JP2010070653A - Insulating sheet and laminated structure - Google Patents

Abstract

[PROBLEMS] To bond a heat conductor having a thermal conductivity of 10 W / m · K or more to a conductive layer, and has excellent handling properties in an uncured state, heat resistance, dielectric breakdown characteristics, and thermal conductivity. Provided is an insulating sheet that gives an excellent cured product.
A polymer (A) having a functional group containing a hydrogen atom having hydrogen bonding properties and a weight average molecular weight of 10,000 or more, an aromatic skeleton, and a weight average molecular weight of 600 or less. At least one monomer (B) of the oxetane monomer (B2) having an epoxy monomer (B1) and an aromatic skeleton and having a weight average molecular weight of 600 or less, a phenol resin, an aromatic skeleton or an alicyclic An insulating sheet containing a curing agent (C) which is an acid anhydride having a skeleton, a water additive or a modified product thereof, and a filler (D).
[Selection figure] None

Description

  The present invention relates to an insulating sheet used for adhering a heat conductor having a thermal conductivity of 10 W / m · K or more to a conductive layer, and more particularly, has excellent handling properties in an uncured state, and The present invention relates to an insulating sheet that gives a cured product excellent in heat resistance, dielectric breakdown characteristics, and thermal conductivity, and a laminated structure using the insulating sheet.

  In recent years, miniaturization and high performance of electric devices have been advanced. Along with this, the mounting density of electronic components is increasing, and the need to dissipate heat generated from electronic components is increasing. As a method of dissipating heat, a method of adhering a heat conductor such as aluminum having high heat dissipation and a thermal conductivity of 10 W / m · K or more to a heat source is widely adopted. In order to bond the heat conductor to a heat source, an insulating adhesive material having insulating properties is used. Insulating adhesive materials are strongly required to have high thermal conductivity.

  As an example of the above insulating adhesive material, the following Patent Document 1 discloses an insulating material in which a glass cloth is impregnated with an adhesive composition containing an epoxy resin, an epoxy resin curing agent, a curing accelerator, an elastomer, and an inorganic filler. An adhesive sheet is disclosed.

Insulating adhesive materials that do not use glass cloth are also known. For example, in the examples of Patent Document 2 below, an insulating adhesive containing bisphenol A type epoxy resin, phenoxy resin, phenol novolac, 1-cyanoethyl-2-phenylimidazole, γ-glycidoxypropyltrimethoxysilane and alumina Is disclosed. Here, tertiary amines, acid anhydrides, imidazole compounds, polyphenol resins, mask isocyanates and the like are listed as curing agents for epoxy resins.
JP 2006-342238 A JP-A-8-332696

  However, in the insulating adhesive sheet described in Patent Document 1, a glass cloth is used in order to improve handling properties. When glass cloth is used, it is difficult to make a thin film, and various processes such as laser processability or drilling are difficult. Furthermore, since the thermal conductivity of the cured product of the insulating adhesive sheet containing glass cloth is relatively low, sufficient heat dissipation may not be obtained. Furthermore, special impregnation equipment had to be prepared in order to impregnate the glass cloth with the adhesive composition.

  The insulating adhesive described in Patent Document 2 was not a sheet having self-supporting property in an uncured state. Since the insulating adhesive before curing is not gelled or is in a B stage state, the handling property is poor.

  The object of the present invention is to adhere a heat conductor having a thermal conductivity of 10 W / m · K or more to a conductive layer, and has excellent handling properties in an uncured state, and has heat resistance, dielectric breakdown characteristics and It is providing the insulating sheet which gives the hardened | cured material excellent in heat conductivity, and the laminated structure using this insulating sheet.

  According to the present invention, there is provided an insulating sheet used for bonding a heat conductor having a thermal conductivity of 10 W / m · K or more to a conductive layer, which has a functional group containing hydrogen atoms having hydrogen bonding properties. And a polymer (A) having a weight average molecular weight of 10,000 or more, an epoxy monomer (B1) having an aromatic skeleton and a weight average molecular weight of 600 or less, an aromatic skeleton, and a weight average molecular weight And at least one monomer (B) of oxetane monomers (B2) having an A of 600 or less, a phenol resin, an acid anhydride having an aromatic skeleton or an alicyclic skeleton, a water additive thereof, or a modified product thereof. A total of 100 weights of all resin components in the insulating sheet containing the curing agent (C) and the filler (D) and including the polymer (A), the monomer (B), and the curing agent (C). %inside, The polymer (A) is in the range of 20 to 60% by weight, the monomer (B) is in the range of 10 to 60% by weight, and the polymer (A) and the monomer (B) are less than 100% by weight in total. An insulating sheet is provided, characterized in that the insulating sheet is contained in an amount.

  The polymer (A) preferably has an aromatic skeleton. In this case, the heat resistance of the cured product of the insulating sheet can be further enhanced.

  The functional group of the polymer (A) is preferably at least one selected from the group consisting of a hydroxyl group, a phosphoric acid group, a carboxyl group, and a sulfonic acid group. In this case, the dielectric breakdown characteristics and thermal conductivity of the cured product of the insulating sheet can be further enhanced.

  It is preferable that pKa of the functional group containing the hydrogen atom having hydrogen bonding property of the polymer (A) is in the range of 2 to 10. When pKa of the said functional group exists in the said range, the dielectric breakdown characteristic and thermal conductivity of the hardened | cured material of an insulating sheet can be improved further.

  The polymer (A) preferably contains a phenoxy resin. When a phenoxy resin is used, the heat resistance of the cured product of the insulating sheet can be further enhanced. The glass transition temperature Tg of the phenoxy resin is preferably 95 ° C. or higher. In this case, the thermal deterioration of the resin can be further suppressed.

  The curing agent (C) is an acid anhydride having a polyalicyclic skeleton, an acid anhydride having an alicyclic skeleton obtained by addition reaction of a terpene compound and maleic anhydride, a water additive thereof, or The modified product is preferable. The curing agent (C) is more preferably an acid anhydride represented by any of the following formulas (1) to (3). When these preferable hardening | curing agents (C) are used, the softness | flexibility, moisture resistance, or adhesiveness of an insulating sheet can be improved further.

  In said formula (3), R1 and R2 show hydrogen, a C1-C5 alkyl group, or a hydroxyl group, respectively.

  The curing agent (C) is preferably a phenol resin having a melamine skeleton or a triazine skeleton, or a phenol resin having an allyl group. When this preferable hardening | curing agent (C) is used, the softness | flexibility and flame retardance of the hardened | cured material of an insulating sheet can be improved further.

  The filler (D) is preferably at least one selected from the group consisting of alumina, boron nitride, aluminum nitride, silicon nitride, silicon carbide, zinc oxide and magnesium oxide. The filler (D) is preferably at least one selected from the group consisting of spherical alumina, crushed alumina and spherical aluminum nitride. When these preferable fillers (D) are used, the heat dissipation of the cured product of the insulating sheet can be further enhanced.

  The laminated structure according to the present invention includes a thermal conductor having a thermal conductivity of 10 W / m · K or more, an insulating layer laminated on at least one surface of the thermal conductor, and the thermal conductor of the insulating layer. And a conductive layer laminated on a surface opposite to the surface laminated with, and the insulating layer is formed by curing an insulating sheet configured according to the present invention.

  In the laminated structure according to the present invention, the heat conductor is preferably a metal.

  According to the present invention, the polymer (A) having a functional group containing a hydrogen atom having hydrogen bonding properties and a weight average molecular weight of 10,000 or more, an aromatic skeleton, and a weight average molecular weight of 600 At least one monomer (B) of the following oxetane monomer (B2) having an epoxy monomer (B) and an aromatic skeleton, and having a weight average molecular weight of 600 or less, a phenol resin, or an aromatic skeleton or Since the acid anhydride having an alicyclic skeleton, its water additive or its modified product, the curing agent (C) and the filler (D) are contained in the above-mentioned specific proportion, The handling property of the insulating sheet can be improved. Furthermore, the heat resistance, dielectric breakdown characteristics, and thermal conductivity of the cured product of the insulating sheet can be enhanced.

