Epoxy resin mixture, curable resin composition and cured product thereof

Abstract

The present invention provides a curable resin composition having little decrease in elastic modulus even in a high-temperature range, and a cured product thereof.　The curable resin composition comprises an epoxy resin represented by formula (1) and thermal cationic polymerization initiator. (In formula (1), n is the average number of repetitions, and denotes a real number within the range 1<n<15.)

Description

Epoxy resin mixture, curable resin composition and cured product thereof

[0001] The present invention relates to an epoxy resin mixture, a curable resin composition, and a cured product thereof, which are suitable for use in electrical and electronic components such as semiconductor encapsulants, printed wiring boards, and build-up laminates, lightweight, high-strength materials such as fiber-reinforced composite materials, 3D printing applications, and adhesives.

[0002] Epoxy resins are widely used in fields such as electrical and electronic components, structural materials, adhesives, and paints due to their workability and the excellent electrical properties, heat resistance, adhesiveness, and moisture resistance (water resistance) of their cured products. In recent years, with the development of the electrical and electronic fields in particular, there has been a demand for further improvements in the properties of resins, such as heat resistance, low dielectric constant, and low dielectric loss tangent. Furthermore, with regard to heat resistance, further improvements are required not only in the electrical and electronic fields but also in the fields of structural materials and adhesives.

[0003] Cured thermosetting resins, such as epoxy resins, used as matrix resins for CFRP and other composites are generally brittle, and require high mechanical strength when used as structural materials for aerospace applications, vehicles, etc. To compensate for the low flexural strength, toughness, adhesiveness, etc. of thermosetting resins, a method of adding a highly tough thermoplastic resin to the thermosetting resin matrix is ​​widely known (Patent Documents 1 to 3). Specifically, the flexural strength and toughness of prepregs are improved by combining particles of thermoplastic resins such as polyethersulfone, polyetherimide, and polyamide with the thermosetting resin matrix resin.

[0004] JP-A No. 60-243113 JP-A No. 09-100358 JP-A No. 2013-155330

[0005] Furthermore, in the field of semiconductor-related materials, power semiconductors that can handle higher voltages and currents than conventional semiconductors have been developed and are being used to achieve higher functionality and performance. Power semiconductors are primarily used for power conversion, such as changing voltage and frequency and switching between direct and alternating current, and are capable of rotating motors with precision, transmitting generated electricity to the power grid without waste, and providing a stable power supply to home appliances and electrical appliances.

[0006] Because power semiconductors handle extremely large amounts of electricity, they generate heat during use and reach high temperatures, which can lead to breakdowns. To ensure long-term high-temperature operation of power semiconductors, a reliability test called a thermal cycling test is conducted, in which temperatures between -55°C and 150°C are cycled for more than 1,000 times. In recent years, temperature conditions have become stricter, and thermal cycling resistance at 200°C is also required.

[0007] Furthermore, power semiconductors used in automobiles are required to have heat resistance of 250°C or higher in addition to the above-mentioned thermal cycle resistance, so materials that exhibit little decrease or change in elastic modulus even in high temperature ranges of 250°C or higher are required.

[0008] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a curable resin composition that exhibits little decrease in elastic modulus even in a high temperature range, and a cured product thereof.

[0009] That is, the present invention relates to the following [1] to [8]. In the present invention, "(Numerical value 1) to (Numerical value 2)" indicates that the upper and lower limits are included. [1] An epoxy resin mixture containing an epoxy resin represented by the following formula (1) and a quaternary ammonium salt:

[0010]

[0011] (In formula (1), n ​​is the average value of the number of repetitions and is a real number in the range of 1<n<15.) [2] The epoxy resin mixture according to the preceding item [1], wherein the quaternary ammonium salt is tetramethylammonium chloride or trimethylbenzylammonium chloride. [3] The epoxy resin mixture according to the preceding item [1] or [2], wherein the content of the quaternary ammonium salt is 1 to 100 ppm relative to 100 parts by mass of the epoxy resin. [4] The epoxy resin mixture according to any one of the preceding items [1] to [3], wherein the epoxy resin has an ICI viscosity (150°C) of 0.01 to 0.20 Pa s. [5] A curable resin composition containing the epoxy resin mixture according to any one of the preceding items [1] to [4] and a thermal cationic polymerization initiator. [6] A curable resin composition containing the epoxy resin mixture according to any one of [1] to [4] above, a curing accelerator, a polymerization initiator, an epoxy resin other than the epoxy resin represented by formula (1), an active ester compound, a phenolic compound, a polyphenylene ether compound, an amine compound, 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 modified products thereof, polystyrene and modified products thereof, polyethylene and modified products thereof, and a benzoxazine compound. [7] The curable resin composition according to [5] or [6] above, which is used for a fiber-reinforced composite material, a semiconductor encapsulant, a printed wiring board, or an interlayer insulating material. [8] A cured product obtained by curing the curable resin composition according to any one of [5] to [7] above.

[0012] According to the present invention, it is possible to provide a curable resin composition and a cured product thereof that exhibit little decrease in elastic modulus even at high temperatures, and thus the present invention is useful for insulating materials for electric and electronic components (such as highly reliable semiconductor encapsulation materials), laminates (such as printed wiring boards and build-up boards), various composite materials including CFRP, adhesives, etc.

[0013] 1 shows a GPC chart of Synthesis Example 1. FIG. 2 shows a GPC chart of Synthesis Example 2.

[0014] Hereinafter, an embodiment of the present invention (hereinafter also referred to as "the present embodiment") will be described in further detail.

[0015] The epoxy resin mixture of the present embodiment contains an epoxy resin represented by the following formula (1) and a quaternary ammonium salt.

