while suppressing corrosion of metals such as copper because it does not contain halogens or the like derived from a chain transfer agent.

The synthesis steps are preferably carried out in solution.
Specifically, it is preferable to carry out the reaction in a mixed liquid containing at least one of water and an organic solvent, the compound represented by formula (1), and a monomer.
The organic solvent is not particularly limited as long as it can dissolve the material of the polymer compound Z. Examples thereof include methanol, ethanol, 2-propanol, acetonitrile, cyclopentanone, cyclohexanone, ethyl acetate, methyl ethyl ketone, dichloromethane, and tetrahydrofuran.
The organic solvent may be used alone or in combination of two or more kinds.
The total content of water and organic solvent is preferably 5 to 99% by mass, more preferably 20 to 90% by mass, and even more preferably 30 to 80% by mass, based on the total mass of the mixed liquid.

The reaction temperature during polymerization is preferably 40 to 100°C, more preferably 45 to 90°C, and even more preferably 50 to 80°C.
When the reaction temperature is 40° C. or higher, the polymerization reaction proceeds smoothly. When the reaction temperature is 100° C. or lower, side reactions can be suppressed and restrictions on usable initiators and solvents can be alleviated.

The reaction time for polymerization can be appropriately changed depending on the target polymer compound Z.
The reaction time during polymerization is preferably from 0.1 to 48 hours, more preferably from 0.5 to 24 hours, and even more preferably from 1.5 to 12 hours.

The method for producing composite particles may involve performing the above synthesis step once or two or more times. When the above synthesis step is performed two or more times, the multiple synthesis steps may be the same or different.

(Compound represented by formula (1))

In formula (1), R ¹ to R ³ each independently represent an alkoxy group, a hydroxyl group, or an alkyl group, ^{L 1} represents a single bond or a divalent linking group, and R ⁴ represents a substituent.

R ¹ to R ³ each independently represent an alkoxy group, a hydroxyl group, or an alkyl group.
R ¹ to R ³ are preferably an alkoxy group or a hydroxyl group.
The alkyl group in the alkoxy group may be linear, branched, or cyclic.
The alkyl group in the alkoxy group preferably has 1 to 10 carbon atoms, and more preferably 1 to 5 carbon atoms.
The alkyl group in the alkoxy group is preferably a methyl group, an ethyl group, or a butyl group, and more preferably a methyl group or an ethyl group.
At least one of R ¹ to R ³ is preferably an alkoxy group or a hydroxyl group, and more preferably all of R ¹ to R ³ are alkoxy groups or hydroxyl groups.

^L1 represents a single bond or a divalent linking group.
Examples of the divalent linking group include an ether group (-O-), a carbonyl group (-CO-), an ester group (-COO-), a thioether group (-S-), -SO ₂ -, -NR- (R represents a hydrogen atom, an alkyl group, or an aryl group), a divalent aliphatic hydrocarbon group (for example, an alkylene group, a cycloalkylene group, an alkenylene group (-CH=CH-, etc.), and an alkynylene group (-C≡C-, etc.)), a divalent aromatic ring group (for example, an arylene group and a heteroarylene group), and a group formed by combining these.
The alkylene group may be either linear or branched.
The alkylene group preferably has 1 to 10 carbon atoms, and more preferably 1 to 5 carbon atoms.
^L1 is preferably a divalent linking group, more preferably an alkylene group.

^R4 represents a substituent.
Examples of the substituent include a substituent selected from the substituent group Y, and an —S-alkyl group or an aryl group is preferred.

(Compound represented by formula (2))
The compound represented by formula (1) preferably includes a compound represented by formula (2).

In formula (2), ^R5 to ^R7 each independently represent an alkoxy group, a hydroxyl group, or an alkyl group. ^R8 and ^R9 each independently represent an alkyl group or a cyano group. ^R10 represents a substituent. n represents an integer of 0 to 2.

R ⁵ to R ⁷ have the same meanings as R ¹ to R ³ above, and the preferred embodiments are also the same.

^R8 and ^R9 each independently represent an alkyl group or a cyano group.
The alkyl group may be straight-chain, branched-chain, or cyclic, and is preferably straight-chain.
The alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms, and even more preferably 1 to 3 carbon atoms.
It is preferred that one of ^R8 and ^R9 represents an alkyl group and the other represents a cyano group.

R ¹⁰ represents a substituent.
Examples of the substituent include the groups exemplified in the substituent group Y, and an alkyl group or an aryl group is preferred.
The alkyl group may be linear, branched, or cyclic.
The alkyl group preferably has 1 to 20 carbon atoms, and more preferably has 3 to 15 carbon atoms.
The aryl group may be either monocyclic or polycyclic.
The aryl group preferably has 6 to 15 carbon atoms, and more preferably 6 to 10 carbon atoms.

n represents an integer of 0 to 2.
n is preferably 1 or 2, and more preferably 2.

Examples of compounds represented by formula (1) include the following compounds:

The compound represented by formula (1) may be used alone or in combination of two or more.
The content of the compound represented by formula (1) is preferably 0.01 to 10% by mass, more preferably 0.05 to 5% by mass, and even more preferably 0.1 to 1% by mass, based on the total mass of the particles X.

The compound represented by formula (1) can be produced, for example, by dehydration condensation of a silane coupling agent and a chain transfer agent.
The silane coupling agent and the chain transfer agent may be commercially available products and may be appropriately selected depending on the compound represented by formula (1) to be used.

Examples of the polymer compound Z include the following compounds.
In the formula, n and m represent integers of 1 or more.

<Contact process>
The contacting step is a step of contacting the polymer compound Z with the particles X to produce composite particles.
The polymer compound Z and the particles X are as described above.