  In the laminated structure according to the present invention, a conductive layer is laminated on at least one surface of a thermal conductor having a thermal conductivity of 10 W / m · K or more via an insulating layer, and the insulating layer is configured according to the present invention. Since the insulating sheet thus formed is cured, heat from the conductive layer side is easily transferred to the heat conductor through the insulating layer. For this reason, heat can be efficiently dissipated by the heat conductor.

  The inventors of the present application have a polymer (A) having a functional group containing a hydrogen atom having hydrogen bonding properties and a weight average molecular weight of 10,000 or more, an aromatic skeleton, and a weight average molecular weight of 600. At least one monomer (B) of the oxetane monomer (B2) having an epoxy monomer (B1) and an aromatic skeleton, and having a weight average molecular weight of 600 or less, a phenol resin, or an aromatic skeleton or By adopting a composition containing the curing agent (C) which is an acid anhydride having an alicyclic skeleton, its water additive or its modified product, and a filler (D) in the above-mentioned specific ratio, in an uncured state It has been found that the handling properties of the insulation sheet can be improved, and that the heat resistance, dielectric breakdown characteristics and thermal conductivity of the cured product of the insulation sheet can be improved, and the present invention has been achieved. It was.

  Details of the present invention will be described below.

  The insulating sheet according to the present invention has a polymer (A) having a functional group containing hydrogen atoms having hydrogen bonding properties and a weight average molecular weight of 10,000 or more, an aromatic skeleton, and a weight average molecular weight. An epoxy monomer (B1) having an aromatic skeleton of at least 600 and an oxetane monomer (B2) having a weight average molecular weight of 600 or less, a phenol resin, or an aromatic It contains a curing agent (C) that is an acid anhydride having a skeleton or an alicyclic skeleton, a water additive or a modified product thereof, and a filler (D).

(Polymer (A))
The polymer (A) contained in the insulating sheet according to the present invention is not particularly limited as long as it has a functional group containing a hydrogen atom having hydrogen bonding properties and has a weight average molecular weight of 10,000 or more. A polymer (A) may be used independently and 2 or more types may be used together.

  The polymer (A) has a functional group containing a hydrogen atom having hydrogen bonding properties. The polymer (A) having a functional group containing a hydrogen atom having hydrogen bonding properties has high affinity with the filler (D). Therefore, the dispersibility of the filler (D) in the insulating sheet and the adhesion between the polymer (A) and the filler (D) can be enhanced. For this reason, the dielectric breakdown characteristics and thermal conductivity of the cured insulating sheet can be further improved without generating voids at the interface between the filler (D) and the resin layer.

  Examples of the functional group containing a hydrogen atom having hydrogen bonding properties include a hydroxyl group (pKa = 16), a phosphoric acid group (pKa = 7), a carboxyl group (pKa = 4), a sulfonic acid group (pKa = 2), and the like. Is mentioned.

  The functional group containing a hydrogen atom having hydrogen bonding property in the polymer (A) is preferably at least one selected from the group consisting of a hydroxyl group, a phosphate group, a carboxyl group, and a sulfonate group. More preferably at least one selected from the group consisting of a carboxyl group and a sulfonic acid group. When the polymer (A) having these preferable functional groups is used, the dielectric breakdown characteristics and the thermal conductivity of the cured insulating sheet can be further enhanced.

  Among them, since the dielectric breakdown characteristics and thermal conductivity of the cured insulating sheet can be further enhanced, the functional group containing a hydrogen atom having the hydrogen bonding property of the polymer (A) is a carboxyl group or a phosphate group. Preferably there is.

  The pKa of the functional group containing a hydrogen atom having hydrogen bonding properties is preferably in the range of 2 to 10, and more preferably in the range of 3 to 9. When the pKa is less than 2, the acidity of the polymer (A) is too high, and the reaction of the epoxy component and the oxetane component in the resin component is easily promoted. For this reason, when the insulating sheet is stored in an uncured state, the storage stability of the insulating sheet may be insufficient. When pKa exceeds 10, the effect which improves the dispersibility of the filler (D) in an insulating sheet may be insufficient. For this reason, it may be difficult to sufficiently enhance the dielectric breakdown characteristics and thermal conductivity of the cured product of the insulating sheet.

  Examples of the polymer (A) having a functional group containing a hydrogen atom having hydrogen bonding property include a heavy group having a functional group containing a hydrogen bonding hydrogen atom such as a carboxylic acid group, a sulfonic acid group, a phosphoric acid group, or a hydroxyl group. Examples include coalescence. As a method for obtaining such a polymer, for example, a method in which a monomer having a functional group containing a hydrogen-bonding hydrogen atom is copolymerized with another monomer, a hydrogen-bonding hydrogen is used as a base trunk polymer. A method of graft-copolymerizing a monomer having a functional group containing an atom, or the derivative group of a polymer having a functional group-derived functional group containing a hydrogen-bonding hydrogen atom, containing the hydrogen atom having the hydrogen-bonding property The method etc. which convert into a functional group are mentioned.

  Specific examples of the polymer having a functional group containing a hydrogen bondable hydrogen atom include a carboxylic acid group-containing styrene polymer, a carboxylic acid group-containing phenoxy resin, a carboxylic acid group-containing polyester, a carboxylic acid group-containing polyether, and a carboxylic acid group. Containing (meth) acrylic polymer, carboxylic acid group-containing aliphatic polymer, carboxylic acid-containing polysiloxane polymer, phosphoric acid group-containing styrene polymer, phosphoric acid group-containing phenoxy resin, phosphoric acid group-containing polyester, phosphoric acid group-containing Polyether, phosphate group-containing (meth) acrylic polymer, phosphate group-containing aliphatic polymer, phosphate group-containing polysiloxane polymer, sulfonic acid-containing styrene polymer, phosphate group-containing phenoxy resin, sulfonate group-containing Polyester, sulfonic acid group-containing polyether, sulfonic acid Limer-containing (meth) acrylic polymer, sulfonic acid group-containing aliphatic polymer, sulfonic acid group-containing polysiloxane polymer, hydroxyl group-containing styrene polymer, hydroxyl group-containing phenoxy resin, hydroxyl group-containing polyester, hydroxyl group-containing polyether, hydroxyl group-containing ( Examples thereof include a (meth) acrylic polymer, a hydroxyl group-containing aliphatic polymer, and a hydroxyl group-containing polysiloxane polymer. The polymer (A) having a functional group containing a hydrogen atom may be used alone or in combination of two or more.

  In 100% by weight of the insulating sheet, the polymer (A) is preferably contained within a range of 0.01 to 20% by weight, and more preferably within a range of 0.1 to 10% by weight. When the polymer (A) having a functional group containing a hydrogen-bonding hydrogen atom is contained within the above range, aggregation of the filler (D) can be suppressed, and the thermal conductivity and dielectric breakdown characteristics of the cured product of the insulating sheet. Can be sufficiently increased.

  The polymer (A) preferably has an aromatic skeleton. In this case, the heat resistance of the cured product of the insulating sheet can be further enhanced.

  When the polymer (A) has an aromatic skeleton, the polymer (A) may have an aromatic skeleton in the entire polymer, may be included in the main chain skeleton, May be included. The polymer (A) preferably has an aromatic skeleton in the main chain skeleton. In this case, the heat resistance of the cured product can be further enhanced.

