Latent curing agents, curable resin compositions, cured products thereof, and printed circuit boards

Abstract

The present invention aims to provide a latent curing agent and a curable resin composition that exhibit excellent storage stability in a single-component form and high catalytic activity from lower temperatures. [Solution] A latent curing agent represented by the following formula (a), comprising a phosphonium cation and a silicate anion residue. TIFF2026067406000017.tif47170 (In formula (a), R1 to R4 each independently represent a hydrocarbon group having 1 to 20 carbon atoms, which may contain heteroatoms. R5 to R 17 Each of these independently represents a hydrocarbon group having 1 to 20 carbon atoms, which may contain a hydrogen atom, a halogen atom, a hydroxyl group, a mercapto group, a silyl group, a silanol group, a nitro group, a nitroso group, a cyano group, a phosphino group, a phosphinyl group, a phosphono group, a phosphonato group, an amino group, or an ammonia group, or a heteroatom.

Description

[Technical Field]

[0001] The present invention relates to a latent curing agent, a curable resin composition containing a latent curing agent, and a cured product thereof. [Background technology]

[0002] Conventionally, curing accelerators for thermosetting resins, particularly for epoxy resins, have included phosphorus-based or pyridine-based accelerators. Phosphorus-based accelerators are known to have high curing power and to produce electrically reliable cured products. Among phosphorus-based accelerators, latent curing agents include, for example, phosphonium borate (Patent Document 1), phosphonium carboxylate (Patent Documents 2-6), phosphonium thiocyanate (Patent Document 7), and 1,2-bis(diphenylphosphin)acetylene (Patent Document 8), but these were not sufficient in terms of latent curing. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Patent No. 3638258 [Patent Document 2] International Publication No. 2010 / 087526 [Patent Document 3] International Publication No. 2009 / 014270 [Patent Document 4] Japanese Patent Application Publication No. 3-20065 [Patent Document 5] Japanese Patent Publication No. 2016-113475 [Patent Document 6] Japanese Patent Application Publication No. 11-158251 [Patent Document 7] Japanese Patent Publication No. 2010-209150 [Patent Document 8] Japanese Patent Publication No. 2015-172136 [Overview of the project] [Problems that the invention aims to solve]

[0004] An object of the present invention is to provide a latent curing agent that has excellent storage stability in a single liquid and exhibits high catalytic activity from a lower temperature, and a curable resin composition.

Means for Solving the Problems

[0005] That is, the present invention relates to a latent curing agent represented by the following formula (a), which is composed of a phosphonium cation and a silicate anion residue.

[0006]

Chemical formula

[0007] In the present application, “(numerical value 1) to (numerical value 2)” indicates that the upper and lower limit values are included.

Effects of the Invention

[0008] According to the present invention, it is possible to provide a latent curing agent that has excellent storage stability in a single liquid and exhibits high catalytic activity from a lower temperature, and a curable resin composition.

Brief Description of the Drawings

[0009] [Figure 1] 1H-NMR chart of Synthesis Example 1. [Figure 2] 1H-NMR chart of Synthesis Example 2. [Figure 3] It is the 1H-NMR chart of Synthesis Example 3. [Figure 4] It is the 1H-NMR chart of Synthesis Example 4. [Figure 5] It is the 1H-NMR chart of Synthesis Example 5. [Figure 6] It is the 1H-NMR chart of Comparative Synthesis Example 1. [Figure 7] It is the 1H-NMR chart of Comparative Synthesis Example 2.

Embodiments for Carrying Out the Invention

[0010] Hereinafter, embodiments according to the present invention (hereinafter also referred to as "the present embodiment") will be described in more detail.

[0011] The latent curing agent of the present invention is composed of a phosphonium cation and a silicate anion residue, and is represented by the following formula (a). A latent curing agent refers to a compound that generates a curing agent upon irradiation with ultraviolet light or visible light or heating.

[0012]

Chemical formula

[0013] In formula (a), R1 to R4 each independently represent a hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom, and may be the same as or different from each other. R1 and R2, R2 and R3, R3 and R4, and R4 and R1 may each be bonded to form a ring structure. The hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom may be a hydrocarbon group having 1 to 20 carbon atoms containing a heteroatom, or may be a hydrocarbon group having 1 to 20 carbon atoms not containing a heteroatom. C1-C20 hydrocarbon groups refer to, but are not limited to, alkyl groups, alkenyl groups, aryl groups, and alkylaryl groups. C1-C6 alkyl groups are preferred, and C1-C4 alkyl groups are more preferred. C1-C6 alkenyl groups are preferred, and C1-C4 alkenyl groups are more preferred. C6-C14 aryl groups are preferred, and phenyl, naphthyl, and anthranyl groups are more preferred. C7-C20 alkylaryl groups are preferred. C6-C1-C20 hydrocarbon groups are preferred, and C6-C14 aryl groups, C7-C20 alkylaryl groups, and C1-C6 alkyl groups are preferred, with C6-C14 aryl groups being more preferred, and phenyl groups being even more preferred from the viewpoint of compatibility with resins. Examples of heteroatoms include, but are not limited to, oxygen, sulfur, nitrogen, silicon, halogen, and phosphorus atoms. In one embodiment of this design, in the case of a hydrocarbon group having 1 to 20 carbon atoms that includes a heteroatom, the hydrocarbon group may have, but is not limited to, a halogen atom, a hydroxyl group, a mercapto group, a silyl group, a silanol group, a nitro group, a nitroso group, a cyano group, a phosphino group, a phosphinyl group, a phosphono group, a phosphonato group, an amino group, or an ammonia group as substituents. Furthermore, in one embodiment of this design, in the case of a hydrocarbon group having 1 to 20 carbon atoms that includes a heteroatom, the aforementioned hydrocarbon group having 1 to 20 carbon atoms may include a carbonyl group, an ether group, an ester group, an amide group, or a sulfide group, but is not limited to these. In this case, it is preferable that it includes a carbonyl group or an ether group. R5~R 17Each of these independently represents a C1-C20 hydrocarbon group which may contain a hydrogen atom, a halogen atom, a hydroxyl group, a mercapto group, a silyl group, a silanol group, a nitro group, a nitroso group, a cyano group, a phosphino group, a phosphinyl group, a phosphono group, a phosphonato group, an amino group, or an ammonia group, or a heteroatom. From the viewpoint of improving the curing speed, an electron-donating group is more preferable to lower the acidity of the conjugate acid of the silicate anion, but it is not limited to these. Also, R5-R 17 These elements may be identical or different from each other. Furthermore, a hydrocarbon group having 1 to 20 carbon atoms that may contain a heteroatom may be a hydrocarbon group having 1 to 20 carbon atoms that contains a heteroatom, or a hydrocarbon group having 1 to 20 carbon atoms that does not contain a heteroatom. Hydrocarbon groups having 1 to 20 carbon atoms refer to, but are not limited to, alkyl groups, alkenyl groups, aryl groups, and alkylaryl groups. C1 to C6 alkyl groups are preferred, and C1 to C4 alkyl groups are more preferred. C1 to C6 alkenyl groups are preferred, C1 to C4 alkenyl groups are more preferred, and vinyl or allyl groups are even more preferred. C6 to C14 aryl groups are preferred, and phenyl, naphthyl, and anthranyl groups are more preferred. C7 to C20 alkylaryl groups are preferred. In the case of a hydrocarbon group having 1 to 20 carbon atoms that contains a heteroatom, it is preferable that the hydrocarbon group has 1 to 20 carbon atoms and contains a carbonyl group, an ether group, an ester group, an amide group, or a sulfide group. Of these, it is preferable that it contains a carbonyl group or an ether group. Specific examples of hydrocarbon groups having 1 to 20 carbon atoms are the same as described above. In one embodiment of this design, in the case of a hydrocarbon group having 1 to 20 carbon atoms that includes a heteroatom, the substituents of the hydrocarbon group may include, but are not limited to, a halogen atom, a hydroxyl group, a mercapto group, a silyl group, a silanol group, a nitro group, a nitroso group, a cyano group, a phosphino group, a phosphinyl group, a phosphono group, a phosphonato group, an amino group, or an ammonia group. R5~R 17Examples thereof include a hydrocarbon group having 1 to 20 carbon atoms which may contain a hydrogen atom, a hydroxyl group, or a carbonyl group, an ether group, an ester group, an amide group or a sulfide group, preferably an alkyl group having 1 to 6 carbon atoms which may contain a hydrogen atom, a hydroxyl group, or a carbonyl group, an ether group, an ester group, an amide group or a sulfide group, an alkenyl group having 1 to 6 carbon atoms, an aryl group having 6 to 14 carbon atoms, or an alkylaryl group having 7 to 20 carbon atoms. R5 to R 17 When it is a hydrocarbon group having 1 to 20 carbon atoms, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 1 to 6 carbon atoms, or an aryl group having 6 to 14 carbon atoms is preferable, an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 14 carbon atoms is more preferable, an alkyl group having 1 to 6 carbon atoms is still more preferable, and a methyl group or a t-butyl group is particularly preferable. R5 to R 17 When it is a hydrocarbon group having 1 to 20 carbon atoms containing a hetero atom, an alkyl group having 1 to 6 carbon atoms containing a carbonyl group or an ether group, or an aryl group having 6 to 14 carbon atoms is preferable.

[0014] The phosphonium cation in the above formula (a) is preferably represented by the following formula (a-1).

Chemical formula

[0015] In formula (a-1), R 18 ~R 37 each independently represents a hydrogen atom, a halogen atom, a hydroxyl group, a mercapto group, a silyl group, a silanol group, a nitro group, a nitroso group, a cyano group, a phosphino group, a phosphinyl group, a phosphono group, a phosphonato group, an amino group, or an ammonio group. Among these, R 18 ~R 37 are preferably a hydrogen atom or a hydroxyl group.

[0016] The compound represented by formula (a) above can be used as a latent curing agent for curable resin compositions. The compound represented by formula (a) has low catalytic activity at low temperatures (e.g., around 50°C) and does not cure curable resin compositions, but exhibits high catalytic activity at a desired curing temperature (e.g., around 160-170°C) and has latent properties that allow it to cure in a short time (e.g., around 300-500 seconds). Therefore, curable resin compositions containing the compound represented by formula (a) have excellent storage stability as a single-component solution.

[0017] When the curable resin composition is liquid, its storage stability can be confirmed by viscosity measurement. In this invention, storage stability is confirmed by dividing the viscosity of the curable resin composition after being left at 25°C for 24 hours by its initial viscosity, and it is preferably 1.8 times or less, and more preferably 1.5 times or less. When the curable resin composition is solid, its storage stability can be confirmed by gel time measurement. In this invention, the gel time ratio is calculated by dividing the gel time of the curable resin composition after being left at 60°C or 100°C for 1 hour by its initial gel time, and the closer the gel time ratio is to 100%, the better the storage stability. Specifically, it is preferably 80% or more, and more preferably 90% or more.

[0018] Furthermore, curability can be confirmed by gel time and DSC (differential scanning calorimetry). Generally, curability and storage stability often have a trade-off relationship, making it difficult to satisfy both properties. Therefore, in curable resin compositions with equivalent storage stability, differences in properties can be compared by comparing their curability.

[0019] When using the latent curing agent of this embodiment as an electrical or electronic component, it is preferable that the cured product contains few conductive impurities.

[0020] The method for synthesizing the compound represented by formula (a) above is not particularly limited, but it can be obtained as follows.

[0021] The compound represented by formula (a) above can be obtained, for example, by a condensation reaction of an alkoxysilane and a catechol derivative, followed by an anion exchange reaction with a tetrasubstituted phosphonium halide, but is not limited to the above. This reaction is preferably carried out without a catalyst, but a catalyst may be used if necessary.

[0022] Specific examples of organic solvents that can be used in the above condensation reaction include alcohols such as methanol and ethanol, alkanes such as hexane, cyclohexane, and heptane, aromatic hydrocarbon compounds such as toluene and xylene, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, and anone, ethers such as diethyl ether, tetrahydrofuran, and dioxane, and ester compounds such as ethyl acetate, butyl acetate, and methyl formate.

[0023] The above condensation reaction proceeds sufficiently even at temperatures of around 10°C. However, due to the need for reaction time, a reaction temperature of 20 to 200°C is preferable.

[0024] Next, the curable resin composition of this embodiment will be described. The curable resin composition of this embodiment can be used in combination with various materials as exemplified below.