The contacting method may be, for example, a method in which the contacting is carried out in a mixed liquid.
Specifically, the particles X, the polymer compound Z, and the polymer compound Z are brought into contact with each other in a mixed liquid containing water and/or an organic solvent.

Examples of the organic solvent include methanol, ethanol, 2-propanol, acetonitrile, cyclopentanone, cyclohexanone, ethyl acetate, methyl ethyl ketone, dichloromethane, and tetrahydrofuran.
The organic solvent may be used alone or in combination of two or more kinds.
The total content of water and organic solvent is preferably 5 to 99% by mass, more preferably 20 to 90% by mass, and even more preferably 30 to 80% by mass, based on the total mass of the mixed liquid.

Examples of methods for contacting particles X and polymer compound Z include a method in which particles X and polymer compound Z are contacted while being stirred using a mechanical stirrer such as a Three-One Motor or a magnetic stirrer, and a method in which particles X are contacted while a solution of polymer compound Z is circulated through a cartridge filled with particles X using a pump or the like.

After the particles X and the polymer compound Z are brought into contact with each other in the mixed solution, the resulting composite particles may be taken out from the mixed solution.
The composite particles can be extracted from the mixture by, for example, filtering the mixture and separating the composite particles as a residue.
It is also preferable to wash the extracted composite particles with water and/or an organic solvent, etc. It is also preferable to dry the washed composite particles in an oven, etc.
In addition, solid components other than the composite particles constituting the composition (e.g., the above-mentioned epoxy compound, etc.) may be added to the above-mentioned mixed liquid, and for example, the composite particles may be produced in the mixed liquid at the same time as the composition is produced.

In the method for producing composite particles, the above contact step may be performed once or twice or more times. When the above contact step is performed twice or more times, the multiple contact steps may be the same or different.

The contact time is preferably from 0.1 to 24 hours, more preferably from 0.5 to 10 hours, and even more preferably from 1.5 to 6 hours.
The temperature of the mixture is preferably from 1 to 200°C, more preferably from 10 to 160°C, and even more preferably from 15 to 140°C.

The content of the particles X is preferably from 1 to 80% by mass, more preferably from 5 to 70% by mass, and even more preferably from 10 to 60% by mass, based on the total mass of the mixed liquid.
The content of the polymer compound Z is preferably from 0.001 to 10% by mass, more preferably from 0.005 to 5% by mass, and even more preferably from 0.01 to 1% by mass, based on the total mass of the mixed liquid.

[Manufacturing method B]
Production method B includes a surface modification step of contacting particles X with a compound represented by formula (1) to obtain surface-modified particles X;
and a production step of polymerizing the monomer in the presence of the surface-modified particles X to produce composite particles.
The particles X, the compound represented by formula (1), and the monomer are as described above.

<Surface modification process>
The surface modification step is a step of obtaining surface-modified particles X by contacting particles X with a compound represented by formula (1).

An example of the surface modification step is the contact step in Production Method A.
The surface-modified particles X are in a state where at least a part of the surface of the particles X is covered with the compound represented by formula (1). This state is the same as the above-described embodiment where at least a part of the surface of the particles X is covered with the polymer compound Y.

<Manufacturing process>
The production step is a step of polymerizing a monomer in the presence of surface-modified particles X to produce composite particles.
The production process may be, for example, the synthesis process in Production Method A described above.

[Other processes]
The method for producing composite particles may include other steps in addition to the steps described above.
Other steps include, for example, a hydrolysis step and a modification step.
In the method for producing composite particles, the above-mentioned other steps may be carried out once or twice or more times. When the above-mentioned other steps are carried out twice or more times, the multiple steps may be the same or different.

<Hydrolysis process>
The hydrolysis step is a step of hydrolyzing the compound represented by formula (1) and/or the polymer compound Z. The hydrolysis step is preferably carried out after the synthesis step and before the contact step in production method A, or before the surface modification step in production method B.
When at least one of R ¹ to R ³ in formula (1) is an alkoxy group and/or when the polymer compound Z has an alkoxysilyl group, it is preferable to carry out a hydrolysis step. In the above cases, the alkoxy group is hydrolyzed to generate a silanol group, and the silanol group can form a bond with the particle X.

There are no particular limitations on the hydrolysis method, as long as the conditions are such that the alkoxy groups are hydrolyzed. Specifically, it is preferable to carry out the hydrolysis using an acidic solution (e.g., an aqueous solution of hydrochloric acid and acetic acid). The acidic solution may also contain an organic solvent.

<Modification step>
The modification step is a step of obtaining modified particles X by contacting particles X with an oxidizing agent in an alkaline aqueous solution.
The modification step is preferably carried out before the contact step in Production Method A, or before the surface modification step in Production Method B.
The pH of the aqueous solution is often 8 or higher, preferably 12 or higher, more preferably greater than 12, even more preferably greater than 13, and particularly preferably greater than 13. The upper limit is preferably 14 or lower. The pH of the aqueous solution refers to the pH of the aqueous solution in a state in which the particles X and the oxidizing agent are contained. In other words, the aqueous solution contains an alkaline compound, water, particles X, and an oxidizing agent as necessary.

The time for which the particles X are brought into contact with the oxidizing agent in the aqueous solution is preferably 0.1 to 24 hours, more preferably 0.5 to 10 hours, and even more preferably 1.5 to 6 hours.
The temperature of the aqueous solution when the particles X are brought into contact with the oxidizing agent is preferably 1 to 95°C, more preferably 25 to 80°C, and even more preferably 45 to 65°C.

Examples of methods for contacting particles X with an oxidizing agent in the aqueous solution include the contact method used in the contacting step.