  The aromatic skeleton is not particularly limited. Specific examples of the aromatic skeleton include naphthalene skeleton, fluorene skeleton, biphenyl skeleton, anthracene skeleton, pyrene skeleton, xanthene skeleton, adamantane skeleton, and bisphenol A skeleton. Of these, a biphenyl skeleton or a fluorene skeleton is preferable. In this case, the heat resistance of the cured product can be further enhanced.

  The polymer (A) is not particularly limited as long as it has a functional group containing a hydrogen atom having hydrogen bonding properties and has a weight average molecular weight of 10,000 or more. Any thermoplastic resin or thermosetting resin can be used as the polymer (A).

  The thermoplastic resin is not particularly limited. Specific examples of the thermoplastic resin include a styrene resin, a phenoxy resin, a phthalate resin, a thermoplastic urethane resin, a polyamide resin, a thermoplastic polyimide resin, a ketone resin, or a norbornene resin.

  The thermosetting resin is not particularly limited. Specific examples of the thermosetting resin include amino resins such as urea resins and melamine resins, phenolic resins, thermosetting urethane resins, epoxy resins, thermosetting polyimide resins, and aminoalkyd resins. It is done.

  As the thermoplastic resin and the thermosetting resin, a heat-resistant resin group called a super engineering plastic can be used. The super engineering plastic is not particularly limited. Examples of the super engineering plastic include thermoplastic resins such as polyphenylene sulfide, polyarylate, polysulfone, polyethersulfone, polyetheretherketone or polyetherketone, thermoplastic polyimide, thermosetting polyimide, benzoxazine, or polybenzoxazole. And a reaction product of benzoxazine.

  Each of the thermoplastic resin and the thermosetting resin may be used alone, or two or more of them may be used in combination. Only a thermoplastic resin may be used, only a thermosetting resin may be used, and both a thermoplastic resin and a thermosetting resin may be used.

  The polymer (A) is preferably at least one of a styrene polymer and a phenoxy resin, and more preferably a phenoxy resin. Moreover, it is preferable that a polymer (A) contains a phenoxy resin. When these preferable polymers (A) are used, the oxidative deterioration of the cured product can be prevented, and the heat resistance of the cured product can be further enhanced.

  Specific examples of the styrenic polymer include a homopolymer of a styrene monomer or a copolymer of a styrene monomer and a (meth) acrylic monomer. Of these, a styrene polymer having a styrene-glycidyl methacrylate structure is preferred.

  Specific examples of the styrene monomer include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, p-ethylstyrene, p- n-butyl styrene, p-tert-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, 2,4 -Dimethylstyrene, 3, 4- dichlorostyrene, etc. are mentioned. A styrene-type monomer may be used independently and 2 or more types may be used together.

  Examples of the (meth) acrylic monomer include acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, acrylate-2-ethylhexyl, cyclohexyl acrylate, phenyl acrylate, methyl methacrylate, and methacrylic acid. Ethyl acetate, butyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, glycidyl methacrylate, ethyl β-hydroxyacrylate, propyl γ-aminoacrylate, stearyl methacrylate, dimethylaminoethyl methacrylate or diethylaminoethyl methacrylate Etc. An acrylic monomer may be used independently and 2 or more types may be used together.

  Specifically, the phenoxy resin is, for example, a resin obtained by reacting an epihalohydrin and a divalent phenol compound, or a resin obtained by reacting a divalent epoxy compound and a divalent phenol compound.

  The phenoxy resin comprises a bisphenol A skeleton, a bisphenol F skeleton, a bisphenol A / F mixed skeleton, a naphthalene skeleton, a fluorene skeleton, a biphenyl skeleton, an anthracene skeleton, a pyrene skeleton, a xanthene skeleton, an adamantane skeleton, and a dicyclopentadiene skeleton. A phenoxy resin having at least one skeleton selected from the group is preferable. Among these, a phenoxy resin having at least one of a fluorene skeleton and a biphenyl skeleton is preferable. When these preferable phenoxy resins are used, the heat resistance of the cured product can be further enhanced.

  The phenoxy resin preferably has at least one of the skeletons represented by the following formulas (4) to (9).

In the above formula (4), R ₁ may be the same or different from each other, and is a hydrogen atom, a hydrocarbon group having 1 to 10 carbon atoms or a halogen atom, and X ₁ is a single bond, having 1 to 1 carbon atoms. 7 divalent hydrocarbon group, —O—, —S—, —SO ₂ —, or —CO—.

In the above formula (5), R _1a may be the same as or different from each other, and is a hydrogen atom, a hydrocarbon group having 1 to 10 carbon atoms, or a halogen atom, and R ₂ is a hydrogen atom, carbon number 1 10 is a hydrocarbon group having 1 to 10 carbon atoms or a halogen atom, R ₃ is a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, and m is an integer of 0 to 5.

In the above formula (6), R _1b may be the same or different from each other, and is a hydrogen atom, a hydrocarbon group having 1 to 10 carbon atoms or a halogen atom, and R ₄ is the same or different from each other. It is a hydrogen atom, a C1-C10 hydrocarbon group, or a halogen atom, and l is an integer of 0-4.

In the formula (8), _{R 5} and _{R 6} are each hydrogen atom, an alkyl group or a halogen atom having 1 to 5 carbon atoms, _{X 2} is _{-SO 2 -, - CH 2 -} , - C (CH 3) _2- or -O-, and k is a value of 0 or 1.

  As the polymer (A), for example, a phenoxy resin represented by the following formula (10) or the following formula (11) is preferably used.

In the above formula (10), A ₁ has a structure represented by any of the above formulas (4) to (6), and the structure is 0 to 60 mol of the structure represented by the above formula (4). %, The structure represented by the above formula (5) is 5 to 95 mol%, and the structure represented by the above formula (6) is 5 to 95 mol%, and A ₂ is a hydrogen atom or the above formula (7 ), And n ₁ is an average value of 25 to 500.

In the above formula (11), A ₃ has a structure represented by the above formula (8) or the above formula (9), and n ₂ is a value of at least 21 or more.

  The glass transition temperature Tg of the polymer (A) is preferably in the range of 60 to 200 ° C, and more preferably in the range of 90 to 180 ° C. If the Tg of the polymer (A) is too low, the resin may be thermally deteriorated. If the Tg of the polymer (A) is too high, the compatibility between the polymer (A) and the other resin is deteriorated, and the heat resistance of the cured product may be lowered.

  When the polymer (A) contains a phenoxy resin, the glass transition temperature Tg of the phenoxy resin is preferably 95 ° C or higher, more preferably 100 ° C or higher, and within the range of 110 to 200 ° C. Is more preferable, and it is especially preferable that it exists in the range of 110-180 degreeC. If the Tg of the phenoxy resin is too low, the resin may be thermally deteriorated. If the Tg of the phenoxy resin is too high, the compatibility between the phenoxy resin and the other resin is deteriorated, and the heat resistance of the cured product may be reduced.

  The polymer (A) has a weight average molecular weight of 10,000 or more. The weight average molecular weight of the polymer (A) is preferably in the range of 10,000 to 1,000,000, more preferably in the range of 30,000 to 1,000,000, More preferably, it is in the range of 000 to 250,000. If the weight average molecular weight is too small, the resin may be thermally deteriorated. When the weight average molecular weight is too large, the compatibility between the polymer (A) and the other resin is deteriorated, and the heat resistance of the cured product may be lowered.

  The polymer (A) is contained within a range of 20 to 60% by weight in a total of 100% by weight of all resin components in the insulating sheet. The polymer (A) is preferably contained within a range of 30 to 50% by weight in a total of 100% by weight of all resin components in the insulating sheet. When there is too much quantity of a polymer (A), dispersion | distribution of a filler (D) may become difficult. If the amount of the polymer (A) is too small, the handleability of the insulating sheet in an uncured state may be inferior. The total resin component refers to the sum of the polymer (A), the monomer (B), the curing agent (C), and other resin components added as necessary.

