TWI867257B - Epoxy resin, curable resin composition, and cured product thereof - Google Patents

Abstract

The present invention provides an epoxy resin and an epoxy resin composition, wherein the cured product has high heat resistance, high elastic modulus and low water absorption. The epoxy resin is represented by the following formula (1), wherein the total content of the epoxy resin represented by the following formula (2) to (4) is 80% by area or less in the epoxy resin represented by the following formula (1). (In formula (1), n is the number of repetitions, and its average value is 1＜n＜5.)

Description

Epoxy resin, curable resin composition, and cured product thereof

The present invention relates to an epoxy resin having a specific structure, a curable resin composition, and a cured product thereof.

Epoxy resins are hardened with various hardeners to form hardened 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, coatings, laminates, forming materials, and casting materials. Carbon fiber reinforced composite materials (carbon fiber reinforced plastic (CFRP)) made by impregnating reinforcing fibers with epoxy resin and hardener as matrix resin and hardening them have been widely used in aircraft structural components, windmill blades, automobile outer panels, integrated circuit (IC) trays, notebook computer frames (casings) and other computer applications in recent years due to their lightweight and high-strength properties. In particular, they are used in matrix resins for aircraft applications by utilizing the lightweight and high-strength properties of their molded bodies.

Generally speaking, as the resin used in the base resin of CFRP, bisphenol A type epoxy resin, bisphenol F type epoxy resin, tetraglycidyl diamino diphenyl methane and the like are used, and in aircraft applications, glycidylamine type epoxy resin, tetraglycidyl diamino diphenyl methane and the like are used.

In recent years, the required properties of CFRP have become more stringent, and when used as structural materials for aerospace applications or vehicles, heat resistance of more than 180°C is required (Patent Document 1). Glycidylamine-based materials have high heat resistance, but have a high water absorption rate, and there is a problem of deterioration of properties after water absorption. On the other hand, general glycidyl ether-type epoxy resins have a relatively low water absorption rate, but there is a problem of low elastic modulus. Therefore, a material with high heat resistance and high elastic modulus and low water absorption is required. [Prior Art Document] [Patent Document]

[Patent Document 1] International Publication No. 2010/204173

[The problem that the invention wants to solve]

In view of the above-mentioned problem, the purpose of the present invention is to provide an epoxy resin and an epoxy resin composition, the cured product of which has high heat resistance, high elastic modulus and low water absorption rate. [Means for solving the problem]

The inventors of the present invention have made intensive research to solve the above-mentioned problems and have completed the present invention. That is, the present invention relates to the following [1] to [8]. [1] An epoxy resin represented by the following formula (1), wherein the total content of the epoxy resin represented by the following formula (2) to (4) in the epoxy resin represented by the following formula (1) is 80% by volume or less.

[Chemistry 1]

(In formula (1), n is the number of repetitions, and its average value is 1＜n＜5.)

[Chemistry 2]

[2] The epoxy resin described in the above item [1], wherein the component where n=1 in the above formula (1) accounts for 80% by area or less. [3] The epoxy resin described in the above item [1] or the above item [2], represented by the following formula (5).

[Chemistry 3]

(In formula (5), n is the number of repetitions, and its average value is 1＜n＜5.) [4] A curable resin composition comprising an epoxy resin as described in any one of the preceding items [1] to [3]. [5] The curable resin composition as described in the preceding item [4] further comprises a curing agent. [6] A cured product obtained by curing the curable resin composition as described in the preceding item [4] or the preceding item [5]. [Effect of the invention]

The present invention relates to an epoxy resin having a specific structure, a curable resin composition and a cured product thereof, wherein the cured product has high heat resistance, high modulus of elasticity and low water absorption. Therefore, the present invention can be effectively used in insulating materials for electrical and electronic parts (high reliability semiconductor sealing materials, etc.) and laminated boards (printed wiring boards, build-up substrates, etc.) or various composite materials represented by CFRP, adhesives, coatings, etc.

Hereinafter, the present invention will be described in detail.

The epoxy resin of the present invention can use an aromatic amine resin represented by the following formula (6) as a precursor.