[0016]

[0017] (In formula (1), n ​​is the average number of repetitions and is a real number in the range of 1<n<15.)

[0018] In the formula (1), the value of n can be calculated from the number average molecular weight of the epoxy resin determined by gel permeation chromatography (GPC, detector: RI) or the area ratio of each separated peak. n is preferably a real number in the range of 1<n<15, more preferably 1<n<10, and particularly preferably 1<n<5.

[0019] The epoxy equivalent of the epoxy resin represented by formula (1) is preferably 210 g / eq. or more and 220 g / eq. or less, more preferably 211 g / eq. or more and 218 g / eq. or less, and even more preferably 213 g / eq. or more and 218 g / eq. or less. When the epoxy equivalent is 210 g / eq. or more, high heat resistance is obtained, and when it is 220 g / eq. or less, a high flexural modulus is obtained. In other words, when the epoxy equivalent is 210 g / eq. or more and 220 g / eq. or less, it is possible to achieve both high heat resistance and a high flexural modulus.

[0020] The softening point of the epoxy resin represented by the formula (1) is preferably 40° C. or higher and 55° C. or lower, and more preferably 45° C. or higher and 55° C. or lower. When the softening point is 45° C. or higher, the epoxy resin has high heat resistance, and when it is 55° C. or lower, the epoxy resin has good handleability.

[0021] The epoxy resin represented by the formula (1) can be obtained by reacting a phenol resin represented by the following formula (2) with epihalohydrin.

[0022]

[0023] (In formula (2), n is the average number of repetitions and is a real number in the range of 1<n<15.)

[0024] The preferred range of n in the formula (2) is the same as that in the formula (1).

[0025] The epihalohydrin is readily available on the market. The amount of epihalohydrin used is preferably 2.0 to 10 mol, more preferably 3.0 to 8.0 mol, and even more preferably 3.5 to 6.0 mol, per mol of hydroxyl groups in the raw material phenol mixture. Preferred epihalohydrins that can be used in this embodiment include epichlorohydrin, α-methylepichlorohydrin, β-methylepichlorohydrin, and epibromohydrin, with epichlorohydrin being particularly preferred because it is easily available industrially.

[0026] In the above reaction, an alkali metal hydroxide can be used as a catalyst to promote the epoxidation step. Usable alkali metal hydroxides include sodium hydroxide, potassium hydroxide, etc. A solid or an aqueous solution thereof may be used, but in this embodiment, the use of a solid formed into flakes is particularly preferred from the standpoints of solubility and handling. The amount of alkali metal hydroxide used is preferably 0.90 to 1.5 mol, more preferably 0.95 to 1.25 mol, and even more preferably 0.99 to 1.15 mol, per mol of hydroxyl groups in the raw material phenol mixture.

[0027] To promote the reaction, a quaternary ammonium salt such as tetramethylammonium chloride, tetramethylammonium bromide, or trimethylbenzylammonium chloride is added as a catalyst. The amount of the quaternary ammonium salt used is preferably 0.1 to 15 g, more preferably 0.2 to 10 g, per mole of hydroxyl groups in the raw material phenol mixture.

[0028] The reaction temperature is preferably 30 to 90°C, more preferably 35 to 80°C. In particular, in this embodiment, for higher purity epoxidation, a temperature of 50°C or higher is preferred, and 60°C or higher is particularly preferred. The reaction time is preferably 0.5 to 10 hours, more preferably 1 to 8 hours, and particularly preferably 1 to 3 hours. A short reaction time is not preferred because the reaction does not proceed to completion, while a long reaction time is not preferred because by-products are produced.

[0029] The reaction products of these epoxidation reactions are washed with water, or without washing, and then heated under reduced pressure to remove epihalohydrin and solvent. Furthermore, to obtain epoxy resins with a reduced hydrolyzable halogen content, the recovered epoxy resins can be dissolved in a ketone compound having 4 to 7 carbon atoms (e.g., 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 the solution to carry out the reaction and ensure ring closure. In this case, the amount of alkali metal hydroxide used is preferably 0.01 to 0.3 mol, more preferably 0.05 to 0.2 mol, per mol of hydroxyl groups in the raw phenol mixture used in the epoxidation. The reaction temperature is preferably 50 to 120°C, and the reaction time is preferably 0.5 to 2 hours.

[0030] After completion of the reaction, the produced salt is removed by filtration, washing with water, or the like, and the solvent is further distilled off under heating and reduced pressure, thereby obtaining an epoxy resin mixture of the present embodiment containing the epoxy resin represented by formula (1) and a quaternary ammonium salt.

[0031] In addition, in the epoxy resin mixture of this embodiment, a quaternary ammonium salt may be added after synthesizing the epoxy resin represented by the formula (1).

[0032] In the epoxy resin represented by formula (1), the epoxy groups of the epoxy resin react and polymerize in the presence of a curing agent or polymerization initiator, and the furan ring moiety in the epoxy resin represented by formula (1) also reacts. It is believed that the quaternary ammonium salt contained in the epoxy resin mixture acts as a cationic polymerization initiator, promoting the reaction of the furan ring moiety. The furan rings react with each other while maintaining their ring structure, resulting in a cured product with high crosslink density, resulting in small changes in elastic modulus and high elasticity. Furthermore, the reaction of some furan rings while opening the rings slightly reduces the crosslink density, thereby increasing stress and elongation. This results in a cured product that can achieve both reduced changes in elastic modulus and improved mechanical strength (high elastic modulus, high stress, and high elongation).

