TWI894455B - Maleimide resin mixture, curable resin composition, prepreg and cured article thererof - Google Patents

Abstract

A maleimide resin mixture of this invention contains a maleimide resin (A) represented by the following formula (1), and a maleimide resin (B) obtained by reacting a diamine (b), and a maleic acid anhydride.

(In the formula (1), plurality of R each independently represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. M represents an integer of 0 to 3; n is a repetition number and the average value is 1 <n <5.)

Description

Maleimide resin mixture, curable resin composition, prepreg and cured product thereof

The present invention relates to a maleimide resin mixture, a curable resin composition, a prepreg, and a cured product thereof. These materials are suitable for use in electrical and electronic components such as semiconductor packaging materials, printed wiring boards, build-up laminates, lightweight, high-strength materials such as carbon fiber reinforced plastics and glass fiber reinforced plastics, and 3D printing applications.

In recent years, the requirements for multilayer boards (PCBs) carrying electrical and electronic components have become more extensive and sophisticated as their applications have expanded. While semiconductor chips have traditionally been mounted on metal lead frames, semiconductor chips with high processing power, such as CPUs, are now more commonly mounted on multilayer boards made of polymer materials. As CPUs and other components operate at higher speeds and clock frequencies increase, signal transmission delays and losses have become increasingly important. Consequently, multilayer boards made of polymer materials are being required to have lower dielectric constants and dielectric tangents.

Furthermore, from the perspective of advancements in communications technology, the recent rise in 5G device operations has led to an explosive growth in communications devices using not only the Sub-6 band but also quasi-millimeter waves above 10 GHz, particularly above 28 GHz, and millimeter waves. This has necessitated the development of substrate materials capable of handling these high frequencies in base stations, antennas, and communications devices. High dielectric properties (particularly dielectric tangent) are crucial for these substrate materials to prevent a decrease in transmission speed, and there is a growing demand for materials that can be reliably used in these areas.

Furthermore, with the increasing prevalence of portable electronic devices such as mobile phones, precision electronic devices are being used and carried outdoors or on the human body, necessitating substrate materials with durability against external environments (particularly, resistance to heat and humidity). Furthermore, with the rapid advancement of electrification in the automotive sector, precision electronic devices are often placed near the engine, demanding even higher levels of heat and humidity resistance.

Wiring boards using BT resin, a resin comprising a bisphenol A cyanate ester compound and a bismaleimide compound disclosed in Patent Document 1, have been widely used as high-performance wiring boards due to their excellent heat resistance, chemical resistance, and dielectric properties. However, improvements are necessary to address the higher performance requirements described above.

Among these, commercially available maleimide resins offer significantly improved heat resistance compared to epoxy resins, which have been used for these applications, and exhibit excellent dielectric properties in the high-frequency range. However, these highly heat-resistant maleimide resins have the disadvantages of low moisture resistance, rigidity, and brittleness, as well as low adhesion to copper foil.

In contrast, although maleimide resins such as those described in Patents 2 and 3 have been developed, their application is still far from sufficient.

Furthermore, although a composition comprising a maleimide resin and an acrylic-containing phenolic resin has been proposed, as described in Patent Document 4, residual phenolic hydroxyl groups that do not participate in the reaction remain during the curing reaction. This results in not only insufficient dielectric properties but also high water absorption.

[Prior Art Literature]

[Patent Literature]

[Patent Document 1] Japanese Patent Publication No. 54-30440

[Patent Document 2] Japanese Patent Application Laid-Open No. 03-100016

[Patent Document 3] Japanese Patent No. 5030297

[Patent Document 4] Japanese Patent Application Laid-Open No. 04-359911

[Patent Document 5] Japanese Patent Publication No. 04-75222

[Patent Document 6] Japanese Patent Publication No. 06-37465

The present invention was developed in view of this situation, and its purpose is to provide a maleimide resin mixture, a curable resin composition, and its cured product that exhibit excellent heat resistance, mechanical properties, and dielectric properties after moisture absorption.

The inventors of the present invention have completed this invention as a result of their dedicated research to solve the above-mentioned problems. That is, this invention is related to the following [1] to [11].

[1]

A maleimide resin mixture comprises a maleimide resin (A) represented by the following formula (1) and a maleimide resin (B), wherein the maleimide resin (B) is obtained by reacting a diamine (B) with maleic anhydride;

(In formula (1), the plural Rs independently represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. m represents an integer from 0 to 3. n represents a repeated number, and its average value is 1<n<5.)

[2]

The maleimide resin mixture as described in the above item [1], wherein the component (b) is obtained by reacting a diamine (b-1) having 4 to 60 carbon atoms with a tetracarboxylic dianhydride (b-2).

[3]

The maleimide resin mixture as described in item [2] above, wherein the component (b-1) is a diamine (b-1a) derived from a dimer acid.

[4]

The maleimide resin mixture as described in the above item [2] or [3], wherein the aforementioned component (b-2) is represented by the following formula (4).

[5]

The maleimide resin mixture as described in any one of the above items [1] to [4], wherein the aforementioned component (A) is represented by the following formula (2),

(In formula (2), the plural Rs independently represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. m represents an integer from 0 to 3. n represents a repeated number, and its average value is 1<n<5.)

[6]

The maleimide resin mixture as described in any one of the above items [1] to [5], wherein the component (B) is represented by the following formula (3).

(In formula (3), ^R1 represents a divalent alkyl group (c) derived from a dimer acid, ^R2 represents a divalent organic group (d) other than a divalent alkyl group (c) derived from a dimer acid, ^R3 represents any one selected from the group consisting of a divalent alkyl group (c) derived from a dimer acid and a divalent organic group (d) other than a divalent alkyl group (c) derived from a dimer acid, ^R4 and R ^{R4 and R5} each independently represent one or more organic groups selected from a tetravalent organic group having 4 to 40 carbon atoms with a monocyclic or condensed polycyclic alicyclic structure, a tetravalent organic group having 8 to 40 carbon atoms in which alicyclic organic groups having a monocyclic structure are linked directly or via a crosslink, and a tetravalent organic group having 8 to 40 carbon atoms with a semi-alicyclic structure having both an alicyclic structure and an aromatic ring. m is an integer from 1 to 30, n is an integer from 0 to 30, and ^R4 and ^R5 may be the same or different.

[7]

The maleimide resin mixture as described in any one of the above items [1] to [6], wherein the weight ratio of the aforementioned component (A) to the aforementioned component (B) is 99/1 to 60/40.

[8]

A hardening resin composition comprising the maleimide resin mixture described in any one of items [1] to [7] above.

[9]

The maleimide resin mixture described in the previous item [8] further contains a hardening accelerator.

[10]

A prepreg comprising the maleimide resin mixture described in any one of items [1] to [7] above, or the curable resin composition described in item [8] or [9] above, retained on a sheet-like fiber substrate.

[11]

A cured product obtained by curing the maleimide resin mixture described in any one of the preceding items [1] to [7], the curable resin composition described in the preceding item [8] or [9], or the prepreg described in the preceding item [10].

The maleimide resin mixture and curable resin composition of the present invention have excellent heat resistance, mechanical properties, and dielectric properties after moisture absorption.

Figure 1 is the GPC chart of Synthesis Example 1.

Figure 2 is the GPC chart of Synthesis Example 2.

The maleimide resin mixture of the present invention contains a maleimide resin represented by the following formula (1) (hereinafter also referred to as component (A)) and a maleimide resin (B) (hereinafter also referred to as component (B), wherein the maleimide resin (B) is obtained by reacting a diamine (B) with maleic anhydride.

(In formula (1), the plural Rs independently represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. m represents an integer from 0 to 3. n represents a repeated number, and its average value is 1<n<5.)

In the aforementioned formula (1), m is usually 0 to 3, preferably 0 to 2, and more preferably 0. R is usually a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, preferably a hydrogen atom, a methyl group, or an ethyl group, and more preferably a hydrogen atom. When m is greater than 3 or when R is an alkyl group having 6 or more carbon atoms, there is a risk that the electrical properties may be reduced due to molecular vibration of the alkyl group when exposed to high frequencies.

In the above formula (1), the value of n can be obtained by measuring the number average molecular weight of the maleimide resin by gel permeation chromatography (GPC, detector: RI), or calculated from the area ratio of each separated peak.

In the above formula (1), when n=1, the solubility in the solvent is low. Moreover, when n is 5 or more, the fluidity during molding deteriorates and the properties as a cured product cannot be fully exerted.

Component (A) preferably has a molecular weight distribution. In the aforementioned formula (1), the content of the n=1 body as determined by GPC analysis (RI) is preferably 98% by volume or less, more preferably 20 to 90% by volume, even more preferably 30 to 80% by volume, and particularly preferably 40 to 80% by volume. When the content of the n=1 body is 98% by volume or less, heat resistance improves. Furthermore, crystallinity decreases, improving solvent solubility. On the other hand, when the lower limit of the n=1 body is 20% by volume or more, the viscosity of the resin solution decreases, improving impregnation properties. Furthermore, the solvent can be removed at low temperatures when the body is taken out as a solid, making self-polymerization less likely and making handling easier.

Component (A) improves solvent solubility by increasing the proportion of asymmetric structures with different orientations relative to the maleimide group, and improves dielectric properties in its cured product. The orientation ratio of the n=1 form in the aforementioned formula (1) can be determined from HPLC analysis (225nm). The ortho-para form preferably accounts for 30% by volume or more and less than 60% by volume of the total n=1 form, more preferably 35% by volume or more and less than 55% by volume, and particularly preferably 40% by volume or more and less than 55% by volume.

The softening point of component (A) is preferably 50°C to 150°C, more preferably 80°C to 120°C, even more preferably 90°C to 120°C, and particularly preferably 95°C to 120°C. Furthermore, the melt viscosity at 150°C is 0.05 to 100 Pa·s, preferably 0.1 to 40 Pa·s.

The compound represented by the aforementioned formula (1) is more preferably represented by the following formula (2). In formula (1), the crystallinity is reduced when the propyl group is substituted at the para position relative to the benzene ring not bonded to the maleimide group.

(In formula (2), the plural Rs independently represent a hydrogen atom or an alkyl group with 1 to 5 carbon atoms. m represents an integer from 0 to 3. n represents a repeated number, and its average value is 1<n<5.)

The preferred ranges of R and m in the aforementioned formula (2) are the same as those in the aforementioned formula (1).