[Chemistry 4]

(In formula (6), n is the number of repetitions, and its average value is 1＜n＜5.)

The aromatic amine resin represented by formula (6) is preferably represented by the following formula (7). The reason for this is that the crystallinity is reduced compared to when the substitution position of each isopropylidene bond relative to the benzene ring not bonded to the amine group in formula (6) is ortho or para. By reducing the crystallinity, the solvent stability is increased, and the preparation of the resin solution becomes easier. In addition, the crystallinity of the compound derived therefrom can also be reduced. Therefore, crystal precipitation can also be suppressed during storage after the composition is formed.

[Chemistry 5]

(In formula (7), n is the number of repetitions, and its average value is 1＜n＜5.)

The method for preparing the aromatic amine resin represented by the formula (6) or (7) is not particularly limited. For example, in Japanese Patent Publication No. 61-000044, by reacting aniline with m-diisopropenylbenzene or m-di(α-hydroxyisopropyl)benzene in the presence of an acidic catalyst at 180°C to 250°C, the n=1 isomer in the formula (4) can be obtained as the main component, but it contains three isomers, namely, 1,3-bis(p-aminocumyl)benzene, 1-(oxamidocumyl)-3-(p-aminocumyl)benzene, and 1,3-bis(oxamidocumyl)benzene. Furthermore, n=2 to 5 isomers are also generated as byproducts, but in Japanese Patent Publication No. 61-000044, these are purified by crystallization to obtain 1,3-bis(p-aminocumyl)benzene with a purity of 98%. In the present invention, the isomers and polymer components in the aromatic amine resin that were previously removed as useless components are focused on, and these are epoxidized instead of removed, thereby developing an epoxy resin that exhibits high heat resistance, low water absorption, high elastic modulus and low viscosity. That is, the amine resin as the raw material of the epoxy resin of the present invention does not require a purification step such as crystallization, so it can be produced in a short time and at a low cost, thereby improving industrial applicability.

The acidic catalyst used in the synthesis of the aromatic amine resin represented by the formula (6) can be exemplified by: hydrochloric acid, phosphoric acid, sulfuric acid, formic acid, zinc chloride, ferric chloride, aluminum chloride, p-toluenesulfonic acid, methanesulfonic acid, activated clay, ion exchange resin, etc. These can be used alone or in combination of two or more. The amount of the catalyst used is 0.1 wt% to 50 wt%, preferably 1 wt% to 30 wt%, relative to the aniline used. If it is too much, the viscosity of the reaction solution is too high and stirring becomes difficult. If it is too little, the reaction proceeds slowly.

The reaction can be carried out using an organic solvent such as toluene or xylene as required, or can be carried out without a solvent. For example, after adding an acidic catalyst to a mixed solution of aniline and a solvent, when the catalyst contains water, it is preferred to remove the water from the system by azeotropy. Then, diisopropenylbenzene or di(α-hydroxyisopropyl)benzene is added, and then the temperature is raised while removing the solvent from the system, and the reaction is carried out at 140°C to 220°C, preferably 160°C to 200°C, for 5 hours to 50 hours, preferably 5 hours to 30 hours. When di(α-hydroxyisopropyl)benzene is used, water is produced as a by-product, so it is removed from the system while azeotroping with the solvent when the temperature is raised. After the reaction is completed, the acidic catalyst is neutralized with an alkaline aqueous solution, and a water-insoluble organic solvent is added to the oil layer. The waste water is repeatedly washed with water until the waste water becomes neutral, and then the solvent and excess aniline derivatives are removed under heating and reduced pressure. When activated clay or ion exchange resin is used, the reaction solution is filtered after the reaction is completed to remove the catalyst. In addition, since diphenylamine is generated as a by-product depending on the reaction temperature or the type of catalyst, the diphenylamine derivative is removed to less than 1% by weight, preferably less than 0.5% by weight, and more preferably less than 0.2% by weight, under high temperature and high vacuum, or by using water vapor distillation.

The epoxy resin of the present invention is represented by the following formula (1), and the total content of the epoxy resins represented by the following formulas (2) to (4) in the epoxy resin represented by the following formula (1) is 80% by volume or less.