[0025] [Epoxy resin] The curable resin composition of this embodiment may contain an epoxy resin. Preferred epoxy resins are exemplified below, but are not limited to these. The epoxy resin may be liquid or solid, and may be used alone or in combination of multiple types.

[0026] Examples of liquid epoxy resins include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AF type epoxy resin, naphthalene type epoxy resin, glycidyl ester type epoxy resin, glycidylamine type epoxy resin, phenol novolac type epoxy resin, alicyclic epoxy resin having an ester skeleton, cyclohexane type epoxy resin, cyclohexanedimethanol type epoxy resin, and epoxy resin having a butadiene structure. Specific examples include "RE310S", "RE410S" (both manufactured by Nippon Kayaku Co., Ltd., bisphenol A type epoxy resin), "RE303S", "RE304S", "RE403S", "RE404S" (all manufactured by Nippon Kayaku Co., Ltd., bisphenol F type epoxy resin), "HP4032", "HP4032D", "HP4032SS" (all manufactured by DIC Corporation, naphthalene type epoxy resin), "jER828", "jER828US", "jER828EL", "jER825", "jER828XA" (all manufactured by Mitsubishi Chemical Corporation, bisphenol A type epoxy resin), "jER807", "jER1750" (both manufactured by Mitsubishi Chemical Corporation, bisphenol F type epoxy resin), and "jER152" (manufactured by Mitsubishi Chemical Corporation, bisphenol F type epoxy resin). Examples include: "jER630" and "jER630LSD" (both manufactured by Mitsubishi Chemical Corporation, glycidylamine type epoxy resins), "ZX1059" (manufactured by Nippon Steel Chemical & Material Corporation, a mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin), "EX-721" (manufactured by Nagase ChemteX Corporation, glycidyl ester type epoxy resin), "Celoxide 2021P" (manufactured by Daicel Corporation, alicyclic epoxy resin with an ester skeleton), "PB-3600" (manufactured by Daicel Corporation, epoxy resin with a butadiene structure), "ZX1658" and "ZX1658GS" (both manufactured by Nippon Steel Chemical & Material Corporation, liquid 1,4-glycidylcyclohexane type epoxy resins). These may be used individually or in combination of two or more types.

[0027] Preferred solid epoxy resins include, for example, bixylenol-type epoxy resin, naphthalene-type epoxy resin, naphthalene-type tetrafunctional epoxy resin, cresol novolac-type epoxy resin, dicyclopentadiene-type epoxy resin, trisphenol-type epoxy resin, naphthol-type epoxy resin, biphenyl-type epoxy resin, naphthylene ether-type epoxy resin, anthracene-type epoxy resin, bisphenol A-type epoxy resin, bisphenol AF-type epoxy resin, and tetraphenylethane-type epoxy resin. Specific examples include: "HP4032H" (manufactured by DIC Corporation, naphthalene-type epoxy resin), "HP-4700", "HP-4710" (both manufactured by DIC Corporation, naphthalene-type tetrafunctional epoxy resin), "N-690" (manufactured by DIC Corporation, cresol novolac-type epoxy resin), "N-695" (manufactured by DIC Corporation, cresol novolac-type epoxy resin), "HP-7200", "HP-7200HH", "HP-7200H" (both manufactured by DIC Corporation, dicyclopentadiene-type epoxy resin), "EXA-7311", "EXA-7311-G3", "EXA-7311-G4", "EXA-7311-G4S", "HP-6000" (all manufactured by DIC Corporation, naphthylene ether-type epoxy resin), "EPPN-502H" (manufactured by Nippon Kayaku Co., Ltd., trisphenol-type epoxy resin), "NC-7000L", "NC- 7300 (manufactured by Nippon Kayaku Co., Ltd., naphthol-cresol novolac type epoxy resin), "NC-3000H", "NC-3000", "NC-3000L", "NC-3100" (manufactured by Nippon Kayaku Co., Ltd., biphenyl aralkyl type epoxy resin), "XD-1000-2L", "XD-1000-L", "XD-1000-H" (manufactured by Nippon Kayaku Co., Ltd., dicyclopentadiene type epoxy resin), "ESN475V" (manufactured by Nippon Steel Chemical & Material Co., Ltd., naphthol type epoxy resin), "ESN485" (manufactured by Nippon Steel Chemical & Material Co., Ltd., naphthol novolac type epoxy resin), "YX-4000H", "YX-4000", "YL6121" (manufactured by Mitsubishi Chemical Corporation, biphenyl type epoxy resin), "YX-4000HK" (manufactured by Mitsubishi Chemical Corporation, bixylenol type epoxy resin),Examples include "YX-8800" (manufactured by Mitsubishi Chemical Corporation, anthracene-type epoxy resin), "PG-100", "CG-500" (manufactured by Osaka Gas Chemical Co., Ltd., fluorene-based epoxy resin), "YL-7760" (manufactured by Mitsubishi Chemical Corporation, bisphenol AF-type epoxy resin), "YL-7800" (manufactured by Mitsubishi Chemical Corporation, fluorene-type epoxy resin), "jER1010" (manufactured by Mitsubishi Chemical Corporation, solid bisphenol A-type epoxy resin), "jER1031S" (manufactured by Mitsubishi Chemical Corporation, tetraphenylethane-type epoxy resin), CNE-195LL (manufactured by Changchun Artificial Resin Co., Ltd., orthocresol novolac-type epoxy resin), and "TEPIC-S" (manufactured by Nissan Chemical Corporation, isocyanuryl-type epoxy resin). These may be used individually or in combination of two or more types.

[0028] Among these epoxy resins, those with high heat resistance are preferred, so bixylenol-type epoxy resin, naphthalene-type epoxy resin, naphthalene-type tetrafunctional epoxy resin, cresol novolac-type epoxy resin, dicyclopentadiene-type epoxy resin, trisphenol-type epoxy resin, naphthol-type epoxy resin, biphenyl-type epoxy resin, naphthylene ether-type epoxy resin, anthracene-type epoxy resin, bisphenol A-type epoxy resin, bisphenol F-type epoxy resin, and tetraphenylethane-type epoxy resin are preferred, and glycidyl ether-type epoxy resins such as naphthol-type epoxy resin, bisphenol AF-type epoxy resin, naphthalene-type epoxy resin, and biphenyl-type epoxy resin are more preferred.

[0029] The compound represented by formula (a) above is preferably used in an amount of 0.001 to 15 parts by mass per 100 parts by mass of epoxy resin, and more preferably in an amount of 0.01 to 5 parts by mass.

[0030] [Hardening agent] The curable resin composition of this embodiment may be used in combination with a curing agent. Examples of curing agents that can be used in combination include amine resins, acid anhydride compounds, phenol resins, carboxylic acid compounds, and activated ester compounds. Among these, amine resins, acid anhydride compounds, phenol resins, carboxylic acid compounds, activated ester compounds, and benzoxazine compounds are preferred, but the invention is not limited to these.

[0031] [Amine resin] As amine resins, compounds having two or more amino groups in the molecule are preferred, for example, 4,4'-methylenebis(2-ethyl-6-methylaniline) (MDEA), diaminodiphenylmethane, 4,4'-diamino-3,3'-diethyl-5,5'-dimethyldiphenylmethane, diaminodiphenylsulfone, isophoronediamine, naphthalenediamine, aniline novolac (reaction product of aniline and formalin), N-methylaniline novolac (reaction product of N-methylaniline and formalin), orthoethylaniline novolac (reaction product of orthoethylaniline and formalin), reaction product of 2-methylaniline and formalin, reaction product of 2,6-diisopropylaniline and formalin, reaction product of 2,6-diethylaniline and formalin, reaction product of 2-ethyl-6-ethylaniline and formalin. Examples of such substances include, but are not limited to, the reaction product of 2,6-dimethylaniline and formalin, aniline resin obtained by the reaction of aniline and xylylene chloride, the reaction product of aniline and substituted biphenyls (such as 4,4'-bis(chloromethyl)-1,1'-biphenyl and 4,4'-bis(methoxymethyl)-1,1'-biphenyl) as described in Japanese Patent Publication No. 6429862, the reaction product of aniline and substituted phenyls (such as 1,4-bis(chloromethyl)benzene, 1,4-bis(methoxymethyl)benzene and 1,4-bis(hydroxymethyl)benzene), 4,4'-(1,3-phenylenediisopropylidene)bisaniline, the reaction product of aniline and diisopropenylbenzene, and dimer amines. Furthermore, these may be used individually or in combination of multiple types.

[0032] [Acid anhydride compound] Examples of acid anhydride compounds include phthalic anhydride, pyromellitic anhydride, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, nadic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, butanetetracarboxylic anhydride, bicyclo[2.2.1]heptane-2,3-dicarboxylic anhydride, methylbicyclo[2.2.1]heptane-2,3-dicarboxylic anhydride, etc., and a commonly available acid anhydride compound is "KAYAHARD Examples include "MCD" (manufactured by Nippon Kayaku Co., Ltd.), "Licacid MH-700" (manufactured by Shin Nippon Rika Co., Ltd., 4-methylhexahydrophthalic anhydride), "Licacid TH" (manufactured by Shin Nippon Rika Co., Ltd., tetrahydrophthalic anhydride), "Licacid HH" (manufactured by Shin Nippon Rika Co., Ltd., hexahydrophthalic anhydride), and "Licacid MH-T" (manufactured by Shin Nippon Rika Co., Ltd.; main component is 4-methylhexahydrophthalic anhydride), but are not limited to these. Furthermore, these can be used individually or in combination.

[0033] [Phenol compounds] Preferred phenolic compounds are those having two or more phenolic hydroxyl groups in their molecule. Examples include reaction products of phenols and aldehydes (phenol novolac curing agents), reaction products of phenols and diene compounds, reaction products of phenols and ketones, reaction products of phenols and substituted biphenyls, reaction products of phenols and substituted phenyls, and reaction products of bisphenols and aldehydes. Commonly available phenolic compounds include phenol novolac curing agent H-1 (manufactured by UBE Corporation) and cresol novolac curing agent KA-1160 (manufactured by DIC Corporation), but are not limited to these. These may be used individually or in combination. Specific examples of each of the above ingredients are given below, but this list is not exhaustive. <Phenols> Phenols, alkyl-substituted phenols, aromatic-substituted phenols, hydroquinones, resorcinols, naphthols, alkyl-substituted naphthols, dihydroxybenzenes, alkyl-substituted dihydroxybenzenes, dihydroxynaphthalenes, etc. <Aldehydes> Formaldehyde, acetaldehyde, alkylaldehyde, benzaldehyde, alkyl-substituted benzaldehyde, hydroxybenzaldehyde, naphthaldehyde, glutaraldehyde, phthalaldehyde, crotonaldehyde, cinnamaldehyde, furfural, etc. <Diene compounds> Dicyclopentadiene, terpenes, vinylcyclohexene, norbornadiene, vinylnorbornene, tetrahydroindene, divinylbenzene, divinylbiphenyl, diisopropenylbiphenyl, butadiene, isoprene, etc. <Ketones> Acetone, methyl ethyl ketone, methyl isobutyl ketone, acetophenone, benzophenone, fluorenone, etc. <Substituted biphenyls> 4,4'-bis(chloromethyl)-1,1'-biphenyl, 4,4'-bis(methoxymethyl)-1,1'-biphenyl, 4,4'-bis(hydroxymethyl)-1,1'-biphenyl, etc. <Substituted Phenyl Groups> 1,4-Bis(chloromethyl)benzene, 1,4-Bis(methoxymethyl)benzene, 1,4-Bis(hydroxymethyl)benzene, etc.

[0034] [Carboxylic acid compounds] Preferred carboxylic acid compounds are those having two or more carboxyl groups in their molecule. Examples include aromatic carboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, benzophenonetetracarboxylic acid, and franciocarboxylic acid, as well as succinic acid, adipic acid, dodecanedioic acid, sebacic acid, thiodipropionic acid, cyclohexanedicarboxylic acid, tris(2-carboxymethyl)isocyanurate, tris(2-carboxyethyl)isocyanurate, tris(2-carboxypropyl)isocyanurate, and bis(2-carboxyethyl)isocyanurate, but are not limited to these. These compounds may be used individually or in combination.

