Epoxy resin, curable resin composition, and cured product

Abstract

To provide an epoxy resin, a curable resin composition, and a cured product thereof, which achieve high elastic modulus, high strength, and low water absorption.SOLUTION: Provided is an epoxy resin obtained by reacting a compound represented by the following formula (1) with epihalohydrin.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an epoxy resin, a curable resin composition, and a cured product.

Background Art

[0002] Epoxy resins can be cured with various curing agents to form cured products with excellent mechanical properties, water resistance, chemical resistance, heat resistance, electrical properties, etc., and are used in a wide range of fields such as adhesives, paints, laminates, molding materials, and casting materials. Carbon fiber reinforced composite materials (CFRP) obtained by impregnating and curing reinforcing fibers with epoxy resins and curing agents as matrix resins can impart characteristics such as weight reduction and high strength. Therefore, in recent years, they have been widely used in aircraft structural members, wind turbine blades, automotive exterior panels, and computer applications such as IC trays and laptop computer housings, and their demand is increasing. In particular, taking advantage of the lightweight and high-strength characteristics of the molded body, it is used as a matrix resin for aircraft applications.

[0003] High mechanical strength is required for CFRP materials, but thermosetting resins such as epoxy resins used in the matrix resins of CFRP are generally brittle and have low strength, toughness, adhesiveness, etc. Therefore, a method of adding a highly tough thermoplastic resin to the thermosetting resin to compensate for the characteristics is widely adopted (Patent Documents 1 to 3). Specifically, the strength and toughness of prepregs are improved by combining particles of thermoplastic resins such as polyethersulfone, polyetherimide, and polyamide with thermosetting resins.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

[0005] In recent years, the development of higher-strength CFRP materials has been demanded. For this purpose, not only the strengthening of thermosetting resins but also the compatibility with high elastic modulus are essential. This is because a thermosetting resin with a high elastic modulus fills and adheres between carbon fibers, so that stress is transmitted to adjacent CF filaments through the thermosetting resin, and many CF filaments can contribute to the expression of material strength, enabling high strength to be achieved as a composite material. In addition, further reduction of water absorption of the thermosetting resin is also required to prevent dimensional changes and reduction of mechanical strength due to moisture absorption.

[0006] The present invention has been made in view of the above circumstances, and an object thereof is to provide an epoxy resin, a curable resin composition, and a cured product thereof that are excellent in high elastic modulus, high strength, and low water absorption. [Means for Solving the Problems]

[0007] That is, the present invention is as shown in the following [1] to [4]. In the present application, “(numerical value 1) to (numerical value 2)” indicates that the upper and lower limit values are included.

[0008] [1] An epoxy resin obtained by reacting a compound represented by the following formula (1) with epihalohydrin.

[0009] [Chemical Formula]

[0010] [2] A curable resin composition comprising the epoxy resin according to the above [1], a curing agent and / or a curing accelerator. [3] A curable resin composition for a CFRP material containing the epoxy resin according to the above [1], a curing agent and / or a curing accelerator. [4] A cured product obtained by curing the curable resin composition according to the preceding paragraph [2] or [3].

Advantages of the Invention

[0011] According to the present invention, it is possible to provide an epoxy resin, a curable resin composition, and a cured product thereof that are excellent in high elastic modulus, high strength, and low water absorption.

Brief Description of the Drawings

[0012]

Figure 1

Modes for Carrying Out the Invention

[0013] Hereinafter, embodiments according to the present invention (hereinafter also referred to as "the present embodiments") will be described in more detail.

[0014] The epoxy resin of the present embodiment is obtained by reacting a compound represented by the following formula (1) with epihalohydrin.

[0015]

Chemical formula

[0016] As the epihalohydrin, epichlorohydrin which is easily available industrially is preferable. The amount of epihalohydrin used is usually 4.0 to 10 moles, preferably 4.5 to 8.0 moles, more preferably 4.5 to 7.0 moles per 1 mole of the hydroxyl group of the raw material phenol mixture.

[0017] In the above reaction, an alkali metal hydroxide can be used as a catalyst for promoting the epoxidation step. Examples of the alkali metal hydroxide that can be used include sodium hydroxide, potassium hydroxide, etc. A solid may be used, or an aqueous solution thereof may be used. In the present embodiment, in particular, the use of a solid molded into flakes is preferred from the viewpoints of solubility and handling. The amount of alkali metal hydroxide used is usually 0.90 to 1.5 moles, preferably 0.95 to 1.25 moles, more preferably 0.99 to 1.15 moles, per mole of the hydroxyl group in the raw material phenol mixture.

[0018] In addition, quaternary ammonium salts such as tetramethylammonium chloride, tetramethylammonium bromide, and trimethylbenzylammonium chloride may be added as a catalyst to accelerate the reaction. The amount of the quaternary ammonium salt used is usually 0.1 to 15 g, preferably 0.2 to 10 g, per mole of the hydroxyl group in the raw material phenol mixture.

[0019] During the epoxidation reaction, it is preferably to carry out the reaction by adding alcohols such as methanol, ethanol, and isopropyl alcohol, and aprotic polar solvents such as dimethyl sulfone, dimethyl sulfoxide, tetrahydrofuran, and dioxane. When using alcohols, the amount used is usually 2 to 50% by weight, preferably 4 to 20% by weight, based on the amount of epihalohydrin used. When using an aprotic polar solvent, it is usually 5 to 100% by weight, preferably 10 to 80% by weight, based on the amount of epihalohydrin used. The reaction temperature is usually 30 to 90 °C, preferably 35 to 80 °C. Particularly in this embodiment, a temperature of 50 °C or higher is preferred for higher purity epoxidation, and a temperature of 60 °C or higher is particularly preferred. The reaction time is usually 0.5 to 10 hours, preferably 1 to 8 hours, particularly preferably 1 to 3 hours. If the reaction time is short, the reaction does not proceed completely, and if the reaction time is long, by-products are formed, which is not preferred. After washing the reactants of these epoxidation reactions with water or without water washing, epihalohydrin, solvents, etc. are removed under heating and reduced pressure. Further, in order to obtain an epoxy resin with less hydrolyzable halogen, the recovered epoxy resin is dissolved using a ketone compound having 4 to 7 carbon atoms (for example, methyl isobutyl ketone, methyl ethyl ketone, cyclopentanone, cyclohexanone, etc.) as a solvent, and an aqueous solution of an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide is added to carry out the reaction, and ring closure can also be made reliable. In this case, the amount of the alkali metal hydroxide used is usually 0.01 to 0.3 mol, preferably 0.05 to 0.2 mol, per 1 mol of the hydroxyl group of the raw material phenol mixture used for epoxidation. The reaction temperature is usually 50 to 120 °C, and the reaction time is usually 0.5 to 2 hours. In the reaction with epihalohydrin, it is preferable to carry out the reaction while blowing an inert gas such as nitrogen into the air or liquid. If the inert gas is not blown in, the resulting resin may be colored. The blowing amount of the inert gas varies depending on the volume of the reaction vessel, but it is preferable to blow an amount of inert gas that can replace the volume of the reaction vessel in 0.5 to 10 hours.

[0020] After the reaction is completed, the generated salt is removed by filtration, washing with water, etc., and the solvent is distilled off under heating and reduced pressure to obtain the epoxy resin of the present embodiment represented by the following formula (2).

[0021]

Chemical formula

[0022] The epoxy equivalent of the epoxy resin of the present embodiment is preferably 212 g / eq. or more and 232 g / eq. or less, and more preferably 212 g / eq. or more and 226 g / eq. or less. In addition, with respect to the theoretical epoxy equivalent of the epoxy resin (the theoretical value of the epoxy equivalent calculated from the compound obtained by adding epihalohydrin to all phenolic hydroxyl groups of the phenol form in formula (1)), the epoxy equivalent is preferably 1.00 to 1.10, more preferably 1.00 to 1.07.