It is preferable that the particles X are brought into contact with the oxidizing agent in the aqueous solution, and then the resulting modified particles X are taken out from the aqueous solution.
The modified particles X can be extracted from the aqueous solution by, for example, filtering the aqueous solution and isolating the modified particles X as a residue.
It is also preferable to wash the extracted modified particles X with water and/or an organic solvent.

The water content in the aqueous solution is preferably 20 to 99% by mass, more preferably 50 to 95% by mass, and even more preferably 65 to 90% by mass, based on the total mass of the aqueous solution.

(oxidizing agent)
Examples of the oxidizing agent include persulfates such as sodium persulfate, potassium persulfate, and ammonium persulfate; nitrates such as cerium ammonium nitrate, sodium nitrate, and ammonium nitrate; peroxides such as hydrogen peroxide and tert-butyl hydroperoxide; transition metal compounds such as divalent copper compounds and manganese compounds; hypervalent iodine compounds such as potassium periodate and sodium periodate; quinone compounds such as benzoquinone, naphthoquinone, anthraquinone, and chloranil; and salts of halogen oxoacids such as sodium hypochlorite and sodium chlorite.
Preferably, the oxidizing agent comprises a persulfate, and more preferably is a persulfate.
In addition, a catalyst may be used in addition to the oxidizing agent to assist the action of the oxidizing agent. Examples of the catalyst include divalent iron compounds (e.g., _FeSO4 ) and trivalent iron compounds. The oxidizing agent and/or catalyst may be a hydrate.

The standard redox potential of the oxidizing agent is preferably 0.30 V or higher, more preferably 1.50 V or higher, and even more preferably 1.70 V or higher. The upper limit is preferably 4.00 V or lower, more preferably 2.50 V or lower. The above standard redox potential is based on the standard hydrogen electrode.

The oxidizing agents may be used alone or in combination of two or more.
The content of the oxidizing agent in the aqueous solution is preferably 0.05 to 20 parts by mass, more preferably 0.1 to 20 parts by mass, and even more preferably 1 to 20 parts by mass, per 100 parts by mass of water in the aqueous solution.

The catalyst may be used alone or in combination of two or more.
When the aqueous solution contains a catalyst, the content of the catalyst is preferably 0.005 to 2 parts by mass, more preferably 0.01 to 2 parts by mass, and even more preferably 0.1 to 2 parts by mass, per 100 parts by mass of water in the aqueous solution.

(alkali compounds)
The aqueous solution preferably contains an alkaline compound in addition to the above components in order to adjust the pH of the aqueous solution.
Examples of the alkaline compound include inorganic bases such as alkali metal hydroxides (for example, sodium hydroxide, etc.) and alkaline earth metal hydroxides; and organic bases.
The content of the alkaline compound in the aqueous solution may be any amount that allows the pH of the aqueous solution to be adjusted to a desired value, and may be, for example, 0.1 to 10 parts by mass per 100 parts by mass of water in the aqueous solution.

[Method of producing the composition]
The composition can be produced by a known method, for example, by mixing the various components described above. When mixing, the various components may be mixed all at once or sequentially.
The method for mixing the components is not particularly limited, and known methods can be used. The mixing device used for mixing is preferably a submerged disperser, and examples include agitators such as a planetary centrifugal mixer, a high-speed rotary shear type agitator, a colloid mill, a roll mill, a high-pressure injection type disperser, an ultrasonic disperser, a bead mill, and a homogenizer. The mixing device may be used alone or in combination of two or more types. Degassing treatment may be performed before, after, and/or simultaneously with mixing.

[Method for curing the composition]
The composition of the present invention is preferably a composition for forming a thermally conductive material.
The composition of the present invention is cured to obtain a thermally conductive material.
The composition is preferably cured by a thermal curing reaction.
The heating temperature during the thermosetting reaction is not particularly limited and may be appropriately selected, for example, within the range of 50 to 250° C. Furthermore, when carrying out the thermosetting reaction, heat treatments at different temperatures may be carried out multiple times.
The curing treatment is preferably carried out on a composition in the form of a film or sheet. Specifically, for example, the composition may be applied to form a film and then subjected to a curing reaction.
When performing the curing treatment, it is preferable to apply the composition to a substrate to form a coating film and then cure it. In this case, the coating film formed on the substrate may be brought into contact with another substrate before the curing treatment. The cured product (thermal conductive material) obtained after curing may or may not be separated from one or both of the substrates.
Alternatively, when performing the curing treatment, the composition may be applied to separate substrates to form coating films on each substrate, and the curing treatment may be performed while the resulting coating films are in contact with each other. The cured product (thermal conductive material) obtained after curing may or may not be separated from one or both of the substrates.

The curing treatment may be completed when the composition is in a semi-cured state, or after the composition is in a semi-cured state, further curing treatment may be carried out to complete the curing.
The curing treatment for bringing the composition into a semi-cured state (also referred to as "semi-curing treatment") and the curing treatment for complete curing (also referred to as "main curing treatment") may be carried out in separate steps.

For example, in the semi-curing treatment, after applying a composition to a substrate to form a coating film, the coating film on the substrate may be heated without pressure to form a semi-cured thermal conductive material (also referred to as a "semi-cured film" or "semi-cured sheet"). Alternatively, the coating film on the substrate may be heated while also being pressed to form a semi-cured film. When press processing is performed, the press processing may be performed before, after, or during the heating process. Press processing in the semi-curing treatment may facilitate adjustment of the film thickness of the resulting semi-cured film and/or reduction of the amount of voids in the semi-cured film.
The semi-curing treatment may be carried out in a state where coating films formed on different substrates are laminated together, or may be carried out without laminating the coating films together. The semi-curing treatment may also be carried out in a state where the coating film formed from the composition is in contact with a material other than the coating film.