[0033] The epoxy resin mixture of this embodiment preferably has a quaternary ammonium salt content of 1 to 100 ppm, more preferably 3 to 50 ppm, and particularly preferably 5 to 30 ppm, as determined by ion chromatogram using the method described in the Examples below. A quaternary ammonium salt content of less than 1 ppm fails to achieve high mechanical strength and a low linear expansion coefficient, while a quaternary ammonium salt content of more than 100 ppm is undesirable because it may cause corrosion of metal joints (wire bonding joints) when used, for example, as an encapsulant for semiconductors. In other words, when the quaternary ammonium salt content is within the above range, the cured product of the epoxy resin mixture can achieve excellent mechanical strength and a low linear expansion coefficient.

[0034] In the synthesis method of the phenolic resin represented by the formula (2), when furfural is reacted (condensed) with a phenol, the amount of the phenol is preferably 1.5 to 20 moles, particularly preferably 3 to 10 moles, per mole of furfural.

[0035] Examples of phenols include disubstituted phenols such as catechol, resorcinol, and hydroquinone, and monosubstituted phenols such as phenol, and these may be used alone or in combination of two or more.

[0036] Examples of the solvent include, but are not limited to, methanol, ethanol, propanol, isopropanol, toluene, xylene, etc., and these may be used alone or in combination of two or more. When a solvent is used, the amount used is preferably in the range of 5 to 500 parts by weight, more preferably 10 to 300 parts by weight, per 100 parts by weight of phenol.

[0037] In the condensation reaction, a base catalyst is preferably used. Polycondensation is possible with an acidic catalyst, but reactions between furfurals occur, resulting in increased by-products. Alternatively, an organometallic compound can be used, but this is cost-inefficient. Specific examples of base catalysts include alkali metal hydroxides such as lithium hydroxide, sodium hydroxide, and potassium hydroxide; alkaline earth metal hydroxides such as magnesium hydroxide and calcium hydroxide; alkali metal alkoxides such as sodium methoxide, sodium ethoxide, potassium methoxide, potassium ethoxide, and potassium tert-butoxide; and alkaline earth metal alkoxides such as magnesium methoxide and magnesium ethoxide. However, the catalyst is not limited to these, and may be used alone or in combination of two or more. The amount of catalyst used is preferably 0.005 to 2.0 times, more preferably 0.01 to 1.1 times, the moles per mole of phenol.

[0038] The condensation reaction in the presence of these base catalysts is preferably carried out in the range of 40 to 180° C., particularly preferably in the range of 80 to 165° C., and the reaction time can be selected preferably in the range of 0.5 to 10 hours. The reaction product thus obtained is neutralized so that the system becomes neutral, or is repeatedly washed with water in the presence of a solvent, and then the water is separated and drained, and the solvent and unreacted materials are removed under heating and reduced pressure, thereby obtaining the phenolic resin represented by formula (2).

[0039] The curable resin composition of this embodiment may contain a polymerization initiator. A thermal cationic polymerization initiator is particularly preferred as the polymerization initiator. Preferred examples of the thermal cationic polymerization initiator are listed below, but the present invention is not limited thereto. These may be used alone or in combination of two or more. The thermal cationic polymerization initiator is preferably an organic onium salt compound in which a cationic component and an anionic component are paired. Examples of the cationic component include organic sulfonium, organic oxonium, organic ammonium, organic phosphonium, and organic iodonium. Examples of the anionic component include BF ４ － , B(C ６ F ５ ) ４ － , SbF ４ － , Sb(C ６ F ５ ) ４ － , AsF ６ － , P.F. ６ － , C.F. ３ SO ３ － , C ４ F ９ SO ３ － and (CF ３ SO ２ ) ３ C －Examples of commercially available thermal cationic polymerization initiators include TA-60, TA-60B, TA-100, TA-120, and TA-160 (all manufactured by San-Apro Co., Ltd.), K-PURE (registered trademark) TAG-2678, TAG-2681, TAG-2689, TAG-2690, TAG-2700, CXC-1612, CXC-1614, CXC-1615, CXC-1616, CXC-1733, CXC-1738, CXC-1742, CXC-1802, and CXC-1821 (all manufactured by King Chemical Industries, Ltd.). Examples of such sintered body washes include San-Aid SI-45, SI-45L, SI-60, SI-60L, SI-80, SI-80L, SI-100, SI-100L, SI-110, SI-110L, SI-150, SI-150L, ​​SI-180, SI-180L, SI-B2, SI-B2A, SI-B3, SI-B3A, SI-B4, SI-B5, SI-200, SI-210, SI-220, SI-300, and SI-360 (all manufactured by Sanshin Chemical Industry Co., Ltd.). Among these, salts having a quaternary sulfonium cation are preferred, and salts having a quaternary sulfonium cation and a borate anion (BF) are more preferred. ４ － , B(C ６ F ５ ) ４ － salts consisting of quaternary sulfonium cations and antimony anions (SbF etc.); ４ － , Sb(C ６ F ５ ) ４ － and the like), and particularly preferred is a salt consisting of a quaternary sulfonium cation and a borate anion (BF ４ － , B(C ６ F ５ ) ４ － etc.)

[0040] The amount of the thermal cationic polymerization initiator added is preferably 0.001 to 10 parts by mass, more preferably 0.01 to 5 parts by mass, and even more preferably 0.1 to 2.5 parts by mass, relative to 100 parts by mass of the epoxy resin represented by the formula (1). If the amount of the thermal cationic polymerization initiator added is less than 0.001 part by mass, there is a risk of reduced curability, whereas if it is more than 10 parts by mass, there is a risk of corrosion of wiring when the composition is used in electronic materials (copper-clad laminates, resin-coated copper foils, interlayer insulating materials, and semiconductor encapsulants).