The following describes the production method of component (A), but is not limited to this method.

[Manufacturing method of aromatic amine resin]

Component (A) can use an aromatic amine resin represented by the following formula (5) as a precursor.

(In formula (5), the plural Rs independently represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. m represents an integer from 0 to 3. n is a repeated number, and its average value is 1<n<5.)

The preferred ranges of R and m in the aforementioned formula (5) are the same as those in the aforementioned formula (1).

The method for preparing the aromatic amine resin represented by the aforementioned formula (5) is not particularly limited. For example, in Patent Document 5, aniline is reacted with m-diisopropenylbenzene or m-di(α-hydroxyisopropyl)benzene in the presence of an acidic catalyst at 180 to 250°C to obtain the n=1 isomer in the aforementioned formula (5) as the main component. The n=1 isomer includes three isomers, such as 1,3-bis(p-aminoisopropyl)benzene and 1,3-bis(o-aminoisopropyl)benzene, in which the orientation of the aniline molecules is the same, which are symmetrical structures, or 1-(o-aminoisopropyl)-3-(p-aminoisopropyl)benzene, in which the orientation of the aniline molecules is different, which are asymmetric structures. Furthermore, n=2 to 5 isomers are also produced as by-components, but in Patent 5, these are purified by crystallization to obtain 1,3-bis(p-aminoisopropyl)benzene with a purity of 98%. Furthermore, in Patent 6, 1,3-bis(p-aminoisopropyl)benzene is subjected to maleimidation to synthesize N,N'-(1,3-phenylene-di-(2,2-propylene)-di-p-phenylene)bismaleimide, resulting in a crystalline product. However, heating is required to dissolve this product in the solvent. If left at room temperature after heating, the crystals will completely precipitate after several hours. Therefore, when adjusting the resin composition, crystals may precipitate. The higher the concentration of N,N'-(1,3-phenylene-di-(2,2-propylene)-di-p-phenylene) bismaleimide, the greater the likelihood of crystallization. For printed wiring boards or composite materials, glass cloth or carbon fiber may be impregnated with the varnish to adhere to the resin. However, if crystals precipitate, the impregnation process becomes impossible. Furthermore, if the temperature is raised to maintain the dissolved state, the composition reacts too quickly, shortening the varnish's usable life.

When synthesizing the aromatic amine resin represented by the aforementioned formula (5), the acidic catalyst used can be hydrochloric acid, phosphoric acid, sulfuric acid, formic acid, zinc chloride, ferrous chloride, aluminum chloride, p-toluenesulfonic acid, methanesulfonic acid, and the like. In the present invention, protonic acids such as hydrochloric acid, p-toluenesulfonic acid, and methanesulfonic acid are preferred. These acids can be used alone or in combination of two or more. The amount of catalyst used is preferably 1 to 12 weight percent, more preferably 1 to 10 weight percent, and particularly preferably 1 to 7 weight percent relative to 100 weight percent of the aniline used. If the amount is more than 12 weight percent, the target asymmetric structure compound is less, and the compound with a symmetric structure is completed first. On the other hand, if the amount is less than 1%, not only will the reaction proceed more slowly, but the reaction may not be completed at all, which is not desirable.

The reaction can be carried out using an organic solvent such as toluene or xylene, or it can be carried out solvent-free. For example, after adding an acidic catalyst to a mixed solution of aniline and solvent, if the catalyst contains water, it is preferably removed from the system by azeotropy. Then, diisopropenylbenzene or di(α-hydroxyisopropyl)benzene is added. The temperature is then raised while the solvent is removed from the system, allowing the reaction to proceed at 140 to 190°C, preferably 160 to 190°C, for 5 to 50 hours, preferably 5 to 30 hours. If the reaction temperature is too high, the asymmetric structure will form and then bond, and the symmetric structure will complete first, preventing the desired solvent solubility and electrical properties from being fully realized. When using di(α-hydroxyisopropyl)benzene, water is produced as a byproduct. Therefore, it is removed from the system while azeotropically coexisting with the solvent during heating. After the reaction is terminated, the acidic catalyst is neutralized with an alkaline aqueous solution. A non-water-soluble organic solvent is then added to the oil layer and washed repeatedly with water until the wastewater is neutral. The solvent and excess aniline derivatives are then removed under heating and reduced pressure. When using activated clay or ion exchange resin, the catalyst is removed by filtering the reaction solution after the reaction is terminated.

Furthermore, since phenylamine may be produced as a byproduct depending on the reaction temperature and the type of catalyst, it is best removed as needed. Under high temperature/high vacuum conditions, or by using steam distillation, diphenylamine derivatives are removed to a concentration below 1 wt%, preferably below 0.5 wt%, and even more preferably below 0.2 wt%.

Furthermore, the compound represented by the aforementioned formula (5) is more preferably a structure represented by the following formula (5-a).

(In formula (5-a), plural Rs independently represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. m represents an integer from 0 to 3. n represents a repeated number, and its average value is 1<n<5.)

The preferred ranges of R and m in the aforementioned formula (5-a) are the same as those in the aforementioned formula (1).

[Manufacturing method of maleimide resin]

Component (A) is obtained by subjecting the aromatic amine resin represented by the aforementioned formula (5) obtained by the above steps to an addition reaction or a dehydration condensation reaction with maleic acid or maleic anhydride (hereinafter also referred to as "maleic anhydride") in the presence of a solvent and a catalyst.

The solvent used in the reaction must be able to remove the water generated during the reaction from the system, so it is best to use a water-insoluble solvent. Examples include aromatic solvents such as toluene and xylene, aliphatic solvents such as cyclohexane and n-hexane, ethers such as diethyl ether and diisopropyl ether, ester solvents such as ethyl acetate and butyl acetate, and ketone solvents such as methyl isobutyl ketone and cyclopentanone. However, the solvent is not limited to these solvents and two or more solvents may be used in combination.

In addition to the aforementioned water-insoluble solvents, aprotic polar solvents may also be used in combination. Examples include dimethylsulfonium, dimethylsulfoxide, dimethylformamide, dimethylacetamide, 1,3-dimethyl-2-imidazolidinedione, and N-methyl-2-pyrrolidone. Two or more aprotic polar solvents may be used in combination. When using an aprotic polar solvent, it is preferred that one have a higher boiling point than the water-insoluble solvent used in combination.

The catalyst used in the reaction is an acidic catalyst, and is not particularly limited. Examples include p-toluenesulfonic acid, hydroxy-p-toluenesulfonic acid, methanesulfonic acid, sulfuric acid, and phosphoric acid. The amount of the acid catalyst used is typically 0.1 to 10% by weight, preferably 1 to 5% by weight, relative to the aromatic amine resin.

For example, the aromatic amine resin represented by the above formula (5) is dissolved in toluene and N-methyl-2-pyrrolidone, maleic anhydride is added thereto to generate acylamine, and then p-toluenesulfonic acid is added, and the reaction is carried out while removing the generated water from the system under reflux conditions.

Alternatively, maleic acid is dissolved in toluene, and a solution of the aromatic amine resin represented by the aforementioned formula (5) in N-methyl-2-pyrrolidone is added under stirring to generate acylamine. Subsequently, p-toluenesulfonic acid is added, and the reaction is carried out under reflux conditions while removing the generated water from the system.

Alternatively, maleic anhydride is dissolved in toluene, p-toluenesulfonic acid is added, and while stirring/refluxing, a solution of the aromatic amine resin represented by formula (5) in N-methyl-2-pyrrolidone is added dropwise, while azeotropic distillation is performed midway, the water is removed from the system, and the toluene is returned to the system to react (the above is the first stage reaction).

In either method, maleic anhydride is generally used in an amount of 1.0 to 3.0 equivalents, preferably 1.2 to 2.0 equivalents, relative to the amino groups of the aromatic amine resin represented by formula (5).

To reduce the amount of unclosed acylamine, water is added to the reaction solution after the maleimidization reaction described above, and the solution is separated into a resin solution layer and an aqueous layer. Excess maleic acid or maleic anhydride, aprotic polar solvent, and catalyst are dissolved in the aqueous layer and are removed by separation. The same operation is repeated to completely remove the excess maleic acid or maleic anhydride, aprotic polar solvent, and catalyst. After removing excess maleic acid or maleic anhydride, aprotic polar solvent, and catalyst from the organic layer of the maleimide resin solution, the catalyst is added again and the residual amide undergoes a dehydration and ring-closure reaction under heating and reflux conditions. This yields a maleimide resin solution with a low acid value (the above is the second-stage reaction).

The dehydration and ring-closure reaction typically lasts 1 to 5 hours, preferably 1 to 3 hours. The aforementioned aprotic polar solvent may be added as needed. After the reaction is complete, the solution is cooled and repeatedly washed with water until the wash water becomes neutral. Azeotropic dehydration is then performed under heating and reduced pressure. After removing the water, the solvent can be distilled off or additional solvent can be added to adjust the resin solution to the desired concentration. Alternatively, the solvent can be completely distilled off to remove the resin as a solid component.

Next, let’s explain ingredient (B).

Component (B) can be obtained by reacting diamine (b) with maleic anhydride.

Component (b) may include linear or branched aliphatic diamines, aliphatic ether diamines, cyclic aliphatic diamines, or aromatic diamines. A single diamine may be used, or two or more types may be used.

Examples of the linear or branched aliphatic diamines include 1,4-butanediamine, 1,6-hexanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine, 1,11-undecanediamine, 1,12-dodecanediamine, 1,14-tetradecanediamine, 1,16-hexadecanediamine, 1,18-octadecanediamine, 1,20-eicosanediamine, 2-methyl-1,8-octanediamine, 2-methyl-1,9-nonanediamine, and 2,7-dimethyl-1,8-octanediamine. Furthermore, from the perspective of obtaining a cured product with a lower tensile modulus, the diamine preferably has 6 to 60 carbon atoms, and diamines derived from dimer acids are more preferred.

Examples of the above-mentioned aliphatic ether diamines include 2,2'-oxybis(ethylamine), 3,3'-oxybis(propylamine), and 1,2-bis(2-aminoethoxy)ethane.

Examples of the above-mentioned cyclic aliphatic diamines include 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 1,4-diaminocyclohexane, methylcyclohexanediamine, and isophoronediamine.