The resulting semi-cured film may be used as a heat conductive material as is, or may be further subjected to a main curing treatment and then used as a completely cured heat conductive material.
In the main curing treatment, the semi-cured film may be heated as is without pressure, or may be heated after or while being pressed. In this case, the main curing treatment may be performed with separate semi-cured films stacked on top of each other, or may be performed without stacking the semi-cured films on top of each other.
The main curing treatment may be carried out in a state where the semi-cured film is placed in contact with a device or the like in which it is used. It is also preferable that the main curing treatment adheres the device to the thermally conductive material of the present invention.

There is no limitation on the press used for the press working that may be carried out during the hardening treatment in the semi-hardening treatment and/or the full hardening treatment, and for example, a plate press or a roll press may be used.
When using a roll press, for example, it is preferable to sandwich a coated substrate obtained by forming a coating film on a substrate between a pair of opposing rolls, and apply pressure in the film thickness direction of the coated substrate while rotating the pair of rolls to pass the coated substrate. The coated substrate may have a substrate on only one side of the coating film, or may have a substrate on both sides of the coating film. The coated substrate may be passed through the roll press once or multiple times.
During the hardening treatment in the semi-hardening treatment and/or the full hardening treatment, either one of the treatment by platen pressing and the treatment by roll pressing may be carried out, or both may be carried out.

For information on creating thermally conductive materials, including curing reactions, please also refer to "High Thermally Conductive Composite Materials" (CMC Publishing, written by Takezawa Yoshitaka).

The shape of the thermally conductive material is not particularly limited, and it can be molded into various shapes depending on the application. A typical shape of the molded thermally conductive material is, for example, a sheet shape.
That is, the thermally conductive material obtained using the composition of the present invention is preferably a thermally conductive sheet.
Furthermore, it is preferable that the thermal conductivity of the thermally conductive material obtained using the composition of the present invention is isotropic rather than anisotropic.

The thermally conductive material is preferably insulating (electrically insulating), in other words, the composition of the present invention is preferably a thermally conductive insulating composition.
For example, the volume resistivity of the thermal conductive material at 23° C. and a relative humidity of 65% is preferably 10 ¹⁰ Ω·cm or more, more preferably 10 ¹² Ω·cm or more, and even more preferably 10 ¹⁴ Ω·cm or more. The upper limit is preferably 10 ¹⁸ Ω·cm or less.

[Uses of thermal conductive materials]
The thermally conductive material obtained using the composition of the present invention can be used as a heat dissipation material such as a heat dissipation sheet, and can be used for heat dissipation applications in various devices. More specifically, a device with a thermally conductive layer can be produced by disposing a thermally conductive layer containing the thermally conductive material of the present invention on the device, and the heat generated from the device can be efficiently dissipated by the thermally conductive layer. The thermally conductive layer may be a thermally conductive layer containing a thermally conductive multilayer sheet, as described below.
The thermally conductive material obtained using the composition of the present invention has sufficient thermal conductivity and high heat resistance, and is therefore suitable for heat dissipation applications in power semiconductor devices used in various electrical equipment such as personal computers, general home appliances, and automobiles.
Furthermore, since the thermally conductive material obtained using the composition of the present invention has sufficient thermal conductivity even in a semi-cured state, it can be used as a heat dissipation material to be placed in areas where it is difficult for light for photocuring to reach, such as gaps between components of various devices.In addition, since it has excellent adhesive properties, it can also be used as a thermally conductive adhesive.

The thermally conductive material obtained using the composition of the present invention may be used in combination with other components other than the component formed from the present composition.
For example, a thermally conductive material (such as a thermally conductive sheet) may be combined with a support (adherend) other than the layer formed from the present composition.
Examples of the support (adherend) include plastic materials, metal materials, and glass. Examples of the plastic materials include polyesters such as polyethylene terephthalate (PET), polycarbonates, acrylic resins, epoxy resins, polyurethanes, polyamides, polyolefins, cellulose derivatives, and silicones. Examples of the metal materials include copper and aluminum.
The support (adherend) is also preferably in the form of a sheet.
The thickness of the sheet-like thermally conductive material (thermally conductive sheet) is preferably 100 to 300 μm, more preferably 150 to 250 μm.

Furthermore, the thermally conductive material (preferably the thermally conductive sheet) may be combined with an adhesive layer and/or a pressure-sensitive adhesive layer.
By joining the thermally conductive material to an object to which heat should be transferred, such as a device, via such an adhesive layer and/or pressure-sensitive adhesive layer, a stronger bond between the thermally conductive material and the object can be achieved. The thermally conductive material formed from the composition of the present invention also has good adhesion to the adhesive layer and pressure-sensitive adhesive layer, and peeling at the interface between the thermally conductive material and the adhesive layer or pressure-sensitive adhesive layer can be suppressed.
For example, a thermally conductive multilayer sheet may be produced which has a thermally conductive sheet and an adhesive layer or pressure-sensitive adhesive layer provided on one or both sides of the thermally conductive sheet.
One or both sides of the thermally conductive sheet may be provided with either an adhesive layer or a pressure-sensitive adhesive layer, or both. An adhesive layer may be provided on one side of the thermally conductive sheet, and a pressure-sensitive adhesive layer may be provided on the other side. Furthermore, an adhesive layer and/or a pressure-sensitive adhesive layer may be provided partially or entirely on one or both sides of the thermally conductive sheet.
As described above, in the present invention, the thermally conductive material such as the thermally conductive sheet may be in a semi-cured state (semi-cured film), and the thermally conductive sheet in the thermally conductive multilayer sheet may be in a semi-cured state. The adhesive layer in the thermally conductive multilayer sheet may be in a cured, semi-cured, or uncured state.