[0041] In the curable resin composition of this embodiment, the epoxy resin represented by formula (1) can be used in combination with other epoxy resins. When used in combination, the proportion of the epoxy resin represented by formula (1) in the total epoxy resins is preferably 5 to 95 wt %, more preferably 10 to 95 wt %, and even more preferably 15 to 95 wt %. If the amount added is small, sufficient heat resistance may not be achieved.

[0042] Specific examples of epoxy resins that can be used in combination with the epoxy resin represented by formula (1) include polycondensates of bisphenols (bisphenol A, bisphenol F, bisphenol S, biphenol, bisphenol AD, etc.) or phenols (phenol, alkyl-substituted phenol, aromatic-substituted phenol, naphthol, alkyl-substituted naphthol, dihydroxybenzene, alkyl-substituted dihydroxybenzene, dihydroxynaphthalene, etc.) with various aldehydes (formaldehyde, acetaldehyde, alkylaldehyde, benzaldehyde, alkyl-substituted benzaldehyde, hydroxybenzaldehyde, naphthaldehyde, glutaraldehyde, phthalaldehyde, crotonaldehyde, cinnamaldehyde, etc.); polycondensates of the phenols with various diene compounds (dicyclopentadiene, terpenes, vinylcyclohexene, norbornadiene, vinylnorbornene, tetrahydroindene, divinylbenzene, etc.); polycondensates of the phenols with aromatic dimethanols (benzenedimethanol, biphenyldimethanol, etc.); polycondensates of the phenols with aromatic dichloromethyls (α,α'-dichloroxylene, bischloromethylbiphenyl, etc.); polycondensates of the phenols with aromatic bisalkoxymethyls (bismethoxymethylbenzene, bismethoxymethylbiphenyl, bisphenoxymethylbiphenyl, etc.); and glycidyl ether epoxy resins, alicyclic epoxy resins, glycidylamine epoxy resins, and glycidyl ester epoxy resins obtained by glycidylating polycondensates of the bisphenols with various aldehydes or alcohols, etc. Specific examples of epoxy resins containing plant-derived components include compounds obtained by epoxidizing polycondensates obtained by polycondensing various aldehydes with cardanol derived from cashew oil as the phenol, and compounds obtained by epoxidizing linseed oil or soybean oil. These are not limited to these, as long as they are commonly used epoxy resins. These may be used alone or in combination of two or more.

[0043] The curable resin composition of this embodiment may be used in combination with a curing agent. Examples include acid anhydride compounds, amine compounds, amide compounds, phenolic compounds, and active ester compounds. Specific examples of curing agents that can be used in combination include amide compounds such as dicyandiamide and polyamide resins synthesized from a linolenic acid dimer and ethylenediamine; acid anhydride compounds such as phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, hexahydrophthalic anhydride, and methylhexahydrophthalic anhydride;o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 4,4'-diaminodiphenyl sulfone, 3,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 2,2'-diaminodiphenyl sulfone, diethyltoluenediamine, dimethylthiotoluenediamine, diaminodiphenylmethane, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 3,3'-diethyl-4,4'-diaminodiphenyl fluorene, 4,4'-diamino-3,3'-diethyl-5,5'-dimethyldiphenylmethane, 4,4'-diamino-3,3',5,5'-tetramethyldiphenylmethane, 4,4'-diamino-3,3',5,5'-tetraethyldiphenylmethane, 4,4'-diamino-3,3',5,5'-tetraisopropyldiphenylmethane, 4,4'-methylenebis(N-methylaniline), bis(aminophenyl)fluorene, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 2,2'-bis[4-(4-aminophenoxy)phenyl]propane, bis[4-(4-aminophenoxy)phenyl]sulfone, 1,3'-bis(4-aminophenoxy)benzene, 1,4'-bis(4-aminophenoxy)benzene, 1,4'-bis(4-aminophenoxy)biphenyl, 4,4'-(1,3-phenylenediisopropylidene)bisaniline, 4,4'-(1,4-phenylenediisopropylidene)bisaniline aromatic amine compounds such as 1,3-bis(aminomethyl)cyclohexane, isophoronediamine, 4,4'-methylenebis(cyclohexylamine), norbornanediamine, ethylenediamine, propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, dimer diamine, and triethylenetetramine;Polycondensates of bisphenols (bisphenol A, bisphenol F, bisphenol S, biphenol, bisphenol AD, etc.) or phenols (phenol, alkyl-substituted phenol, aromatic-substituted phenol, naphthol, alkyl-substituted naphthol, dihydroxybenzene, alkyl-substituted dihydroxybenzene, dihydroxynaphthalene, etc.) with various aldehydes (formaldehyde, acetaldehyde, alkylaldehyde, benzaldehyde, alkyl-substituted benzaldehyde, hydroxybenzaldehyde, naphthaldehyde, glutaraldehyde, phthalaldehyde, crotonaldehyde, cinnamaldehyde, etc.), or polycondensates of the above phenols with various diene compounds (dicyclopentadiene, terpenes, vinylcyclohexene, norbornadiene, vinylnorbornene, tetrahydroindene, divinylbenzene, divinylbiphenyl, diisopropenylbiphenyl, butadiene, isoprene, etc.). phenolic compounds such as polymers of the phenols and ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, acetophenone, benzophenone, etc.), polycondensates of the phenols and aromatic dimethanols (benzenedimethanol, biphenyldimethanol, etc.), polycondensates of the phenols and aromatic dichloromethyls (α,α'-dichloroxylene, bischloromethylbiphenyl, etc.), polycondensates of the phenols and aromatic bisalkoxymethyls (bismethoxymethylbenzene, bismethoxymethylbiphenyl, bisphenoxymethylbiphenyl, etc.), polycondensates of the bisphenols and various aldehydes, and modified products thereof; active ester compounds such as phenol esters, thiophenol esters, N-hydroxyamine esters, and esters of heterocyclic hydroxy compounds;