[0023] The epoxy resin of this embodiment preferably has a resinous form with a softening point, and the softening point is preferably 70°C or higher and 100°C or lower, more preferably 70°C or higher and 90°C or lower. When the softening point is 70°C or higher, it means that an appropriate molecular weight distribution is achieved or there is no residue such as a solvent, and problems such as poor curing and voids during molding can be suppressed. Conversely, when the softening point is 100°C or lower, the handling during kneading with other resins becomes good.

[0024] The ICI melt viscosity (150°C) is preferably 0.01 to 0.10 Pa·s. If the viscosity is higher than 0.10 Pa·s, problems occur in fluidity, and problems occur in flowability and embedability during pressing, which is not preferable.

[0025] Hereinafter, the curable resin composition of this embodiment will be described. In the curable resin composition of this embodiment, the epoxy resin of this embodiment can be used alone or in combination with other epoxy resins described later. When used in combination, the proportion of the epoxy resin of this embodiment in all epoxy resins is preferably 10 to 98% by weight, more preferably 20 to 95% by weight, and even more preferably 30 to 95% by weight. By setting the addition amount to 10% or more, high elastic modulus, high strength, and low water absorption can be exhibited.

[0026] [Curing Agent] The curable resin composition of this embodiment can improve curability by adding a curing agent. The curing agent refers to a compound having active hydrogen or other functional groups that react with an epoxy group, and any compound can be used as long as it can react with an epoxy group. For example, active ester compounds, phenolic resins, polyphenylene ether compounds, amine resins, isocyanate resins, polyamide resins, maleimide compounds, cyanate ester resins, polyimide resins, polybutadiene and its modified products, polystyrene and its modified products, polyethylene and its modified products described later, and the acid anhydrides exemplified below can be used as curing agents.

[0027] [Acid anhydride] Examples include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methyl nadic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, etc., alkenyl succinic anhydride, styrene-maleic anhydride copolymer, butadiene-maleic anhydride copolymer, propylene-maleic anhydride copolymer, etc., but are not limited thereto. Also, these may be used alone or in combination of two or more.

[0028] [Curing accelerator] The curable resin composition of this embodiment can also improve its curability by adding a curing accelerator. As the curing accelerator, an anionic curing accelerator that promotes the curing reaction by generating anions upon irradiation with ultraviolet rays or visible light or heating, or a cationic curing accelerator that promotes the curing reaction by generating cations upon irradiation with ultraviolet rays or visible light or heating is preferable.

[0029] Examples of the anionic curing accelerator include imidazoles such as 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, trialkylamines such as triethylamine and tributylamine, 4-dimethylaminopyridine, benzyldimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, 1,8-diazabicyclo(5,4,0)-undecene, etc., and 4-dimethylaminopyridine and 1,8-diazabicyclo(5,4,0)-undecene are preferable. In addition, phosphines such as triphenylphosphine, quaternary ammonium salts such as tetrabutylammonium salt, triisopropylmethylammonium salt, trimethyldecylammonium salt, cetyltrimethylammonium salt, hexadecyltrimethylammonium hydroxide, etc. are included, but are not limited thereto. Also, these may be used alone or in combination of two or more.

[0030] Examples of cationic curing accelerators include quaternary phosphonium salts such as triphenylbenzylphosphonium salts, triphenylethylphosphonium salts, and tetrabutylphosphonium salts (the counter ions of the quaternary salts are halogens, organic acid ions, hydroxide ions, etc., and there is no particular specification, but organic acid ions and hydroxide ions are particularly preferred), tin octylate, zinc carboxylates (zinc 2-ethylhexanoate, zinc stearate, zinc behenate, zinc myristate), zinc phosphate esters (zinc octyl phosphate, zinc stearyl phosphate), and other transition metal compounds (transition metal salts), etc. However, it is not limited to these. Also, these may be used alone or in combination of multiple types.

[0031] The compounding amount of the curing accelerator is used as needed in an amount of 0.01 to 5.0 parts by mass per 100 parts by mass of the curable resin composition.

[0032] [Inorganic filler] The curable resin composition of this embodiment may contain an inorganic filler. Examples of the inorganic filler include 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, glass powder, etc., or inorganic fillers obtained by shaping these into spherical or crushed shapes. However, it is not limited to these. Also, these may be used alone or in combination of multiple types.

[0033] When obtaining a curable resin composition for semiconductor encapsulation, the usage amount of the inorganic filler is preferably 80 to 92 parts by mass, more preferably 83 to 90 parts by mass, per 100 parts by mass of the total amount of the curable resin composition. Also, when obtaining a curable resin composition for substrate materials such as interlayer insulating layer forming materials, copper-clad laminates, prepregs, and RCCs, the usage amount of the above inorganic filler is preferably 5 to 80 parts by mass, more preferably 10 to 60 parts by mass, per 100 parts by mass of the total amount of the curable resin composition.

[0034] [Polymerization initiator] The curable resin composition of this embodiment can also improve curability by adding a polymerization initiator. A polymerization initiator is a compound capable of polymerizing olefin functional groups such as ethylenically unsaturated bonds, and examples include olefin metathesis polymerization initiators, anionic polymerization initiators, cationic polymerization initiators, radical polymerization initiators, and the like. Among these, it is preferable to use a radical polymerization initiator having curability and appropriate stability. A radical polymerization initiator refers to a compound that generates radicals upon irradiation with ultraviolet light or visible light or heating, and initiates a chain polymerization reaction. Examples of radical polymerization initiators that can be used include organic peroxides, azo compounds, benzopinacols, etc. It is preferable to use organic peroxides because they have less influence on curability temperature control, outgas suppression, and the electrical properties of decomposition products.

[0035] Examples of the organic peroxide include, but are not limited to, 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; alkyl peresters such as α-cumyl peroxyneodecanoate, t-butyl peroxyneodecanoate, t-butyl peroxypivalate, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, t-amyl peroxy-2-ethylhexanoate, t-butyl peroxy-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-butylperoxycarbonyloxy)hexane; and t-butyl hydroperoxide, cumene hydroperoxide, t-butyl peroxy octoate, lauroyl peroxide, etc. These may be used alone or in combination. Among these organic peroxides, ketone peroxides, diacyl peroxides, hydroperoxides, dialkyl peroxides, peroxyketals, alkyl peresters, percarbonates, etc. are preferred, and dialkyl peroxides are more preferred.

[0036] Examples of the azo compound include, but are not limited to, azobisisobutyronitrile, 4,4'-azobis(4-cyanovaleric acid), 2,2'-azobis(2,4-dimethylvaleronitrile), etc. These may be used alone or in combination.

[0037] As the addition amount of the polymerization initiator, 0.01 to 5 parts by mass, preferably 0.01 to 3 parts by mass, is preferable in 100 parts by mass of the curable resin composition. If the amount of the polymerization initiator used is less than 0.01 part by mass, the molecular weight may not sufficiently increase during the polymerization reaction, and if it is more than 5 parts by mass, the dielectric properties such as the dielectric constant and the dielectric loss tangent may be impaired.

[0038] [Polymerization inhibitor] The curable resin composition of this embodiment may contain a polymerization inhibitor. By containing a polymerization inhibitor, the storage stability is improved, and the reaction start temperature can be controlled. By controlling the reaction start temperature, it becomes easy to ensure fluidity, the impregnation property into a glass cloth or the like is not impaired, and B-staging such as prepreg formation becomes easy. If the polymerization reaction proceeds too much during prepreg formation, problems such as difficulty in lamination in the lamination process are likely to occur.

[0039] The polymerization inhibitor may be added when synthesizing the epoxy resin of this embodiment or after the synthesis. The amount of the polymerization inhibitor used is 0.008 to 1 part by weight, preferably 0.01 to 0.5 part by weight, based on 100 parts by weight of the epoxy resin of this embodiment.