(Monomer (B))
The insulating sheet according to the present invention contains at least one monomer (B) of the epoxy monomer (B1) and the oxetane monomer (B2). The epoxy monomer (B1) has an aromatic skeleton. The weight average molecular weight of the epoxy monomer (B1) is 600 or less. The oxetane monomer (B2) has an aromatic skeleton. The weight average molecular weight of the oxetane monomer (B2) is 600 or less.

  In the insulating sheet according to the present invention, as the monomer (B), only the epoxy monomer (B1) may be used, or only the oxetane monomer (B2) may be used, and the epoxy monomer (B1) and the oxetane monomer (B2). ) May be used.

  The epoxy monomer (B1) is not particularly limited as long as it has an aromatic skeleton and a weight average molecular weight of 600 or less. Specific examples of the epoxy monomer (B1) include an epoxy monomer having a bisphenol skeleton, an epoxy monomer having a dicyclopentadiene skeleton, an epoxy monomer having a naphthalene skeleton, an epoxy monomer having an adamantene skeleton, an epoxy monomer having a fluorene skeleton, and biphenyl. Examples thereof include an epoxy monomer having a skeleton, an epoxy monomer having a bi (glycidyloxyphenyl) methane skeleton, an epoxy monomer having a xanthene skeleton, an epoxy monomer having an anthracene skeleton, and an epoxy monomer having a pyrene skeleton. As for these epoxy monomers (B1), only 1 type may be used and 2 or more types may be used together.

  Examples of the epoxy monomer having a bisphenol skeleton include an epoxy monomer having a bisphenol A type, bisphenol F type, or bisphenol S type bisphenol skeleton.

  Examples of the epoxy monomer having a dicyclopentadiene skeleton include dicyclopentadiene dioxide and a phenol novolac epoxy monomer having a dicyclopentadiene skeleton.

  Examples of the epoxy monomer having a naphthalene skeleton include 1-glycidylnaphthalene, 2-glycidylnaphthalene, 1,2-diglycidylnaphthalene, 1,5-diglycidylnaphthalene, 1,6-diglycidylnaphthalene, 1,7-diglycidyl. Naphthalene, 2,7-diglycidylnaphthalene, triglycidylnaphthalene, 1,2,5,6-tetraglycidylnaphthalene, and the like can be given.

  Examples of the epoxy monomer having an adamantene skeleton include 1,3-bis (4-glycidyloxyphenyl) adamanten, 2,2-bis (4-glycidyloxyphenyl) adamanten, and the like.

  Examples of the epoxy monomer having a fluorene skeleton include 9,9-bis (4-glycidyloxyphenyl) fluorene, 9,9-bis (4-glycidyloxy-3-methylphenyl) fluorene, and 9,9-bis (4- Glycidyloxy-3-chlorophenyl) fluorene, 9,9-bis (4-glycidyloxy-3-bromophenyl) fluorene, 9,9-bis (4-glycidyloxy-3-fluorophenyl) fluorene, 9,9-bis (4-Glycidyloxy-3-methoxyphenyl) fluorene, 9,9-bis (4-glycidyloxy-3,5-dimethylphenyl) fluorene, 9,9-bis (4-glycidyloxy-3,5-dichlorophenyl) Fluorene or 9,9-bis (4-glycidyloxy-3,5-dibromophenyl) Fluorene, and the like.

  Examples of the epoxy monomer having a biphenyl skeleton include 4,4'-diglycidylbiphenyl, 4,4'-diglycidyl-3,3 ', 5,5'-tetramethylbiphenyl, and the like.

  Examples of the epoxy monomer having a bi (glycidyloxyphenyl) methane skeleton include 1,1′-bi (2,7-glycidyloxynaphthyl) methane, 1,8′-bi (2,7-glycidyloxynaphthyl) methane, 1,1′-bi (3,7-glycidyloxynaphthyl) methane, 1,8′-bi (3,7-glycidyloxynaphthyl) methane, 1,1′-bi (3,5-glycidyloxynaphthyl) methane 1,8'-bi (3,5-glycidyloxynaphthyl) methane, 1,2'-bi (2,7-glycidyloxynaphthyl) methane, 1,2'-bi (3,7-glycidyloxynaphthyl) Examples include methane or 1,2′-bi (3,5-glycidyloxynaphthyl) methane.

  Examples of the epoxy monomer having a xanthene skeleton include 1,3,4,5,6,8-hexamethyl-2,7-bis-oxiranylmethoxy-9-phenyl-9H-xanthene.

  The oxetane monomer (B2) is not particularly limited as long as it has an aromatic skeleton and a weight average molecular weight of 600 or less. Specific examples of the oxetane monomer (B2) include, for example, 4,4′-bis [(3-ethyl-3-oxetanyl) methoxymethyl] biphenyl, 1,4-benzenedicarboxylic acid bis [(3-ethyl-3 -Oxetanyl) methyl] ester, 1,4-bis [(3-ethyl-3-oxetanyl) methoxymethyl] benzene, or oxetated phenol novolak. As for these oxetane monomers (B2), only 1 type may be used and 2 or more types may be used together.

  The weight average molecular weight of the said epoxy monomer (B1) and oxetane monomer (B2), ie, the weight average molecular weight of a monomer (B), is 600 or less. The minimum with a preferable weight average molecular weight of a monomer (B) is 200, and a preferable upper limit is 550. If the weight average molecular weight of the monomer (B) is too small, the volatility of the monomer (B) may be too high, and the handleability of the insulating sheet may be reduced. If the weight average molecular weight of the monomer (B) is too large, the insulating sheet may be hard and brittle, or the adhesiveness of the cured product of the insulating sheet may be reduced.

  In a total of 100% by weight of all resin components contained in the insulating sheet containing the polymer (A), the monomer (B), and the curing agent (C), the monomer (B) is 10 to 60% by weight. % In the range. The monomer (B) is preferably contained within a range of 10 to 40% by weight in a total of 100% by weight of all the resin components. The polymer (A) and the monomer (B) are each contained in an amount such that the sum of the polymer (A) and the monomer (B) is less than 100% by weight. When there is too little quantity of a monomer (B), the adhesiveness and heat resistance of the hardened | cured material of an insulating sheet may fall. When there is too much quantity of a monomer (B), the softness | flexibility of an insulating sheet may fall.

(Curing agent (C))
The curing agent (C) contained in the insulating sheet according to the present invention is a phenol resin, an acid anhydride having an aromatic skeleton or an alicyclic skeleton, a water additive thereof, or a modified product thereof. By using this hardening | curing agent (C), the hardened | cured material of the insulating sheet excellent in heat resistance, moisture resistance, and the balance of an electrical property can be obtained. A hardening | curing agent (C) may be used independently and 2 or more types may be used together.

  The phenol resin is not particularly limited. Specific examples of the phenol resin include phenol novolak, o-cresol novolak, p-cresol novolak, t-butylphenol novolak, dicyclopentadiene cresol, polyparavinylphenol, bisphenol A type novolak, xylylene modified novolak, decalin modified novolak, Examples include poly (di-o-hydroxyphenyl) methane, poly (di-m-hydroxyphenyl) methane, and poly (di-p-hydroxyphenyl) methane. Especially, since the softness | flexibility and flame retardance of an insulating sheet can be improved further, the phenol resin which has a melamine skeleton, the phenol resin which has a triazine skeleton, or the phenol resin which has an allyl group is preferable.