[0044] An inorganic filler can be added to the curable resin composition of this embodiment as needed. Examples of inorganic fillers include, but are not limited to, powders such as crystalline silica, fused silica, alumina, zircon, calcium silicate, calcium carbonate, silicon carbide, silicon nitride, boron nitride, zirconia, fosterite, steatite, spinel, titania, and talc, as well as spherical beads thereof. These fillers may be used alone or in combination of two or more. The amount of these inorganic fillers used varies depending on the application. For example, when used as a semiconductor sealant, the inorganic fillers are preferably used in an amount of 20% by weight or more, more preferably 30% by weight or more, of the cured product of the curable resin composition in terms of heat resistance, moisture resistance, mechanical properties, and flame retardancy. Furthermore, it is even more preferable to use them in an amount of 70 to 95% by weight, particularly to improve the linear expansion coefficient with the lead frame.

[0045] The curable resin composition of this embodiment can be blended with a release agent to improve release from the mold during molding. Any conventionally known release agent can be used, including ester waxes such as carnauba wax and montan wax, fatty acids such as stearic acid and palmitic acid and their metal salts, and polyolefin waxes such as oxidized polyethylene and non-oxidized polyethylene. These may be used alone or in combination of two or more. The blend amount of these release agents is preferably 0.5 to 3 wt % of the total organic components. If the amount is less than this, release from the mold is poor, and if the amount is too much, adhesion to a lead frame or the like is poor.

[0046] The curable resin composition of this embodiment can be blended with a coupling agent to improve adhesion between the inorganic filler and the resin component. Any conventionally known coupling agent can be used, including, for example, various alkoxysilane compounds such as vinylalkoxysilane, epoxyalkoxysilane, styrylalkoxysilane, methacryloxyalkoxysilane, acryloxyalkoxysilane, aminoalkoxysilane, mercaptoalkoxysilane, and isocyanatoalkoxysilane, alkoxytitanium compounds, and aluminum chelates. These may be used alone or in combination of two or more. The coupling agent may be added by first treating the surface of the inorganic filler with the coupling agent and then kneading it with the resin, or by mixing the coupling agent with the resin and then kneading the inorganic filler.

[0047] The curable resin composition of the present embodiment may contain known additives as needed. Specific examples of the additives that can be used include polyphenylene ether compounds, compounds having an ethylenically unsaturated bond, isocyanate resins, polyamide resins, benzoxazine compounds, polybutadiene and modified products thereof, modified acrylonitrile copolymers, polyphenylene ethers, polystyrene and modified products thereof, polyethylene and modified products thereof, polyimide resins, fluororesins, maleimide compounds, cyanate ester resins, silicone gels, silicone oils, and colorants such as carbon black, phthalocyanine blue, and phthalocyanine green.

[0048] Examples of polyphenylene ether compounds 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).

[0049] Examples of the compound having an ethylenically unsaturated bond include reaction products of a phenol resin with an ethylenically unsaturated bond-containing halogen-based compound (chloromethylstyrene, allyl chloride, methallyl chloride, acrylic acid chloride, methacrylic acid chloride, etc.), reaction products of an ethylenically unsaturated bond-containing phenol (2-allylphenol, 2-propenylphenol, 4-allylphenol, 4-propenylphenol, eugenol, isoeugenol, etc.) with a halogen-based compound (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 with (meth)acrylic acids (acrylic acid, methacrylic acid, etc.), and acid-modified products thereof.

[0050] 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, and naphthalene diisocyanate; aliphatic or alicyclic diisocyanates such as isophorone diisocyanate, hexamethylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, hydrogenated xylene diisocyanate, norbornene diisocyanate, and lysine diisocyanate; polyisocyanates such as biuret compounds of one or more types of isocyanate monomers or isocyanate compounds obtained by trimerizing the above diisocyanate compounds; and polyisocyanates obtained by a urethanization reaction between the above isocyanate compounds and polyol compounds.

[0051] 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'-diphenylether bismaleimide, 4,4'-diphenylsulfone bismaleimide, 1,3-bis(3-maleimidophenoxy)benzene, 1,3-bis(4-maleimidophenoxy)benzene, and Xylox-type maleimide compounds (anilix maleimide, manufactured by Mitsui Chemicals Fine Co., Ltd.), biphenylaralkyl-type maleimide compounds (solidified by distilling off the solvent under reduced pressure from a resin solution containing the maleimide compound (M2) described in Example 4 of JP 2009-001783 A), bisaminocumylbenzene-type maleimide (maleimide compounds described in WO 2020 / 054601 A), maleimide compounds having an indane structure described in Japanese Patent No. 6629692 or WO 2020 / 217679, MATERIAL STAGE Vol. 18, No. 12 2019 "Continued Epoxy Resin CAS Number Story - Curing Agent CAS Number Memorandum No. 31 Bismaleimide (1)" and MATERIAL STAGE Vol. 19, No. 12 2019 Examples include the maleimide compounds described in "Continued Epoxy Resin CAS Number Story - Hardener CAS Number Memorandum No. 32 Bismaleimide (2)" published in 2019.

[0052] Examples of cyanate ester resins include dicyanatobenzene, tricyanatobenzene, dicyanatonaphthalene, dicyanatobiphenyl, 2,2'-bis(4-cyanatophenyl)propane, bis(4-cyanatophenyl)methane, bis(3,5-dimethyl-4-cyanatophenyl)methane, 2,2'-bis(3,5-dimethyl-4-cyanatophenyl)propane, 2,2'-bis(4-cyanatophenyl)ethane, 2,2'-bis(4-cyanatophenyl)hexafluoropropane, bis(4-cyanatophenyl)sulfone, bis(4-cyanatophenyl)thioether, phenol novolac cyanate, and phenol-dicyclopentadiene co-condensates in which hydroxyl groups have been converted to cyanate groups.