[0040] Examples of the polymerization inhibitor include phenolic, sulfur-based, phosphorus-based, hindered amine-based, nitroso-based, nitroxyl radical-based, etc. Also, the polymerization inhibitor may be used alone or in combination of a plurality. Among these, in this embodiment, phenolic, hindered amine-based, nitroso-based, and nitroxyl radical-based are preferable.

[0041] Examples of the phenolic polymerization inhibitor include monophenols such as 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, 2,4-bis[(octylthio)methyl]-o-cresol, etc.; bisphenols such as 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, calcium bis(3,5-di-t-butyl-4-hydroxybenzylsulfonic acid ethyl), etc.; and 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 of the polymeric phenols include, but are not limited to, 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.

[0042] Examples of the sulfur-based polymerization inhibitors include, but are not limited to, dilauryl-3,3’-thiodipropionate, dimyristyl-3,3’-thiodipropionate, and distearyl-3,3’-thiodipropionate.

[0043] Examples of the phosphorus-based polymerization inhibitors include, but are not limited to, phosphites such as triphenyl phosphite, diphenylisodecyl phosphite, phenyl diisodecyl phosphite, tris(nonylphenyl) phosphite, diisodecyl pentaerythritol phosphite, tris(2,4-di-t-butylphenyl) phosphite, cyclic neopentanetetrayl bis(octadecyl) phosphite, cyclic neopentanetetrayl bis(2,4-di-t-butylphenyl) phosphite, cyclic neopentanetetrayl bis(2,4-di-t-butyl-4-methylphenyl) phosphite, and bis[2-t-butyl-6-methyl-4-{2-(octadecyloxycarbonyl)ethyl}phenyl] hydrogen phosphite; and oxaphosphaphenanthrene oxides such as 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.

[0044] Examples of the hindered amine polymerization inhibitor include, but are not limited to, Adeka Stab LA-40MP, Adeka Stab LA-40Si, Adeka Stab LA-402AF, Adeka Stab LA-87, Adeka Stab LA-82, Adeka Stab LA-81, Adeka Stab LA-77Y, Adeka Stab LA-77G, Adeka Stab LA-72, Adeka Stab LA-68, Adeka Stab LA-63P, Adeka Stab LA-57, Adeka Stab LA-52, Chimassorb 2020FDL, Chimassorb 944FDL, Chimassorb 944LD, Tinuvin 622SF, Tinuvin PA144, Tinuvin 765, Tinuvin 770DF, Tinuvin XT55FB, Tinuvin 111FDL, Tinuvin 783FDL, Tinuvin 791FB, etc.

[0045] Examples of the nitroso polymerization inhibitor include, but are not limited to, p-nitrosophenol, N-nitrosodiphenylamine, ammonium salt of N-nitrosophenylhydroxyamine, (cupferron), etc. Among these, the ammonium salt of N-nitrosophenylhydroxyamine (cupferron) is preferred.

[0046] Examples of the nitroxyl radical polymerization inhibitor include, but are not limited to, di-tert-butyl nitroxide, 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, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl, etc.

[0047] [Flame Retardant] The curable resin composition of this embodiment may use a flame retardant. Examples of the flame retardant include halogen-based flame retardants, inorganic flame retardants (such as antimony compounds, metal hydroxides, nitrogen compounds, boron compounds, etc.), phosphorus-based flame retardants, etc. From the viewpoint of achieving halogen-free flame retardancy, phosphorus-based flame retardants are preferred. The above phosphorus-based flame retardant may be a reactive type or an additive type. Specific examples include phosphate esters such as trimethyl phosphate, triethyl phosphate, tricresyl phosphate, trixylylenyl phosphate, cresyl diphenyl phosphate, cresyl-2,6-dixylylenyl phosphate, 1,3-phenylene bis(dixylylenyl phosphate), 1,4-phenylene bis(dixylylenyl phosphate), 4,4'-biphenyl (dixylylenyl phosphate), etc., phosphanes such as 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10(2,5-dihydroxyphenyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide, etc. In addition, phosphorus-containing epoxy compounds obtained by reacting epoxy resins with the active hydrogen of the above phosphanes, red phosphorus, etc. may be mentioned, but are not limited thereto. These may be used alone or in combination of two or more. Among the above-exemplified substances, phosphate esters, phosphanes or phosphorus-containing epoxy compounds are preferred, and 1,3-phenylene bis(dixylylenyl phosphate), 1,4-phenylene bis(dixylylenyl phosphate), 4,4'-biphenyl (dixylylenyl phosphate) or phosphorus-containing epoxy compounds are particularly preferred.

[0048] The content of the flame retardant is preferably in the range of 0.1 to 10 parts by mass in 100 parts by mass of the curable resin composition. If it is less than 0.1 part by mass, the flame retardancy may be insufficient, and if it is more than 10 parts by mass, it may adversely affect the hygroscopicity and mechanical properties of the cured product.

[0049] [Light stabilizer] The curable resin composition of this embodiment may use a light stabilizer. As the light stabilizer, a hindered amine-based light stabilizer, particularly HALS, etc. are suitable. Examples of HALS include the 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, the reaction product of dimethyl succinate-1-(2-hydroxyethyl)-4-hydroxy-2,2,6,6-tetramethylpiperidine, 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)imino}], bis(1,2,2,6,6-pentamethyl-4-piperidyl)[[(3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]butyl malonate, bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate, 2-(3,5-di-t-butyl-4-hydroxybenzyl)-2-n-butyl malonic acid bis(1,2,2,6,6-pentamethyl-4-piperidyl), etc., but are not limited thereto. Also, these may be used alone or in combination of multiple kinds.

[0050] The content of the light stabilizer is preferably in the range of 0.001 to 0.1 parts by mass in 100 parts by mass of the curable resin composition. If it is less than 0.001 parts by mass, there is a risk that the light stabilizing effect may not be sufficiently exhibited, and if it is more than 0.1 parts by mass, there is a risk of adversely affecting the hygroscopicity and dielectric properties of the cured product.

[0051] [Binder resin] The curable resin composition of this embodiment may use a binder resin. Examples of the binder resin include, but are not limited to, butyral resins, acetal resins, acrylic resins, epoxy-nylon resins, NBR-phenol resins, epoxy-NBR resins, silicone resins, etc. These may be used alone or in combination of two or more.

[0052] The blending amount of the binder resin is preferably in a range that does not impair the flame retardancy and heat resistance of the cured product, preferably 0.05 to 50 parts by mass, more preferably 0.05 to 20 parts by mass per 100 parts by mass of the curable resin composition, and is used as needed.

[0053] [Additives] The curable resin composition of this embodiment may use additives. Examples of the additives include modified products of acrylonitrile copolymers, polyethylene, fluororesins, silicone gels, silicone oils, surface treatment agents for fillers such as silane coupling agents, release agents, carbon black, phthalocyanine blue, phthalocyanine green and other colorants.

[0054] The blending amount of the additives is preferably 1 part by mass or less, more preferably 0.7 part by mass or less based on 100 parts by mass of the total amount of the curable resin composition.

[0055] The curable resin composition of this embodiment may further use an epoxy resin, an active ester compound, a phenol resin, a polyphenylene ether compound, an amine resin, a compound having an ethylenically unsaturated bond, an isocyanate resin, a polyamide resin, a maleimide compound, a cyanate ester resin, a polyimide resin, polybutadiene and its modified products, polystyrene and its modified products, polyethylene and its modified products, etc. These may be used alone or in combination of two or more. Among these compounds, from the balance of heat resistance, adhesion, and dielectric properties, it is preferable to contain a polyphenylene ether compound, a compound having an ethylenically unsaturated bond, a cyanate ester resin, polybutadiene and its modified products, polystyrene and its modified products. By containing these compounds, the brittleness of the cured product can be improved and the adhesion to metal can be enhanced, and the package cracks in reliability tests such as solder reflow and thermal cycling can be suppressed. When there is no particular instruction, the total usage amount of the above compounds is preferably 10 times by mass or less, more preferably 5 times by mass or less, and particularly preferably 3 times by mass or less with respect to the epoxy resin of this embodiment. Also, the preferable lower limit is 0.1 times by mass or more, more preferably 0.25 times by mass or more, and still more preferably 0.5 times by mass or more. By being within the above range, while making use of the effects of the epoxy resin of this embodiment, the effects of each added compound can be added. For this component, those exemplified below can be used.