The present invention will be described in more detail below with reference to examples. The materials, amounts used, ratios, treatment details, treatment procedures, etc. shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the examples shown below.
The weight average molecular weight is a weight average molecular weight determined by gel permeation chromatography (GPC) in terms of polystyrene.

[Preparation and Evaluation of Compositions]
[Various ingredients]
The various components used in the examples and comparative examples are listed below.

<Phenol compounds>
The average value of n in A-3 is 1.

<Epoxy Compound>
The weight average molecular weight of B-8 is 3000, and the average value of n of B-9 is 10. * indicates the bonding position.

<Maleimide Compound>
E-1: MIR-3000-70MT, the average value of n for E-1 is 1, manufactured by Nippon Kayaku Co., Ltd. E-2: BMI-70, manufactured by Keiai Kasei Co., Ltd.

<Curing accelerator>
C-1: Tetraphenylphosphonium tetra-p-tolylborate (TPP-MK, manufactured by Hokko Chemical Co., Ltd.)

<Particles X, modified particles X>
Each particle X was used to produce modified particles X1 to X11 through a modification step.
Particle X1: PTX-60, boron nitride aggregate, particle size D ₅₀ : 60 μm, manufactured by Momentive Corporation. Particle X2: HP-40, boron nitride aggregate, particle size D ₅₀ : 40 μm, manufactured by Mizushima Ferroalloy Co., Ltd. Particle X3: PCTL5MHF, boron nitride aggregate, particle size D ₅₀ : 80 μm, manufactured by Saint-Gobain. Particle X4: PT-110, flaky boron nitride, particle size D ₅₀ : 45 μm, manufactured by Momentive Corporation. Particle X5: SGPS, boron nitride aggregate, particle size D ₅₀ : 12 μm, manufactured by Denka Co., Ltd. Modified particle X1: Modified boron nitride produced by production method 1 shown below Modified particle X2: Modified boron nitride produced by production method 2 shown below Modified particle X3: Modified boron nitride produced by production method 3 shown below Modified particle X4: Modified boron nitride produced by production method 4 shown below Modified particle X5: Modified boron nitride produced by production method 5 shown below Modified particle X6: Modified boron nitride produced by production method 6 shown below Modified particle X7: Modified boron nitride produced by production method 7 shown below Modified particle X8: Modified boron nitride produced by production method 8 shown below Modified particle X9: Modified boron nitride produced by production method 9 shown below Modified particle X10: Modified boron nitride produced by production method 10 shown below Modified particle X11: Modified boron nitride produced by production method 11 shown below Modified particle X12: Modified boron nitride produced by production method 12 shown below

(Manufacturing method 1)
Boron nitride (particles X1, 50 g) was added to aqueous NaOH (40 g NaOH/400 mL water) and stirred. Sodium persulfate solution (9.6 g sodium persulfate/100 mL water) was then added to the aqueous NaOH, and the resulting solution was heated to 50°C and stirred for an additional 3 hours (modification step). Stirring was performed at 150 rpm using a Three-One Motor (manufactured by Shinto Scientific Co., Ltd.).
After the NaOH water was cooled to room temperature, the boron nitride in the NaOH water was filtered off, and the filtered boron nitride was washed with water (500 mL) and acetonitrile (250 mL) to obtain modified particles X1.

(Manufacturing method 2)
Boron nitride (particles X1, 50 g) was added to water (400 mL) and stirred to obtain a mixed solution. 30% by mass hydrogen peroxide solution (30 mL) was further added to the mixed solution, and the mixed solution was then heated to 50°C and stirred for an additional 3 hours. Stirring was performed at 150 rpm using a Three-One Motor (manufactured by Shinto Scientific Co., Ltd.).
After the mixture was cooled to room temperature, the boron nitride in the mixture was filtered off and washed with water (500 mL) and acetonitrile (250 mL) to obtain modified particles X2.

(Manufacturing method 3)
Modified particles X3 were obtained in the same manner as in Production Method 1, except that the NaOH water in Production Method 1 was changed to (NaOH: 0.02 g/water: 400 mL).
In Production Method 3, the pH of the liquid (aqueous solution) obtained by mixing NaOH water (NaOH: 0.02 g/water: 400 mL), boron nitride (50 g), and sodium persulfate water (sodium persulfate: 9.6 g/water: 100 mL) was 11.

(Manufacturing method 4)
Boron nitride (particles X1, 50 g) was heated at 1,000° C. for 1 hour in an oxidizing atmosphere to obtain modified particles X4.

(Manufacturing method 5)
Boron nitride (particles X2, 15 g) was subjected to vacuum plasma treatment (gas type: O ₂ , pressure: 30 Pa, output: 500 W) using a plasma cleaner PDC210 (manufactured by Yamato Scientific Co., Ltd.) The boron nitride to be treated was stirred every 5 minutes of vacuum plasma treatment, and the vacuum plasma treatment was continued until the total treatment time reached 30 minutes, thereby obtaining modified particles X5.

(Manufacturing method 6)
Modified particles X6 were obtained in the same manner as in Production Method 1, except that boron nitride (particles X1, 50 g) was changed to boron nitride (particles X2, 50 g).

(Manufacturing method 7)
Boron nitride (particles X2, 50 g) was added to water (400 mL) and stirred to obtain a mixed solution. Sodium hypochlorite water (sodium hypochlorite pentahydrate: 48 g / water: 100 mL) was further added to the mixed solution, and the mixed solution was heated to 50 ° C. and stirred for an additional 3 hours. Stirring was performed at 150 rpm using a Three-One Motor (manufactured by Shinto Scientific Co., Ltd.).
After the mixture was cooled to room temperature, the boron nitride in the mixture was filtered off and washed with water (500 mL) and acetonitrile (250 mL) to obtain modified particles X7.