[0035] [Activated ester compounds] An active ester compound is a compound that contains at least one ester bond in its structure, with aliphatic chains, aliphatic rings, or aromatic rings bonded to both sides of the ester bond. Examples of active ester compounds include compounds having two or more highly reactive ester groups in one molecule, such as phenol esters, thiophenol esters, N-hydroxyamine esters, and esters of heterocyclic hydroxy compounds. These are obtained by a condensation reaction between at least one compound of a carboxylic acid compound, an acid chloride, or a thiocarboxylic acid compound and at least one compound of a hydroxy compound or a thiol compound. Particularly from the viewpoint of improving heat resistance, it is preferable that they be obtained from a carboxylic acid compound or an acid chloride and a hydroxy compound, and phenol compounds or naphthol compounds are preferred as the hydroxy compound. Active ester compounds may be used alone or in combination of two or more.

[0036] Examples of the carboxylic acid compounds mentioned above include benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid, and pyromellitic acid.

[0037] Examples of the above-mentioned acid chlorides include acetyl chloride, acrylate chloride, methacrylate chloride, malonyl chloride, succinate dichloride, diglycolyl chloride, glutarate dichloride, suberic acid dichloride, sebacate dichloride, adipic acid dichloride, dodecanediol dichloride, azera oil chloride, 2,5-franzicarbonyl dichloride, phthaloyl chloride, isophthaloyl chloride, terephthaloyl chloride, trimesic acid chloride, bis(4-chlorocarbonylphenyl) ether, 4,4'-diphenyldicarbonyl chloride, and 4,4'-azodibenzoyl dichloride.

[0038] Examples of the above-mentioned phenol compounds and naphthol compounds include hydroquinone, resorcinol, bisphenol A, bisphenol F, bisphenol S, phenolphthalein, 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, phenol novolac, and phenol resins described later. Here, "dicyclopentadiene-type diphenol compound" refers to a diphenol compound obtained by the condensation of two molecules of phenol with one molecule of dicyclopentadiene.

[0039] Preferred examples of active ester compounds include active ester compounds containing a dicyclopentadiene-type diphenol structure, active ester compounds containing a naphthalene structure, active ester compounds containing an acetylated phenol novolac, active ester compounds containing a benzoylated phenol novolac, the compounds described in Example 2 of International Publication No. 2020 / 095829, and the compounds disclosed in International Publication No. 2020 / 059625. Among these, active ester compounds containing a naphthalene structure and active ester compounds containing a dicyclopentadiene-type diphenol structure are more preferred. The dicyclopentadiene-type diphenol structure represents a divalent structural unit consisting of phenylene-dicyclopentylene-phenylene.

[0040] Commercially available active ester compounds include, for example, active ester compounds containing a dicyclopentadiene-type diphenol structure such as "EXB9451," "EXB9460," "EXB9460S," "HPC-8000-65T," "HPC-8000H-65TM," "EXB-8000L-65TM," and "EXB-8150-65T" (manufactured by DIC Corporation), and active ester compounds containing a naphthalene structure such as "EXB9416-70BK" (manufactured by DIC Corporation), and compounds containing acetylated phenol novolacs. Examples of active ester compounds include "DC808" (manufactured by Mitsubishi Chemical Corporation), active ester compounds containing benzoylated phenol novolacs include "YLH1026", "YLH1030", and "YLH1048" (manufactured by Mitsubishi Chemical Corporation), active ester curing agents that are acetylated phenol novolacs include "DC808" (manufactured by Mitsubishi Chemical Corporation), active ester curing agents containing phosphorus atoms include "EXB-9050L-62M" manufactured by DIC Corporation, and active ester compounds containing a bisphenol A structure include "Unifiner W-575", etc.

[0041] Regarding the blending ratio of the active ester compound and epoxy resin, the ratio of the active ester equivalent (α) to the epoxy equivalent (β) (α / β) is preferably 0.5 to 1.5, more preferably 0.8 to 1.2, and even more preferably 0.90 to 1.10. If it falls outside the above range, there is a risk that excess epoxy groups or active ester groups will remain in the system, which may lead to deterioration of properties in high-temperature storage tests (e.g., 150°C, 1000 hours) or long-term reliability tests under high-temperature and high-humidity conditions (e.g., temperature: 85°C, humidity: 85%).

[0042] The mixing ratio of epoxy resin to curing agent is preferably such that, for every equivalent of epoxy groups in the epoxy resin, the amount of active groups (such as acid anhydride groups or hydroxyl groups) in the curing agent that can react with the epoxy groups is 0.5 to 1.5 equivalents (considering carboxylic acids as monofunctional and acid anhydrides as monofunctional), and particularly preferably 0.5 to 1.2 equivalents. If the amount is less than 0.5 equivalents or more than 1.5 equivalents per equivalent of epoxy groups, curing may be incomplete, and good cured properties may not be obtained.

[0043] [Benzoxazine compounds] The curable resin composition of this embodiment may also contain a benzoxazine compound. The benzoxazine compound is preferably one having two or more amino groups in its molecule. Examples include bisphenol A-type benzoxazine BA-BXZ (manufactured by Konishi Chemical Co., Ltd.), bisphenol F-type benzoxazine BF-BXZ (manufactured by Konishi Chemical Co., Ltd.), bisphenol S-type benzoxazine BS-BXZ (manufactured by Konishi Chemical Co., Ltd.), and phenolphthalein-type benzoxazine, but is not particularly limited. These benzoxazine compounds can be used individually or in appropriate mixtures of two or more.

[0044] [Curing accelerator] In addition to the compound represented by formula (a) above, a curing accelerator may also be used in combination with the curable resin composition of this embodiment. Preferably, the curing accelerator is an anionic curing accelerator that promotes the curing reaction by generating anions upon irradiation with ultraviolet light or visible light or by heating, or a cationic curing accelerator that promotes the curing reaction by generating cations upon irradiation with ultraviolet light or visible light or by heating.

[0045] [Anionic curing accelerator] Examples of anionic curing accelerators include imidazoles such as 2-methylimidazole, 2-ethylimidazole, and 2-ethyl-4-methylimidazole; trialkylamines such as triethylamine and tributylamine; 4-dimethylaminopyridine, benzyldimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, and 1,8-diazabicyclo(5,4,0)-undecene, with 4-dimethylaminopyridine and 1,8-diazabicyclo(5,4,0)-undecene being preferred. Other examples include phosphines such as triphenylphosphine, tetrabutylammonium salt, triisopropylmethylammonium salt, trimethyldecanylammonium salt, cetyltrimethylammonium salt, and quaternary ammonium salts such as hexadecyltrimethylammonium hydroxide, but are not limited to these. These can be used individually or in combination.

[0046] [Cationic curing accelerator] Examples of cationic curing accelerators include quaternary phosphonium salts such as triphenylbenzylphosphonium salt, triphenylethylphosphonium salt, and tetrabutylphosphonium salt (the counterions of the quaternary salts are halogens, organic acid ions, hydroxide ions, etc., with no particular preference, but organic acid ions and hydroxide ions are particularly preferred), transition metal compounds (transition metal salts) such as tin octylate, octopzinc (2-ethylhexanoate), zinc carboxylate (zinc 2-ethylhexanoate, zinc stearate, zinc behenate, zinc myristate), and zinc phosphate esters (zinc octyl phosphate, zinc stearyl phosphate), but are not limited to these. Furthermore, these may be used individually or in combination of multiple types.

[0047] The curing accelerator is preferably used in an amount of 0.001 to 15 parts by mass per 100 parts by mass of epoxy resin, and more preferably in an amount of 0.01 to 5 parts by mass.

[0048] [Organic peroxide] Examples of organic peroxides include ketone peroxides such as methyl ethyl ketone peroxide and acetylacetone peroxide, diacyl peroxides such as benzoyl peroxide, dialkyl peroxides such as dicumyl peroxide and 1,3-bis-(t-butylperoxyisopropyl)benzene, peroxyketals such as t-butyl peroxybenzoate and 1,1-di-t-butylperoxycyclohexane, α-cumyl peroxyneodecanoate, t-butyl peroxyneodecanoate, t-butyl peroxypivalate, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, t-amyl peroxy-2-ethylhexanoate, and t-butyl peroxy Examples of such substances include alkyl peresters such as oxy-2-ethylhexanoate, t-amyl peroxy-3,5,5-trimethylhexanoate, t-butyl peroxy-3,5,5-trimethylhexanoate, and t-amyl peroxybenzoate; peroxycarbonates such as di-2-ethylhexyl peroxydicarbonate, bis(4-t-butylcyclohexyl) peroxydicarbonate, t-butyl peroxyisopropyl carbonate, and 1,6-bis(t-butyl peroxycarbonyloxy)hexane; t-butyl hydroperoxide, cumene hydroperoxide, t-butyl peroxyoctoate, and lauroyl peroxide, but are not limited to these. These substances may be used individually or in combination. Among the above organic peroxides, ketone peroxides, diacyl peroxides, hydroperoxides, dialkyl peroxides, peroxyketals, alkyl peresters, and peroxycarbonates are preferred, with dialkyl peroxides being more preferred.

[0049] [Azo compounds] Examples of azo compounds include, but are not limited to, azobisisobutyronitrile, 4,4'-azobis(4-cyanovaleric acid), and 2,2'-azobis(2,4-dimethylvaleronitrile). Furthermore, these compounds may be used individually or in combination.

[0050] [Polymerization initiator] The curable resin composition of this embodiment may contain a polymerization initiator. Either a thermal polymerization initiator or a photopolymerization initiator may be used.

[0051] [Thermal polymerization initiator] A thermal polymerization initiator is a compound capable of polymerizing olefin functional groups such as ethylenically unsaturated bonds, and examples include olefin metathesis polymerization initiators, thermal anionic polymerization initiators, thermal cationic polymerization initiators, and thermal radical polymerization initiators. Among these, it is preferable to use a thermal radical polymerization initiator that has curability and appropriate stability. A thermal radical polymerization initiator is a compound that generates radicals upon heating and initiates a chain polymerization reaction. Examples of thermal radical polymerization initiators include organic peroxides, azo compounds, and benzopinacols, and it is preferable to use organic peroxides because they have less influence on curing temperature control, outgassing suppression, and the electrical properties of decomposition products.

[0052] [Photopolymerization initiator] The curable resin composition of this embodiment may contain a photopolymerization initiator. Examples of photopolymerization initiators include radical-based photopolymerization initiators, cationic-based photopolymerization initiators, and photobase initiators. Among these, radical-based photopolymerization initiators, which have high curability, are preferred.

[0053] [Radical-based photopolymerization initiators] Examples of radical photopolymerization initiators include 1,2-octanedione,1-[4-(phenylthio)-,2-(O-benzoyloxime)] (BASF Japan, "IRGACURE OXE-01") and ethanone,1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-,1-(O-acetyloxime) (BASF Japan, "IRGACURE Oximes such as "OXE-02"; Benzoins such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, and benzoin isobutyl ether; Acetophenones such as acetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 2-hydroxy-2-methylphenylpropan-1-one, diethoxyacetophenone, 1-hydroxycyclohexylphenyl ketone, and 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propan-1-one; 2-ethylanthraquinone, 2-t-butylanthraquinone, 2-chloroanthraquinone, and 2-amylane Examples of commonly known radical photopolymerization initiators include anthraquinones such as traquinone; thioxanthones such as 2,4-diethylthioxanthone (manufactured by Nippon Kayaku Co., Ltd., "DETX-S"), 2-isopropylthioxanthone, and 2-chlorothioxanthone; ketals such as acetophenone dimethyl ketal and benzyl dimethyl ketal; benzophenones such as benzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, and 4,4'-bismethylaminobenzophenone; and phosphine oxides such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide.

[0054] [Cationic photopolymerization initiators] Cationic photopolymerization initiators include diazonium salts of Lewis acids, iodonium salts of Lewis acids, sulfonium salts of Lewis acids, phosphonium salts of Lewis acids, other halides, triazine-based photopolymerization initiators, borate-based photopolymerization initiators, and other photoacid generators.

[0055] <Diazonium salts of Lewis acids> Examples of diazonium salts of Lewis acids include p-methoxyphenyldiazonium fluorophosphonate and N,N-diethylaminophenyldiazonium hexafluorophosphonate (e.g., San-Aid SI-60L / SI-80L / SI-100L manufactured by Sanshin Chemical Industry Co., Ltd.). Examples of iodonium salts of Lewis acids include diphenyliodonium hexafluorophosphonate and diphenyliodonium hexafluoroantimonate. Examples of sulfonium salts of Lewis acids include triphenylsulfonium hexafluorophosphonate (e.g., CyracureUVI-6990 manufactured by UnionCarbide Inc.) and triphenylsulfonium hexafluoroantimonate (e.g., CyracureUVI-6974 manufactured by UnionCarbide Inc.). Examples of phosphonium salts of Lewis acids include triphenylphosphonium hexafluoroantimonate.