[0056] [Other epoxy resins] In this embodiment, other epoxy resins may be used in combination with the epoxy resin of this embodiment. Preferred epoxy resins are exemplified below, but are not limited thereto. The property of the epoxy resin may be liquid or solid, and it may be used alone or in combination of two or more.

[0057] Examples of the liquid epoxy resin 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, glycidyl amine type epoxy resin, phenol novolac type epoxy resin, alicyclic epoxy resin having an ester skeleton, cyclohexane type epoxy resin, cyclohexanedimethanol type epoxy resin, glycidyl amine type epoxy resin, and epoxy resin having a butadiene structure. Specific examples include "RE310S", "RE410S" (manufactured by Nippon Kayaku Co., Ltd., bisphenol A type epoxy resin), "RE303S", "RE304S", "RE403S", "RE404S" (manufactured by Nippon Kayaku Co., Ltd., bisphenol F type epoxy resin), "HP4032", "HP4032D", "HP4032SS" (manufactured by DIC Corporation, naphthalene type epoxy resin), "828US", "jER828EL", "825", "828EL" (manufactured by Mitsubishi Chemical Corporation, bisphenol A type epoxy resin), "jE807", "1750" (manufactured by Mitsubishi Chemical Corporation, bisphenol F type epoxy resin), "jER152" (manufactured by Mitsubishi Chemical Corporation, phenol novolac type epoxy resin), "630", "630LSD" (manufactured by Mitsubishi Chemical Corporation, glycidyl amine type epoxy resin), "ZX1059" (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., 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 having an ester skeleton), "PB-3600" (manufactured by Daicel Corporation, epoxy resin having a butadiene structure), "ZX1658", "ZX1658GS" (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., liquid 1,4-glycidylcyclohexane type epoxy resin), etc. These may be used alone or in combination of two or more.

[0058] Examples of the solid epoxy resin include, for example, a bixylenol type epoxy resin, a naphthalene type epoxy resin, a naphthalene type tetrafunctional epoxy resin, a cresol novolak type epoxy resin, a dicyclopentadiene type epoxy resin, a trisphenol type epoxy resin, a naphthol type epoxy resin, a biphenyl type epoxy resin, a naphthylene ether type epoxy resin, an anthracene type epoxy resin, a bisphenol A type epoxy resin, a bisphenol AF type epoxy resin, and a tetraphenylethane type epoxy resin, and preferably include a naphthol type epoxy resin, a bisphenol AF type epoxy resin, a naphthalene type epoxy resin, and a biphenyl 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 novolak-type epoxy resin), "N-695" (manufactured by DIC Corporation, cresol novolak-type epoxy resin), "HP-7200" (manufactured by DIC Corporation, dicyclopentadiene-type epoxy resin), "HP-7200", "HP-7200HH", "HP-7200H" (all 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., tris-phenol-type epoxy resin), "NC-7000L", "NC-7300" (both manufactured by Nippon Kayaku Co., Ltd., naphthol-cresol novolak-type epoxy resin), "NC-3000H", "NC-3000", "NC-3000L", "NC-3100" (all manufactured by Nippon Kayaku Co., Ltd., biphenyl aralkyl-type epoxy resin), "XD-1000-2L", "XD-1000-L", "XD-1000-H", "XD-1000-H" (all manufactured by Nippon Kayaku Co., Ltd., dicyclopentadiene-type epoxy resin), "ESN475V" (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., naphthol-type epoxy resin), "ESN485" (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., naphthol novolak-type epoxy resin), "YX-4000H", "YX-4000", "YL6121" (all manufactured by Mitsubishi Chemical Corporation, biphenyl-type epoxy resin), "YX-4000HK" (manufactured by Mitsubishi Chemical Corporation, bixylenol-type epoxy resin), "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), and the like.These may be used alone or in combination of two or more.

[0059] [Active ester compound] An active ester compound refers to a compound that contains at least one ester bond in its structure and has an aliphatic chain, an aliphatic ring, or an aromatic ring 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 phenolic esters, thiophenolic esters, N-hydroxyamine esters, esters of heterocyclic hydroxy compounds, etc., and are obtained by a condensation reaction of at least one of a carboxylic acid compound, an acid chloride, or a thiocarboxylic acid compound with at least one of a hydroxy compound or a thiol compound. In particular, from the viewpoint of improving heat resistance, it is preferably obtained from a carboxylic acid compound or an acid chloride and a hydroxy compound, and as the hydroxy compound, a phenol compound or a naphthol compound is preferred. The active ester compound may be used alone or in combination of two or more.

[0060] Examples of the above-mentioned carboxylic acid compounds include benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid, pyromellitic acid, etc.

[0061] Examples of the above-mentioned acid chlorides include acetyl chloride, acrylic acid chloride, methacrylic acid chloride, malonyl chloride, succinic acid dichloride, diglycolyl chloride, glutaric acid dichloride, suberic acid dichloride, sebacic acid dichloride, adipic acid dichloride, dodecanedioyl dichloride, azelaoyl chloride, 2,5-furandicarbonyl dichloride, phthaloyl chloride, isophthaloyl chloride, terephthaloyl chloride, trimesic acid chloride, bis(4-chlorocarbonylphenyl) ether, 4,4'-diphenyldicarbonyl chloride, 4,4'-azodibenzoyl dichloride, etc.

[0062] Examples of the phenolic compound and the naphthol compound include hydroquinone, resorcin, 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, phenolic resins described below, and the like. Here, the "dicyclopentadiene-type diphenol compound" refers to a diphenol compound obtained by condensing two molecules of phenol with one molecule of dicyclopentadiene.

[0063] Preferable specific examples of the active ester compound include an active ester compound containing a dicyclopentadiene-type diphenol structure, an active ester compound containing a naphthalene structure, an active ester compound containing an acetylated product of phenol novolac, an active ester compound containing a benzoylated product of phenol novolac, the compound described in Example 2 of International Publication No. 2020 / 095829, the compound disclosed in International Publication No. 2020 / 059625, and the like. Among them, an active ester compound containing a naphthalene structure and an active ester compound containing a dicyclopentadiene-type diphenol structure are more preferable. The dicyclopentadiene-type diphenol structure represents a divalent structural unit composed of phenylene-dicyclopentylene-phenylene.

[0064] Examples of commercially available active ester compounds include, for example, as active ester compounds containing a dicyclopentadiene type diphenol structure, "EXB9451", "EXB9460", "EXB9460S", "HPC-8000-65T", "HPC-8000H-65TM", "EXB-8000L-65TM", "EXB-8150-65T" (manufactured by DIC Corporation); as active ester compounds containing a naphthalene structure, "EXB9416-70BK" (manufactured by DIC Corporation); as active ester compounds containing an acetylated product of phenol novolak, "DC808" (manufactured by Mitsubishi Chemical Corporation); as active ester compounds containing a benzoylated product of phenol novolak, "YLH1026", "YLH1030", "YLH1048" (manufactured by Mitsubishi Chemical Corporation); as an active ester curing agent which is an acetylated product of phenol novolak, "DC808" (manufactured by Mitsubishi Chemical Corporation); and as a phosphorus atom-containing active ester curing agent, "EXB-9050L-62M" manufactured by DIC Corporation, etc.