  Examples of commercially available phenol resins include MEH-8005, MEH-8010 and NEH-8015 manufactured by Meiwa Kasei Co., Ltd., YLH903 manufactured by Japan Epoxy Resin Co., Ltd., LA-7052, LA-7054 and LA- 7751, LA-1356 and LA-3018-50P, and PS6313 and PS6492 manufactured by Gunei Chemical Co., Ltd.

  The acid anhydride having the aromatic skeleton, its water additive or its modified product is not particularly limited. Examples of the acid anhydride having an aromatic skeleton, its water additive or its modified product include styrene / maleic anhydride copolymer, benzophenone tetracarboxylic acid anhydride, pyromellitic acid anhydride, trimellitic acid anhydride, 4, 4'-oxydiphthalic anhydride, phenylethynyl phthalic anhydride, glycerol bis (anhydrotrimellitate) monoacetate, ethylene glycol bis (anhydrotrimellitate), methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride Or trialkyltetrahydrophthalic anhydride. Of these, methyl nadic acid anhydride or trialkyltetrahydrophthalic anhydride is preferable. When methyl nadic acid anhydride or trialkyltetrahydrophthalic anhydride is used, the water resistance of the cured product of the insulating sheet can be increased.

  Examples of commercially available acid anhydrides having the above-mentioned aromatic skeleton, their water additives or their modified products include SMA Resin EF30, SMA Resin EF40, SMA Resin EF60 and SMA Resin EF80 manufactured by Sartomer Japan, and Manac Corporation. ODPA-M and PEPA, Rikagit MTA-10, Rikagit MTA-15, Rikagit TMTA, Rikagit TMEG-100, Rikagit TMEG-200, Rikagit TMEG-300, Rikagit TMEG-500, Rikagit TMEG-S, manufactured by Shin Nippon Chemical Co., Ltd. Rikagit TH, Rikagit HT-1A, Rikagit HH, Rikagit MH-700, Rikagit MT-500, Rikagit DSDA and Rikagit TDA-100, EPICLON B4400, EPIC made by Dainippon Ink and Chemicals ON B 650, and EPICLON B570, and the like.

  An acid anhydride having an alicyclic skeleton, a water additive thereof, or a modified product thereof is an acid anhydride having a polyalicyclic skeleton, an alicyclic obtained by an addition reaction of a terpene compound and maleic anhydride. An acid anhydride having a skeleton, a water additive thereof, or a modified product thereof is preferable. In this case, the flexibility, moisture resistance or adhesion of the insulating sheet can be further enhanced. Examples of the acid anhydride having an alicyclic skeleton, a water additive thereof, or a modified product thereof include methyl nadic acid anhydride, an acid anhydride having a dicyclopentadiene skeleton, or a modified product thereof.

  Commercially available products of the acid anhydride having the alicyclic skeleton, its water additive or its modified product include Rikajito HNA and Rikajito HNA-100 manufactured by Shin Nippon Rika Co., Ltd., and EpiCure YH306 manufactured by Japan Epoxy Resin Co., Ltd. YH307, epicure YH308H, epicure YH309, etc. are mentioned.

  The curing agent (C) is more preferably an acid anhydride represented by any of the following formulas (1) to (3). In this case, the flexibility, moisture resistance or adhesion of the insulating sheet can be further enhanced.

  In said formula (3), R1 and R2 show hydrogen, a C1-C5 alkyl group, or a hydroxyl group, respectively.

  In order to adjust the curing speed and the physical properties of the cured product, a curing accelerator may be used in addition to the curing agent.

  The said hardening accelerator is not specifically limited. Specific examples of the curing accelerator include, for example, tertiary amines, imidazoles, imidazolines, triazines, organophosphorus compounds, quaternary phosphonium salts, diazabicycloalkenes such as organic acid salts, organometallic compounds, Quaternary ammonium salts or metal halides can be used. Examples of the organometallic compounds include zinc octylate, tin octylate, and aluminum acetylacetone complex.

  As the above-mentioned curing accelerator, a high melting point imidazole curing accelerator, a high melting point dispersion type latent curing accelerator, a microcapsule type latent curing accelerator, an amine salt type latent curing accelerator, or a high temperature dissociation type and thermal cation A polymerization-type latent curing accelerator or the like can also be used. These hardening accelerators may be used independently and 2 or more types may be used together.

  Examples of the high melting point dispersion type latent accelerator include amine addition type accelerators in which dicyandiamide or amine is added to an epoxy monomer or the like. Examples of the microcapsule-type latent accelerator include a microcapsule-type latent accelerator in which the surface of an imidazole-based, phosphorus-based or phosphine-based accelerator is coated with a polymer. Examples of the high temperature dissociation type and thermal cationic polymerization type latent curing accelerator include Lewis acid salt or Bronsted acid salt.

  Especially, it is preferable that the said hardening accelerator is a high melting-point imidazole type hardening accelerator. When a high melting point imidazole curing accelerator is used, the reaction system can be easily controlled, and the curing speed of the insulating sheet and the physical properties of the cured product can be more easily adjusted. A high-melting-point curing accelerator having a melting point of 100 ° C. or higher is excellent in handleability. Accordingly, the melting accelerator preferably has a melting point of 100 ° C. or higher.

(Filler (D))
By including the filler (D) in the insulating sheet according to the present invention, the heat dissipation of the cured product of the insulating sheet can be enhanced.

  Moreover, since the said polymer (A) has a functional group containing the hydrogen atom which has hydrogen bonding property, the dispersibility of a filler (D) can be improved. For this reason, the dielectric breakdown characteristic and thermal conductivity of the hardened | cured material of an insulating sheet can be improved further.

  The filler (D) is not particularly limited. A filler (D) may be used independently and 2 or more types may be used together. The filler (D) is preferably at least one selected from the group consisting of alumina, boron nitride, aluminum nitride, silicon nitride, silicon carbide, zinc oxide and magnesium oxide. When these preferable fillers (D) are used, the heat dissipation of the cured product of the insulating sheet can be further enhanced.

  The filler (D) is more preferably at least one selected from the group consisting of spherical alumina, crushed alumina and spherical aluminum nitride. In this case, the heat dissipation of the cured product of the insulating sheet can be further enhanced.

  The filler (D) may be a spherical filler or a crushed filler.

  Examples of the crushed filler include crushed alumina. The crushed filler can be obtained, for example, by crushing a massive inorganic substance using a uniaxial crusher, a biaxial crusher, a hammer crusher, a ball mill, or the like. By using the crushed filler, the filler (D) in the insulating sheet is likely to be bridged or have a structure in which the filler is efficiently brought close. Therefore, the thermal conductivity of the cured product of the insulating sheet can be further enhanced. Moreover, the crushed filler is generally cheaper than a normal filler. For this reason, the cost of an insulating sheet can be reduced by using the crushed filler.

  Moreover, when the crushed filler is used, the crushed surfaces which are in contact with each other tend to strongly aggregate. For this reason, when the crushed filler is used, it is difficult to disperse the crushed filler in the insulating sheet with high density. For this reason, the handling property of the uncured insulating sheet, the dielectric breakdown characteristics and the thermal conductivity of the cured product of the insulating sheet may be deteriorated. However, by using the polymer (A) together with the crushed filler, the crushed filler can be dispersed with high density in the insulating sheet. Therefore, the handling property of the uncured insulating sheet, the dielectric breakdown characteristics and the thermal conductivity of the cured product of the insulating sheet can be improved.

  The average particle size of the crushed filler is preferably 12 μm or less. If the average particle diameter exceeds 12 μm, the crushed filler cannot be dispersed with high density in the insulating sheet, and the dielectric breakdown characteristics of the cured product of the insulating sheet may deteriorate. A preferable upper limit of the average particle diameter of the crushed filler is 10 μm, and a preferable lower limit is 1 μm. If the average particle size of the filler is too small, it may be difficult to fill the crushed filler with high density.