[0056] <Other halogenated compounds> Other halides include 2,2,2-trichloro-[1-4'-(dimethylethyl)phenyl]ethanone (e.g., TrigonalPI from AKZO), 2,2-dichloro-1-4-(phenoxyphenyl)ethanone (e.g., Sandray1000 from Sandoz), and α,α,α-tribromomethylphenylsulfone (e.g., BMPS from Seitetsu Kagaku Co., Ltd.). Examples of triazine-based initiators include 2,4,6-tris(trichloromethyl)-triazine, 2,4-trichloromethyl-(4'-methoxyphenyl)-6-triazine (e.g., Triazine A from Panchim), 2,4-trichloromethyl-(4'-methoxystyryl)-6-triazine (e.g., Triazine PMS from Panchim), 2,4-trichloromethyl-(piperonyl)-6-triazine (e.g., Triazine PP from Panchim), 2,4-trichloromethyl-(4'-methoxynaphthyl)-6-triazine (e.g., Triazine B from Panchim), 2[2'(5-methylfuryl)ethylidene]-4,6-bis(trichloromethyl)-s-triazine (e.g., Sanwa Chemical Co., Ltd.), and 2(2'-furylethylidene)-4,6-bis(trichloromethyl)-s-triazine (e.g., Sanwa Chemical Co., Ltd.).

[0057] <Borate-based photopolymerization initiators> Examples of borate-based initiators include NK-3876 and NK-3881 from Nippon Photosensitive Dye Co., Ltd., while other photoacid generators include 9-phenylacridine, 2,2'-bis(o-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2-biimidazole (e.g., biimidazole from Kurogane Chemical Co., Ltd.), 2,2-azobis(2-amino-propane)dihydrochloride (e.g., V50 from Fujifilm Wako Pure Chemical Industries, Ltd.), and 2,2-azobis[2-(imidazolin-2yl)propane Examples include dihydrochlorides (such as VA044 from Fujifilm Wako Pure Chemical Industries), [eta-5-2-4-(cyclopentadecyl)(1,2,3,4,5,6,eta)-(methylethyl)-benzene]iron(II) hexafluorophosphonate (such as Irgacure261 from CibaGeigy), and bis(y5-cyclopentadienyl)bis[2,6-difluoro-3-(1H-pyri-1-yl)phenyl]titanium (such as CGI-784 from CibaGeigy).

[0058] [Photobase initiator] Examples of photobase initiators include TRD-001 (manufactured by Nippon Kayaku Co., Ltd.), TRD-008 (manufactured by Nippon Kayaku Co., Ltd.), WPBG-300 (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), WPBG-345 (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), PBG-266 (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), WPBG-018 (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), WPBG-027 (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), WPBG-140 (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), and WPBG-165 (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.).

[0059] The amount of photopolymerization 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. One type of photopolymerization initiator may be used alone, or two or more types may be used in combination.

[0060] [Polymerization inhibitor] The curable resin composition of this embodiment may contain a polymerization inhibitor. Including a polymerization inhibitor improves storage stability and allows control of the reaction initiation temperature. Controlling the reaction initiation temperature makes it easier to ensure fluidity, prevents impregnation of glass cloth and the like, and facilitates B-stage processes such as prepreg formation. If the polymerization reaction proceeds too far during prepreg formation, problems such as difficulty in lamination during the lamination process are likely to occur.

[0061] The amount of polymerization inhibitor used is 0.008 to 1 part by mass, preferably 0.01 to 0.5 parts by mass, per 100 parts by mass of the curable resin composition of this embodiment.

[0062] Examples of polymerization inhibitors include phenol-based, sulfur-based, phosphorus-based, hindered amine-based, nitroso-based, and nitroxyl radical-based agents. Furthermore, polymerization inhibitors may be used individually or in combination of multiple types. Of these, phenol-based, hindered amine-based, nitroso-based, and nitroxyl radical-based agents are preferred in this embodiment.

[0063] [Phenol-based polymerization inhibitors] Examples of phenolic polymerization inhibitors include 2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-t-butyl-p-ethylphenol, stearyl-β-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, isooctyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, 2,4-bis-(n-octylthio)-6-(4-hydroxy-3,5-di-t-butylanilino)-1,3,5-triazine, and 2,4-bis[(octylthio)methyl]-o-cresol. Monophenols such as zoles, 2,2'-methylenebis(4-methyl-6-t-butylphenol), 2,2'-methylenebis(4-ethyl-6-t-butylphenol), 4,4'-thiobis(3-methyl-6-t-butylphenol), 4,4'-butylidenebis(3-methyl-6-t-butylphenol), triethylene glycol-bis[3-(3-t-butyl-5-methyl-4-hydroxyphenyl)propionate], 1,6-hexanediol-bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate] ], N,N'-hexamethylenebis(3,5-di-t-butyl-4-hydroxy-hydrocinnamamide), 2,2-thio-diethylenebis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], 3,5-di-t-butyl-4-hydroxybenzylphosphonate-diethyl ester, 3,9-bis[1,1-dimethyl-2-{β-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy}ethyl]2,4,8,10-tetraoxaspiro[5,5]undecane, bis(3,5-di-t-butyl Bisphenols such as calcium hydroxybenzylsulfonate ethyl, 1,1,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl)butane, 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene, tetrakis-[methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]methane, bis[3,3'-bis-(4'-hydroxy-3'-t-butylphenyl)butyric acid]glycol ester, tris-(3,Examples include, but are not limited to, high molecular weight phenols such as 5-di-t-butyl-4-hydroxybenzyl)-isocyanurate, 1,3,5-tris(3',5'-di-t-butyl-4'-hydroxybenzyl)-S-triazine-2,4,6-(1H,3H,5H)trione, and tocopherol.

[0064] [Sulfur-based polymerization inhibitors] Examples of sulfur-based polymerization inhibitors include, but are not limited to, dilauryl-3,3'-thiodipropionate, dimyristyl-3,3'-thiodipropionate, and distearyl-3,3'-thiodipropionate.

[0065] [Phosphorus polymerization inhibitors] Examples of phosphorus polymerization inhibitors include triphenyl phosphite, diphenylisodecyl phosphite, phenyldiisodecyl phosphite, tris(nonylphenyl) phosphite, diisodecylpentaerythritol phosphite, tris(2,4-di-t-butylphenyl) phosphite, cyclic neopentanetetraylbis(octadecyl) phosphite, cyclic neopentanetetraylbis(2,4-di-t-butylphenyl) phosphite, cyclic neopentanetetraylbis(2,4-di-t-butyl-4-methylphenyl) phosphite, and bis[2-t Examples include, but are not limited to, phosphites such as -butyl-6-methyl-4-{2-(octadecyloxycarbonyl)ethyl}phenyl]hydrogen phosphite, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-(3,5-di-t-butyl-4-hydroxybenzyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and 10-decyloxy-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide.

[0066] [Hindered amine polymerization inhibitors] Examples of hindered amine polymerization inhibitors include, but are not limited to, Adekastab LA-40MP, Adekastab LA-40Si, Adekastab LA-402AF, Adekastab LA-87, Adekastab LA-82, Adekastab LA-81, Adekastab LA-77Y, Adekastab LA-77G, Adekastab LA-72, Adekastab LA-68, Adekastab LA-63P, Adekastab LA-57, Adekastab LA-52, Chimassorb2020FDL, Chimassorb944FDL, Chimassorb944LD, Tinuvin622SF, TinuvinPA144, Tinuvin765, Tinuvin770DF, TinuvinXT55FB, Tinuvin111FDL, Tinuvin783FDL, and Tinuvin791FB.

[0067] [Nitrosopolymer Inhibitors] Examples of nitroso polymerization inhibitors include, but are not limited to, p-nitrosophenol, N-nitrosodiphenylamine, ammonium salts of N-nitrosophenylhydroxyamine, and (cuperone). Of these, ammonium salts of N-nitrosophenylhydroxyamine (cuperone) are preferred.

[0068] [Nitroxyl radical polymerization inhibitors] Examples of nitroxyl radical polymerization inhibitors include, but are not limited to, di-tert-butylnitroxide, 2,2,6,6-tetramethylpiperidine-1-oxyl, 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl, 4-oxo-2,2,6,6-tetramethylpiperidine-1-oxyl, 4-amino-2,2,6,6-tetramethylpiperidine-1-oxyl, 4-methoxy-2,2,6,6-tetramethylpiperidine-1-oxyl, 4-acetoxy-2,2,6,6-tetramethylpiperidine-1-oxyl, and 4-benzoyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl.

[0069] [Flame retardant] The curable resin composition of this embodiment may contain a flame retardant. Examples of flame retardants include halogen-based flame retardants, inorganic flame retardants (antimony compounds, metal hydroxides, nitrogen compounds, boron compounds, etc.), and phosphorus-based flame retardants, but phosphorus-based flame retardants are preferred from the viewpoint of achieving halogen-free flame retardancy.

[0070] The phosphorus-based flame retardants mentioned above may be reactive or additive types. Specific examples include phosphate esters such as trimethyl phosphate, triethyl phosphate, tricresyl phosphate, trixyllenyl phosphate, cresyl diphenyl phosphate, cresyl-2,6-dixyllenyl phosphate, 1,3-phenylenebis(dixyllenyl phosphate), 1,4-phenylenebis(dixyllenyl phosphate), and 4,4'-biphenyl(dixyllenyl phosphate); phosphanes such as 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and 10(2,5-dihydroxyphenyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide; phosphorus-containing epoxy compounds obtained by reacting epoxy resin with the active hydrogen of the above phosphanes; and red phosphorus, but are not limited to these. Furthermore, these may be used individually or in combination of multiple types. Among the above example substances, phosphate esters, phosphans, or phosphorus-containing epoxy compounds are preferred, and 1,3-phenylenebis(dixyllenyl phosphate), 1,4-phenylenebis(dixyllenyl phosphate), 4,4'-biphenyl(dixyllenyl phosphate), or phosphorus-containing epoxy compounds are particularly preferred.

[0071] The flame retardant content is preferably in the range of 0.1 to 0.6 parts by mass per 100 parts by mass of the curable resin composition. If the content is less than 0.1 parts by mass, the flame retardancy may be insufficient, and if it is more than 0.6 parts by mass, it may adversely affect the hygroscopicity and dielectric properties of the cured product.

[0072] [Light stabilizer] The curable resin composition of this embodiment may contain a light stabilizer. Suitable light stabilizers include hindered amine-based light stabilizers, particularly HALS. Examples of HALS include: a reaction product of dibutylamine·1,3,5-triazine·N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-1,6-hexamethylenediamine and N-(2,2,6,6-tetramethyl-4-piperidyl)butylamine; a reaction product of dimethyl-1-(2-hydroxyethyl)-4-hydroxy-2,2,6,6-tetramethylpiperidine succinate; and poly[{6-(1,1,3,3-tetramethylbutyl)amino-1,3,5-triazine-2,4-diyl}{(2,2,6,6-tetramethyl-4-piperidyl)imino}hexamethylene{(2,2,6,6-tetramethyl-4-piperidyl Examples include, but are not limited to, bis(1,2,2,6,6-pentamethyl-4-piperidyl)[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]butylmalonate, bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, bis(1-octyroxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate, 2-(3,5-di-t-butyl-4-hydroxybenzyl)-2-n-butylmalonate bis(1,2,2,6,6-pentamethyl-4-piperidyl). Furthermore, these may be used individually or in combination.

[0073] The amount of light stabilizer is preferably in the range of 0.001 to 0.1 parts by mass per 100 parts by mass of the curable resin composition. If the amount is less than 0.001 parts by mass, it may be insufficient to exhibit the light stabilization effect, and if it is more than 0.1 parts by mass, it may adversely affect the hygroscopicity and dielectric properties of the cured product.

[0074] [Binder resin] The curable resin composition of this embodiment may contain a binder resin. Examples of binder resins include, but are not limited to, polyphenylene ether compounds, polyamide resins, polyimide resins, polybutadiene and modified thereof, polystyrene and modified thereof, polyethylene and modified thereof, butyral resins, acetal resins, acrylic resins, epoxy-nylon resins, NBR-phenolic resins, epoxy-NBR resins, and silicone resins. Furthermore, these may be used individually or in combination of multiple types.