[0053] The polyimide resin may be a mixture of the above diamines and tetracarboxylic dianhydrides (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-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-tetracarboxylic dianhydride, Cyclohexane-1,2,4,5-tetracarboxylic acid dianhydride, 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 -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 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 acid anhydride), 9,9'-bis(3,4-dicarboxyphenyl)fluorene dianhydride, etc., reaction products thereof,

[0054] Examples of polybutadiene and modified products thereof, polystyrene and modified products thereof, and polyethylene and modified products thereof include polybutadiene, hydroxyl-terminated polybutadiene, (meth)acrylate-terminated polybutadiene, carboxylic acid-terminated polybutadiene, amine-terminated polybutadiene, styrene-butadiene rubber, RICON-100, RICON-181, RICON-184 (all manufactured by Cray Valley Chemical Industry Co., Ltd.), 1,2-SBS (manufactured by Nippon Soda Co., Ltd.), B-1000, B-2000, B-3000 (all manufactured by Nippon Soda Co., Ltd.); polystyrene, styrene-2-isopropenyl-2-oxazoline copolymer (Epocross RPS-1005, RP-61, both manufactured by Nippon Shokubai Co., Ltd.), and SEP (styrene-ethylene-propylene copolymer: Septon 1020) 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 (styrene-ethylene / ethylene propylene-styrene block copolymer with a terminal hydroxyl group: 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.);Examples of such copolymers include ethylene-propylene copolymers, ethylene-styrene copolymers, ethylene-propylene-ethylidenenorbornene copolymers (EBT: K-8370EM, K-9330M, etc., manufactured by Mitsui Chemicals, Inc.), ethylene-propylene-vinylnorbornene copolymers (VNB-EPT: PX-006M, PX-008M, PX-009M, etc., manufactured by Mitsui Chemicals, Inc.), ethylene-vinyl alcohol copolymers, and ethylene-vinyl acetate copolymers;

[0055] Examples of the benzoxazine compound include benzoxazine P-d, Fa, and ALP-d (all manufactured by Shikoku Chemical Industry Co., Ltd.), JBZ-BA100N, JBZ-FA100N, JBZ-DP100N, JBZ-OP100N, JBZ-OP100D, and JBZ-OP100I (all manufactured by JFE Chemical Corporation), and BTBz (manufactured by Japan Material Technology Co., Ltd.).

[0056] The curable resin composition of this embodiment can be obtained by uniformly mixing the above components. The curable resin composition of this embodiment can be easily cured using methods similar to those known in the art. For example, the curable resin composition of this embodiment can be obtained by thoroughly mixing an epoxy resin and a curing agent, as well as optionally a curing accelerator, an inorganic filler, a release agent, a silane coupling agent, and additives, using an extruder, kneader, rolls, or the like, until uniform, and then molding the resulting mixture using a melt casting method, transfer molding method, injection molding method, compression molding, or the like, followed by heating at 80 to 200°C for 2 to 10 hours to obtain a cured product.

[0057] The curable resin composition of this embodiment may also contain a solvent. The solvent-containing curable resin composition (varnish) is impregnated into a fibrous material (substrate) such as glass fiber, carbon fiber, polyester fiber, polyamide fiber, alumina fiber, or paper, and the resulting prepreg is heat-dried and then hot-press molded to produce a cured product of the curable resin composition of this embodiment. The solvent content of this curable resin composition is preferably about 10 to 70 wt %, more preferably about 15 to 70 wt %, based on the total weight. Examples of the solvent include γ-butyrolactones; amide solvents such as N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, and N,N-dimethylimidazolidinone; sulfones such as tetramethylene sulfone; ether solvents such as diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, and propylene glycol monobutyl ether, preferably mono- or di-lower (1 to 3 carbon atoms) alkyl ethers of lower (1 to 3 carbon atoms) alkylene glycols; ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone, preferably di-lower (1 to 3 carbon atoms) alkyl ketones in which the two alkyl groups may be the same or different; and aromatic solvents such as toluene and xylene. These may be used alone or in combination.

[0058] Furthermore, a sheet-like adhesive (the sheet of this embodiment) can be obtained by applying the varnish to a release film, removing the solvent under heating, and then B-staging the varnish. This sheet-like adhesive can be used as an interlayer insulating material in multilayer substrates and the like.

[0059] The cured product of this embodiment can be used in various applications. Specifically, it can be used in general applications in which thermosetting resins such as epoxy resins are used, such as adhesives, paints, coating agents, molding materials (including sheets, films, fiber-reinforced composite materials, etc.), insulating materials (including printed wiring boards, electric wire coatings, etc.), semiconductor encapsulants, and additives for other resins, etc. Among these, it can be suitably used in fiber-reinforced composite materials, semiconductor encapsulants, printed wiring boards, and interlayer insulating materials.

[0060] The curable resin composition of the present invention can be heated and melted to reduce viscosity, and then impregnated into reinforcing fibers such as glass fibers, carbon fibers, polyester fibers, polyamide fibers, and alumina fibers to produce a prepreg. Specific examples include glass fibers such as E-glass cloth, D-glass cloth, S-glass cloth, Q-glass cloth, spherical glass cloth, NE-glass cloth, and T-glass cloth; inorganic fibers other than glass; polyparaphenylene terephthalamide (Kevlar®, manufactured by DuPont Co., Ltd.); wholly aromatic polyamides; polyesters; and organic fibers such as polyparaphenylene benzoxazole, polyimides, and carbon fibers, but are not limited thereto. The shape of the substrate is not particularly limited, but examples include woven fabrics, nonwoven fabrics, rovings, and chopped strand mats. Known weaving methods for woven fabrics include plain weave, saddle-weave, and twill weave, and these known methods can be appropriately selected depending on the intended application and performance. Also suitable are woven fabrics that have been subjected to fiber-opening treatment and glass woven fabrics that have been surface-treated with a silane coupling agent or the like. The thickness of the substrate is not particularly limited, but is preferably about 0.01 to 0.4 mm. Also, a prepreg can be obtained by impregnating reinforcing fibers with the varnish and drying the impregnated fibers by heating.