  The aspect ratio of the crushed filler is not particularly limited. The aspect ratio of the crushed filler is preferably in the range of 1.5-20. Fillers with an aspect ratio of less than 1.5 are relatively expensive. Therefore, the cost of the insulating sheet increases. When the aspect ratio exceeds 20, it may be difficult to fill the crushed filler.

  The aspect ratio of the crushed filler can be determined, for example, by measuring the crushed surface of the filler using a digital image analysis type particle size distribution measuring device (trade name: FPA, manufactured by Nippon Luft).

  When the said filler (D) is a spherical filler, it is preferable that the average particle diameter of a spherical filler exists in the range of 0.1-40 micrometers. When the average particle size is less than 0.1 μm, it may be difficult to fill with high density. When the average particle diameter exceeds 40 μm, the dielectric breakdown characteristics of the cured product of the insulating sheet may be deteriorated.

  The “average particle diameter” is an average particle diameter obtained from a volume average particle size distribution measurement result measured by a laser diffraction particle size distribution measuring apparatus.

  In 100% by volume of the insulating sheet, the filler (D) is preferably contained within a range of 50 to 90% by volume. When the amount of the filler (D) is less than 50% by volume, the heat dissipation of the cured product of the insulating sheet may not be sufficiently improved. When the amount of the filler (D) exceeds 90% by volume, the flexibility and adhesiveness of the insulating sheet may be significantly reduced.

(Rubber particles (E))
The insulating sheet according to the present invention preferably contains rubber particles (E).

  The rubber particles (E) are not particularly limited. As the rubber particles (E), for example, acrylic rubber, butadiene rubber, isoprene rubber, acrylonitrile butadiene rubber, styrene butadiene rubber, styrene isoprene rubber, urethane rubber, silicone rubber, fluorine rubber, natural rubber, or the like is preferably used. Especially, it is preferable that the said rubber particle (E) is silicone rubber. When silicone rubber is used, the stress relaxation property and flexibility of the cured product of the insulating sheet can be enhanced.

  When the rubber particles (E) and the filler (D) are used in combination, the coefficient of linear thermal expansion of the cured product of the insulating sheet can be lowered, and the stress relaxation ability can be expressed in the cured product. Furthermore, it becomes more difficult for the cured product to peel off, crack, or the like under high temperature or cold cycle conditions.

  The rubber particles (E) are preferably contained in the range of 0.1 to 40% by weight and more preferably in the range of 0.3 to 20% by weight in 100% by weight of the insulating sheet. preferable. If the amount of the rubber particles (E) is too small, the stress relaxation property of the cured product may not be sufficiently exhibited. When there is too much quantity of rubber particles (E), the adhesiveness of hardened | cured material may become low.

(Other ingredients)
The insulating sheet according to the present invention may contain a base material such as a glass cloth, a glass nonwoven fabric or an aramid nonwoven fabric in order to further improve handling properties. But even if it does not contain a base material, the insulating sheet of the present invention has excellent handling properties even in an uncured state at room temperature (23 ° C.). The insulating sheet preferably does not contain a base material, and more preferably does not contain glass cloth. In this invention, since each said component (A)-(D) is contained in the said specific ratio, even if it does not contain the said base material, the insulating sheet excellent in the handleability in an unhardened state is obtained. be able to. When an insulating sheet does not contain the said base material, the thickness of an insulating sheet can be made thin and the thermal conductivity of an insulating sheet can be improved further. Furthermore, when an insulating sheet does not contain the said base material, various processes, such as a laser processing or a drilling process, can also be easily performed to an insulating sheet as needed.

  Moreover, the insulating sheet of the present invention may contain a thixotropic agent, a dispersant, a flame retardant, or a colorant as necessary.

  The thixotropic agent is not particularly limited. Examples of the thixotropic agent include polyamide resin, fatty acid amide resin, polyamide resin, dioctyl phthalate resin, and the like.

  Examples of the dispersant include an anionic dispersant, a cationic dispersant, and a nonionic dispersant.

  Examples of the anionic dispersant include fatty acid soap, alkyl sulfate, sodium dialkylsulfosuccinate, sodium alkylbenzenesulfonate, and the like. Examples of the cationic dispersant include decylamine acetate, trimethylammonium chloride, and dimethyl (benzyl) ammonium chloride.

  Examples of the nonionic dispersant include polyethylene glycol ether, polyethylene glycol ester, sorbitan ester, sorbitan ester ether, monoglyceride, polyglycerin alkyl ester, fatty acid diethanolamide, alkyl polyether amine, amine oxide or ethylene glycol distearate. It is done.

  The flame retardant is not particularly limited. Examples of the flame retardant include metal oxides, phosphorus compounds, nitrogen compounds, layered double hydrates, antimony compounds, bromine compounds, or bromine-containing epoxy resins.

  Examples of the metal oxide include aluminum hydroxide, magnesium hydroxide, dawsonite, calcium aluminate, dihydrate gypsum, calcium hydroxide, and the like. Examples of the phosphorus compound include red phosphorus, ammonium polyphosphate, triphenyl phosphate, tricyclohexyl phosphate, phosphate ester, phosphorus-containing epoxy resin, phosphorus-containing phenoxy resin, or phosphorus-containing vinyl compound. Examples of the nitrogen-based compound include melamine, melamine cyanurate, melamine isocyanurate, melamine phosphate, and melamine derivatives obtained by subjecting these to surface treatment. Examples of the layered double hydrate include hydrotalcite. Examples of the antimony compounds include antimony trioxide and antimony pentoxide. Examples of the bromine-based compound include decabromodiphenyl ether or triallyl isocyanurate hexabromide. Examples of the bromine-containing epoxy resin include tetrabromobisphenol A. Among these, metal hydroxides, phosphorus compounds, bromine compounds, or melamine derivatives are preferably used.

  As the colorant, for example, carbon black, graphite, fullerene, titanium carbon, manganese dioxide, pigment or dye is used. Examples of the pigment include phthalocyanine.

(Insulating sheet)
The manufacturing method of the insulating sheet which concerns on this invention is not specifically limited. For example, an insulating sheet can be obtained by forming a mixture obtained by mixing the above-described materials into a sheet shape by a solvent casting method or an extrusion film formation method. Defoaming is preferred when forming into a sheet. Since the insulating sheet according to the present invention contains the components (A) to (D) at the specific ratio, it is excellent in handling properties in an uncured state. In addition, the insulating sheet has a self-supporting property at room temperature (23 ° C.) and is excellent in handleability.

  The film thickness of the insulating sheet is not particularly limited. The thickness of the insulating sheet is preferably in the range of 10 to 300 μm, more preferably in the range of 50 to 200 μm, and still more preferably in the range of 70 to 120 μm. If the film thickness is too thin, the insulating property may be lowered. If the film thickness is too thick, the heat dissipation may decrease when the metal body is bonded to the conductive layer.

  In particular, when the film thickness is large, the dielectric breakdown characteristics of the insulating sheet according to the present invention can be greatly enhanced. But in this invention, even if a film thickness is thin, the dielectric breakdown characteristic of an insulating sheet can fully be improved.

  Moreover, it is preferable that the glass transition temperature Tg in the uncured state of the insulating sheet which concerns on this invention is 25 degrees C or less. When the glass transition temperature exceeds 25 ° C., the glass transition temperature may be hard and brittle at room temperature, which causes a decrease in handling of the insulating sheet in an uncured state.

  The heat conductivity of the cured product of the insulating sheet is preferably 1.5 W / m · k or more. The thermal conductivity of the cured product of the insulating sheet is more preferably 2.0 W / m · k or more, and further preferably 3.0 W / m · k or more. When heat conductivity is too low, the heat dissipation of hardened | cured material may become low.