[0075] [Polyphenylene ether compounds] From the viewpoint of heat resistance and electrical properties, the polyphenylene ether compound is preferably a polyphenylene ether compound having an ethylenically unsaturated bond, and more preferably a polyphenylene ether compound having an acrylic group, a methacrylic group, or a styrene structure. Examples of commercially available products include SA-9000 (manufactured by SABIC, a polyphenylene ether compound having a methacrylic group) and OPE-2St 1200 (manufactured by Mitsubishi Gas Chemical Company, a polyphenylene ether compound having a styrene structure). The number-average molecular weight (Mn) of the polyphenylene ether compound is preferably 500 to 5000, more preferably 2000 to 5000, and even more preferably 2000 to 4000. If the molecular weight is less than 500, the cured product tends not to have sufficient heat resistance. If the molecular weight is greater than 5000, the melt viscosity increases, and sufficient fluidity cannot be obtained, which tends to lead to molding defects. Furthermore, the reactivity decreases, requiring a long time for the curing reaction, increasing the amount of unreacted material that is not incorporated into the curing system, lowering the glass transition temperature of the cured product, and tending to reduce the heat resistance of the cured product. If the number-average molecular weight of the polyphenylene ether compound is between 500 and 5000, it is possible to achieve excellent heat resistance and moldability while maintaining excellent dielectric properties. Specifically, the number-average molecular weight can be measured using methods such as gel permeation chromatography.

[0076] Polyphenylene ether compounds may be obtained by polymerization reactions, or by redistributing high molecular weight polyphenylene ether compounds with a number average molecular weight of approximately 10,000 to 30,000. Alternatively, these may be used as raw materials and reacted with compounds having ethylenically unsaturated bonds, such as methacrylate chloride, acrylate chloride, and chloromethylstyrene, to impart radical polymerizability. Polyphenylene ether compounds obtained by redistribution reactions can be obtained, for example, by heating a high molecular weight polyphenylene ether compound in a solvent such as toluene in the presence of a phenolic compound and a radical initiator to induce a redistribution reaction. Polyphenylene ether compounds obtained by such redistribution reactions are preferable because they maintain even higher heat resistance due to having hydroxyl groups derived from phenolic compounds that contribute to curing at both ends of the molecular chain, and because functional groups can be introduced to both ends of the molecular chain even after modification with compounds having ethylenically unsaturated bonds. Furthermore, polyphenylene ether compounds obtained by polymerization reactions are preferable because they exhibit excellent fluidity.

[0077] The molecular weight of polyphenylene ether compounds can be adjusted by adjusting polymerization conditions, etc., in the case of polyphenylene ether compounds obtained by polymerization reactions. In the case of polyphenylene ether compounds obtained by redistribution reactions, the molecular weight of the resulting polyphenylene ether compound can be adjusted by adjusting the conditions of the redistribution reaction, etc. More specifically, this can be done by adjusting the amount of phenolic compound used in the redistribution reaction. That is, the higher the amount of phenolic compound used, the lower the molecular weight of the resulting polyphenylene ether compound. In this case, poly(2,6-dimethyl-1,4-phenylene ether) can be used as the high molecular weight polyphenylene ether compound that undergoes the redistribution reaction. Furthermore, the phenolic compound used in the above redistribution reaction is not particularly limited, but polyfunctional phenolic compounds having two or more phenolic hydroxyl groups in the molecule, such as bisphenol A, phenol novolac, and cresol novolac, are preferably used. These may be used individually or in combination of two or more.

[0078] The content of the polyphenylene ether compound is not particularly limited, but is preferably 5 to 1000 parts by mass, and more preferably 10 to 750 parts by mass, per 100 parts by mass of the curable resin composition. When the content of the polyphenylene ether compound is within the above range, it is preferable not only to obtain a cured product that is excellent in heat resistance and the like, but also in that the excellent dielectric properties of the polyphenylene ether compound are fully exhibited.

[0079] [Polyamide resin] Examples of polyamide resins include reaction products of one or more of diamines, diisocyanates, or oxazolines with dicarboxylic acids, reaction products of diamines and acid chlorides, and ring-opening polymers of lactam compounds. These can be used individually or in combination. Specific examples of each of the above ingredients are given below, but this list is not exhaustive. <Diamine> 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, dimer amine, cyclohexanediamine, bis-(4-aminocyclohexyl)methane, bis(3-methyl-4-aminocyclohexyl)methane, xylylenediamine, norbornanediamine, isophoronediamine, bisaminomethyltricyclodecane, phenylenediamine, diethyltoluenediamine, naphthalenediamine, diaminodiphenylmethane, bis(4-amino-3,5-dimethylphenyl)methane, bis(4-amino-3,5-diethylphenyl)methane 4,4'-methylenebis-o-toluidine, 4,4'-methylenebis-o-ethylaniline, 4,4'-methylenebis-2-ethyl-6-methylaniline, 4,4'-methylenebis-2,6-diisopropylaniline, 4,4-ethylenedianiline, diaminodiphenyl sulfone, diaminodiphenyl ether, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 4,4-bis(4-aminophenoxy)biphenyl, 2,2-bis[4-(4-amino [phenoxy)phenyl]propane, bis[4-(4-aminophenoxy)phenyl]sulfone, 2,2-bis(3-amino-4-hydroxyphenyl)propane, 2,2-bis(4-aminophenyl)hexafluoropropane, 4,4'-(1,3-phenylenediisopropylidene)bisaniline, 4,4'-(1,4-phenylenediisopropylidene)bisaniline, 9,9-bis(4-aminophenyl)fluorene, 2,7-diaminofluorene, aminobenzylamine, diaminobenzophenone, etc. <Diisocyanate> Benzene diisocyanate, toluene diisocyanate, 1,3-bis(isocyanatomethyl)benzene, 1,3-bis(isocyanatomethyl)cyclohexane, bis(4-isocyanatophenyl)methane, isophorone diisocyanate, 1,3-bis(2-isocyanato-2-propyl)benzene, 2,2-bis(4-isocyanatophenyl)hexafluoropropane, dicyclohexylmethane-4,4'-diisocyanate, etc. <Dicarboxylic acid> Oxalic acid, malonic acid, succicic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, undecanediic acid, dodecanediic acid, terephthalic acid, isophthalic acid, 5-hydroxyisophthalic acid, 2-chloroterephthalic acid, 2-methylterephthalic acid, 5-methylisophthalic acid, 5-sodium sulfoisophthalic acid, hexahydroterephthalic acid, hexahydroisophthalic acid, cyclohexanedicarboxylic acid, biphenyldicarboxylic acid, naphthalenedicarboxylic acid, benzophenonedicarboxylic acid, francicarboxylic acid, 4,4'-dicarboxydiphenyl ether, 4,4'-dicarboxydiphenyl sulfide, etc. <Acid chlorides> Acetyl chloride, acrylate chloride, methacrylate chloride, malonyl chloride, succinate dichloride, diglycolyl chloride, glutarate dichloride, suberate dichloride, sebacate dichloride, adipic acid dichloride, dodecanediol dichloride, azera oil chloride, 2,5-franzicarbonyl dichloride, phthaloyl chloride, isophthaloyl chloride, terephthaloyl chloride, trimesinate chloride, bis(4-chlorocarbonylphenyl) ether, 4,4'-diphenyldicarbonyl chloride, 4,4'-azodibenzoyl dichloride, etc. <Lactam> ε-caprolactam, ω-undecanlactam, ω-laurolactam, etc.

[0080] [Polyimide resin] Examples of polyimide resins include, but are not limited to, the reaction products of the above-mentioned diamine and the tetracarboxylic dianhydride exemplified below. A specific example is LDFI089 (a polyimide compound obtained by the method described in WO2023013224A1). These can be used individually or in combination. <Tetracarboxylic acid dianhydride> 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methylcyclohexene-1,2-dicarboxylic acid anhydride, pyromellitic dianhydride, 1,2,3,4-benzenetetracarboxylic acid dianhydride, 3,3',4,4'-benzophenonetetracarboxylic acid dianhydride, 2,2',3,3'-benzophenonetetracarboxylic acid dianhydride, 3,3',4,4'-biphenyltetracarboxylic acid dianhydride, 3,3',4,4'-diphenylsulfonetetracarboxylic acid dianhydride, 2,2',3, 3'-Biphenyltetracarboxylic acid dianhydride, methylene-4,4'-diphthalic acid dianhydride, 1,1-ethylidene-4,4'-diphthalic acid dianhydride, 2,2'-propyridene-4,4'-diphthalic acid dianhydride, 1,2-ethylene-4,4'-diphthalic acid dianhydride, 1,3-trimethylene-4,4'-diphthalic acid dianhydride, 1,4-tetramethylene-4,4'-diphthalic acid dianhydride, 1,5-pentamethylene-4,4'-diphthalic acid dianhydride, 4,4'-oxydiphthalic acid dianhydride, thio-4,4'-diphthalic acid dianhydride, sulfonyl-4,4'-diphthalic acid Dianhydride, 1,3-bis(3,4-dicarboxyphenyl)benzene dianhydride, 1,3-bis(3,4-dicarboxyphenoxy)benzene dianhydride, 1,4-bis(3,4-dicarboxyphenoxy)benzene dianhydride, 1,3-bis[2-(3,4-dicarboxyphenyl)-2-propyl]benzene dianhydride, 1,4-bis[2-(3,4-dicarboxyphenyl)-2-propyl]benzene dianhydride, bis[3-(3,4-dicarboxyphenoxy)phenyl]methane dianhydride, bis[4-(3,4-dicarboxyphenoxy)phenyl]meth 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 acid dianhydride, 1,4,5,8-naphthalenetetracarboxylic acid dianhydride, 1,2,5,6-naphthalenetetracarboxylic acid 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, Cyclohexane-1,2,3,4-Tetocarboxylic dianhydride, Cyclohexane-1,2,4,5-Tetocarboxylic dianhydride Dianhydride of 3,3',4,4'-bicyclohexyltetracarboxylic 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-ethylidene-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, 2,2-propyridene- 4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, oxy-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, thio-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, sulfonyl-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, bicyclo[2,2,2]octo-7-ene-2,3,5,6-tetracarboxylic acid dianhydride, rel-[1S,5R,6R]-3-oxabicyclo[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 acid anhydride, ethylene glycol-bis-(3,4-dicarboxylic acid anhydride phenyl) ether, 4,4'-biphenylbis(trimellitic acid monoester anhydride), 9,9'-bis(3,4-dicarboxyphenyl)fluorene dianhydride, etc.

[0081] [Allyl compounds] Examples of the allyl compounds mentioned above include monoallyl isocyanurate, diallyl isocyanurate, and triallyl isocyanurate. Specific examples include "TAIC" (manufactured by Mitsubishi Chemical Corporation), "MA-DGIC," and "DA-MGIC" (both manufactured by Shikoku Chemicals Corporation).

[0082] [Polybutadiene and its modified forms] Polybutadiene and its modified products are compounds that have polybutadiene or a structure derived from polybutadiene within their molecule. The structure derived from polybutadiene may have some or all of its unsaturated bonds converted to single bonds by hydrogenation. Examples of polybutadiene and its modified products include, but are not limited to, polybutadiene, hydroxyl-terminated polybutadiene, terminally (meth)acrylated polybutadiene, carboxylic acid-terminated polybutadiene, amine-terminated polybutadiene, and styrene-butadiene rubber. Furthermore, these may be used individually or in combination. Of these, polybutadiene or styrene-butadiene rubber are preferred from the viewpoint of dielectric properties. Examples of styrene-butadiene rubber (SBR) include RICON-100, RICON-181, RICON-184 (all manufactured by Clay Valley Corporation), and 1,2-SBS (manufactured by Nippon Soda Co., Ltd.). Examples of polybutadiene include B-1000, B-2000, and B-3000 (all manufactured by Nippon Soda Co., Ltd.). The weight-average molecular weight of polybutadiene and styrene-butadiene rubber is preferably 500 to 10000, more preferably 750 to 7500, and even more preferably 1000 to 5000. Below the lower limit of the above range, the volatility is high, making it difficult to adjust the solid content during prepreg preparation, and above the upper limit of the above range, the compatibility with other curable resins deteriorates. In general, in the case of compounds containing heteroatoms such as oxygen and nitrogen, such as bismaleimide and polymaleimide, it is difficult to ensure compatibility with low-polarity compounds such as compounds mainly composed of hydrocarbons or compounds consisting only of hydrocarbons, due to their polarity. On the other hand, because the compounds of this embodiment do not have a framework design that actively incorporates heteroatoms such as oxygen and nitrogen, they exhibit excellent compatibility with materials that have low polarity and low dielectric properties, as well as with compounds composed solely of hydrocarbons.