Examples of the aromatic diamines include 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(aminomethyl)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene, 1,4-diaminobenzene, 1,3-diaminobenzene, 2,4-diaminotoluene, 4,4'-diaminodiphenylmethane; 4,4'-diaminodiphenylsulfone; 3,3'-diaminodiphenylsulfone; 4,4-diaminobenzophenone; 4,4-diaminodiphenylsulfide; and 2,2-bis[4-(4-aminophenoxy)phenyl]propane.

More preferably, component (b) is obtained by reacting a diamine (b-1) having 4 to 60 carbon atoms with a tetracarboxylic dianhydride (b-2). Component (b-1) is particularly preferably a diamine (b-1a) derived from a dimer acid. In this case, component (B) can be obtained by reacting the diamine (b-1a) derived from a dimer acid with tetracarboxylic dianhydride (b-2) and maleic anhydride. Component (B) has a divalent alkyl group (c) derived from the dimer acid bonded to a cyclic imide.

The aforementioned divalent alkyl group (c) derived from the dimer acid refers to a divalent residue formed by removing two carboxyl groups from the dicarboxylic acid contained in the dimer acid. In the present invention, such a divalent alkyl group (c) derived from the dimer acid can be exemplified by diamine (b-1a) obtained by replacing the two carboxyl groups of the dicarboxylic acid contained in the dimer acid with amino groups, which reacts with tetracarboxylic dianhydride (b-2) and maleic anhydride described below to form an imide bond, thereby allowing the diamine to be incorporated into the maleimide resin.

In the present invention, the dimer acid is preferably a dicarboxylic acid having 20 to 60 carbon atoms. Specific examples of the dimer acid include those obtained by dimerizing unsaturated carboxylic acids such as linoleic acid, oleic acid, and linolenic acid, followed by distillation purification. The dimer acid in the above-mentioned specific examples mainly contains a dicarboxylic acid having 36 carbon atoms, and generally contains a tricarboxylic acid having 54 carbon atoms at a limit of approximately 5% by mass, and a monocarboxylic acid at a limit of approximately 5% by mass. The diamine (b-1a) derived from the dimer acid in the present invention (hereinafter referred to as the dimer acid-derived diamine (b-1a) as the case may be) is a diamine obtained by replacing two carboxyl groups of each dicarboxylic acid contained in the dimer acid with amino groups, and is generally a mixture. In the present invention, examples of such diamines (b-1a) derived from dimer acids include diamines such as [3,4-bis(1-aminoheptyl)6-hexyl-5-(1-octenyl)]cyclohexane, or diamines obtained by further hydrogenating such diamines to saturate unsaturated bonds.

The divalent alkyl group (c) derived from dimer acid introduced into the maleimide resin of the present invention using such a dimer acid-derived diamine (b-1a) is preferably a residue obtained by removing two amino groups from the dimer acid-derived diamine (b-1a). Furthermore, when the maleimide resin (B) of the present invention is obtained using the dimer acid-derived diamine (b-1a), the dimer acid-derived diamine (b-1a) may be used alone or in combination of two or more types having different compositions. For example, commercially available products such as "PRIAMINE 1074" (manufactured by CRODA JAPAN Co., Ltd.) can be used as such a dimer acid-derived diamine (b-1a).

In the present invention, the tetracarboxylic dianhydride (b-2) has an alicyclic structure adjacent to the anhydride group. When the maleimide resin is formed after the reaction, the imide ring-bonding site is the tetracarboxylic dianhydride having an alicyclic structure. If the imide ring-bonding site is an alicyclic structure, other structures may contain aromatic rings.

In the present invention, component (B) is preferably represented by the following formula (3): In the following formula (3), ^R4 and ^R5 are derived from the structure of tetracarboxylic dianhydride (b-2).

(In formula (3), ^R1 represents a divalent alkyl group (c) derived from a dimer acid, ^R2 represents a divalent organic group (d) other than a divalent alkyl group (c) derived from a dimer acid, ^R3 represents any one selected from the group consisting of a divalent alkyl group (c) derived from a dimer acid and a divalent organic group (d) other than a divalent alkyl group (c) derived from a dimer acid, ^R4 and R ^{R and R} each independently represent one or more organic groups selected from a tetravalent organic group having 4 to 40 carbon atoms (preferably 6 to 40 carbon atoms) with a monocyclic or condensed polycyclic alicyclic structure, a tetravalent organic group having 8 to 40 carbon atoms in which organic groups having a monocyclic alicyclic structure are linked directly or via a crosslink, and a tetravalent organic group having 8 to 40 carbon atoms with a semi-alicyclic structure having both an alicyclic structure and an aromatic ring. m is an integer from 1 to 30, n is an integer from 0 to 30, and ^R and ^R may be the same or different.

In the present invention, the tetracarboxylic dianhydride (b-2) is preferably a tetracarboxylic dianhydride (b-2) having an alicyclic structure represented by the following formula (6). The tetracarboxylic dianhydride (b-2) having an alicyclic structure represented by the following formula (6) has an alicyclic structure adjacent to an anhydride group.

(In formula (6), Cy is a tetravalent organic group containing 4 to 40 carbon atoms and including a cyclic ring. The organic group may also include an aromatic ring.)

Specifically, the tetracarboxylic dianhydride (b-2) having an alicyclic structure represented by the above formula (6) can be represented by the following formula (6-a).

(In formula (6-a), ^R6 is a tetravalent organic group having 4 to 40 carbon atoms and containing a cyclic ring. The organic group may also contain an aromatic ring.)

In the present invention, the tetracarboxylic dianhydride (b-2) is preferably a tetracarboxylic dianhydride (b-2) having an alicyclic structure represented by the following formulas (7-1) to (7-11). The tetracarboxylic dianhydride (b-2) represented by formulas (7-1) to (7-11) has a structure including: a tetravalent organic group having 4 to 40 carbon atoms (preferably 6 to 40 carbon atoms) with a monocyclic or condensed polycyclic alicyclic structure, a tetravalent organic group having 8 to 40 carbon atoms in which organic groups having a monocyclic alicyclic structure are linked directly or via a cross-linking structure, or a tetravalent organic group having 8 to 40 carbon atoms with a semi-alicyclic structure having both an alicyclic structure and an aromatic ring.

(In formula (7-4), _X1 is a direct bond, an oxygen atom, a sulfur atom, a sulfonyl group, or a divalent organic group having 1 to 3 carbon atoms. In formula (7-6), _X2 is a direct bond, an oxygen atom, a sulfur atom, a sulfonyl group, a divalent organic group having 1 to 3 carbon atoms, or an aryl group.)

The tetracarboxylic dianhydride (b-2) having an alicyclic structure represented by the above formulas (7-1) to (7-11) can be specifically represented by the following formulas (7-1a) to (7-11a).

(In formula (7-4a), _X1 is a direct bond, an oxygen atom, a sulfur atom, a sulfonyl group, or a divalent organic group having 1 to 3 carbon atoms. In formula (7-6a), _X2 is a direct bond, an oxygen atom, a sulfur atom, a sulfonyl group, a divalent organic group having 1 to 3 carbon atoms, or an aryl group.)

The tetracarboxylic dianhydride (b-2) used in the present invention is a tetravalent organic group having 4 to 40 carbon atoms (preferably 6 to 40 carbon atoms) with a monocyclic or condensed polycyclic alicyclic structure, a tetravalent organic group having 8 to 40 carbon atoms in which organic groups having a monocyclic alicyclic structure are linked directly or via a crosslinking structure, or a tetravalent organic group having 8 to 40 carbon atoms with a semi-alicyclic structure having both an alicyclic structure and an aromatic ring. Specific examples of the tetracarboxylic dianhydride (b-2) having an alicyclic structure include 1,2,3,4-cyclobutanetetracarboxylic dianhydride (CBDA), 1,2-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride (H-PMDA), 1,1'-bicyclohexane-3,3',4,4'-tetracarboxylic acid-3,4:3',4'-dianhydride (H-BPDA), 4-(2,5-dioxotetrahydrofuran-3-yl)-1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic dianhydride, 5-( Various alicyclic tetracarboxylic dianhydrides such as 2,5-dihydrofuryl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, 2,3,4,5-tetrahydrofurantetracarboxylic dianhydride, and 3,5,6-tricarboxy-2-norbornaneacetic dianhydride, or compounds in which the aromatic rings of these are substituted with alkyl groups or halogen atoms; various semi-alicyclic tetracarboxylic dianhydrides such as 1,3,3a,4,5,9b-hexahydro-5(tetrahydro-2,5-dihydrofuryl)naphtho[1,2-c]furan-1,3-dione, or compounds in which the hydrogen atoms of the aromatic rings of these are substituted with alkyl groups or halogen atoms.

In the present invention, the tetracarboxylic dianhydride (b-2) is preferably a tetracarboxylic dianhydride (b-2) having an alicyclic structure represented by the following formula (8).

In the present invention, the tetracarboxylic dianhydride (b-2) is preferably a tetracarboxylic dianhydride (b-2) having an alicyclic structure represented by the following formula (4).

In the present invention, tetracarboxylic dianhydride (b-2) is a tetracarboxylic dianhydride (b-2) having an alicyclic structure represented by the following formula (9).

In the present invention, tetracarboxylic dianhydride (b-2) is a tetracarboxylic dianhydride (b-2) having an alicyclic structure represented by the following formula (10).

In the present invention, in addition to the tetracarboxylic dianhydride (b-2) having an alicyclic structure, an acid dianhydride without an alicyclic structure or an acid dianhydride containing an aromatic ring adjacent to the anhydride group may be added. The lower limit of the tetracarboxylic dianhydride (b-2) content in the total amount of the acid dianhydride is preferably 40 mol% or greater, more preferably 80 mol% or greater, and particularly preferably 90 mol% or greater. The upper limit may be 100 mol% or less. If the content of the tetracarboxylic dianhydride (b-2) in the total amount of the acid dianhydride is less than 40 mol%, there is a risk of increased aromatic ring structure and decreased dielectric properties.