  The dielectric breakdown voltage of the cured product of the insulating sheet is preferably 30 kV / mm or more. The dielectric breakdown voltage of the cured product of the insulating sheet is more preferably 40 kV / mm or more, and further preferably 50 kV / mm or more. If the dielectric breakdown voltage is too low, the insulation may be lowered when used for large current applications such as for power devices.

The volume resistivity of the cured product of the insulating sheet is preferably 10 ¹⁴ Ω · cm or more, and more preferably 10 ¹⁶ Ω · cm or more. If the volume resistivity is too low, the insulation between the conductor layer and the heat conductor may not be maintained.

  The coefficient of thermal expansion of the cured product of the insulating sheet is preferably 30 ppm / ° C. or less, and more preferably 20 ppm / ° C. or less. If the coefficient of thermal expansion is too high, the cold cycle resistance of the cured product may deteriorate.

  The insulating sheet according to the present invention is used for bonding a heat conductor having a thermal conductivity of 10 W / m · K or more to a conductive layer. The insulating sheet according to the present invention constitutes an insulating layer of a laminated structure in which a conductive layer is laminated on at least one surface of a thermal conductor having a thermal conductivity of 10 W / m · K or more via an insulating layer. It is used suitably for.

  In the laminate according to the present invention, a thermal conductor having a thermal conductivity of 10 W / m · K or more, an insulating layer laminated on at least one surface of the thermal conductor, and a thermal conductor of the insulating layer are laminated. A conductive layer stacked on a surface opposite to the surface. The insulating layer is formed by curing an insulating sheet configured according to the present invention.

  For example, after attaching a metal body to each conductive layer such as a laminated board or multilayer wiring board provided with copper circuits on both sides, copper foil, copper plate, semiconductor element or semiconductor package via an insulating sheet, the insulating sheet The laminated structure can be obtained by curing.

  In FIG. 1, the laminated structure which concerns on one Embodiment of this invention is typically shown with a partial notch front sectional drawing.

  In the laminated structure 1 shown in FIG. 1, a heat conductor 4 is laminated on a surface 2 a of a conductive layer 2 as a heat source via an insulating layer 3. The insulating layer 3 is formed by curing the insulating sheet of the present invention. As the heat conductor 4, a heat conductor having a thermal conductivity of 10 W / m · K or more is used.

  In the laminated structure 1, since the insulating layer 3 has a high thermal conductivity, heat from the conductive layer 2 side is transmitted to the thermal conductor 4 having a thermal conductivity of 10 W / m · K or more through the insulating layer 3. Cheap. For this reason, in the laminated structure 1, heat can be efficiently dissipated by the heat conductor 4.

  The heat conductor having the heat conductivity of 10 W / m · K or more is not particularly limited. Examples of the heat conductor having a thermal conductivity of 10 W / m · K or more include aluminum, copper, alumina, beryllia, silicon carbide, silicon nitride, aluminum nitride, and graphite sheet.

  The heat conductor having a thermal conductivity of 10 W / m · K or more is preferably copper or aluminum. Copper or aluminum is excellent in heat dissipation.

  The insulating sheet according to the present invention is suitably used for bonding a heat conductor having a thermal conductivity of 10 W / m · K or more to a conductive layer of a semiconductor device in which a semiconductor element is mounted on a substrate. The insulating sheet according to the present invention is used to adhere a thermal conductor having a thermal conductivity of 10 W / m · K or more to a conductive layer of an electronic component device in which electronic component elements other than semiconductor elements are mounted on a substrate. Are also preferably used.

  When the semiconductor element is a power device element for a large current, the cured product of the insulating sheet is required to be more excellent in insulation or heat resistance. Therefore, the insulating sheet of this invention is used suitably for such a use.

  Hereinafter, the present invention will be clarified by giving specific examples and comparative examples of the present invention. The present invention is not limited to the following examples.

  The following materials were prepared.

Polymer (A)
(1) Carboxyl group-containing acrylic resin (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name: PSY-130, Mw = 30,000, Tg = 109 ° C.)
(2) Sulfonic acid group-containing styrene resin (manufactured by Nippon SC, trade name: VERSA-TL 72, Mw = 70,000, Tg = 98 ° C.)
(3) Phosphoric acid group-containing acrylic resin (synthesized in Synthesis Example 1, Mw = 12,000, Tg = 97 ° C.)

Synthesis example 1:
After adding 0.7 mol of methyl methacrylate and 0.3 mol of glycidyl methacrylate to a flask equipped with a thermometer, a stirrer, a dropping funnel and a reflux condenser, methyl ethyl ketone as a solvent and azobisisobutyroyl as a catalyst Nitrile was further added, and the mixture was stirred at 80 ° C. for 18 hours under a nitrogen atmosphere. Then, it cooled and added methyl hydroquinone as a polymerization inhibitor. 1 mol of water was added to this solution and maintained at 40 ° C., and 0.1 mol of phosphoric anhydride was gradually added while stirring. Then, it was made to react for 3 hours and the solution of the polymer containing a phosphate group was obtained.

    (4) High heat-resistant phenoxy resin (product name: FX-293, Mw = 43,700, manufactured by Toto Kasei Co., Ltd., Tg = 163 ° C.)

Polymers other than polymer (A) (1) Epoxy group-containing acrylic resin (manufactured by NOF Corporation, trade name: Marproof G-0130S, Mw = 9,000, Tg = 69 ° C.)

Epoxy monomer (B1)
(1) Bisphenol A type liquid epoxy resin (made by Japan Epoxy Resin, trade name: Epicoat 828US, Mw = 370)
(2) Bisphenol F type liquid epoxy resin (made by Japan Epoxy Resin, trade name: Epicoat 806L, Mw = 370)
(3) Trifunctional glycidyldiamine type liquid epoxy resin (manufactured by Japan Epoxy Resin Co., Ltd., trade name: Epicoat 630, Mw = 300)
(4) Fluorene skeleton epoxy resin (manufactured by Osaka Gas Chemical Co., Ltd., trade name: ONCOAT EX1011, Mw = 486)
(5) Naphthalene skeleton liquid epoxy resin (Dainippon Ink Chemical Co., Ltd., trade name: EPICLON HP-4032D, Mw = 304)

Oxetane monomer (B2)
(1) Benzene skeleton oxetane resin (manufactured by Ube Industries, trade name: etanacol OXTP, Mw = 362.4)

Monomers other than epoxy monomer (B1) and oxetane monomer (B2) (1) Hexahydrophthalic acid skeleton liquid epoxy resin (manufactured by Nippon Kayaku Co., Ltd., trade names: AK-601, Mw = 284)
(2) Bisphenol A type solid epoxy resin (product name: 1003, Mw = 1300, manufactured by Japan Epoxy Resin Co., Ltd.)