[0083] [Polystyrene and its modified forms] Polystyrene and its modified products are compounds that have polystyrene or a structure derived from polystyrene within their molecule. Examples of polystyrene and its modified products include polystyrene, styrene-2-isopropenyl-2-oxazoline copolymer (Epocross RPS-1005, RP-61, both manufactured by Nippon Shokubai Co., Ltd.), SEP (styrene-ethylene-propylene copolymer: Septon 1020, manufactured by Kuraray Co., Ltd.), SEPS (styrene-ethylene-propylene-styrene copolymer: Septon 2002, Septon 2004F, Septon 2005, Septon 2006, Septon 2063, Septon 2104, all manufactured by Kuraray Co., Ltd.), SEEPS (styrene-ethylene / ethylene-propylene-styrene block copolymer: Septon 4003, Septon 4044, Septon 4055, Septon 4077, Septon 4099, all manufactured by Kuraray Co., Ltd.), and SEBS (styrene-ethylene-butylene-styrene). Examples of block copolymers include Septon 8004, Septon 8006, Septon 8007L (all manufactured by Kuraray Co., Ltd.), SEEPS-OH (a compound having hydroxyl groups at the ends of styrene-ethylene / ethylene-propylene-styrene block copolymers: Septon HG252, manufactured by Kuraray Co., Ltd.), SIS (styrene-isoprene-styrene block copolymers: Septon 5125, Septon 5127, both manufactured by Kuraray Co., Ltd.), hydrogenated SIS (hydrogenated styrene-isoprene-styrene block copolymers: Hybrar 7125F, Hybrar 7311F, both manufactured by Kuraray Co., Ltd.), SIBS (styrene-isobutylene-styrene block copolymers: SIBSTAR073T, SIBSTAR102T, SIBSTAR103T (all manufactured by Kaneka Corporation), Septon V9827 (manufactured by Kuraray Co., Ltd.)), but are not limited to these. Furthermore, these can be used individually or in combination of multiple types. Polystyrene and its modified products are preferable to be those without unsaturated bonds, as they have higher heat resistance and are less susceptible to oxidative degradation. Furthermore, while there are no particular restrictions on the weight-average molecular weight of polystyrene and its modified products as long as it is 10,000 or more, if it is too high, the compatibility with polyphenylene ether compounds, as well as low molecular weight components with a weight-average molecular weight of about 50 to 1,000 and oligomer components with a weight-average molecular weight of about 1,000 to 5,000 deteriorates, making it difficult to ensure mixing and solvent stability. Therefore, it is preferable that the molecular weight be around 10,000 to 300,000.

[0084] [Polyethylene and its modified forms] Polyethylene and its modified products refer to polyethylene or compounds having a polyethylene-derived structure within their molecules. Examples of polyethylene and its modified products include, but are not limited to, ethylene-propylene copolymers, ethylene-styrene copolymers, ethylene-propylene-ethylidene norbornene copolymers (Mitsui Chemicals EBT: K-8370EM, K-9330M, etc.), ethylene-propylene-vinyl norbornene copolymers (Mitsui Chemicals VNB-EPT: PX-006M, PX-008M, PX-009M, etc.), ethylene-vinyl alcohol copolymers, and ethylene-vinyl acetate copolymers. From the viewpoint of improving heat resistance, it is preferable to use ethylene-propylene-ethylidene norbornene copolymers or ethylene-propylene-vinyl norbornene copolymers that contain a crosslinkable structure. Furthermore, these may be used individually or in combination of multiple types. While there are no particular restrictions on the weight-average molecular weight of polyethylene and its modified products as long as it is 10,000 or more, if it is too high, the compatibility with polyphenylene ether compounds, as well as low molecular weight components with a weight-average molecular weight of about 50 to 1,000 and oligomer components with a weight-average molecular weight of about 1,000 to 5,000 deteriorates, making it difficult to ensure mixing and solvent stability. Therefore, it is preferable that the molecular weight be around 10,000 to 300,000.

[0085] The amount of binder resin added is preferably within a range that does not impair the flame retardancy and heat resistance of the cured product, preferably 0.05 to 50 parts by mass per 100 parts by mass of the curable resin composition, and more preferably 0.05 to 20 parts by mass as needed. Among these compounds, it is preferable to include polyphenylene ether compounds, polybutadiene and modified thereof, and polystyrene and modified thereof, based on the balance of heat resistance, adhesion, and dielectric properties. By including these compounds, the brittleness of the cured product can be improved and adhesion to metal can be enhanced, and cracks in the package can be suppressed during reliability tests such as solder reflow and thermal cycling.

[0086] [Inorganic fillers] The curable resin composition of this embodiment may contain an inorganic filler. Examples of inorganic fillers include, but are not limited to, powders such as fused silica, crystalline silica, porous silica, alumina, zircon, calcium silicate, calcium carbonate, quartz powder, silicon carbide, silicon nitride, boron nitride, zirconia, aluminum nitride, graphite, forsterite, steatite, spinel, mullite, titania, talc, clay, iron oxide, asbestos, and glass powder, or inorganic fillers made by shaping these into spheres or crushed forms. Furthermore, these may be used individually or in combination of multiple types.

[0087] When obtaining a curable resin composition for semiconductor encapsulants, stators, magnetic encapsulants, heat conduction and heat dissipation materials, etc., the amount used is preferably 80 to 92 parts by mass, and more preferably 83 to 90 parts by mass, per 100 parts by mass of the curable resin composition. Furthermore, when obtaining a curable resin composition for interlayer insulating layer forming materials, copper-clad laminates, prepregs, RCCs, and other substrate materials, the amount used is preferably 5 to 80 parts by mass, and more preferably 10 to 60 parts by mass, per 100 parts by mass of the curable resin composition.

[0088] The curable resin composition of this embodiment may further contain isocyanate compounds, maleimide compounds, cyanate compounds, compounds having ethylenically unsaturated bonds, etc., and these may be used individually or in combination of multiple types.

[0089] [Isocyanate compounds] An isocyanate compound is a compound that has two or more isocyanate groups in its molecule. Examples of isocyanate resins include, but are not limited to, aromatic diisocyanates such as p-phenylenediisocyanate, m-phenylenediisocyanate, p-xylenediisocyanate, m-xylenediisocyanate, 2,4-tollylenediisocyanate, 2,6-tollylenediisocyanate, 4,4'-diphenylmethanediisocyanate, and naphthalenediisocyanate; aliphatic or alicyclic diisocyanates such as isophorone diisocyanate, hexamethylenediisocyanate, 4,4'-dicyclohexylmethanediisocyanate, hydrogenated xylenediisocyanate, norbornenediisocyanate, and lysinediisocyanate; biuret compounds of one or more isocyanate monomers; or isocyanates obtained by trimerizing the above diisocyanate compounds; and polyisocyanates obtained by urethane reaction between the above isocyanate compounds and polyol compounds. Furthermore, these can be used individually or in combination.

[0090] [Maleimide compounds] Maleimide compounds are compounds that have one or more maleimide groups in their molecule. Examples of maleimide compounds include phenylmaleimide, 4,4'-diphenylmethanebismaleimide, polyphenylmethanemaleimide, m-phenylenebismaleimide, 2,2'-bis[4-(4-maleimoidphenoxy)phenyl]propane, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethanebismaleimide, 4-methyl-1,3-phenylenebismaleimide, 4,4'-diphenyletherbismaleimide, 4,4'-diphenylsulfonebismaleimide, 1,3-bis(3-maleimoidphenoxy)benzene, 1,3-bis(4-maleimoidphenoxy)benzene, and Zylok-type maleimide compounds (anilix). Examples include maleimide (manufactured by Mitsui Chemicals Fine Co., Ltd.), biphenylaralkyl type maleimide compounds (solidified by solvent distillation under reduced pressure of a resin solution containing the maleimide compound (M2) described in Example 4 of Japanese Patent Publication No. 2009-001783), bisaminocumylbenzene type maleimide (maleimide compound described in International Publication No. 2020 / 054601), maleimide compounds having an indan structure described in Japanese Patent No. 6629692 or International Publication No. 2020 / 217679, and maleimide compounds described in MATERIAL STAGE Vol. 18, No. 12 2019 "Continued Epoxy Resin CAS Number Story - Curing Agent CAS Number Memo No. 31 Bismaleimide (1)" and MATERIAL STAGE Vol. 19, No. 2 2019 "Continued Epoxy Resin CAS Number Story - Curing Agent CAS Number Memo No. 32 Bismaleimide (2)". Commercially available products include MIR-3000-70MT (biphenylaralkyl-type maleimide compound, manufactured by Nippon Kayaku Co., Ltd.) and MIZ-001 (manufactured by Nippon Kayaku Co., Ltd.), but are not limited to these. Furthermore, these can be used individually or in combination.

[0091] [Cyanate ester resin] Cyanate ester resins are cyanate ester compounds obtained by reacting phenol resins with cyanide halides. Specific examples include dicyanatebenzene, tricyanatebenzene, dicyanatenaphthalene, dicyanatebiphenyl, 2,2'-bis(4-cyanatephenyl)propane, bis(4-cyanatephenyl)methane, bis(3,5-dimethyl-4-cyanatephenyl)methane, 2,2'-bis(3,5-dimethyl-4-cyanatephenyl)propane, 2,2'-bis(4-cyanatephenyl)ethane, 2,2'-bis(4-cyanatephenyl)hexafluoropropane, bis(4-cyanatephenyl)sulfone, bis(4-cyanatephenyl)thioether, phenol novolac cyanate, and compounds obtained by converting the hydroxyl groups of phenol-dicyclopentadiene cocondensates to cyanate groups. A commercially available example is SYTESTER TA (manufactured by Mitsubishi Gas Chemical Co., Ltd., a bisphenol A type cyanate resin), but it is not limited to this product. Furthermore, these can be used individually or in combination. Furthermore, the cyanate ester resin whose synthesis method is described in Japanese Patent Publication No. 2005-264154 is particularly preferred as a cyanate ester resin because it has excellent low hygroscopicity, flame retardancy, and dielectric properties.

[0092] Cyanate ester resins may also contain catalysts such as zinc naphthenate, cobalt naphthenate, copper naphthenate, lead naphthenate, zinc octoate, tin octoate, lead acetylacetonate, and dibutyltin maleate to trimerize the cyanate groups as needed and form sym-triazine rings. It is preferable to use 0.0001 to 0.10 parts by mass, preferably 0.00015 to 0.0015 parts by mass, of the catalyst per 100 parts by mass of the cyanate ester resin and the curable resin composition.

[0093] [Compounds containing ethylenically unsaturated bonds] Compounds containing ethylenically unsaturated bonds are compounds that have one or more ethylenically unsaturated bonds in their molecule, which can be polymerized by heat or light, regardless of whether a polymerization initiator is used or not. Compounds containing ethylenically unsaturated bonds are those other than the maleimide compounds, polybutadienes, and their modified forms mentioned above. Compounds containing ethylenically unsaturated bonds include, for example, (meth)acrylate compounds such as isobornyl acrylate and acryloylmorpholine, reaction products of the above phenolic compounds with halogenated compounds containing ethylenically unsaturated bonds (chloromethylstyrene, allyl chloride, methallyl chloride, acrylate chloride, methacrylate chloride, etc.), and phenols containing ethylenically unsaturated bonds (2-allylphenol, 2-propenylphenol, 4-allylphenol, 4-propenylphenol, eugenol, isoeugenol, etc.) and halogenated compounds (1,4-bis(chloromethyl)benzene, 4, Examples include, but are not limited to, reaction products of 4'-bis(chloromethyl)biphenyl, 4,4'-difluorobenzophenone, 4,4'-dichlorobenzophenone, 4,4'-dibromobenzophenone, cyanuryl chloride, etc.; reaction products of epoxy resins or alcohols with (meth)acrylic acids (acrylic acid, methacrylic acid, etc.) and their acid-modified products; styrene resins; allyl group-containing compounds; acenaphthyl group-containing compounds (acenaphthylene, etc.); isocyanuric acid derivatives (TAIC from Mitsubishi Chemical Corporation, MA-DGIC, DA-MGIC, MeDAIC, L-DAIC, DD-1 from Shikoku Chemicals, etc.); and these may be used individually or in combination.