Specific examples of the acid dianhydride containing an aromatic ring adjacent to the anhydride group other than the tetracarboxylic dianhydride (b-2) include pyromellitic dianhydride, 4,4'-oxydiphthalic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,3,3',4'-biphenyltetracarboxylic dianhydride, 2,2',3,3'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 2,2',3,3'-benzophenonetetracarboxylic dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, 2,2-bis(2,3-dicarboxyphenyl)propane dianhydride, 1,1-bis(3,4-dicarboxyphenyl)ethane dianhydride, 1,1-bis(3,4-dicarboxyphenyl)ethane dianhydride, Aromatic tetracarboxylic dianhydrides such as (2,3-dicarboxyphenyl)ethane dianhydride, bis(3,4-dicarboxyphenyl)methane dianhydride, bis(2,3-dicarboxyphenyl)methane dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 2,3,5,6-pyridinetetracarboxylic dianhydride, and 3,4,9,10-perylenetetracarboxylic dianhydride; or aromatic acid dianhydrides such as bis(3,4-dicarboxyphenyl)sulfonium dianhydride, bis(3,4-dicarboxyphenyl)ether dianhydride, and 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride, or compounds in which the aromatic ring of these compounds is substituted with an alkyl group or a halogen atom; and acid dianhydrides having an amide group. These can be used in combination with two or more acid dianhydrides having an alicyclic structure with 4 to 40 carbon atoms or a half-alicyclic structure.

The component (b-1) is not limited to the dimer acid-derived diamine (b-1a). It may be a maleimide resin obtained by reacting a diamine (b-1b) other than the dimer acid-derived diamine (b-1a), the tetracarboxylic dianhydride (b-2), and maleic anhydride. Furthermore, it may be a maleimide resin obtained by reacting the dimer acid-derived diamine (b-1a), a diamine (b-1b) other than the dimer acid-derived diamine (b-1a), the tetracarboxylic dianhydride (b-2), and maleic anhydride. By copolymerizing a diamine (b-1b) other than the dimer acid-derived diamine (b-1a), it is possible to control desired physical properties of the resulting cured product, such as further reducing the tensile modulus of elasticity.

The so-called diamine (b-1b) other than the aforementioned diamine (b-1a) derived from dimer acid (hereinafter referred to as simply diamine (b-1b) depending on the circumstances) refers to a diamine other than the diamine contained in the aforementioned diamine (b-1a) derived from dimer acid in the present invention. Such diamine (b-1b) is not particularly limited, and examples thereof include aliphatic diamines such as 1,6-hexamethylenediamine; alicyclic diamines such as 1,4-diaminocyclohexane and 1,3-bis(aminomethyl)cyclohexane; 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(aminomethyl)benzene, 1,3-bis(4-aminophenoxy)benzene; Aromatic diamines such as benzene, 1,3-bis(3-aminophenoxy)benzene, 1,4-diaminobenzene, 1,3-diaminobenzene, 2,4-diaminotoluene, and 4,4'-diaminodiphenylmethane; 4,4'-diaminodiphenylsulfone; 3,3'-diaminodiphenylsulfone; 4,4'-diaminobenzophenone; 4,4'-diaminodiphenylsulfide; and 2,2-bis[4-(4-aminophenoxy)phenyl]propane. Among these, from the perspective of obtaining a cured product with a lower tensile modulus, more preferred are aliphatic diamines having 6 to 12 carbon atoms, such as 1,6-hexamethylenediamine; diaminocyclohexanes, such as 1,4-diaminocyclohexane; and aromatic diamines having an aliphatic structure having 1 to 4 carbon atoms in the aromatic skeleton, such as 2,2-bis[4-(4-aminophenoxy)phenyl]propane. Furthermore, when using these diamines (b-1b) to obtain the maleimide resin (B) of the present invention, one of these diamines (b-1b) may be used alone, or two or more may be used in combination.

The method for reacting the aforementioned diamine (b-1a) derived from a dimer acid, the aforementioned tetracarboxylic dianhydride having an alicyclic structure (b-2), and the aforementioned maleic anhydride, or the method for reacting the aforementioned diamine (b-1a) derived from a dimer acid, the aforementioned diamine (b-1b), the aforementioned tetracarboxylic dianhydride having an alicyclic structure (b-2), and the aforementioned maleic anhydride, is not particularly limited, and any suitable known method can be employed. For example, first, the aforementioned diamine (b-1a) derived from the dimer acid, the aforementioned tetracarboxylic dianhydride (b-2), and, if necessary, the aforementioned diamine (b-1b) are stirred in a solvent such as toluene, xylene, tetrahydronaphthalene, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, or a mixed solvent thereof at room temperature (approximately 23° C.) for 30 to 60 minutes to synthesize polyamine. Then, maleic anhydride is added to the obtained polyamine, and the mixture is stirred at room temperature (approximately 23° C.) for 30 to 60 minutes to synthesize a polyamine having maleic acid added to both ends. A solvent that forms an azeotropic mixture with water, such as toluene, is added to the polyamic acid. The mixture is then refluxed at 100 to 160°C for 3 to 6 hours while removing the water produced by the imidization reaction. The desired maleimide resin can be obtained. A catalyst such as pyridine or methanesulfonic acid can also be added to this method.

The mixing ratio of the raw materials in the aforementioned reaction is preferably such that the total molar number of all diamines contained in the diamine (b-1a) derived from the dimer acid and the diamine (b-1b)): (the total molar number of the alicyclic tetracarboxylic dianhydride (b-2) + 1/2 of the molar number of maleic anhydride) is 1:1. Furthermore, when the aforementioned diamine (b-1b) is used in combination, the ratio (molar number of diamine (b-1b))/(molar number of all diamines contained in the diamine (b-1a) derived from the dimer acid) is preferably 1 or less, and more preferably 0.4 or less, from the perspective of promoting the softness derived from the dimer acid and tending to produce a cured product with a lower modulus of elasticity. When the aforementioned diamine (b-1b) is used in combination, the polymerization of the amide units composed of the diamine (b-1a) derived from the dimer acid and the tetracarboxylic dianhydride (b-2) having an alicyclic structure, and the amide units composed of the diamine (b-1b) and the tetracarboxylic dianhydride (b-2) having an alicyclic structure, can be either random polymerization or block polymerization.

The component (B) obtained in this manner is preferably represented by the following formula (3).

(In formula (3), ^R1 represents a divalent alkyl group (c) derived from a dimer acid, ^R2 represents a divalent organic group (d) other than a divalent alkyl group (c) derived from a dimer acid, ^R3 represents any one selected from the group consisting of a divalent alkyl group (c) derived from a dimer acid and a divalent organic group (d) other than a divalent alkyl group (c) derived from a dimer acid, ^R4 and R ^{R4 and R5} each independently represent one or more organic groups selected from a tetravalent organic group having 4 to 40 carbon atoms with a monocyclic or condensed polycyclic alicyclic structure, a tetravalent organic group having 8 to 40 carbon atoms in which alicyclic organic groups having a monocyclic structure are linked directly or via a crosslink, and a tetravalent organic group having 8 to 40 carbon atoms with a semi-alicyclic structure having both an alicyclic structure and an aromatic ring. m is an integer from 1 to 30, n is an integer from 0 to 30, and ^R4 and ^R5 may be the same or different.

The aforementioned divalent alkyl group (c) derived from the dimer acid in the aforementioned formula (3) is as described above. Furthermore, in the present invention, the divalent organic group (d) other than the divalent alkyl group (c) derived from the dimer acid in the aforementioned formula (2) refers to a divalent residue obtained by removing two amino groups from the aforementioned diamine (b-1b). However, in the same compound, the aforementioned divalent alkyl group (c) derived from the dimer acid and the aforementioned divalent organic group (d) are different. Furthermore, the aforementioned tetravalent organic group in the aforementioned formula (2) refers to a tetravalent residue obtained by removing two groups represented by -CO-O-CO- from the aforementioned tetracarboxylic dianhydride.

In the aforementioned formula (3), m represents the number of repeating units containing the aforementioned divalent alkyl group (c) derived from the dimer acid (hereinafter, referred to as the dimer acid-derived structure, as the case may be), and represents an integer from 1 to 30. When the value of m exceeds the aforementioned upper limit, the solubility in the solvent decreases, and in particular, the solubility in the developer during development described below tends to decrease. Furthermore, from the perspective of ensuring appropriate solubility in the developer during development, the value of m is particularly preferably 3 to 10.

In the aforementioned formula (3), n represents the number of repeating units comprising the aforementioned divalent organic group (d) (hereinafter, referred to as a structure derived from an organic diamine, as the case may be), and is an integer from 0 to 30. When the value of n exceeds the aforementioned upper limit, the flexibility of the resulting cured product deteriorates, and there is a tendency for the cured product to become a hard and brittle resin. Furthermore, from the perspective of the tendency to obtain a cured product with a low modulus of elasticity, a value of n of 0 to 10 is particularly preferred.

Furthermore, when m in the aforementioned formula (3) is 2 or greater, R ¹ and R ⁴ may be the same or different between each repeating unit. Furthermore, when n in the aforementioned formula (3) is 2 or greater, R ² and R ⁵ may be the same or different between each repeating unit. Furthermore, in the maleimide resin represented by the aforementioned formula (3), the dimer acid-derived structure and the organic diamine-derived structure may be random or block-form.

When the maleimide resin (B) of the present invention is obtained from the dimer acid-derived diamine (b-1a), maleic anhydride, tetracarboxylic dianhydride (b-2), and, if necessary, the aforementioned organic diamine (f), and the reaction rate is 100%, n and m can be represented by the mixed molar ratio of all diamines contained in the dimer acid-derived diamine (b-1a), the diamine (b-1b), maleic anhydride, and the tetracarboxylic dianhydride (b-2). That is, (m+n):(m+n+2) is expressed as (the total molar number of all diamines contained in the diamine (b-1a) derived from the dimer acid and the diamine (b-1b)):(the total molar number of maleic anhydride and tetracarboxylic dianhydride (b-2)), m:n is expressed as (the molar number of all diamines contained in the diamine (b-1a) derived from the dimer acid):(the molar number of diamine (b-1b)), and 2:(m+n) is expressed as (the molar number of maleic anhydride):(the molar number of tetracarboxylic dianhydride (b-2)).

Furthermore, in component (B), the sum of m and n (m+n) is preferably 2 to 30, from the perspective of obtaining a cured product with a lower modulus of elasticity. Furthermore, from the perspective of developing the softness derived from the dimer acid and obtaining a cured product with a lower modulus of elasticity, the ratio of m to n (n/m) is preferably 1 or less, and more preferably 0.4 or less.

The curable resin composition of the present invention may use component (B) alone or in combination of two or more.