Curing agent (C)
(1) Alicyclic skeleton acid anhydride (manufactured by Shin Nippon Chemical Co., Ltd., trade name: MH-700)
(2) Aromatic skeleton acid anhydride (manufactured by Sartomer Japan, trade name: SMA resin EF60)
(3) Polyalicyclic skeleton acid anhydride (manufactured by Shin Nippon Rika Co., Ltd., trade name: HNA-100)
(4) Terpene skeleton acid anhydride (trade name: Epicure YH-306, manufactured by Japan Epoxy Resin Co., Ltd.)
(5) Biphenyl skeleton phenolic resin (Madewa Kasei Co., Ltd., trade name: MEH-7851-S)
(6) Allyl skeleton phenol resin (product name: YLH-903, manufactured by Japan Epoxy Resin Co., Ltd.)
(7) Triazine skeleton phenolic resin (Dainippon Ink Chemical Co., Ltd., trade name: Phenolite KA-7052-L2)
(8) Melamine skeleton phenol resin (manufactured by Gunei Chemical Industry Co., Ltd., trade name: PS-6492)
(9) Isocyanur-modified solid dispersion type imidazole (imidazole curing accelerator, manufactured by Shikoku Kasei Co., Ltd., trade name: 2MZA-PW)

Inorganic filler (D)
(1) Spherical alumina (Denka Co., Ltd., trade name: DAM-10, average particle size 10 μm)
(2) Crushed alumina (manufactured by Nippon Light Metal Co., Ltd., trade name: LS-242C, average particle diameter 2 μm)
(3) Boron nitride (manufactured by Showa Denko KK, trade name: UHP-1, average particle size 8 μm)
(4) Aluminum nitride (manufactured by Toyo Aluminum Co., Ltd., trade name: TOYALNITE-FLX, average particle size 14 μm)
(5) Silicon carbide (manufactured by Shinano Electric Smelting Co., Ltd., trade name: Shinano Random GP # 700, average particle size 17 μm)

Rubber particles (E)
(1) Core shell type rubber fine particles (manufactured by Mitsubishi Rayon Co., Ltd., trade name: KW4426, rubber fine particles having a shell made of methyl methacrylate and a core made of butyl acrylate, an average particle size of 5 μm)
(2) Silicone rubber fine particles (manufactured by Dow Corning Toray, trade name: Trefil E601, average particle size 2 μm)

Additives (1) Epoxysilane coupling agent (Shin-Etsu Chemical Co., Ltd., trade name: KBE403)

Solvent (1) Methyl ethyl ketone

Example 1
Using a homodisper type stirrer, each raw material was blended at a ratio shown in Table 1 below (blending unit is parts by weight) and kneaded to prepare an insulating material.

  The insulating material was applied to a release PET sheet having a thickness of 50 μm so as to have a thickness of 100 μm, and dried in an oven at 90 ° C. for 30 minutes to produce an insulating sheet on the PET sheet.

(Examples 2 to 21 and Comparative Examples 1 to 4)
An insulating material was prepared in the same manner as in Example 1 except that the type and blending amount of each raw material used were changed as shown in Tables 1 to 3 below, and an insulating sheet was produced on the PET sheet.

(Evaluation of Examples and Comparative Examples)
(1. Handling property)
A laminated sheet having a PET sheet and an insulating sheet formed on the PET sheet was cut into a size of 460 mm × 610 mm to prepare a test sample. Using this test sample, the handling property when the uncured insulating sheet was peeled from the PET sheet at room temperature (23 ° C.) was evaluated according to the following criteria.

○: The insulating sheet is not deformed and can be easily peeled. Δ: The insulating sheet can be peeled, but the sheet is stretched or broken. ×: The insulating sheet cannot be peeled (2. Thermal conductivity)
The thermal conductivity of the insulating sheet was measured using a thermal conductivity meter “Quick Thermal Conductivity Meter QTM-500” manufactured by Kyoto Electronics Industry Co., Ltd.

(3. Breakdown voltage)
The insulating sheet was cut into a size of 100 mm × 100 mm to obtain an uncured test sample. The obtained test sample was cured in a 120 ° C. oven for 1 hour and further in a 200 ° C. oven for 1 hour to produce a cured insulating sheet. Using a withstand voltage tester (MODEL7473, manufactured by EXTECH Electronics), an AC voltage was applied to the cured product of the insulating sheet so that the voltage increased at a rate of 1 kV / second. The voltage at which the cured product of the insulating sheet was broken was defined as the dielectric breakdown voltage.

(4. Solder heat resistance test)
An insulating sheet is sandwiched between an aluminum plate having a thickness of 1 mm and an electrolytic copper foil having a thickness of 35 μm, and the insulating sheet is press-cured for 1 hour at 120 ° C. and further for 1 hour at 200 ° C. while maintaining a pressure of 4 MPa with a vacuum press machine. A copper clad laminate was formed. This copper-clad laminate was cut into a size of 50 mm × 60 mm to obtain a test sample. The obtained test sample was floated in a solder bath at 288 ° C. with the copper foil side facing down, and the time until the copper foil swelled or peeled off was measured and judged according to the following criteria.

◯: No swelling or peeling even after 3 minutes △: Swelling or peeling occurred after 1 minute and before 3 minutes passed. ×: Swelling or peeling occurred before 1 minute passed. It shows in Tables 1-3.

FIG. 1 is a partially cutaway front sectional view schematically showing a laminated structure according to an embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Laminated structure 2 ... Conductive layer 2a ... Surface 3 ... Insulating layer 4 ... Thermal conductor

Claims (13)

An insulating sheet used for adhering a heat conductor having a thermal conductivity of 10 W / m · K or more to a conductive layer,
A polymer (A) having a functional group containing a hydrogen atom having hydrogen bonding properties and having a weight average molecular weight of 10,000 or more;
At least one of the epoxy monomer (B1) having an aromatic skeleton and a weight average molecular weight of 600 or less and the oxetane monomer (B2) having an aromatic skeleton and a weight average molecular weight of 600 or less (B) and
A curing agent (C) which is a phenol resin, or an acid anhydride having an aromatic skeleton or an alicyclic skeleton, a water additive thereof or a modified product thereof;
Containing filler (D),
In a total of 100% by weight of all resin components in the insulating sheet containing the polymer (A), the monomer (B), and the curing agent (C), the polymer (A) is 20 to 60% by weight. Insulating sheet characterized by containing the monomer (B) in the range of 10 to 60% by weight and the polymer (A) and the monomer (B) in a total amount of less than 100% by weight. .   The insulating sheet according to claim 1, wherein the polymer (A) has an aromatic skeleton.   The insulating sheet according to claim 1 or 2, wherein the functional group of the polymer (A) is at least one selected from the group consisting of a hydroxyl group, a phosphate group, a carboxyl group, and a sulfonate group.   The insulating sheet according to any one of claims 1 to 3, wherein a pKa of a functional group containing a hydrogen atom having hydrogen bonding property of the polymer (A) is within a range of 2 to 10.   The insulating sheet according to any one of claims 1 to 4, wherein the polymer (A) contains a phenoxy resin.   The insulating sheet according to claim 5, wherein the phenoxy resin has a glass transition temperature Tg of 95 ° C. or higher.   The curing agent (C) is an acid anhydride having a polyalicyclic skeleton, an acid anhydride having an alicyclic skeleton obtained by addition reaction of a terpene compound and maleic anhydride, a water additive thereof, or The insulating sheet according to any one of claims 1 to 6, which is a modified product thereof. The insulating sheet according to claim 7, wherein the curing agent (C) is an acid anhydride represented by any of the following formulas (1) to (3).

In said formula (3), R1 and R2 show hydrogen, a C1-C5 alkyl group, or a hydroxyl group, respectively.   The insulating sheet according to any one of claims 1 to 6, wherein the curing agent (C) is a phenol resin having a melamine skeleton or a triazine skeleton, or a phenol resin having an allyl group.   The filler (D) according to any one of claims 1 to 9, wherein the filler (D) is at least one selected from the group consisting of alumina, boron nitride, aluminum nitride, silicon nitride, silicon carbide, zinc oxide, and magnesium oxide. The insulating sheet described.   The insulating sheet according to any one of claims 1 to 10, wherein the filler (D) is at least one selected from the group consisting of spherical alumina, crushed alumina, and spherical aluminum nitride. A thermal conductor having a thermal conductivity of 10 W / m · K or more;
An insulating layer laminated on at least one surface of the thermal conductor;
A conductive layer laminated on a surface opposite to the surface on which the thermal conductor of the insulating layer is laminated,
The said insulating layer is formed by hardening the insulating sheet of any one of Claims 1-11, The laminated structure characterized by the above-mentioned.   The laminated structure according to claim 12, wherein the heat conductor is a metal.

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