[0061] A laminate can be produced by laminating the prepregs prepared by the above method. The method for producing a laminate can be any known method, and is not particularly limited. For example, a multi-stage press, a multi-stage vacuum press, a continuous molding machine, an autoclave molding machine, or the like can be used to form a metal foil-clad laminate. The prepregs are laminated together and then heated and pressurized to obtain a laminate. The heating temperature is not particularly limited, but is preferably 65 to 300°C, more preferably 120 to 270°C. The pressure applied is also not particularly limited, but too high a pressure can make it difficult to adjust the resin solids content of the laminate, resulting in unstable quality. Too low a pressure can result in bubbles and poor adhesion between the laminate layers. Therefore, a pressure of 2.0 to 5.0 MPa is preferred, more preferably 2.5 to 4.0 MPa. By providing a layer made of metal foil, the laminate can be suitably used as a metal foil-clad laminate. The prepreg is cut into a desired shape and laminated with copper foil or the like as needed. The laminate is then heated and cured while applying pressure by press molding, autoclave molding, sheet winding molding or the like, to thereby obtain an electrical and electronic laminate (printed wiring board) or a fiber-reinforced composite material (FRP).

[0062] Examples of adhesives include adhesives for civil engineering, construction, automobiles, general office use, and medical use, as well as adhesives for electronic materials. Among these, adhesives for electronic materials include interlayer insulating materials for multilayer substrates such as build-up substrates, die bonding agents, semiconductor adhesives such as underfills, underfills for reinforcing BGAs, and mounting adhesives such as anisotropic conductive films (ACFs) and anisotropic conductive pastes (ACPs).

[0063] Examples of the sealant include potting, dipping, and transfer mold sealing for capacitors, transistors, diodes, light-emitting diodes, ICs, and LSIs; potting sealing for COB, COF, TAB, and the like for ICs and LSIs; underfill for flip chips; and sealing (including reinforcing underfill) when mounting IC packages such as QFP, BGA, and CSP.

[0064] The present invention will be explained in more detail below with reference to synthesis examples and examples. The materials, processing details, processing procedures, etc. shown below can be changed as appropriate without departing from the spirit of the present embodiment. Therefore, the scope of the present invention should not be interpreted as being limited by the specific examples shown below. Various analytical methods used in the examples will be described below.

[0065] Various analytical methods were carried out under the following conditions. Epoxy equivalent: Measured according to the method described in JIS K-7236, and expressed in g / eq. Softening point: Measured according to the method conforming to JIS K-7234, and expressed in °C. Melt viscosity: Measured by the ICI melt viscosity (150°C) cone-plate method, and expressed in Pa s. Ion chromatogram: Apparatus: ICS-2100 (manufactured by Thermo Corporation) Column: IonPac AS17C Flow rate: 0.3 ml / min Column temperature: 30°C Eluent: KOH aqueous solution Detector: Electrical conductivity detector

[0066] [Synthesis Example 1] 254 parts by weight of phenol, 63 parts by weight of water, and 27 parts by weight of sodium hydroxide were charged into a flask equipped with a stirrer, a reflux condenser, and a stirring device. After stirring and dissolving, the mixture was heated to 110°C, and 44 parts by weight of furfural was added dropwise over 2 hours. The mixture was then reacted at 110°C for 3 hours, and then heated to 145°C. During the temperature increase, the distilled water was removed from the system. After reaching 145°C, the mixture was reacted for 4 hours. The mixture was then cooled to 80°C, and 63 parts by weight of water was charged. 4 parts by weight of phosphoric acid and 63 parts by weight of 35% hydrochloric acid were added for neutralization. After repeated water washing, unreacted phenol was distilled off under reduced pressure with heating to obtain 109 parts by weight of a phenolic resin. To 78 parts by weight of the resulting phenolic resin, 178 parts by weight of epichlorohydrin (ECH, hereinafter the same), 1 part by weight of tetramethylammonium chloride (TMAC, hereinafter the same), and 13 parts by weight of water were charged into a reaction vessel. After heating, stirring, and dissolution, 23 parts by weight of flaky sodium hydroxide were added in portions over 2 hours while maintaining the temperature at 70°C. The reaction was then further carried out at 70°C for 1.5 hours and at 75°C for 30 minutes. After repeated water washing to remove by-product salts, excess epichlorohydrin was distilled off from the oil layer under heating and reduced pressure, and 218 parts by weight of methyl isobutyl ketone was added to the residue and dissolved. This methyl isobutyl ketone solution was heated to 70°C, and 7 parts by weight of a 30% aqueous sodium hydroxide solution was added. The reaction mixture was then repeatedly washed with water until the washings became neutral. The methyl isobutyl ketone was then distilled off from the oil layer under heating and reduced pressure, yielding 99 parts by weight of the epoxy resin represented by formula (1). The epoxy equivalent was 214 g / eq., the softening point was 49°C, the ICI melt viscosity was 0.04 Pa s, and the average repeating unit n was 2.1 as determined by GPC. The trimethylammonium ions remaining in this epoxy resin were quantified by ion chromatography using chloride ions as the counter anions (i.e., TMAC) to find that they were 6 ppm. The GPC chart of the epoxy resin represented by formula (1) is shown in Figure 1.