The weight ratio of component (A) to component (B) in the curable resin composition of the present invention is preferably 99/1 to 60/40, more preferably 97/3 to 60/40, and even more preferably 95/5 to 70/30. When the weight ratio of component (B) is 1 or greater, water absorption properties are improved. On the other hand, when the weight ratio of component (B) is 40 or less, heat resistance is improved.

In addition to components (A) and (B) of the curable resin composition of the present invention, any known resin material may be used. Specifically, phenolic resins, epoxy resins, amine resins, reactive olefin-containing resins, isocyanate resins, polyamide resins, polyimide resins, cyanate resins, acrylic resins, methallyl resins, and reactive ester resins may be used. A single type or a combination of multiple types may be used. Furthermore, maleimide resins may be used in addition to components (A) and (B).

Phenolic resins, epoxy resins, amine resins, active olefin-containing resins, isocyanate resins, polyamide resins, polyimide resins, cyanate resins, and active ester resins are exemplified below, but are not limited thereto.

Phenolic resins: Polycondensates of phenols (phenol, alkyl-substituted phenols, aromatic-substituted phenols, hydroquinone, m-xylenol, naphthol, alkyl-substituted naphthols, dihydroxybenzene, alkyl-substituted dihydroxybenzene, dihydroxynaphthalene, etc.) and various aldehydes (formaldehyde, acetaldehyde, alkyl aldehydes, benzaldehyde, alkyl-substituted benzaldehydes, hydroxybenzenealdehyde, naphthaldehyde, glutaraldehyde, phthalaldehyde, crotonaldehyde, cinnamaldehyde, furfural, etc.), phenols and various diene compounds (dicyclopentadiene, terpenes, vinylcyclohexene, norbatadiene, vinylnorbatene, tetrahydroindene, divinylbenzene, divinylbiphenyl, diisopropylbiphenyl Polymers of phenols (such as butylene, butadiene, isoprene, etc.), condensates of phenols and ketones (such as acetone, methyl ethyl ketone, methyl isobutyl ketone, acetobenzene, and benzophenone), phenolic resins obtained by the condensation of phenols and substituted biphenyls (such as 4,4'-bis(chloromethyl)-1,1'-biphenyl and 4,4'-bis(methoxymethyl)-1,1'-biphenyl) or substituted phenyls (such as 1,4-bis(chloromethyl)benzene, 1,4-bis(methoxymethyl)benzene, and 1,4-bis(hydroxymethyl)benzene), condensates of bisphenols and various aldehydes, and polyphenylene ethers.

Epoxy resins: Glycidyl ether epoxy resins obtained by glycidylating the aforementioned phenolic resins and alcohols, aliphatic epoxy resins represented by 4-vinyl-1-cyclohexene diepoxide or 3,4-epoxycyclohexylmethyl-3,4'-epoxycyclohexanecarboxyl, glycidylamine epoxy resins represented by tetraglycidyldiaminodiphenylmethane (TGDDM) or triglycidyl-p-aminophenol, and glycidyl ester epoxy resins.

Amine resins: diaminodiphenylmethane, diaminodiphenylsulfone, isophoronediamine, naphthalene diamine, aniline novolac, o-ethylaniline novolac, aniline resins obtained by the reaction of aniline and xylene chloride, aniline described in Japanese Patent No. 6429862 and substituted biphenyls (such as 4,4'-bis(chloromethyl)-1,1'-biphenyl and 4,4'-bis(methoxymethyl)-1,1'-biphenyl), or substituted phenyls (such as 1,4-bis(chloromethyl)benzene, 1,4-bis(methoxymethyl)benzene, and 1,4-bis(hydroxymethyl)benzene).

Resins containing active olefins: polycondensates of the aforementioned phenolic resins and halogen compounds containing active olefins (chloromethylstyrene, allyl chloride, methylallyl chloride, acrylyl chloride, allyl chloride, etc.), polycondensates of phenols containing active olefins (2-allylphenol, 2-propenylphenol, 4-allylphenol, 4-propenylphenol, clove oil, isocarpus oil, etc.) and halogen compounds (4,4'-bis(methoxymethyl)-1,1'-biphenyl, 1,4-bis(chloromethyl)benzene, 4,4'-difluorobenzophenone, 4,4'-dichlorobenzophenone, 4,4'-dibromobenzophenone, cyanuric chloride, etc.), epoxy resins or alcohols and substituted or unsubstituted propylene Polycondensates of acid esters (acrylates, methacrylates, etc.), maleimide resins (4,4'-diphenylmethane dimaleimide, polyphenylmethane maleimide, m-phenylene dimaleimide, 2,2'-bis[4-(4-maleimidephenoxy)phenyl]propane, 3,3'-dimethyl-5,5' -Diethyl-4,4'-diphenylmethane bismaleimide, 4-methyl-1,3-phenylene bismaleimide, 4,4'-diphenyl ether bismaleimide, 4,4'-diphenylsulfone bismaleimide, 1,3-bis(3-maleimidophenoxy)benzene, 1,3-bis(4-maleimidophenoxy)benzene).

Isocyanate resins: aromatic diisocyanates such as p-phenylene diisocyanate, m-phenylene diisocyanate, p-xylene diisocyanate, m-xylene diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, and naphthalene diisocyanate; isophorone diisocyanate, hexamethylene diisocyanate, and 4,4'-dicyclohexylmethane Aliphatic or alicyclic diisocyanates such as diisocyanates, hydroxylene diisocyanate, norbornyl diisocyanate, and lysine diisocyanate; polyisocyanates such as biuret forms of one or more isocyanate monomers, or trimerized isocyanates of the above diisocyanate compounds; and polyisocyanates obtained by the urethanization reaction of the above isocyanate compounds with polyol compounds.

Polyamide resin: selected from amino acids (6-aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, p-aminomethylbenzoic acid, etc.), lactamides (ε-caprolactam, ω-undecanolactam, ω-laurolactam), and diamines (ethylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decanediamine, undecanediamine, dodecanediamine, tridecanediamine, tetradecanediamine, pentadecanediamine, hexadecanediamine, heptadecanediamine, octadecanediamine, nonadecanediamine, eicosanediamine, 2-methyl-1,5-diaminopentane, 2-methyl-1,8-diaminooctane Polymers with one or more of a mixture of dicarboxylic acids (aliphatic diamines such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, etc.; aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, 2-chloroterephthalic acid, 2-methylterephthalic acid, 5-methylisophthalic acid, 5-sodiumsulfisophthalic acid, hexahydroterephthalic acid, hexahydroisophthalic acid, etc.; alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid; dialkyl esters and dichlorides of these dicarboxylic acids) as the main raw materials.

Polyimide resin: the aforementioned diamine and tetracarboxylic dianhydride (4,4'-(hexafluoroisopropylidene) diphthalic anhydride, 5-(2,5-dioxytetrahydro-3-furyl)-3-methyl-cyclohexene-1,2-dicarboxylic anhydride, pyromellitic dianhydride, 1,2,3,4-benzene tetracarboxylic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride, 2,2',3,3'-benzophenone tetracarboxylic dianhydride, 3,3',4,4'-biphenyl tetracarboxylic dianhydride, 3 ,3',4,4'-diphenylsulfonium tetracarboxylic dianhydride, 2,2',3,3'-biphenyl tetracarboxylic dianhydride, methylene-4,4'-diphthalic dianhydride, 1,1-ethylene-4,4'-diphthalic dianhydride, 2,2'-propylene-4,4'-diphthalic dianhydride, 1,2-ethylene-4,4'-diphthalic dianhydride, 1,3-trimethylene-4,4'-diphthalic dianhydride, 1,4-tetramethylene-4,4'-diphthalic dianhydride, 1,5-pentamethylene 4,4'-diphthalic dianhydride, 4,4'-oxy diphthalic dianhydride, sulfo-4,4'-diphthalic dianhydride, sulfonyl-4,4'-diphthalic dianhydride, 1,3-bis(3,4-dicarboxyphenyl)phthalic dianhydride, 1,3-bis(3,4-dicarboxyphenoxy)phthalic dianhydride, 1,4-bis(3,4-dicarboxyphenoxy)phthalic dianhydride, 1,3-bis[2-(3,4-dicarboxyphenyl)-2-propyl]phthalic dianhydride, 1,4-bis[2-(3,4 -dicarboxyphenyl)-2-propyl]phthalic dianhydride, bis[3-(3,4-dicarboxyphenoxy)phenyl]methane dianhydride, bis[4-(3,4-dicarboxyphenoxy)phenyl]methane dianhydride, 2,2-bis[3-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride, 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride, bis(3,4-dicarboxyphenoxy)dimethylsilane dianhydride, 1,3-bis(3,4-dicarboxyphenyl) 1,1,3,3-tetramethyldisiloxane dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, 2,3,6,7-anthracenetetracarboxylic dianhydride, 1,2,7,8-phenanthrenetetracarboxylic dianhydride, ethylenetetracarboxylic dianhydride, 1,2,3,4-butanetetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride), cyclopentanetetracarboxylic dianhydride Carboxylic acid dianhydride, cyclohexane-1,2,3,4-tetracarboxylic acid dianhydride, cyclohexane-1,2,4,5-tetracarboxylic acid dianhydride, 3,3',4,4'-bicyclic hexyltetracarboxylic acid dianhydride, carbonyl-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, methylene-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, 1,2-ethylene-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, 1,1-ethylene-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride Hexane-1,2-dicarboxylic acid) dianhydride, 2,2-propylene-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, oxygen-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, sulfur-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, sulfonyl-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetracarboxylic acid dianhydride, rel-[1S,5R, Polymerization of [6R]-3-oxobicyclo[3,2,1]octane-2,4-dione-6-spiro-3'-(tetrahydrofuran-2',5'-dione), 4-(2,5-dioxotetrahydrofuran-3-yl)-1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic anhydride, ethylene glycol-bis-(3,4-dicarboxylic anhydride phenyl) ether, 4,4'-biphenyl bis(trimellitic acid monoester anhydride), and 9,9'-bis(3,4-dicarboxyphenyl)fluorenyl dianhydride).

Cyanate resin: A cyanate compound obtained by reacting a phenol resin with a cyanogen halide. Specific examples include dicyanobenzene, tricyanobenzene, dicyanonaphthalene, dicyanobiphenyl, 2,2'-bis(4-cyanophenyl)propane, bis(4-cyanophenyl)methane, bis(3,5-dimethyl-4-cyanophenyl)methane, 2,2'-bis(3,5-dimethyl-4-cyanophenyl)propane, 2,2'-bis(4-cyanophenyl)ethane, 2,2'-bis(4-cyanophenyl)hexafluoropropane, bis(4-cyanophenyl)sulfone, bis(4-cyanophenyl)sulfide, phenol novolac cyano group, and phenol/dicyclopentadiene co-condensate in which the hydroxyl group is converted to a cyanate group. However, the present invention is not limited to these.