[0094] Commercially available (meth)acrylate compounds can be used, for example, STR-2000 (manufactured by Nippon Kayaku Co., Ltd., Zyloc-type styrene resin), KAYARAD® R-604, KAYARAD® R-684, KAYARAD® HX-220, KAYARAD® HX-620, KAYARAD® DPHA, KAYARAD® DPCA-60, KAYARAD® DPEA-12, KAYARAD® PET-30, KAYARAD® ZXR-1801H (product name, manufactured by Nippon Kayaku Co., Ltd.), KAYARAD® ZXR-1806H (product name) Examples include (product name), KAYARAD(registered trademark) ZXR-1810H (product name), KAYARAD(registered trademark) ZXR-1889H (product name), KAYARAD(registered trademark) ZCR-6001H, KAYARAD(registered trademark) ZCR-6002H, KAYARAD(registered trademark) ZCR-8001H, KAYARAD(registered trademark) ZCR-8002H, KAYARAD(registered trademark) ZAR-2001H, KAYARAD(registered trademark) ZAR-2002H, KAYARAD(registered trademark) UXE-3000, KAYARAD(registered trademark) PCR-1222H, CCR-1171H, KAYARAD(registered trademark) ZFR-1494H, etc. These compounds having ethylenically unsaturated bonds can be used individually or in appropriate mixtures of two or more.

[0095] The curable resin composition of this embodiment may be used in combination with a commonly available latent curing agent. Examples of commonly available latent curing agents include, but are not limited to, tetraphenylphosphonium tetraphenylborate (TPP-K, manufactured by Hokko Chemical Co., Ltd.), tetraphenylborate salt of 1,8-diazabicyclo[5,4,0]-7-undecene (DBU) benzyl modified (U-CAT5002, manufactured by Sunapro Co., Ltd.), phenolic resin salt of 1,5-diazabicyclo[4,3,0]-5-nonene (DBN) (U-CAT881, manufactured by Sunapro Co., Ltd.), adduct-type latent curing agents (PN-23J, manufactured by Ajinomoto Fine Techno Co., Ltd., Fujicure FXR-1030, manufactured by T&K TOKA Co., Ltd., etc.), and thiol-based liquid latent curing agents (Fujicure 7004, manufactured by T&K TOKA Co., Ltd.). Furthermore, these may be used individually or in combination of multiple types.

[0096] [Additives] The curable resin composition of this embodiment may contain additives. Examples of additives include modified acrylonitrile copolymers, polyethylene, fluororesins, silicone gels, silicone oils, surface treatment agents for fillers such as silane coupling agents, mold release agents, and colorants such as carbon black, phthalocyanine blue, and phthalocyanine green.

[0097] The curable resin composition of this embodiment may optionally contain additives other than those mentioned above, such as commonly used epoxy resin additives, for example, dyes, fluorescent whitening agents, reinforcing agents, white pigments or other pigments, nucleating agents, surfactants, plasticizers, viscosity modifiers, flow modifiers, antioxidants, ultraviolet absorbers, and light stabilizers.

[0098] The amount of additive added is preferably 1,000 parts by mass or less, and more preferably 700 parts by mass or less, per 100 parts by mass of the curable resin composition.

[0099] The curable resin composition of this embodiment is not particularly limited in its preparation method and is prepared by measuring predetermined amounts of each of the aforementioned components and stirring and mixing them. For example, after pre-mixing, it can also be prepared by mixing or melt-kneading using a roll kneader, kneader, extruder, etc.

[0100] The curable resin composition of this embodiment is not particularly limited in its curing method, and conventionally known curing equipment such as a closed curing furnace or a tunnel furnace capable of continuous curing can be used. The heating source is also not particularly limited, and conventionally known methods such as hot air circulation, infrared heating, and high-frequency heating can be used. The curing temperature and curing time can be set as appropriate.

[0101] There are no particular restrictions on the uses of the curable resin composition of this embodiment, and it can be applied to various fields and products in which resin materials are used, and can be widely used in electrical and electronic materials, building, civil engineering, automotive, medical materials, and the like.

[0102] For example, in electrical and electronic materials applications, examples include adhesives, adhesive films, sealants, semiconductor encapsulants, insulating materials, heat conduction and heat dissipation materials, magnetic encapsulants, hot melt materials, paints, potting agents, etc. More specifically, examples include encapsulating and layering materials for electronic components such as printed circuit boards, copper foil, copper-clad laminates, interlayer insulating materials, wiring coating films, resin-coated copper foil (RCC), prepregs, inductors, motors, and stators; forming materials for display devices such as color filters, flexible display films, resist materials, solder resist inks, and alignment films; forming materials for semiconductor devices such as resist materials and buffer coat films; and forming materials for optical components such as holograms, optical waveguides, optical circuits, optical circuit components, and anti-reflective films. [Examples]

[0103] The present invention will be described in more detail below based on examples, but the present invention is not limited in any way to such examples. Unless otherwise specified, "parts" and "%" in this text refer to mass.

[0104] [ 1 H-NMR measurement] 1 1H-NMR was measured using the following method. 10 mg of the sample was dissolved in approximately 0.5 ml of heavy DMSO, placed in a φ5 mm sample tube, and measured using a JEOL Ltd. JNM-ECS400. The shift value was referenced to DMSO (δ = 2.49 ppm).

[0105] [Synthesis Example 1] Synthesis of Compound C1 13.69 parts trimethoxyphenylsilane, 14.79 parts 3,4-dihydroxybenzophenone, and 68.35 parts methanol were placed in a 300 ml separable flask and stirred at 25°C until dissolved. Then, a solution of 2.76 parts sodium hydroxide dissolved in 13.67 parts methanol was added dropwise, taking care to avoid exothermic reaction, and the mixture was allowed to react for 0.5 hours. Next, a solution of 28.95 parts tetraphenylphosphonium bromide dissolved in 34.18 parts methanol was added dropwise and the mixture was allowed to react for 2 hours. Then, 200 parts water was added and crystallization was performed. The supernatant was removed by decantation and washed with 100 parts water. The washing was repeated twice, and the precipitated crystals were collected by suction filtration. The obtained wet cake was dried under reduced pressure at 80°C for 1 hour to obtain compound C1, represented by the following formula (1), as an ochre-colored powder in 90% yield. 1 The H-NMR spectral data is shown in Figure 1.

[0106] [ka]

[0107] [Synthesis Example 2] Synthesis of Compound C2 In a 300 ml separable flask, 15.00 parts trimethoxyphenylsilane, 8.33 parts catechol, and 74.91 parts methanol were added and stirred at 25°C until dissolved. Then, a solution of 3.03 parts sodium hydroxide dissolved in 14.98 parts methanol was added dropwise, taking care to avoid exothermic reaction, and the mixture was allowed to react for 0.5 hours. Subsequently, a solution of 31.73 parts tetraphenylphosphonium bromide dissolved in 37.46 parts methanol was added dropwise and the mixture was allowed to react for 2 hours. After that, 200 parts water was added and crystallization was performed. The supernatant was removed by decantation and washed with 100 parts water. The washing was repeated twice, and the precipitated crystals were collected by suction filtration. The obtained wet cake was dried under reduced pressure at 80°C for 1 hour to obtain compound C2, represented by the following formula (2), as a light gray powder in a yield of 67%. 1 The H-NMR spectral data is shown in Figure 2.

[0108] [ka]

[0109] [Synthesis Example 3] Synthesis of Compound C3 14.31 parts trimethoxyphenylsilane, 9.10 parts pyrogallol, and 71.45 parts methanol were placed in a 300 ml separable flask and stirred at 25°C until dissolved. Then, a solution of 2.89 parts sodium hydroxide dissolved in 14.29 parts methanol was added dropwise, taking care to avoid exothermic reaction, and the mixture was allowed to react for 0.5 hours. Next, a solution of 30.26 parts tetraphenylphosphonium bromide dissolved in 35.73 parts methanol was added dropwise and the mixture was allowed to react for 2 hours. Then, 200 parts water was added and crystallization was performed. The supernatant was removed by decantation and washed with 100 parts water. The washing was repeated twice, and the precipitated crystals were collected by suction filtration. The obtained wet cake was dried under reduced pressure at 80°C for 1 hour to obtain compound C3, represented by the following formula (3), as an ochre-colored powder in 96% yield. 1 The H-NMR spectral data is shown in Figure 3.

[0110] [ka]

[0111] [Synthesis Example 4] Synthesis of Compound C4 In a 300 ml separable flask, 12.83 parts trimethoxyphenylsilane, 10.75 parts 4-tertiary-butylcatechol, and 64.04 parts methanol were added and stirred at 25°C until dissolved. Then, a solution of 2.59 parts sodium hydroxide dissolved in 12.81 parts methanol was added dropwise, taking care to avoid exothermic reaction, and the mixture was reacted for 0.5 hours. Next, a solution of 27.12 parts tetraphenylphosphonium bromide dissolved in 32.02 parts methanol was added dropwise and the mixture was reacted for 2 hours. Then, 200 parts water was added and crystallization was performed. The supernatant was removed by decantation, and the mixture was washed with 100 parts water. The washing was repeated twice, and the precipitated crystals were collected by suction filtration. The resulting wet cake was dried under reduced pressure at 80°C for 1 hour to obtain compound C4, represented by the following formula (4), as an ochre-colored powder in 98% yield. 1 The H-NMR spectral data is shown in Figure 4.

[0112] [ka]

[0113] [Synthesis Example 5] Synthesis of Compound C5 In a 300 ml separable flask, 14.39 parts trimethoxyphenylsilane, 9.01 parts 4-methylcatechol, and 71.86 parts methanol were added and stirred at 25°C until dissolved. Then, a solution of 2.90 parts sodium hydroxide dissolved in 14.37 parts methanol was added dropwise, taking care to avoid exothermic reaction, and the mixture was allowed to react for 0.5 hours. Next, a solution of 30.44 parts tetraphenylphosphonium bromide dissolved in 35.93 parts methanol was added dropwise and the mixture was allowed to react for 2 hours. Then, 200 parts water was added and crystallization was performed. The supernatant was removed by decantation and washed with 100 parts water. The washing was repeated twice, and the precipitated crystals were collected by suction filtration. The obtained wet cake was dried under reduced pressure at 80°C for 1 hour to obtain compound C5, represented by the following formula (5), as a brown powder in 90% yield. 1 The H-NMR spectral data is shown in Figure 5.

[0114] [ka]

[0115] [Comparative Synthesis Example 1] Synthesis of Compound C6 13.86 parts of 4-dimethylaminopyridine (4-DMAP) and 83.14 parts of acetone were placed in a 300 ml separable flask and heated to 45°C to dissolve. Then, 20.00 parts of benzyl bromide were added dropwise, taking care to avoid exothermic reaction, and the mixture was reacted for 2 hours. After cooling to 30°C, crystallization was performed. The solid was collected by suction filtration and washed three times with excess acetone. The resulting wet cake was dried under reduced pressure at 45°C for 4 hours to obtain compound C6, represented by the following formula (6), as a white solid in 96% yield. 1 The H-NMR spectral data is shown in Figure 6.

[0116] [ka]

[0117] [Comparative Synthesis Example 2] Synthesis of Compound C7 22.25 parts trimethoxyphenylsilane, 12.36 parts catechol, and 20.00 parts methanol were placed in a 300 ml separable flask and stirred at 25°C until dissolved. Then, a solution of 4.49 parts sodium hydroxide dissolved in 15.00 parts methanol was added dropwise, taking care to avoid exothermic reaction, and the mixture was allowed to react for 0.5 hours. Subsequently, a solution of compound C6 (32.90 parts) dissolved in 16.00 parts methanol was added dropwise and the mixture was allowed to react for 2 hours. The precipitated crystals were collected by suction filtration and washed three times with excess water. The resulting wet cake was dried under reduced pressure at 80°C for 1 hour to obtain compound C7, represented by the following formula (7), as a white powder in 83% yield. 1 The H-NMR spectral data is shown in Figure 7.

[0118] [ka]

[0119] [Examples 1-5 and Comparative Example 1] KAYAHARD GPH-65 (hydroxyl group equivalent 199, manufactured by Nippon Kayaku Co., Ltd.), epoxy resin NC-3000 (hydroxyl group equivalent 275, manufactured by Nippon Kayaku Co., Ltd.), and various latent curing agents were added in the amounts listed in Table 1 and kneaded with a roll to obtain a solid curable resin composition (equivalent ratio of epoxy equivalent to hydroxyl group equivalent 1.0).