[0065] Regarding the mixing ratio of the active ester compound and the epoxy resin, the ratio (α / β) of the active ester equivalent (α) to the epoxy equivalent (β) is preferably 0.5 to 1.5, more preferably 0.8 to 1.2, and still more preferably 0.90 to 1.10. When outside the above range, there is a possibility that the excessive epoxy groups or active ester groups may remain in the system, and the characteristics may deteriorate in long-term reliability tests such as high-temperature storage tests (150 °C, 1000 hours, etc.) and under high-temperature and high-humidity conditions (temperature: 85 °C, humidity: 85%, etc.).

[0066] [Phenolic resin] A phenolic resin is a compound having two or more phenolic hydroxyl groups in the molecule. Examples of phenolic resins include, but are not limited to, reaction products of phenols and aldehydes, 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, reaction products of bisphenols and aldehydes, etc. These may be used alone or in combination of two or more. Specific examples of the above raw materials are illustrated below, but are not limited thereto. <Phenols> Phenol, alkyl-substituted phenol, aromatic-substituted phenol, hydroquinone, resorcinol, naphthol, alkyl-substituted naphthol, dihydroxybenzene, alkyl-substituted dihydroxybenzene, dihydroxynaphthalene, etc. <Aldehydes> Formaldehyde, acetaldehyde, alkyl aldehyde, 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 phenyls> 1,4-Bis(chloromethyl)benzene, 1,4-bis(methoxymethyl)benzene, 1,4-bis(hydroxymethyl)benzene, etc.

[0067] [Polyphenylene ether compound] As the polyphenylene ether compound, from the viewpoints of heat resistance and electrical properties, it 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. When the molecular weight is less than 500, sufficient heat resistance of the cured product tends not to be obtained. When the molecular weight is greater than 5000, the melt viscosity becomes high and sufficient fluidity cannot be obtained, so that molding defects tend to occur. In addition, the reactivity also decreases, the curing reaction takes a long time, the amount of unreacted material that is not incorporated into the curing system increases, the glass transition temperature of the cured product decreases, and the heat resistance of the cured product tends to decrease. If the number average molecular weight of the polyphenylene ether compound is 500 to 5000, excellent heat resistance, moldability, etc. can be exhibited while maintaining excellent dielectric properties. Here, the number average molecular weight can be specifically measured using gel permeation chromatography or the like.

[0068] The polyphenylene ether compound may be obtained by a polymerization reaction or by subjecting a high molecular weight polyphenylene ether compound having a number average molecular weight of about 10,000 to 30,000 to a redistribution reaction. Further, using these as raw materials, radical polymerizability may be imparted by reacting them with a compound having an ethylenically unsaturated bond, such as methacryl chloride, acrylyl chloride, chloromethylstyrene, etc. The polyphenylene ether compound obtained by the redistribution reaction is obtained, for example, by heating a high molecular weight polyphenylene ether compound in a solvent such as toluene in the presence of a phenol compound and a radical initiator to cause a redistribution reaction. The polyphenylene ether compound thus obtained by the redistribution reaction has hydroxyl groups derived from phenol-based compounds that contribute to curing at both ends of the molecular chain. Therefore, in addition to being able to maintain higher heat resistance, it is preferable because functional groups can be introduced at both ends of the molecular chain even after being modified with a compound having an ethylenically unsaturated bond. Further, the polyphenylene ether compound obtained by the polymerization reaction is preferable in terms of exhibiting excellent fluidity.

[0069] In the case of a polyphenylene ether compound obtained by a polymerization reaction, the molecular weight of the polyphenylene ether compound can be adjusted by adjusting the polymerization conditions and the like. Also, in the case of a polyphenylene ether compound obtained by a redistribution reaction, the molecular weight of the resulting polyphenylene ether compound can be adjusted by adjusting the conditions of the redistribution reaction and the like. More specifically, it is conceivable to adjust the blending amount of the phenolic compound used in the redistribution reaction. That is, the larger the blending amount of the phenolic compound, the lower the molecular weight of the resulting polyphenylene ether compound. At this time, as the high molecular weight polyphenylene ether compound that undergoes the redistribution reaction, poly(2,6-dimethyl-1,4-phenylene ether) or the like can be used. Also, the phenolic compound used in the redistribution reaction is not particularly limited, but for example, a polyfunctional phenolic compound having two or more phenolic hydroxyl groups in the molecule, such as bisphenol A, phenol novolak, cresol novolak, etc., is preferably used. These may be used alone or in combination of two or more.

[0070] [amine resin] An amine resin is a compound having two or more amino groups in the molecule. Examples of amine resins include diaminodiphenylmethane, diaminodiphenylsulfone, isophoronediamine, naphthalenediamine, aniline novolak (reaction product of aniline and formalin), N-methylaniline novolak (reaction product of N-methylaniline and formalin), orthoethylaniline novolak (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, reaction product of 2,6-dimethylaniline and formalin, aniline resin obtained by the reaction of aniline and xylylene chloride, reaction product of aniline and substituted biphenyls (such as 4,4'-bis(chloromethyl)-1,1'-biphenyl and 4,4'-bis(methoxymethyl)-1,1'-biphenyl) described in Japanese Patent No. 6429862, reaction product of aniline and substituted benzenes (such as 1,4-bis(chloromethyl)benzene, 1,4-bis(methoxymethyl)benzene and 1,4-bis(hydroxymethyl)benzene), 4,4'-(1,3-phenylenediisopropylidene)bisaniline, 4,4'-(1,4-phenylenediisopropylidene)bisaniline, reaction product of aniline and diisopropenylbenzene, dimer diamine, etc., but are not limited thereto. These may be used alone or in combination of two or more.

[0071] [Compound containing ethylenically unsaturated bond] A compound containing an ethylenically unsaturated bond is a compound having one or more ethylenically unsaturated bonds in the molecule that can be polymerized by heat or light, regardless of the use or non-use of a polymerization initiator. Examples of the compound containing an ethylenically unsaturated bond include reaction products of the above-mentioned phenolic resin and a halogen-based compound containing an ethylenically unsaturated bond (such as chloromethylstyrene, allyl chloride, methallyl chloride, acryloyl chloride, methacryloyl chloride, etc.), reaction products of phenols containing an ethylenically unsaturated bond (such as 2-allylphenol, 2-propenylphenol, 4-allylphenol, 4-propenylphenol, eugenol, isoeugenol, etc.) and a halogen-based compound (such as 1,4-bis(chloromethyl)benzene, 4,4'-bis(chloromethyl)biphenyl, 4,4'-difluorobenzophenone, 4,4'-dichlorobenzophenone, 4,4'-dibromobenzophenone, cyanuric chloride, etc.), reaction products of an epoxy resin or alcohols and (meth)acrylic acids (such as acrylic acid, methacrylic acid, etc.), and acid-modified products thereof, etc., but are not limited thereto. These may be used alone or in combination of two or more.

[0072] [Isocyanate resin] An isocyanate resin is a compound having two or more isocyanate groups in the molecule. Examples of the isocyanate resin include aromatic diisocyanates such as p-phenylene diisocyanate, m-phenylene diisocyanate, p-xylene diisocyanate, m-xylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, naphthalene diisocyanate, etc., aliphatic or alicyclic diisocyanates such as isophorone diisocyanate, hexamethylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, hydrogenated xylene diisocyanate, norbornene diisocyanate, lysine diisocyanate, etc., polyisocyanates such as a burette body of one or more kinds of isocyanate monomers, or an isocyanate body obtained by trimerizing the above diisocyanate compound, and polyisocyanates obtained by urethanization reaction of the above isocyanate compound and a polyol compound, etc., but are not limited thereto. These may be used alone or in combination of two or more.