(Manufacturing method 8)
Boron nitride (particles X2, 50 g) was heated at 1000° C. for 1 hour to obtain modified particles X8.

(Manufacturing method 9)
Boron nitride (particles X2, 50 g) was heated at 900° C. for 4 hours to obtain modified particles X9.

(Manufacturing method 10)
Modified particles X10 were obtained in the same manner as in Production Method 1, except that boron nitride (particles X1, 50 g) was changed to boron nitride (particles X3, 50 g).

(Manufacturing method 11)
Modified particles X11 were obtained in the same manner as in Production Method 1, except that boron nitride (particles X1, 50 g) was changed to boron nitride (particles X4, 50 g).

(Manufacturing method 12)
Modified particles X12 were obtained in the same manner as in Production Method 1, except that boron nitride (particles X1, 50 g) was changed to boron nitride (particles X5, 50 g).

<High molecular compound>
The method for producing each polymer compound Z will be described later.
The value of n in each polymer compound Z corresponds to the weight average molecular weight of each polymer compound Z.
Polymer compound Z-1a and polymer compound Z-1b are compounds having different degrees of polymerization and weight-average molecular weights from polymer compound Z-1.

[Examples 1 to 48, 50 to 52, 54 to 71, 73 to 87]
<Composite particles>
Composite particles BN1 were produced according to the following scheme (corresponding to production method A).
Composite particles BN2 to 48, 50 to 52, and 54 to 69 were produced with reference to the production method for composite particle BN1.
In all of the composite particles, the content of polymer compound Y was more than 0% by mass and less than 1% by mass relative to the total mass of the composite particles.

A dichloromethane (120 mL) solution of 4-cyano-4-[(dodecylsulfanylthiocarbonylcarbonyl)sulfanyl]pentanoic acid (Tokyo Chemical Industry Co., Ltd., 21.9 g) and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (Tokyo Chemical Industry Co., Ltd., 11.4 g) was cooled to 5°C, and a silane coupling agent (KBE-903, Shin-Etsu Chemical Co., Ltd., 12 g) was added dropwise. The temperature was raised to room temperature and the mixture was stirred for an additional 2 hours. The dichloromethane was concentrated and purified by column chromatography. Isopropyl alcohol (IPA) was added to the resulting oily component to obtain a solution containing compound D-1 (solids content 24% by mass, 75 g).

Next, glycidyl methacrylate (GMA, manufactured by Tokyo Chemical Industry Co., Ltd., 171 g) and cyclopentanone (CPO, 17.6 g) were added to the resulting solution containing compound D-1 (solid content 24% by mass, 2.1 g), and the temperature was raised to 75°C under a nitrogen atmosphere. V-601 (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., 47 mg) was then added, and the mixture was stirred for 10 hours while maintaining the temperature at 75°C. After confirming the disappearance of glycidyl methacrylate by NMR, cyclopentanone was added, yielding a solution containing polymer compound Z-1 (solid content 30% by mass, 57 g).

Isopropyl alcohol (3.3 g), distilled water (1.2 g), and acetic acid (0.3 g) were added to the obtained solution containing polymer compound Z-1 (solid content 30% by mass, 4.5 g), and the mixture was stirred at room temperature for 1 hour to obtain a hydrolyzed solution of polymer compound Z-1.
Next, the modified particles X1 (200 g) were added to acetonitrile (400 mL), and the hydrolyzed solution of polymer compound Z-1 was further added and stirred for 1 hour. The boron nitride in the acetonitrile was filtered, washed with acetonitrile (40 mL), and dried in an oven at 40°C to obtain composite particles BN1.

<Preparation of Composition>
As shown in the table, cyclopentanone, a phenol compound, an epoxy compound, a maleimide compound, and a curing accelerator were mixed in this order, and then the composite particles BN1 were added. The resulting mixture was treated for 5 minutes in a planetary centrifugal mixer (THINKY Corporation, Awatori Rentaro ARE-310) to obtain the composition of Example 1.

Example 49
Composite particles BN49 were produced according to the following scheme (corresponding to production method B).
In the composite particles BN49, the content of the polymer compound Y-1 was more than 0% by mass and less than 1% by mass relative to the total mass of the composite particles.

The above compound D-1 (solid content 24% by mass) was obtained using the same procedure as compound D-1 of composite particle BN1.

Next, isopropyl alcohol (0.51 g), distilled water (0.14 g) and acetic acid (20 mg) were added to the obtained solution containing Compound D-1 (solid content 24% by mass, 0.67 g), and the mixture was stirred at room temperature for 1 hour.
The modified particles X1 (20 g) and acetonitrile (40 mL) were added to the solution and stirred at room temperature for 1 hour. The modified particles X1 in the acetonitrile were filtered, washed with acetonitrile (40 mL), and dried in an oven at 40° C. to obtain composite particle precursors.
Cyclopentanone (CPO, 30 mL) was added to the obtained composite particle precursor, followed by the addition of glycidyl methacrylate (Tokyo Chemical Industry Co., Ltd., 10.0 g) and V-601 (Fujifilm Wako Pure Chemical Industries, Ltd., 47 mg), and the mixture was stirred for 10 hours while maintaining the temperature at 75° C. The particles in the obtained reaction solution were collected by filtration, washed with cyclopentanone (40 mL), and dried in an oven at 40° C. to obtain composite particles BN49.

Example 53
Composite particles BN53 were produced (corresponding to production method A) in the same manner as the production method for composite particles BN1 in Example 1, except that polymer compound Z-1 in Example 1 was changed to polymer compound Z-6 produced by the following procedure, thereby obtaining the composition of Example 53. In composite particles BN53, the content of polymer compound Y-6 was more than 0% by mass and less than 1% by mass, relative to the total mass of the composite particles.