[0120] [Curlast Torque Measurement] The gel time (time until torque rise) at 175°C was measured for the curable resin compositions obtained in Examples 1-5 and Comparative Example 1 using a Curlastometer (registered trademark, manufactured by JSR Corporation). This result is shown in Table 1 as the initial gel time. Furthermore, the gel time ratio was determined by dividing the gel time obtained after storing the curable resin composition at 60°C or 100°C for 60 minutes and measuring it using a Curlastometer (registered trademark) in the same manner as above, by the initial gel time, and the results are shown in Table 1.

[0121] [DSC measurement] The curable resin compositions obtained in Examples 1-5 and Comparative Example 1 were measured using a differential thermogravimetric analyzer (Mettler Toledo TGA / DSC1) under the conditions of a measurement temperature range of 50-580°C and a heating rate of 10°C / min. The exothermic peak top temperatures are shown in Table 1.

[0122] [Table 1]

[0123] As shown in Table 1, the curable resin composition of the example was found to have superior curability because it had a shorter gel time and a lower exothermic peak top temperature than the curable resin composition of the comparative example. Furthermore, it was found to have excellent storage stability due to its high gel time ratio.

[0124] <Curing test> [Reference example 1] One part of the compound (C5) obtained in Synthesis Example 5, 20 parts of NC-3000 (manufactured by Nippon Kayaku Co., Ltd., biphenyl aralkyl type epoxy resin), 0.5 parts of MDEA: 4,4'-methylenebis(2-ethyl-6-methylaniline) (manufactured by Tokyo Chemical Industry Co., Ltd., amine compound), 1 part of DICY: dicyandiamide (manufactured by Tokyo Chemical Industry Co., Ltd., amide compound), 0.5 parts of KAYAHARD MCD (manufactured by Nippon Kayaku Co., Ltd., acid anhydride compound), KAYAHARD 0.5 parts of GPH-65 (manufactured by Nippon Kayaku Co., Ltd., biphenylaralkyl type phenol resin), 0.5 parts of Unifiner W-575 (manufactured by Unitika Corporation, activated ester resin), 0.5 parts of G4-142MHR (manufactured by Nippon Kayaku Co., Ltd., carboxylic acid compound), 2.5 parts of MIR-3000-70MT (manufactured by Nippon Kayaku Co., Ltd., maleimide compound), 2.5 parts of MIZ-001 (manufactured by Nippon Kayaku Co., Ltd., maleimide compound), 0.5 parts of Phenylmaleimide (manufactured by Tokyo Chemical Industry Co., Ltd., maleimide compound), 0.5 parts of CYTESTER TA (manufactured by Mitsubishi Gas Chemical Company, bisphenol A type cyanate resin), 60 parts of OPE-2st 2200 (manufactured by Mitsubishi Gas Chemical Company, polyphenylene ether compound), 3 parts of STR-2000 (manufactured by Nippon Kayaku Co., Ltd., compound with ethylenically unsaturated bonds), KAYARAD 1 part R-684 (manufactured by Nippon Kayaku Co., Ltd., compound having an ethylenically unsaturated bond), 0.5 parts acenaphthylene (manufactured by Tokyo Chemical Industry Co., Ltd., compound having an ethylenically unsaturated bond), 1 part polyimide compound obtained by the method described in WO2023 / 013224A1, 1 part TAIC: triallyl isocyanurate (manufactured by Mitsubishi Chemical Corporation, allyl compound), 1 part Septon 2104 (manufactured by Kuraray Co., Ltd., modified polystyrene), 0.5 parts benzoxazine Pd (manufactured by Shikoku Chemicals Co., Ltd., benzoxazine compound), 0.5 parts 2E4MZ: 2-ethyl-4-methylimidazole (manufactured by Shikoku Chemicals Co., Ltd., curing accelerator), 0.5 parts TPP: triphenylphosphine (manufactured by Hokko Chemical Co., Ltd., curing accelerator), 0.1 parts Octop Zn (manufactured by Hope Pharmaceutical Co., Ltd., curing accelerator), Sun-Aid 0.1 parts of SI-B5 (manufactured by Sanshin Chemical Co., Ltd., curing accelerator), 1 part of DCP: dicumyl peroxide (manufactured by Kayaku Nurion Co., Ltd., polymerization initiator), 99.2 parts of toluene as solvent, and 49 parts of tetrahydrofuran.By mixing the ingredients in a 6:1 ratio and heating them under a nitrogen atmosphere at 110°C for 10 minutes, then at 220°C for 1 hour, a cured product was obtained.

[0125] [Reference example 2] The compound (C5) obtained in Synthesis Example 5 was mixed in the following proportions: 0.5 parts, NC-3000 (manufactured by Nippon Kayaku Co., Ltd., biphenyl aralkyl epoxy resin), 10 parts, MIZ-001 (manufactured by Nippon Kayaku Co., Ltd., maleimide resin), 5 parts, STR-2000 (manufactured by Nippon Kayaku Co., Ltd., styrene resin), 45 parts, KAYARAD R-684 (manufactured by Nippon Kayaku Co., Ltd., acrylate resin), 1 part, Irgacure OXE-04 (manufactured by BASF, photopolymerization initiator), and 1 part, Irgacure 290 (manufactured by BASF, photopolymerization initiator). This mixture was coated onto a PET film to a thickness of 100 μm, and a PET film was attached to the side not in contact with the film. The mixture was then subjected to a high-pressure mercury lamp (365 nm) at a concentration of 3000 mJ / cm². 2 By irradiating it with ultraviolet light, a cured product could be obtained.

[0126] [Reference examples 3~6] The compound (C5) obtained in Synthesis Example 5 was added to the thermosetting resin composition shown in Table 2, and a cured product was obtained by heating at 110°C for 10 minutes and then at 220°C for 1 hour under a nitrogen atmosphere. The obtained cured product was measured using a differential thermogravimetric analyzer (Mettler-Toledo TGA / DSC1) under the conditions of a measurement temperature range of 50 to 580°C and a heating rate of 10°C / min, and the thermal decomposition temperature is shown in Table 2. The glass transition temperature measured using a Discovery DSC2500 (TA Instruments) under the conditions of a measurement temperature range of 50 to 260°C and a heating rate of 10°C / min is also shown in Table 2.

[0127] [Table 2]

[0128] RE-305: Epoxy resin manufactured by Nippon Kayaku Co., Ltd. KAYAHARD AA: Aromatic amine resin, manufactured by Nippon Kayaku Co., Ltd. Compound D: Active ester resin described in Synthesis Example 1 of Japanese Patent Publication No. 2009-235165 [Industrial applicability]

[0129] The latent curing agent of the present invention can be used, for example, as a latent curing agent for epoxy compounds. Because it has excellent storage stability, refrigeration of the composition is unnecessary, and because it has excellent curing properties, curing is possible at low temperatures. Therefore, the latent curing agent of the present invention is useful for resin encapsulation of various electrical and electronic components and semiconductor components.

[0130] [Note] As described above, this embodiment includes the following disclosures.

[0131] [1] A latent curing agent represented by the following formula (a), consisting of a phosphonium cation and a silicate anion residue.

[0132] [ka] (In formula (a), R1 to R4 each independently represent a hydrocarbon group having 1 to 20 carbon atoms, which may contain heteroatoms, and may be the same or different from each other. R1 and R2, R2 and R3, R3 and R4, and R4 and R1 may each bond to form a ring structure. 17 Each of these independently represents a hydrocarbon group having 1 to 20 carbon atoms, which may contain a hydrogen atom, a halogen atom, a hydroxyl group, a mercapto group, a silyl group, a silanol group, a nitro group, a nitroso group, a cyano group, a phosphino group, a phosphinyl group, a phosphono group, a phosphonato group, an amino group, or an ammonia group, or a heteroatom. [2] In the above equation (a), R5~R 17 Each of the following independently represents a hydrogen atom, a hydroxyl group, or a hydrocarbon group having 1 to 20 carbon atoms, which may contain a carbonyl group, an ether group, an ester group, an amide group, or a sulfide group: the latent curing agent described in [1]. [3] The latent curing agent according to [1] or [2], wherein the phosphonium cation in formula (a) is represented by the following formula (a-1).

[0133] [ka]

[0134] (In formula (a-1), R 18 ~R 37 Each of these independently represents a hydrogen atom, halogen atom, hydroxyl group, mercapto group, silyl group, silanol group, nitro group, nitroso group, cyano group, phosphino group, phosphinyl group, phosphono group, phosphonato group, amino group, or ammonia group. [4] A curable resin composition containing a latent curing agent as described in any of [1] to [3]. [5] The curable resin composition described in [4] further contains an epoxy resin. [6] The curable resin composition according to [4] or [5] further contains an amine resin, an acid anhydride compound, a phenol resin, a carboxylic acid compound, an active ester compound, or a benzoxazine compound as a curing agent. [7] The curable resin composition according to any one of [4] to [6] further contains at least one selected from the group consisting of maleimide compounds, polyphenylene ether compounds, polyamide resins, polyimide resins, compounds having ethylenically unsaturated bonds, cyanate ester resins, isocyanate compounds, polybutadiene and modified thereof, polystyrene and modified thereof, polyethylene and modified thereof. [8] A curable resin composition according to any one of [4] to [7], further comprising at least one selected from a thermal polymerization initiator, a photopolymerization initiator, an anionic curing accelerator, and a cationic curing accelerator. [9] A curable resin composition according to any one of [4] to [8], used in any of semiconductor encapsulants, adhesives, adhesive films, prepregs, interlayer insulating materials, stators, magnetic encapsulants, and heat conduction and heat dissipation materials.

[10] A cured product of any of the curable resin compositions described in [4] to [9].

[11]

[10] A printed circuit board having the cured material described above.

Claims

1. A latent curing agent represented by the following formula (a), consisting of a phosphonium cation and a silicate anion residue. 【Chemistry 1】 (In formula (a), R １ ~R ４ each independently represents a hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom, and they may be the same as or different from each other. R １ and R ２ , R ２ and R ３ , R ３ and R ４ , R ４ and R １ may each combine to form a ring structure. R ５ ~R １７ each independently represents a hydrogen atom, a halogen atom, a hydroxyl group, a mercapto group, a silyl group, a silanol group, a nitro group, a nitroso group, a cyano group, a phosphino group, a phosphinyl group, a phosphono group, a phosphonato group, an amino group, or an ammonio group, or a hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom.)

2. In the above formula (a), R ５ ~R １７ The latent curing agent according to claim 1, wherein each of the following independently represents a hydrogen atom, a hydroxyl group, or a hydrocarbon group having 1 to 20 carbon atoms, which may include a carbonyl group, an ether group, an ester group, an amide group, or a sulfide group.

3. The latent curing agent according to claim 2, wherein the phosphonium cation in formula (a) is represented by the following formula (a-1). 【Chemistry 2】 (In formula (a-1), R １８ ~R ３７ Each of these independently represents a hydrogen atom, halogen atom, hydroxyl group, mercapto group, silyl group, silanol group, nitro group, nitroso group, cyano group, phosphino group, phosphinyl group, phosphono group, phosphonato group, amino group, or ammonia group.

4. A curable resin composition containing the latent curing agent described in claims 1 to 3.

5. The curable resin composition according to claim 4, further containing an epoxy resin.

6. The curable resin composition according to claim 4, further comprising an amine resin, an acid anhydride compound, a phenol resin, a carboxylic acid compound, an active ester compound, or a benzoxazine compound as a curing agent.

7. The curable resin composition according to claim 4, further comprising at least one selected from the group consisting of maleimide compounds, polyphenylene ether compounds, polyamide resins, polyimide resins, compounds having ethylenically unsaturated bonds, cyanate ester resins, isocyanate compounds, polybutadiene and modified thereof, polystyrene and modified thereof, polyethylene and modified thereof.

8. The curable resin composition according to claim 4, further comprising at least one selected from a thermal polymerization initiator, a photopolymerization initiator, an anionic curing accelerator, and a cationic curing accelerator.

9. The curable resin composition according to claim 4, which is used in any of the following: semiconductor encapsulants, adhesives, adhesive films, prepregs, interlayer insulating materials, stators, magnetic encapsulants, and heat conduction and heat dissipation materials.

10. A cured product of the curable resin composition according to claim 4.

11. A printed circuit board having the cured product according to claim 10.

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