[0073] [Polyamide resin] Examples of the polyamide resin include, for example, a reaction product of any one or more of diamine, diisocyanate, and oxazoline with dicarboxylic acid, a reaction product of diamine and acid chloride, and a ring-opening polymer of a lactam compound. Further, these may be used alone or in combination of two or more. Specific examples of each of the above raw materials are exemplified below, but are not limited thereto. [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 diamine, 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, diaminodiphenylsulfone, diaminodiphenylether, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 4,4-bis(4-aminophenoxy)biphenyl, 2,2-bis[4-(4-aminophenoxy)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, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic 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, furandicarboxylic acid, 4,4'-dicarboxydiphenyl ether, 4,4'-dicarboxydiphenyl sulfide, etc. <Acid chloride> Acetyl chloride, acryloyl chloride, methacryloyl chloride, malonyl chloride, succinyl dichloride, diglycolyl chloride, glutaric acid dichloride, suberic acid dichloride, sebacic acid dichloride, adipic acid dichloride, dodecanedioyl dichloride, azelaoyl chloride, 2,5-furandicarbonyl dichloride, phthaloyl chloride, isophthaloyl chloride, terephthaloyl chloride, trimesic acid chloride, bis(4-chlorocarbonylphenyl) ether, 4,4'-diphenyldicarbonyl chloride, 4,4'-azodibenzoyl dichloride, etc. <Lactam> ε-Caprolactam, ω-undecanolactam, ω-laurolactam, etc.

[0074] [Polyimide resin] Examples of the polyimide resin include, but are not limited to, reaction products of the diamine and tetracarboxylic dianhydrides exemplified below. These may be used alone or in combination of two or more. <Tetracarboxylic dianhydride> 4,4'-(Hexafluoroisopropylidene)diphthalic anhydride, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-cyclohexene-1,2-dicarboxylic anhydride, pyromellitic dianhydride, 1,2,3,4-benzenetetracarboxylic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 2,2',3,3'-benzophenonetetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride, 2,2',3,3'-biphenyltetracarboxylic dianhydride, methylene-4,4'-diphthalic dianhydride, 1,1-ethylidene-4,4'-diphthalic dianhydride, 2,2'-propylidene-4,4'-diphthalic dianhydride, 1,2-ethylene-4,4'-diphthalic dianhydride, 1,3-trimethylene-4,4'-diphthalic dianhydride, 1,4-tetramethylene-4,4'-diphthalic dianhydride, 1,5-pentamethylene-4,4'-diphthalic dianhydride, 4,4'-oxydiphthalic dianhydride, thio-4,4'-diphthalic dianhydride, sulfonyl-4,4'-diphthalic 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]methane dianhydride, 2,2-bis[3-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride, 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride, bis(3,4-dicarboxyphenoxy)dimethylsilane dianhydride, 1,3-bis(3,4-dicarboxyphenyl)-1,1,3,3-tetramethyldisiloxane dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 3,4,9,10 - Perylene tetracarboxylic dianhydride, 2,3,6,7 - Anthracene tetracarboxylic dianhydride, 1,2,7,8 - Phenanthrene tetracarboxylic dianhydride, Ethylene tetracarboxylic dianhydride, 1,2,3,4 - Butane tetracarboxylic dianhydride, 1,2,3,4 - Cyclobutane tetracarboxylic dianhydride, Cyclopentane tetracarboxylic dianhydride, Cyclohexane - 1,2,3,4 - tetracarboxylic dianhydride, Cyclohexane - 1,2,4,5 - tetracarboxylic dianhydride, 3,3’,4,4’ - Bicyclohexyltetracarboxylic 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 - Propylidene - 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]oct - 7 - ene - 2,3,5,6 - tetracarboxylic 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 anhydride, Ethylene glycol - bis-(3,4 - dicarboxylic anhydride phenyl) ether, 4,4’ - Biphenylbis(trimellitic monoester anhydride), 9,9’ - Bis(3,4 - dicarboxyphenyl)fluorene dianhydride, etc.,

[0075] [Maleimide compound] The curable resin composition of this embodiment may contain a maleimide compound. The maleimide compound is a compound having one or more maleimide groups in the molecule. Examples of the maleimide compound include 4,4'-diphenylmethane bismaleimide, polyphenylmethane maleimide, m-phenylene bismaleimide, 2,2'-bis[4-(4-maleimidophenoxy)phenyl]propane, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethane bismaleimide, 4-methyl-1,3-phenylene bismaleimide, 4,4'-diphenyl ether bismaleimide, 4,4'-diphenyl sulfone bismaleimide, 1,3-bis(3-maleimidophenoxy)benzene, 1,3-bis(4-maleimidophenoxy)benzene, Zairock type maleimide compound (Anilix maleimide, manufactured by Mitsui Chemicals Fine Co., Ltd.), biphenyl aralkyl type maleimide compound (solidified by distilling off the solvent under reduced pressure from the resin solution containing the maleimide compound (M2) described in Example 4 of JP-A-2009-001783), bisaminocumylbenzene type maleimide (maleimide compound described in International Publication No. 2020 / 054601), maleimide compounds having an indane structure described in Patent No. 6629692 or International Publication No. 2020 / 217679, maleimide compounds described in MATERIAL STAGE Vol.18, No.12 2019 "~Continued·Epoxy Resin CAS Number Story~Hardener CAS Number Memorandum No. 31 Bismaleimide (1)" and MATERIAL STAGE Vol.19, No.2 2019 "~Continued·Epoxy Resin CAS Number Story~Hardener CAS Number Memorandum No. 32 Bismaleimide (2)", etc., but are not limited thereto. These may be used alone or in combination of two or more.

[0076] [Cyanate Ester Resin] The cyanate ester resin is a cyanate ester compound obtained by reacting a phenolic resin with a cyanogen halide. Specific examples include dicyanate benzene, tricyanate benzene, dicyanate naphthalene, dicyanate biphenyl, 2,2'-bis(4-cyanate phenyl) propane, bis(4-cyanate phenyl) methane, bis(3,5-dimethyl-4-cyanate phenyl) methane, 2,2'-bis(3,5-dimethyl-4-cyanate phenyl) propane, 2,2'-bis(4-cyanate phenyl) ethane, 2,2'-bis(4-cyanate phenyl) hexafluoropropane, bis(4-cyanate phenyl) sulfone, bis(4-cyanate phenyl) thioether, phenol novolac cyanate, and those obtained by converting the hydroxyl groups of a phenol-dicyclopentadiene co-condensate into cyanate groups, etc., but are not limited thereto. Further, these may be used alone or in combination of two or more. In addition, the cyanate ester compound described in JP-A-2005-264154 is particularly preferable as a cyanate ester compound because it has excellent low hygroscopicity, flame retardancy, and dielectric properties. The cyanate ester resin may contain a catalyst such as zinc naphthenate, cobalt naphthenate, copper naphthenate, lead naphthenate, zinc octylate, tin octylate, lead acetylacetonate, dibutyltin maleate, etc. in order to trimerize the cyanate groups as necessary to form a sym-triazine ring.

[0077] The catalyst is preferably used in an amount of 0.0001 to 0.10 parts by mass, preferably 0.00015 to 0.0015 parts by mass, based on 100 parts by mass of the cyanate ester resin.

[0078] [Polybutadiene and its modified products] Polybutadiene and its modified products are compounds having polybutadiene or a structure derived from polybutadiene in the molecule. The structure derived from polybutadiene may have some or all of the 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, (meth)acrylate-terminated polybutadiene, carboxylic acid-terminated polybutadiene, amine-terminated polybutadiene, styrene-butadiene rubber, etc. These may be used alone or in combination. Among these, polybutadiene or styrene-butadiene rubber is preferred from the viewpoint of dielectric properties. Examples of styrene-butadiene rubber (SBR) include RICON-100, RICON-181, RICON-184 (all manufactured by Kray Valley), 1,2-SBS (manufactured by Nippon Soda Co., Ltd.), etc. Examples of polybutadiene include B-1000, B-2000, B-3000 (all manufactured by Nippon Soda Co., Ltd.), etc. The weight average molecular weight of polybutadiene and styrene-butadiene rubber is preferably 500 to 10,000, more preferably 750 to 7,500, and even more preferably 1,000 to 5,000. If it is below the lower limit of the above range, the volatilization amount is large, and it becomes difficult to adjust the solid content during prepreg preparation. If it is above the upper limit of the above range, the compatibility with other curable resins deteriorates.