Furthermore, the cyanate compound whose synthesis method is described in Japanese Patent Application Laid-Open No. 2005-264154 is particularly preferred as a cyanate compound due to its low hygroscopicity, flame retardancy, and excellent dielectric properties.

To trimerize the cyanate groups to form sym-triazine rings as needed, cyanate resins may also contain catalysts such as zinc cycloalkanoate, cobalt cycloalkanoate, copper cycloalkanoate, lead cycloalkanoate, zinc octylate, tin octylate, lead acetylacetone, and dibutyltin maleate. The catalyst is typically used in an amount of 0.0001 to 0.10 parts by mass, preferably 0.00015 to 0.0015 parts by mass, per 100 parts by mass of the curable resin composition.

Active ester resins: Compounds containing one or more active ester groups per molecule can be used as hardeners for curable resins such as epoxy resins, as needed. Preferred active ester hardeners are compounds containing two or more highly reactive ester groups per molecule, such as phenolic esters, thiophenolic esters, N-hydroxylamine esters, and esters of heterocyclic hydroxyl compounds. These active ester hardeners are preferably obtained by a condensation reaction of at least one of a carboxylic acid compound and a thiocarboxylic acid compound with at least one of a hydroxyl compound and a thiol compound. In particular, from the perspective of improving heat resistance, active ester hardeners derived from carboxylic acid compounds and hydroxyl compounds are preferred, and those derived from carboxylic acid compounds and at least one of a phenolic compound and a naphthol compound are even more preferred.

Examples of carboxylic acid compounds include benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid, and pyromellitic acid.

Examples of the phenolic compound or naphthol compound include hydroquinone, resorcinol, bisphenol A, bisphenol F, bisphenol S, phenolnaphthalene, methylated bisphenol A, methylated bisphenol F, methylated bisphenol S, phenol, o-cresol, m-cresol, p-cresol, catechol, α-naphthol, β-naphthol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucin, benzenetriol, dicyclopentadiene-type diphenol compounds, and phenol novolac. Here, the term "dicyclopentadiene-type diphenol compound" refers to a diphenol compound obtained by condensing two phenol molecules into one dicyclopentadiene molecule.

Preferred examples of active ester hardeners include active ester compounds containing a dicyclopentadiene diphenol structure, active ester compounds containing a naphthalene structure, active ester compounds containing acetylated phenol novolacs, and active ester compounds containing benzoylated phenol novolacs. Among these, active ester compounds containing a naphthalene structure and active ester compounds containing a dicyclopentadiene diphenol structure are particularly preferred. The term "dicyclopentadiene diphenol structure" refers to a divalent structural unit consisting of phenylene-dicyclopentylene-phenylene.

Commercially available products of active ester curing agents include, for example, "EXA9451", "EXA9460", "EXA9460S", "HPC-8000-65T", "HPC-8000H-65TM", "EXA-8000L-65TM", and "EXA-8150-65T" (manufactured by DIC Corporation) as active ester compounds containing a dicyclopentadiene-type diphenol structure; "EXA9416-70AK" (manufactured by DIC Corporation) as active ester compounds containing a naphthalene structure; and "EXA9416-70AK" (manufactured by DIC Corporation) as active ester compounds containing a phenol structure. Examples of active ester compounds of acetylated novolacs include "DC808" (Mitsubishi Chemical Corporation); examples of active ester compounds of benzoyl compounds containing phenol novolacs include "YLH1026," "YLH1030," and "YLH1048" (Mitsubishi Chemical Corporation); examples of active ester hardeners for acetylated phenol novolacs include "DC808" (Mitsubishi Chemical Corporation); examples of active ester hardeners containing phosphorus atoms include "EXA-9050L-62M" from DIC Corporation, etc.

The curable resin composition of the present invention may also be combined with a curing accelerator (curing catalyst) to improve the curing property. Specific examples of the curing accelerator include imidazoles such as 2-methylimidazole, 2-ethylimidazole, and 2-ethyl-4-methylimidazole, tertiary amines such as 2-(dimethylaminomethyl)phenol or 1,8-diaza-biscyclo(5,4,0)undecene-7, phosphines such as triphenylphosphine, tetrabutylammonium salt, triisopropylmethylammonium salt, trimethyldecylammonium salt, cetyltrimethylammonium salt, hexadecyltrimethylammonium hydroxide, and triphenylbenzylphosphonium salt. Quaternary phosphonium salts such as triphenylethylphosphonium salt, tetrabutylphosphonium salt (the counter ions of the quaternary salts are halogens, organic acid ions, hydroxide ions, etc., and are not particularly specified, but organic acid ions and hydroxide ions are particularly preferred), transition metal compounds (transition metal salts) of zinc compounds such as tin octylate, zinc carboxylates (zinc 2-ethylhexanoate, zinc stearate, zinc behenate, zinc myristate), or zinc phosphates (zinc octylphosphate, zinc stearylphosphate, etc.). The amount of the curing accelerator used is 0.01 to 5.0 parts by weight based on the actual use, relative to 100 parts by weight of the curable resin composition.

The curable resin composition of the present invention may be added with or used in combination with a free radical polymerization initiator or a curing accelerator as needed. Examples of free radical polymerization initiators include ketone peroxides such as methyl ethyl ketone peroxide and acetylacetone peroxide, diacyl peroxides such as benzoyl peroxide, dialkyl peroxides such as diisopropylbenzene peroxide and 1,3-bis-(tert-butylperoxyisopropyl)-benzene, peroxyketal such as tert-butylperoxybenzoate and 1,1-di-tert-butylperoxycyclohexane, α-isopropylbenzene peroxyneodecanoate, tert-butylperoxyneodecanoate, tert-butylperoxytrimethylacetate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, tert-amylperoxy-2-ethylhexanoate, tert-butylperoxy-2-ethylhexanoate, tert-amylperoxy-3,5,5-tetramethyl ... Examples of the curing accelerator include, but are not limited to, alkyl peroxyesters such as di-2-ethylhexyl peroxydicarbonate, bis(4-tert-butylcyclohexyl)peroxydicarbonate, tert-butylperoxyisopropyl carbonate, and 1,6-bis(tert-butylperoxycarbonyloxy)hexane; organic peroxides such as tert-butyl hydroperoxide, isopropyl hydroperoxide, tert-butylperoxyoctanoate, and lauryl peroxide; and azo compounds such as azobisisobutyronitrile, 4,4'-azobis(4-cyanoethyl oxalate), and 2,2'-azobis(2,4-dimethylvaleronitrile). Ketone peroxides, diacyl peroxides, hydroperoxides, dialkyl peroxides, peroxyketals, alkyl peroxyesters, and peroxycarbonates are preferred, with dialkyl peroxides being even more preferred. The amount of free radical polymerization initiator added is preferably 0.01 to 5 parts by mass, and particularly preferably 0.01 to 3 parts by mass, per 100 parts by mass of the curable resin composition. Excessive amounts of free radical polymerization initiator may deteriorate the dielectric properties of the cured product.

Furthermore, the curable resin composition of the present invention may also contain a phosphorus-containing compound as a flame retardant imparting component. The phosphorus-containing compound may be a reactive type or an additive type. Specific examples of the phosphorus-containing compound include trimethyl phosphate, triethyl phosphate, tricresyl phosphate, trixylyleneyl phosphate, cresyldiphenyl phosphate, cresyl-2,6-dixylenyl phosphate, and cresyl-2,6-dixylenyl phosphate. Phosphates such as phosphate, 1,3-phenylenebis(dixylyl phosphate), 1,4-phenylenebis(dixylyl phosphate), and 4,4'-biphenyl(dixylyl phosphate); 9,10-dihydro-9-oxo-10-phosphaphenanthrene-10-oxide, 10(2,5-dihydroxyphenyl)-10H-9-oxo-10-phosphaphenanthrene-10-oxide Phosphanes such as phosphanes; phosphorus-containing epoxides obtained by reacting epoxy resins with the active hydrogen of the aforementioned phosphanes; red phosphorus; etc., but phosphates, phosphanes, or phosphorus-containing epoxides are preferred, with 1,3-phenylenebis(dixylyl phosphate), 1,4-phenylenebis(dixylyl phosphate), 4,4'-biphenyl(dixylyl phosphate), or phosphorus-containing epoxides being particularly preferred. The phosphorus-containing compound content is preferably in the range of 0.1 to 0.6 (by weight) of the phosphorus-containing compound to the resin component in the curable resin composition. Below 0.1, flame retardancy is insufficient, while above 0.6 may adversely affect the hygroscopicity and dielectric properties of the cured product.

Furthermore, a light stabilizer may be added to the curable resin composition of the present invention as needed. The light stabilizer is a hindered amine-based light stabilizer, with HALS being particularly suitable. HALS are not particularly limited, but representative examples include polycondensates of dibutylamine/1,3,5-triazine/N,N'-bis(2,2,6,6-tetramethyl-4-piperidinyl-1,6-hexamethylenediamine and N-(2,2,6,6-tetramethyl-4-piperidinyl)butylamine, dimethyl-1-(2-hydroxyethyl)-4-hydroxy-2,2,6,6-tetramethylpiperidinyl succinate polycondensate, poly[{6-(1,1,3,3-tetramethylbutyl)amino-1,3,5-triazine-2,4-diyl}{(2,2,6,6-tetramethyl-4-piperidinyl)imino}hexamethylene{(2,2,6,6-tetramethyl-4-piperidinyl)imino] )imino}], bis(1,2,2,6,6-pentamethyl-4-piperidinyl){3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl}methyl]butyl malonate, bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate, bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidinyl) sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidinyl)2-(3,5-di-tert-butyl-4-hydroxybenzyl)-2-n-butylmalonate, etc. HALS may be used alone or in combination of two or more.

Furthermore, the curable resin composition of the present invention may also be blended with a binder resin as needed. Examples of such binder resins include, but are not limited to, butyraldehyde resins, acetal resins, acrylic resins, epoxy-nylon resins, NAR-phenol resins, epoxy-NAR resins, polyamide resins, polyimide resins, and polysilicone resins. The binder resin is preferably blended in an amount that does not compromise the flame resistance and heat resistance of the cured product, preferably between 0.05 and 50 parts by mass per 100 parts by mass of the resin component, and more preferably between 0.05 and 20 parts by mass, depending on the need.