[0067] [Synthesis Example 2] 254 parts by weight of phenol, 63 parts by weight of water, and 27 parts by weight of sodium hydroxide were charged into a flask equipped with a stirrer, a reflux condenser, and a stirring device. After stirring and dissolving, the mixture was heated to 110°C, and 44 parts by weight of furfural was added dropwise over 2 hours. The mixture was then reacted at 110°C for 3 hours, and then heated to 145°C. During the temperature increase, the distilled water was removed from the system. After reaching 145°C, the mixture was reacted for 4 hours. The mixture was then cooled to 80°C, and 63 parts by weight of water was charged. 4 parts by weight of phosphoric acid and 63 parts by weight of 35% hydrochloric acid were added for neutralization. After repeated water washing, unreacted phenol was distilled off under reduced pressure with heating to obtain 109 parts by weight of a phenolic resin. To 78 parts by weight of the resulting phenolic resin, 254 parts by weight of ECH, 64 parts by weight of dimethyl sulfoxide (DMSO), and 13 parts by weight of water were charged into a reaction vessel. After heating, stirring, and dissolution, 23 parts by weight of flaky sodium hydroxide were added in portions over 2 hours while maintaining the temperature at 45°C. The reaction was then continued for 2 hours at 45°C and 60 minutes at 70°C. After repeated water washing to remove by-product salts and dimethyl sulfoxide, excess epichlorohydrin was removed from the oil layer under heating and reduced pressure, and 218 parts by weight of methyl isobutyl ketone was added to the residue and dissolved. This methyl isobutyl ketone solution was heated to 70°C, and 7 parts by weight of 30% aqueous sodium hydroxide was added. The reaction mixture was then repeatedly washed with water until the washings became neutral. The methyl isobutyl ketone was then removed from the oil layer under heating and reduced pressure to obtain 97 parts by weight of the epoxy resin represented by formula (1). The epoxy equivalent was 214 g / eq., the softening point was 49°C, the ICI melt viscosity was 0.04 Pa s, and the average repeating unit n was 2.1 as determined by GPC. The residual TMAC was 0 ppm. The GPC chart of the epoxy resin represented by formula (1) is shown in Figure 2.

[0068] [Example 1, Comparative Example 1] The epoxy resins obtained in Synthesis Examples 1 and 2 were used as the main component, and SAN-AID SI-B3A (4-acetoxyphenylmethylbenzylsulfonium tetrakis(pentafluorophenyl)borate, manufactured by Sanshin Chemical Industry Co., Ltd.) was blended as a thermal cationic polymerization initiator in the weight ratio shown in Table 1, and a varnish with a solids content of 50% was prepared with acetone. The resulting varnish was heated under vacuum at 60°C for 30 minutes, and then at 80°C for 30 minutes, to obtain a resin composition. The resulting resin composition was cured at 250°C for 2 hours to produce a cured product.

[0069] The physical properties were measured under the following conditions. <Heat resistance test> Manufacturer: TA-instruments Dynamic viscoelasticity measuring device: DMA-Q800 Measurement temperature range: 25 to 270°C Heating rate: 2°C / min Measurement frequency: 10 Hz In the storage modulus curve obtained by DMA analysis, the temperature at the intersection of the baseline tangent before the storage modulus decreases and the tangent at the inflection point (minimum value of the temperature derivative curve of the storage modulus) when the storage modulus decreases was defined as the modulus decrease temperature. <Mechanical strength test> Manufacturer: Shimadzu Corporation Mechanical strength measuring device: Autograph AGS-X Tensile speed: 0.5 mm / min The test piece was clamped so that the length was 5 cm, and tension measurement was performed in the 180° direction at the above test speed. <Linear Expansion Test> Manufacturer: TA-instruments Thermomechanical analyzer: TMA-Q400 Measurement temperature range: 25 to 270°C Heating rate: 2°C / min The change in linear expansion coefficient from 225°C to 250°C was taken as α2.

[0070]

[0071] In Example 1, no sudden change in the elastic modulus was observed in the temperature range of 25°C to 270°C, and it was confirmed that Example 1 had excellent heat resistance. It was also confirmed that Example 1 had excellent mechanical strength and low linear expansion.

Claims

1. An epoxy resin mixture containing an epoxy resin represented by the following formula (1) and a quaternary ammonium salt: (In formula (1), n is the average number of repetitions and is a real number in the range of 1<n<15.) 2. The epoxy resin mixture according to claim 1, wherein the quaternary ammonium salt is tetramethylammonium chloride or trimethylbenzylammonium chloride.

3. The epoxy resin mixture according to claim 2, wherein the content of the quaternary ammonium salt is 1 to 100 ppm per 100 parts by mass of the epoxy resin.

4. The epoxy resin mixture according to claim 1, wherein the epoxy resin has an ICI viscosity (150°C) of 0.01 to 0.20 Pa·s.

5. A curable resin composition comprising the epoxy resin mixture according to any one of claims 1 to 4 and a thermal cationic polymerization initiator.

6. A curable resin composition comprising the epoxy resin mixture according to any one of claims 1 to 4, and at least one selected from the group consisting of a curing accelerator, a polymerization initiator, an epoxy resin other than the epoxy resin represented by formula (1), an active ester compound, a phenolic compound, a polyphenylene ether compound, an amine compound, 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 modified products thereof, polystyrene and modified products thereof, polyethylene and modified products thereof, and a benzoxazine compound.

7. The curable resin composition according to claim 5, which is used for a fiber-reinforced composite material, a semiconductor encapsulant, a printed wiring board, or an interlayer insulating material.

8. A cured product obtained by curing the curable resin composition according to claim 5.

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