[0079] [Polystyrene and its modified products] Polystyrene and its modified products are compounds having a structure derived from polystyrene in the molecule. Examples of polystyrene and its modified products include, but are not limited to, polystyrene, styrene-2-isopropenyl-2-oxazoline copolymer (both Epocros RPS-1005 and RP-61 are 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.), SEBS (styrene-ethylene·butylene-styrene block copolymer: Septon 8004, Septon 8006, Septon 8007L, all manufactured by Kuraray Co., Ltd.), SEEPS-OH (compound having a hydroxyl group at the end of a styrene-ethylene / ethylene·propylene-styrene block copolymer: Septon HG252 manufactured by Kuraray Co., Ltd.), SIS (styrene-isoprene-styrene block copolymer: Septon 5125, Septon 5127, both manufactured by Kuraray Co., Ltd.), hydrogenated SIS (hydrogenated styrene-isoprene-styrene block copolymer: Hybrar 7125F, Hybrar 7311F, both manufactured by Kuraray Co., Ltd.), SIBS (styrene-isobutylene-styrene block copolymer: SIBSTAR073T, SIBSTAR102T, SIBSTAR103T (all manufactured by Kaneka Corporation), Septon V9827 (manufactured by Kuraray Co., Ltd.)). These may be used alone or in combination. Polystyrene and its modified products preferably do not have unsaturated bonds because they have higher heat resistance and are less prone to oxidative degradation. Also, there is no particular limitation as long as the weight average molecular weight of polystyrene and its modified products is 10,000 or more. However, if it is too large, in addition to the polyphenylene ether compound, the compatibility with a low molecular weight component having a weight average molecular weight of about 50 to 1000 and an oligomer component having a weight average molecular weight of about 1000 to 5000 deteriorates, making it difficult to ensure mixing and solvent stability. Therefore, it is preferably about 10,000 to 300,000.

[0080] [Polyethylene and its modified products] Polyethylene and its modified products are compounds that have polyethylene or a structure derived from polyethylene in the molecule. Examples of polyethylene and its modified products include, but are not limited to, ethylene-propylene copolymer, ethylene-styrene copolymer, ethylene-propylene-ethylidene norbornene copolymer (such as EBT: K-8370EM, K-9330M manufactured by Mitsui Chemicals, Inc.), ethylene-propylene-X-006M, PX-008M, PX-009M, etc., ethylene-vinyl alcohol copolymer, ethylene-vinyl acetate copolymer, etc. From the viewpoint of improving heat resistance, it is preferable to use an ethylene-propylene-ethylidene norbornene copolymer or an ethylene-propylene-vinyl norbornene copolymer containing a crosslinkable structure. These may be used alone or in combination of two or more. The weight average molecular weight of polyethylene and its modified products is not particularly limited as long as it is 10,000 or more, but if it is too large, in addition to the polyphenylene ether compound, the compatibility with a low molecular weight component having a weight average molecular weight of about 50 to 1,000 and an oligomer component having 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 preferably about 10,000 to 300,000.

[0081] Furthermore, an organic solvent can be added as needed to form a varnish-like composition (hereinafter simply referred to as varnish). The curable resin composition of this embodiment can be dissolved in a solvent such as toluene, xylene, acetone, methyl ethyl ketone, methyl isobutyl ketone, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, etc. as needed to form a varnish, and impregnated into a substrate such as glass fiber, carbon fiber, polyester fiber, polyamide fiber, alumina fiber, paper, etc., and then heated and dried to prepare a prepreg. The solvent used at this time is used in an amount that occupies 10 to 70% by weight, preferably 15 to 70% by weight in the mixture of the curable resin composition of this embodiment and the solvent.

[0082] When the curable resin composition of the present embodiment is in the form of a prepreg, the curable resin composition of the present embodiment and / or a resin sheet (obtained by molding the curable resin composition into a film form) are heated and melted to reduce the viscosity and impregnated into a fiber substrate to obtain the prepreg of the present embodiment.

[0083] After cutting and laminating the above prepreg into a desired shape, the CFRP of the present embodiment can be obtained by heating and curing the curable resin composition while applying pressure to the laminate by a press molding method, an autoclave molding method, a sheet winding molding method, or the like. Also, a copper foil or an organic film can be laminated during the lamination of the prepreg.

[0084] Furthermore, the molding method of the CFRP of the present embodiment can also be obtained by molding by a known method in addition to the above method. For example, a carbon fiber substrate (usually, a carbon fiber fabric is used) is cut, laminated, and shaped to produce a preform (a preform before impregnation with resin), the preform is placed in a mold, the mold is closed, resin is injected to impregnate and cure the preform, and then the mold is opened to take out the molded product. A resin transfer molding technique (RTM method) can also be used. Also, as a kind of the RTM method, for example, the VaRTM method, the SCRIMP (Seeman’s Composite Resin Infusion Molding Process) method, and the CAPRI (Controlled Atmospheric Pressure Resin Infusion) method described in JP-T-2005-527410, in which the resin supply tank is evacuated to a pressure lower than atmospheric pressure, circulation compression is used, and the net molding pressure is controlled to more appropriately control the resin injection process, particularly the VaRTM method, can also be used.

[0085] Furthermore, methods such as film stacking method of sandwiching a fiber substrate with a resin sheet (film), a method of attaching a powdery resin to a reinforcing fiber substrate for improving impregnation, a molding method (Powder Impregnated Yarn) using a fluidized bed or a fluid slurry method in the process of mixing a resin with a fiber substrate, and a method of mixing resin fibers with a fiber substrate can also be used.

[0086] Examples of carbon fibers include acrylic-based, pitch-based, and rayon-based carbon fibers. Among them, acrylic-based carbon fibers with high tensile strength are preferably used. As the form of carbon fibers, twisted yarns, untwisted yarns, and non-twisted yarns can be used. However, untwisted yarns or non-twisted yarns are preferably used because of the good balance between the moldability and strength characteristics of the fiber-reinforced composite material.

[0087] The cured product obtained in this embodiment can be used in various applications other than the above-mentioned applications such as CFRP. Specifically, general applications where thermosetting resins such as epoxy resins are used are mentioned. For example, adhesives, paints, coating agents, molding materials (including sheets, films, CFRP, etc.), encapsulants for semiconductor elements, encapsulants for liquid crystal display elements, encapsulants for organic EL elements, laminates (printed wiring boards, substrates for BGA, build-up substrates, etc.) and other electrical and electronic components, composite materials for lightweight and high-strength structural materials such as carbon fiber reinforced plastics and glass fiber reinforced plastics, 3D printing, and additives to other resins, etc.

[0088] When the curable resin composition of this embodiment is particularly applied to a semiconductor encapsulant, the curable resin composition of this embodiment is placed in a mold on a lead frame or a semiconductor package substrate equipped with a semiconductor element, and molded by a melt casting method, a transfer molding method, an injection molding method, a compression molding method, etc., and then heated at 80 to 200 °C for 2 to 10 hours to obtain a cured product. Examples of semiconductor devices manufactured using this sealing material include potting, dipping, transfer molding sealing for capacitors, transistors, diodes, light-emitting diodes, ICs, LSIs, etc., potting sealing for COB, COF, TAB, etc. of ICs and LSIs, underfill for flip chips, and sealing (including reinforcing underfill) during mounting of IC packages such as QFP, BGA, and CSP.