A cyclopentanone solution (8 mL) of butyl methacrylate (Tokyo Chemical Industry Co., Ltd., 4.4 g) and a silane coupling agent (KBE-503, Shin-Etsu Chemical Co., Ltd., 1.0 g) was heated to 75°C under a nitrogen atmosphere. V-601 (Fujifilm Wako Pure Chemical Industries, Ltd., 0.16 g) was then added, and the mixture was stirred for 6 hours while maintaining the temperature at 75°C. After confirming the disappearance of glycidyl methacrylate by NMR, cyclopentanone was added, yielding a solution containing polymer compound Z-6 (solids content 30% by mass, 18 g).

Example 72
With reference to the method for producing composite particle BN1 in Example 1 above, composite particle BN54 was produced according to the following scheme (corresponding to production method A), thereby obtaining the composition of Example 72. In composite particle BN54, the content of polymer compound Y-7 was more than 0% by mass and less than 1% by mass relative to the total mass of the composite particle.

Comparative Example 1
The composition of Comparative Example 1 was obtained in the same manner as in the production of the composition of Example 1, except that the composite particles BN1 were replaced with particles X1. In other words, the composition of Comparative Example 1 does not contain any composite particles.

Comparative Example 2
A composition of Comparative Example 2 was produced in the same manner as in Example 1, except that composite particle BN1 was replaced with particle X1, and the compound covering at least a portion of the surface of particle X1 was a silane coupling agent (molecular weight 236, KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.). Note that this compound does not fall under the category of polymer compound Z.

The amount of solvent added to each composition was set so that the solid content of each composition would be 50 to 80% by mass.
The solid content of each composition was adjusted within the above range so that the viscosity of each composition was approximately the same.
The amounts of the epoxy compound and the phenol compound added were adjusted so that the total content of the epoxy compound and the phenol compound relative to the total solid content of the composition was the amount shown in the "Total amount (mass%)" column in the table, and so that the epoxy compound and the phenol compound were equivalent in amount (amounts such that the number of epoxy groups in the epoxy compound was equal to the number of hydroxyl groups in the phenol compound).
In the composition, the amounts of the maleimide compound, the curing accelerator, and the composite particles were adjusted to the amounts (mass %) shown in parentheses in each column of the table, relative to the total solid content of the composition.

[evaluation]
[Preparation of semi-cured sheet (semi-cured film)]
Using an applicator with a micrometer, the prepared composition was uniformly applied onto the release surface of a release-treated PET film (PET756501, manufactured by Lintec Corporation, film thickness 75 μm), and then dried at 120°C for 4 minutes to produce a semi-cured sheet (semi-cured film).

[Preparation of thermally conductive sheet]
The surface of the obtained semi-cured sheet opposite the PET film was covered with a release-treated PET film and heat-pressed in air (heat plate temperature 180 ° C, pressure 20 MPa for 5 minutes). This was then heat-treated at 180 ° C for 90 minutes under normal pressure to obtain a resin sheet. The PET films on both sides of the resin sheet were peeled off to obtain a thermally conductive sheet (thermal conductive material) with an average thickness of 120 μm.

[Evaluation of thermal conductivity]
(1) The thermal diffusivity of the thermal conductive sheet in the thickness direction was measured by the laser flash method using "LFA467" manufactured by NETZSCH.
(2) Using a balance "XS204" manufactured by Mettler Toledo, the specific gravity of the thermally conductive sheet was measured by the Archimedes method (using a "solid specific gravity measurement kit").
(3) Using a DSC320/6200 manufactured by Seiko Instruments Inc., the specific heat of the thermally conductive sheet at 25° C. was determined under the condition of a temperature increase of 10° C./min.
(4) The thermal conductivity of the thermally conductive sheet was calculated by multiplying the obtained thermal diffusivity by the specific gravity and specific heat.
The thermal conductivity of the thermally conductive sheet was classified according to the following criteria, and the thermal conductivity of the thermally conductive sheet obtained using the composition of each Example or Comparative Example was evaluated.
A: 15 W/mK or more B: 13 W/mK or more but less than 15 W/mK C: 10 W/mK or more but less than 13 W/mK D: Less than 10 W/mK

[Copper foil peel strength (adhesion)]
The PET film was peeled off from the resulting semi-cured sheet, and the resulting semi-cured sheet was cut into 20 mm × 60 mm strips and sandwiched between an adherend, an electrolytic copper foil (20 mm × 100 mm, 35 μm thick) and an aluminum plate (30 mm × 60 mm, 1 mm thick). The resulting laminate was heat-pressed in air (heat plate temperature 180 ° C, pressure 20 MPa for 5 minutes, followed by heat plate temperature 180 ° C, normal pressure for 90 minutes) to obtain an aluminum base substrate with copper foil in which the thermally conductive sheet and the adherend were integrated.
The copper foil peel strength of the obtained aluminum base substrate with copper foil was measured using a digital force gauge (ZTS-200N, manufactured by Imada Co., Ltd.) and a 90° peel test jig (P90-200N-BB, manufactured by Imada Co., Ltd.) in accordance with the method for measuring peel strength under normal conditions described in JIS C 6481. In the peel strength test, the copper foil was peeled at an angle of 90° to the aluminum base substrate with copper foil, at a peel rate of 50 mm/min. The obtained copper foil peel strength was classified and evaluated according to the following criteria.
A: 5 N/cm or more B: 4 N/cm or more but less than 5 N/cm C: 3 N/cm or more but less than 4 N/cm D: Less than 3 N/cm