Furthermore, the curable resin composition of the present invention may contain, as needed, fused silica, crystalline silica, porous silica, aluminum oxide, zirconium, calcium silicate, calcium carbonate, quartz powder, silicon carbide, silicon nitride, boron nitride, zirconium oxide, aluminum nitride, graphite, olivine, steatite, spinel, mullite, titanium oxide, talc, clay, iron oxide, sponge, glass powder, or other inorganic fillers in the form of spherical or crushed materials. Furthermore, in particular, when obtaining a curable resin composition for semiconductor packaging, the amount of the inorganic filler used in the curable resin composition is generally in the range of 80 to 92 mass %, preferably 83 to 90 mass %.

Furthermore, the curable resin composition of the present invention may be blended with known additives as needed. Specific examples of usable additives include polybutadiene and its modified products, modified acrylonitrile copolymers, polyphenylene ether, polystyrene, polyethylene, polyimide, fluororesins, silicone gels, silicone oils, surface treatment agents for silane coupling fillers, release agents, carbon black, phthalocyanine blue, phthalocyanine green, and other colorants. The amount of these additives blended is preferably no more than 1000 parts by mass, and more preferably no more than 700 parts by mass, per 100 parts by mass of the resin component.

The curable resin composition of the present invention is obtained by uniformly mixing the aforementioned components in predetermined proportions. Pre-curing is typically performed at 130 to 180°C for 30 to 500 seconds, followed by post-curing at 150 to 200°C for 2 to 15 hours to allow for sufficient curing reaction, resulting in the cured product of the present invention. Alternatively, the components of the curable resin composition may be uniformly dispersed or dissolved in a solvent, etc., and then cured after removing the solvent.

The curable resin composition of the present invention obtained in this manner exhibits heat resistance and mechanical properties, and maintains excellent dielectric properties even after absorbing water. Therefore, the curable resin composition of the present invention can be used in a wide range of fields requiring moisture resistance, heat resistance, low dielectric constant, and low dielectric tangent. Specifically, it can be used as a material for all electrical/electronic components, including insulation materials, laminates (printed wiring boards, BGA substrates, build-up substrates, etc.), packaging materials, and resistors. Furthermore, in addition to molding materials and composite materials, it can also be used in coatings, adhesives, and 3D printing. In particular, it contributes to reflow resistance in semiconductor packaging.

Semiconductor devices are packaged with the curable resin composition of the present invention. Examples of semiconductor devices include dual inline packages (DIP), quad flat packages (QFP), ball grid arrays (BGA), chip size packages (CSP), small outline packages (SOP), thin small outline packages (TSOP), and thin quad flat packages (TQFP).

The method for preparing the curable resin composition of the present invention is not particularly limited. However, as described above, the components can be dispersed or dissolved in a solvent, uniformly mixed, and then the solvent can be removed as needed for preparation. Alternatively, the composition can be prepolymerized. For example, prepolymerization can be achieved by heating component (A) and component (B) in the presence or absence of a catalyst and in the presence or absence of a solvent. Similarly, prepolymerization can be achieved by adding curing agents such as epoxy resins, amine compounds, maleimide compounds, cyanate compounds, phenolic resins, acid anhydride compounds, and other additives in addition to component (A) and component (B). The mixing or prepolymerization of the components can be carried out in the absence of a solvent using, for example, an extruder, kneader, or roll. In the presence of a solvent, a reaction kettle equipped with a stirrer can be used.

Uniform mixing without the use of solvents involves kneading at temperatures between 50 and 100°C using a kneader, roller, planetary mixer, or other device to form a uniform curable resin composition. The resulting curable resin composition can be pulverized and then formed into cylindrical tablets, granular powders, or powdered molded bodies using a tablet press or other molding machine. Alternatively, the composition can be melted onto a surface support and formed into sheets with a thickness of 0.05 mm to 10 mm to form a curable resin composition molded body. The resulting molded body is non-sticky at temperatures between 0 and 20°C, and exhibits minimal degradation in fluidity and curability even when stored at -25 to 0°C for more than one week.

The resulting molded product can be formed into a hardened object using a transfer molding machine or a compression molding machine.

An organic solvent may also be added to the curable resin composition of the present invention to form a varnish-like composition (hereinafter referred to as simply "varnish"). The curable resin composition of the present invention may be dissolved in a solvent such as toluene, xylene, acetone, methyl ethyl ketone, methyl isobutyl ketone, dimethylformamide, dimethylacetamide, or N-methylpyrrolidone, as needed, to form a varnish. The varnish is then impregnated into a substrate such as glass fiber, carbon fiber, polyester fiber, polyamide fiber, alumina fiber, or paper, and the resulting prepreg is heat-dried and then heat-extruded to form a cured product of the curable resin composition of the present invention. The solvent used in this application typically accounts for 10 to 70% by weight, preferably 15 to 70% by weight, of the mixture of the curable resin composition of the present invention and the solvent. If the solvent amount is less than this range, the varnish viscosity increases and workability deteriorates. Excessive amounts of solvent may cause voids in the cured product. Alternatively, if the composition is liquid, the cured resin containing carbon fibers can be directly obtained, for example, by RTM.

Furthermore, the curable resin composition of the present invention can be used as a modifier for film-type compositions. Specifically, it can be used to improve flexibility during the A-stage. Such a film-type curable resin composition is prepared by forming the curable resin composition of the present invention into the aforementioned curable resin composition varnish, applying it to a release film, and then performing the A-stage after removing the solvent under heating to obtain a sheet-like adhesive. This sheet-like adhesive can be used as an insulating layer between layers of multi-layer substrates, etc.

The curable resin composition of the present invention can be melted by heating to reduce its viscosity and then impregnated into reinforcing fibers such as glass fibers, carbon fibers, polyester fibers, polyamide fibers, and alumina fibers to obtain a prepreg. Specific examples include, but are not limited to, glass fibers such as E-glass cloth, D-glass cloth, S-glass cloth, Q-glass cloth, spherical glass cloth, NE-glass cloth, and T-glass cloth; inorganic fibers other than glass; poly(p-phenylene terephthalamide) (Kevlar (registered trademark), manufactured by Dupont Inc.), wholly aromatic polyamides, polyesters; and organic fibers such as poly(p-phenylene benzoxazole), polyimide, and carbon fibers. The shape of the substrate is not particularly limited, but examples thereof include woven fabric, non-woven fabric, yarn, and chopped strands. Known weaving methods for the fabric include plain weave, basket weave, and twill weave, and a suitable weave can be selected from these known methods depending on the intended application and performance. Suitable materials include fiber-opening fabrics and glass fabrics surface-treated with a silane coupling agent or the like. The thickness of the substrate is not particularly limited, but is preferably approximately 0.01 to 0.4 mm. Alternatively, a prepreg can be obtained by impregnating the reinforcing fibers with the varnish and then heat-drying.

The laminate of this embodiment has one or more of the above-mentioned prepregs. The laminate is not particularly limited as long as it has one or more prepregs, and may have any other layers. The manufacturing method of the laminate is generally applicable to known methods and is not particularly limited. For example, when forming a metal foil laminate, a multi-stage extruder, a multi-stage vacuum extruder, a continuous forming machine, a high-pressure autoclave forming machine, etc. can be used to stack the above-mentioned prepregs on each other, and heat and pressurize the laminate to obtain the laminate. At this time, the heating temperature is not particularly limited, but 65 to 300°C is preferred, and 120 to 270°C is more preferred. The pressure applied during the pressurization is not particularly limited. However, if the pressure is too high, it becomes difficult to adjust the solid content of the laminate resin and the quality becomes unstable. If the pressure is too low, air bubbles may form or the adhesion between the laminate layers may deteriorate. Therefore, a pressure of 2.0 to 5.0 MPa is preferred, and 2.5 to 4.0 MPa is even more preferred. The laminate of this embodiment, having a layer composed of metal foil, is suitable for use as a metal-foil-clad laminate, as described below.

The prepreg is cut into the desired shape and laminated with copper foil or the like as needed. The laminate is then heat-cured while applying pressure using extrusion, autoclave molding, sheet winding, or other methods. This produces an electrical electronic laminate (printed wiring board) or carbon fiber reinforced material.

The cured product of the present invention can be used in various applications, including molding materials, adhesives, composite materials, and coatings. The cured product of the curable resin composition described in the present invention exhibits excellent heat resistance and dielectric properties, making it suitable for use in electronic components such as semiconductor device packaging materials, liquid crystal display device packaging materials, organic EL device packaging materials, printed wiring boards, and build-up laminates, as well as composite materials for lightweight, high-strength structural materials such as carbon fiber reinforced plastics and glass fiber reinforced plastics.

[Example]

The present invention is described in detail below using Examples and Comparative Examples. "Parts" and "%" herein represent "parts by weight" and "% by weight," respectively. The softening point and melt viscosity were measured according to the following methods.

‧GPC (Gel Permeation Chromatography) Analysis

Manufacturer: Waters

Columns: SHODEX GPCKF-601 (2 copies), KF-602, KF-602.5, KF-603

Flow rate: 0.5ml/min.

Column temperature: 40°C

Solvent used: THF (tetrahydrofuran)

Detector: RI (differential refractometer)

‧HPLC (High-Performance Liquid Chromatography) Analysis

Column: Inertsil ODS-2

Flow rate: 1.0ml/min.

Column temperature: 40°C

Solvent used: Acetonitrile and water

Detector: Photodiode array (225nm)

‧Amine equivalent

The obtained value is used as the amine equivalent according to JIS K-7236 Appendix A (Revised method for glycidylamine).

DMA Analysis

Manufacturer: TA Instrument

Device: DMAQ800

Measurement mode: Tensile

Heating rate: 2°C/min.

Measuring temperature range: 25℃ to 350℃

Measurement frequency: 10Hz

The temperature at which the tanδ value reaches its maximum is defined as Tg.

‧Mechanical strength

Manufacturer: Shimadzu Manufacturing Co., Ltd.

Device: Autograph AGS-X

Tensile speed: 0.5mm/min

Clamp the test piece so that it is 5 cm long and perform the tensile test in the 180° direction at the above test speed.