[0089] When the curable resin composition of this embodiment is particularly applied to printed wiring boards, a prepreg can also be obtained by heating and melting it to reduce its viscosity and impregnating it into reinforcing fibers such as glass fibers and polyamide fibers. Specific examples include, but are not particularly limited to, glass fibers such as E-glass cloth, D-glass cloth, S-glass cloth, Q-glass cloth, spherical glass cloth, NE-glass cloth, and T-glass cloth, and / or organic fibers. The shape of the base material is not particularly limited, and examples include woven fabric, non-woven fabric, roving, and chopped strand mat. Also, as the weaving method of the woven fabric, plain weave, nanako weave, twill weave, etc. are known, and these known ones can be appropriately selected and used according to the intended application and performance. Further, a glass woven fabric obtained by opening the woven fabric or surface-treated with a silane coupling agent, etc. is preferably used. The thickness of the base material is not particularly limited, but is preferably about 0.01 to 0.4 mm. Also, a prepreg can be obtained by impregnating the varnish into the reinforcing fibers and heating and drying it, and based on this, a copper-clad laminate (CCL) can be made. By thermally pressing and molding the obtained prepreg and CCL, a laminate using the curable resin composition of this embodiment can also be made. The laminate is not particularly limited as long as it includes one or more prepregs, and it may have any other layers. Also, a sheet-like adhesive can be obtained by applying the varnish on a release film, removing the solvent under heating, and performing B-staging. This sheet-like adhesive can be used as an interlayer insulating layer in a multilayer substrate or an adhesive sheet when mounting a semiconductor. The curable resin composition of these embodiments can also be suitably used for special substrate materials such as package substrates (substrates) and HDI (high density interconnect).

[0090] Examples of the adhesive include adhesives for civil engineering, construction, automobiles, general office work, medical use, and adhesives for electronic materials. Among these, examples of the adhesive for electronic materials include interlayer adhesives for multilayer substrates such as build-up substrates, die bonding agents, adhesives for semiconductors such as underfills, underfills for BGA reinforcement, anisotropic conductive films (ACF), anisotropic conductive pastes (ACP), and other mounting adhesives, and they can be applied to various uses.

[0091] The cured product of the curable resin composition of this embodiment preferably has a tensile elastic modulus of 2.0 GPa to 4.0 GPa, and more preferably 2.5 GPa to 3.0 GPa. If the tensile elastic modulus is less than 2.0 GPa, the rigidity when used as a carbon fiber composite material is insufficient, leading to a decrease in reliability, which is not preferable. Also, if the tensile elastic modulus is greater than 4.0 GPa, the material becomes brittle, which is not preferable.

[0092] The cured product of the curable resin composition of this embodiment preferably has a maximum principal stress of 60 MPa or more, and more preferably 65 MPa or more.

[0093] Further, the water absorption rate is preferably 1.0% or less, more preferably 0.7% or less, and particularly preferably 0.5% or less. If the water absorption rate exceeds 1.0%, the cured product adsorbs moisture, causing the material to significantly soften and the mechanical strength to decrease, which is not preferable.

Examples

[0094] The present invention will be described more specifically below with reference to synthesis examples and examples. The materials, treatment contents, treatment procedures, etc. shown below can be appropriately changed without departing from the gist of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the specific examples shown below.

[0095] The following conditions were applied to various analysis methods. · Epoxy equivalent Measured by the method described in JIS K-7236, and the unit is g / eq. · Softening point Measured by the method compliant with JIS K-7234, and the unit is °C. · Melt viscosity Measured by the ICI melt viscosity (150 °C) cone plate method, and the unit is Pa·s.

[0096] · GPC (Gel Permeation Chromatography) analysis Manufacturer: Waters Column: Guard column SHODEX GPC KF-601, KF-602 KF-602.5, KF-603 Flow rate: 1.5 ml / min. Column temperature: 40 °C Solvent used: THF (tetrahydrofuran) Detector: RI (differential refractive index detector)

[0097] · High performance liquid chromatography analysis Liquid delivery unit LC-20AD manufactured by Shimadzu Corporation Photodiode array detector SPD-M20A manufactured by Shimadzu Corporation Column oven CTO-20A manufactured by Shimadzu Corporation Column: Intersil ODS-2, 5μm, 4.6×250mm 40 °C Mobile Phase A: Acetonitrile (AN) Mobile Phase B: Water (W) Time Program: 0 - 28 min. AN / W = 50% / 50% → 100% / 0% 28 - 40 min. AN / W = 100% / 0% Flow Rate: 1.0 mL / min. Detection: UV 274nm, PDA

[0098] [Synthesis Example 1] To 50 parts by weight of the tris-phenol resin represented by the formula (1), 157 parts by weight of epichlorohydrin, 33 parts by weight of dimethyl sulfoxide, and 6 parts by weight of water were charged into a reaction vessel. After heating, stirring, and dissolution, while maintaining the temperature at 55°C, 13 parts by weight of flaky sodium hydroxide was charged in portions over 1.5 hours. Then, the reaction was further carried out at 55°C for 1.5 hours and at 70°C for 30 minutes. Subsequently, washing with water was repeated to remove dimethyl sulfoxide and by-product salts. Then, excess epichlorohydrin was distilled off from the oil layer under heating and reduced pressure, and 136 parts by weight of methyl isobutyl ketone was added to and dissolved in the residue. This methyl isobutyl ketone solution was heated to 70°C, 3 parts by weight of a 30% aqueous sodium hydroxide solution was added, and after reacting for 1.5 hours, washing of the reaction solution with water was repeated until the washing liquid became neutral. Then, methyl isobutyl ketone was distilled off from the oil layer under heating and reduced pressure to obtain 53 parts by weight of the epoxy resin (EP1) represented by the formula (2). The epoxy equivalent of the obtained epoxy resin was 222 g / eq, the softening point was 72.0°C, and the ICI melt viscosity (150°C) was 0.095 Pa·s. The results of GPC are shown in Figure 1.

[0099] [Comparative Synthesis Example 1] Based on Example 1 of JP-A-2014-136726, an epoxy resin (EP2) represented by the following formula (3) was synthesized. The epoxy equivalent of the obtained epoxy resin was 208 g / eq, the softening point was 60.5°C, and the ICI melt viscosity (150°C) was 0.11 Pa·s.

[0100] [Chemical Formula]

[0101] [Example 1, Comparative Example 1] Using the epoxy resins obtained in Synthesis Example 1 and Comparative Synthesis Example 1 as the main components, and 2-ethyl-4-methylimidazole (abbreviation: 2E4MZ, manufactured by Shikoku Kasei Co., Ltd.) as the curing accelerator, they were mixed at the weight ratios shown in the blending composition of Table 1 and cured under the curing conditions of 220°C for 2 hours to prepare cured products.

[0102] The physical property values were measured under the following conditions. <Tensile Elastic Modulus Measurement Conditions> The elastic modulus when a test piece with a width of 5 mm, a thickness of 2.5 mm, and a distance between tensile points of 5 cm was subjected to a tensile test at 0.5 mm / min using AGS-X (manufactured by Shimadzu Corporation) <Maximum Point Stress Measurement Conditions> The maximum point stress when a test piece with a width of 5 mm, a thickness of 2.5 mm, and a distance between tensile points of 5 cm was subjected to a tensile test at 0.5 mm / min using AGS-X (manufactured by Shimadzu Corporation) <Water Absorption Rate> · Water absorption rate: The weight increase rate (%) after storing a test piece with a length of 4 cm, a width of 0.5 cm, and a thickness of 2.5 mm in water at 25°C for 24 hours

[0103] [Table 1]

[0104] From the results in Table 1, it was confirmed that Example 1 is excellent in high elastic modulus, high strength, and low water absorption.

Claims

1. An epoxy resin obtained by reacting a compound represented by the following formula (1) with epihalohydrin. 【Chemical Formula 1】

2. A curable resin composition containing the epoxy resin according to Claim 1, a curing agent, and / or a curing accelerator.

3. A curable resin composition for CFRP materials containing the epoxy resin according to Claim 1, a curing agent, and / or a curing accelerator.

4. A cured product obtained by curing the curable resin composition according to Claim 2 or 3.

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