[Evaluation of solder heat resistance]
After peeling the PET film from the obtained semi-cured sheet, the sheet was sandwiched between a copper substrate having a thickness of 2 mm and copper foil having a thickness of 0.15 mm, and then hot-pressed in air (heat plate temperature: 180°C, pressure: 20 MPa, treatment for 5 minutes) to obtain a laminate having a "copper substrate-thermal conductive sheet-copper foil" configuration.
The 0.15 mm copper foil in the laminate was etched into a circular shape with a diameter of 2 cm, and the laminate was used as a sample for solder heat resistance test having a configuration of "copper substrate - thermally conductive sheet - circular copper foil with a diameter of 2 cm".
The sample was subjected to a heat treatment of heating at 300° C. for 5 minutes and then cooling to room temperature (25° C.) 1 to 3 times. After that, a circular copper foil having a diameter of 2 cm was peeled off from the sample that had been heat-treated 1 to 3 times.
The state of failure of the peeled samples was visually observed, and if cohesive failure of the thermally conductive sheet occurred over the entire peeled surface, the sample was deemed to have passed. If interfacial peeling occurred over part or the entire surface between the copper substrate and the thermally conductive sheet and/or between the thermally conductive sheet and the 2 cm diameter circular copper foil, the sample was deemed to have failed.
Based on the relationship between the number of heat treatments and whether the sheet was passed or failed, the solder heat resistance of the thermal conductive sheet was evaluated according to the following classification.
A: Passed the heat treatment three times. B: Passed the heat treatment twice, but failed after three times. C: Passed the heat treatment once, but failed after two times. D: Failed after one heat treatment.

[result]
The evaluation results are shown in the table.
In the "reactive group Y" column, if the polymer compound Y has a reactive group Y (a group selected from the group consisting of an epoxy group, a primary amino group, a secondary amino group, an amide group, an ether group, and a hydroxyl group), it is marked as "A", and otherwise it is marked as "B".
The "Polymerization method" column indicates the polymerization method used in producing polymer compound Z. RAFT stands for reversible addition-fragmentation chain transfer polymerization, and ATRP stands for atom transfer radical polymerization.
In the "Formula (2)" column, when polymer compound Z is synthesized using a compound represented by formula (2), it is marked with "A," and otherwise it is marked with "B." Polymer compound Z-n is a polymer compound that becomes polymer compound Y-n upon contact with particles. n represents an integer of 1 or more. Specifically, composite particle BN1 containing polymer compound Y-1 and particle X1 is formed by contacting polymer compound Z-1 with particle X1.

From the results shown in the table, it was confirmed that the composition can obtain the effects of the present invention.
It was confirmed that when the polymer compound Y has at least one group (reactive group Y) selected from the group consisting of an epoxy group, a primary amino group, a secondary amino group, an amide group, and a hydroxyl group, the adhesion and solder heat resistance are more excellent (e.g., comparison of Examples 1 to 49 and 74 to 85).
It was confirmed that when the weight average molecular weight of polymer compound Y is 3,000 or more, the adhesion and solder heat resistance are more excellent (comparison of Examples 1, 50 and 51, etc.).
It was confirmed that when the polymer compound Z was synthesized using the compound represented by formula (2), the adhesion and solder heat resistance were superior (comparison of Examples 1, etc. and 52 to 53, etc.).
It was confirmed that when the polymer compound Z was produced by a living polymerization method (e.g., a RAFT method or an ATRP method), the adhesion and solder heat resistance were superior (e.g., comparison between Examples 1, 53, and 72). It was also confirmed that when the RAFT method was used, the solder heat resistance was even superior (e.g., comparison between Examples 1 and 72).
It was confirmed that when the composition contained a maleimide compound, the thermal conductivity was superior (e.g., comparison between Examples 1 and 54).
It was confirmed that when the epoxy compound contains at least one of a rod-shaped compound and a disc-shaped compound, the thermal conductivity is superior (comparison between Examples 1 and 55 to 64, etc.).
It was confirmed that when the content of the composite particles was 85 mass % or less based on the total solid content of the composition, the adhesion was superior (comparison between Examples 1 and 69 to 70, etc.).

Claims (9)

A curable composition comprising a curable compound and composite particles,
the composite particle includes a particle X and a polymer compound Y that covers at least a part of the surface of the particle X via a covalent bond ,
the particles X comprise particles selected from boron nitride and agglomerates thereof, having a particle size _D50 of more than 10 μm;
the weight average molecular weight of the polymer compound Y is 1,000 or more;
the covalent bond-forming group is a silanol group,
the polymer compound Y has at least one repeating unit derived from a compound selected from the group consisting of styrene, (meth)acrylic acid, (meth)acrylamide, a vinyl ester compound, a vinyl amide compound, and derivatives thereof;
A curable composition, wherein the curable compound comprises an epoxy compound and a phenolic compound . The curable composition according to claim 1 , wherein the polymer compound Y has at least one group selected from the group consisting of an epoxy group, a primary amino group, a secondary amino group, an amide group, an ether group, and a hydroxyl group. 3. The curable composition of claim 1, wherein the particles X comprise aggregates of boron nitride. The curable composition according to any one of claims 1 to 3 , which satisfies at least one of the following requirements: the epoxy compound includes an epoxy compound having a triazine skeleton; and the phenol compound includes a phenol compound having a triazine skeleton. The curable composition according to any one of claims 1 to 4 , further comprising a curing accelerator. The curable composition of claim 5 , wherein the curing accelerator comprises a compound containing a phosphorus atom. A thermally conductive material obtained by curing the curable composition according to any one of claims 1 to 6 . A thermally conductive sheet comprising the thermally conductive material according to claim 7 . A device with a thermally conductive layer, comprising: a device; and a thermally conductive layer comprising the thermally conductive sheet according to claim 8 disposed on the device.