‧Water absorption test

After immersing in water for 24 hours, remove the sample and measure its weight after placing it in a 25°C 30% humidity environment for 24 hours.

‧Dielectric constant test, dielectric tangent test

Manufacturer: AET Co., Ltd.

Device: 10GHz cavity resonator

Test specimens 2.5 mm wide and 5 cm long were dried in a dryer at 120°C for 2 hours before being measured. Furthermore, the specimens were immersed in water for 24 hours, removed, and placed in a 25°C, 30% humidity environment for 24 hours before being measured again.

[Synthesis Example 1: Synthesis of Aromatic Amine Resin (A-1)]

A flask equipped with a thermometer, cooling tube, DEAN-STARK azeotropic distillation trap, and stirrer was charged with 192 parts of aniline, 112 parts of toluene, and 100 parts of 1,3-bis(2-hydroxy-2-propyl)benzene. 21.5 parts of 35% hydrochloric acid were added dropwise over 10 minutes. The system was heated to 160°C and the reaction was continued at the same temperature for 17 hours while distilling off water and toluene. After cooling to 80°C, 124 parts of toluene were added, and 30 parts of a 30% aqueous sodium hydroxide solution were added dropwise over 10 minutes. The mixture was then stirred at the same temperature for 2 hours and allowed to stand for 30 minutes. The separated lower aqueous layer was removed, and the reaction solution was repeatedly washed with water until the washing liquid became neutral. Excess aniline and toluene were then distilled off from the oil layer using a rotary evaporator under heating and reduced pressure, thereby obtaining 158 parts of the aromatic amine resin (A-1) represented by the aforementioned formula (2). The aromatic amine resin (A-1) had an amine equivalent weight of 186.1 g/eq and a softening point of 58.8°C. GPC analysis (RI) showed that the n=1 structure was 62.5 area %. The GPC chart is shown in Figure 1.

[Synthesis Example 2: Synthesis of Maleimide Resin (M-1)]

A flask equipped with a thermometer, cooling tube, DEAN-STARK azeotropic distillation trap, and stirrer was charged with 73.5 parts of maleic anhydride, 126 parts of toluene, 1.86 parts of methanesulfonic acid, and 12.6 parts of N-methyl-2-pyrrolidone and heated to reflux. Next, a resin solution consisting of 93 parts of aromatic amine resin (A-1) dissolved in 55.8 parts of toluene was added dropwise over 4 hours while maintaining reflux. During this time, the condensed water and toluene, which had been azeotropically distilled under reflux conditions, were cooled and separated in the DEAN-STARK azeotropic distillation trap. The toluene in the organic layer was returned to the system, while the water was discharged. After the resin solution dripping stops, maintain reflux and carry out dehydration while reacting for 10 hours.

After the reaction was complete, the system was washed with water four times to remove methanesulfonic acid and excess maleic anhydride. Water was removed from the system by azeotroping toluene with water under heating and reduced pressure at a temperature below 70°C. Subsequently, 0.93 parts of methanesulfonic acid was added, and the reaction was continued under heating and reflux for four hours. After the reaction was complete, the system was washed with water four times until the wash water became neutral. Water was removed from the system by azeotroping toluene with water under heating and reduced pressure at a temperature below 70°C. The solvent was then distilled off with toluene under heating and reduced pressure until the resin concentration reached approximately 70-80%. Additional toluene was then added to adjust the resin concentration to 60%. This yielded a maleimide solution (V-1) containing a maleimide resin (M-1). GPC analysis (RI) revealed that the obtained maleimide resin (M-1) had an n=1 isomeric ratio of 57.4% by area, an n=2 isomeric ratio of 21.3% by area, and an n=3 or higher isomeric ratio of 21.3% by area. HPLC analysis (225 nm) revealed the orientation ratios of the n=1 isomeric ratio (ortho-ortho/para-para/ortho-para) to be 32.0%/25.4%/42.6%. Furthermore, the softening point was 115.5°C, and the viscosity was 6.0 Pa·s. The GPC chart is shown in Figure 2.

[Synthesis Example 3: Synthesis of Maleimide Resin (B-1)]

In a 500ml round-bottom flask equipped with a Teflon (registered trademark)-coated stir bar, place 110g of toluene and 36g of N-methylpyrrolidone. Next, add 85.6g (0.16mol) of PRIAMINE 1074 (manufactured by CRODA JAPAN Co., Ltd.), followed by the gradual addition of 15.4g (0.16mol) of anhydrous methanesulfonic acid to form the salt. Stir and mix for approximately 10 minutes, then slowly add 1,2,4,5-cyclohexanetetracarboxylic dianhydride (24.5g, 0.08mol) to the stirred mixture. Install a DEAN-STARK trap and condenser in the flask. Heat the mixture under reflux for 6 hours to form an amine-terminated diimide. At this point, the theoretical amount of water produced from the condensation was obtained. The reaction mixture was cooled to below room temperature, and 18.8 g (0.19 mol) of maleic anhydride was added to the flask. The mixture was refluxed for another 8 hours to obtain the expected amount of water. After cooling to room temperature, 200 ml of toluene was added to the flask. The diluted organic layer was then washed with water (100 ml x 3) to remove salts and unreacted starting materials. The solvent was then removed under vacuum to obtain 108 g of amber-colored, waxy maleimide resin (B-1) (90% yield, Mw = 3,600).

[Examples 1 to 5, Comparative Examples 1 to 8]

Various maleimide resins and a thermoplastic resin (SEPTON 2104) were weighed in the proportions shown in Table 1, acetone was added to a resin solids content of 50% by weight, and the mixture was mixed to prepare a varnish. Furthermore, 2-ethyl-4-methylimidazole (2E4MZ, manufactured by Shikoku Chemical Industries, Ltd.) was dissolved in the varnish as a curing accelerator. The varnish containing the curing accelerator was heated in a vacuum dryer at 60°C for 30 minutes and then at 150°C for 1 hour to prepare a curable resin composition. The resulting curable resin composition was sandwiched between copper foils and cured at 220°C for 2 hours under vacuum at a pressure of 1 MPa. The curability at this point was confirmed, and the physical properties were evaluated. The results of various tests on the obtained hardened product are shown in Table 1.

‧M-1 (Component (A), obtained by diluting the solvent from the component obtained in Synthesis Example 2 by heating and reducing the pressure)

‧B-1 (Component (B), obtained in Synthesis Example 3)

‧MIR-3000 (Made by Nippon Kayaku Co., Ltd.) by diluting out the solvent from MIR-3000-70MT by heating and reducing pressure)

‧SEPTON 2104 (thermoplastic resin, manufactured by KURARAY)

‧2E4MZ (hardening accelerator, manufactured by Shikoku Chemical Industries, Ltd.)

[Table 1]

Examples 1 to 5 showed good heat resistance, mechanical properties, water absorption, and dielectric properties. Furthermore, Examples 1 to 4 had a Tg of 200°C or higher, demonstrating even better heat resistance. On the other hand, Comparative Example 1 exhibited poor dielectric properties after water absorption, Comparative Examples 2 to 4 exhibited poor heat resistance, Comparative Examples 5 to 7 exhibited poor dielectric properties, and Comparative Example 8 exhibited poor heat resistance and elastic modulus, failing to meet all required properties.

While the present invention is described in detail with reference to specific aspects, it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the present invention.

This application is based on the Japanese Patent Application No. 2021-056834 filed on March 30, 2021, and its entire contents are incorporated herein by reference. All contents that should be cited are incorporated herein in their entirety.

Claims (8)

A maleimide resin mixture comprises a maleimide resin (A) represented by the following formula (2) and a maleimide resin (B), wherein the maleimide resin (B) is obtained by reacting a diamine (b) with maleic anhydride; wherein the weight ratio of the component (A) to the component (B) is 95/5 to 60/40, the component (b) is obtained by reacting a diamine (b-1) having 4 to 60 carbon atoms with a tetracarboxylic dianhydride (b-2), and the component (b-1) is a diamine (b-1a) derived from a dimer acid; In formula (2), plural Rs independently represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, m represents an integer from 0 to 3, and n is a repeated number, the average value of which is 1<n<5. A maleimide resin mixture comprises a maleimide resin (A) represented by the following formula (2) and a maleimide resin (B), wherein the maleimide resin (B) is obtained by reacting a diamine (b) with maleic anhydride; wherein the weight ratio of the component (A) to the component (B) is 70/30 to 60/40, the component (b) is obtained by reacting a diamine (b-1) having 4 to 60 carbon atoms with a tetracarboxylic dianhydride (b-2), and the component (b-1) is a diamine (b-1a) derived from a dimer acid; In formula (2), plural Rs independently represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, m represents an integer from 0 to 3, and n is a repeated number, the average value of which is 1<n<5. The maleimide resin mixture as claimed in claim 1 or 2, wherein the component (b-2) is represented by the following formula (4): . The maleimide resin mixture as claimed in claim 1 or 2, wherein the component (B) is represented by the following formula (3): In formula (3), ^R1 represents a divalent alkyl group (c) derived from a dimer acid, ^R2 represents a divalent organic group (d) other than a divalent alkyl group (c) derived from a dimer acid, ^R3 represents any one selected from the group consisting of a divalent alkyl group (c) derived from a dimer acid and a divalent organic group (d) other than a divalent alkyl group (c) derived from a dimer acid, ^R4 and R ^{R4 and R5} each independently represent one or more organic groups selected from a tetravalent organic group having 4 to 40 carbon atoms with a monocyclic or condensed polycyclic alicyclic structure, a tetravalent organic group having 8 to 40 carbon atoms in which alicyclic organic groups having a monocyclic structure are linked directly or via a cross-linking structure, and a tetravalent organic group having 8 to 40 carbon atoms with a semi-alicyclic structure having both an alicyclic structure and an aromatic ring. m is an integer from 1 to 30, and n is an integer from 0 to 30. ^R4 and ^R5 may be the same or different. A hardening resin composition comprising the maleimide resin mixture according to any one of claims 1 to 4. The hardening resin composition as described in claim 5 further contains a hardening accelerator. A prepreg comprising the maleimide resin mixture of any one of claims 1 to 4, or the curable resin composition of claim 5 or 6, retained on a sheet-like fiber substrate. A cured product obtained by curing the maleimide resin mixture according to any one of claims 1 to 4, the curable resin composition according to claim 5 or 6, or the prepreg according to claim 7.