[Chemistry 6]

(In formula (1), n is the number of repetitions, and its average value is 1＜n＜5.)

[Chemistry 7]

In formula (1), n is preferably 1<n<5, and more preferably 1<n<3.

The total content of the epoxy resins represented by the formulae (2) to (4) in the epoxy resin represented by the formula (1) can be determined by an analysis method using both gel permeation chromatography and high performance liquid chromatography. In the present invention, the analysis was performed under the following conditions.

･GPC (Gel Permeation Chromatography) Analysis Column: Showa (SHODEX) GPC KF-601 (two), KF-602, KF-602.5, KF-603 Flow rate: 0.5 ml/min. Column temperature: 40℃ Solvent used: tetrahydrofuran (THF) Detector: RI (refractive index) (differential refractometer)

･HPLC (High Performance Liquid Chromatography) Analysis Column: Inertsil ODS-2 Flow rate: 1.0 ml/min. Column temperature: 40°C Solvent used: Acetonitrile/10 mmol/L phosphoric acid aqueous solution Detector: Photodiode array (274 nm)

Specifically, the content (α) of the n=1 component in the epoxy resin represented by the formula (1) can be determined by gel permeation chromatography, and the content (β2 to β4) of the epoxy resin represented by the formula (2) to (4) contained in the n=1 component can be determined by high performance liquid chromatography. Therefore, for example, the product of α and β2 is the content of the epoxy resin represented by the formula (2) contained in the epoxy resin represented by the formula (1).

In the epoxy resin of the present invention, the total content of the epoxy resin represented by the formula (2) to the formula (4) in the epoxy resin represented by the formula (1) is preferably 80% by area or less, more preferably 70% by area or less, and most preferably 60% by area or less. The reason is that if it is 80% by area or less, the orientation and molecular weight distribution can be controlled, so that an epoxy resin having properties that are difficult to exhibit simultaneously, namely, high heat resistance, low water absorption, and high modulus of elasticity can be obtained. In addition, the lower limit may be 0% by area, but is preferably 20% by area or more, and more preferably 40% by area or more.

In the epoxy resin of the present invention, the component where n=1 in the formula (1) is preferably 80% by area or less, more preferably 70% by area or less, and most preferably 65% by area or less. The reason is that if it is 80% by area or less, the rigidity of the molecule becomes higher, so it is easy to show a high elastic modulus and low water absorption. In addition, the lower limit may be 0% by area, but is preferably 20% by area or more, and more preferably 40% by area or more.

The epoxy resin represented by the formula (1) is preferably represented by the following formula (5). The reason is that the isopropylene structures or cross-linking points are further adjacent to each other, and the rigidity of the molecule is improved due to the steric hindrance, so that it is easy to show a high elastic modulus and low water absorption.

[Chemistry 8]

In formula (5), the value and preferred range of n are the same as those in formula (1).

The preparation method of the epoxy resin of the present invention is not particularly limited, and can be obtained, for example, by subjecting the aromatic amine resin represented by the formula (6) to addition or ring-closure reaction with epihalogen alcohol in the presence of a solvent and a catalyst. The amount of epihalogen alcohol used is generally 3.0 mol to 20.0 mol, preferably 3.5 mol to 10.0 mol, relative to 1 mol of the amino group of the amine compound.

As the alkali metal hydroxide that can be used in the epoxidation reaction, sodium hydroxide, potassium hydroxide, etc. can be listed. The alkali metal hydroxide can be a solid substance, and its aqueous solution can also be used. In the case of using an aqueous solution, the following method can be used: the aqueous solution of the alkali metal hydroxide is continuously added to the reaction system, and water and epihalogenated alcohol are continuously distilled under reduced pressure or normal pressure, and then liquid separation is performed to remove water, and the epihalogenated alcohol is continuously returned to the reaction system. The amount of the alkali metal hydroxide used is generally 0.9 mol to 2.5 mol relative to 1 mol of the amino group of the amine compound, and preferably 0.95 mol to 1.5 mol. If the amount of the alkali metal hydroxide used is too small, the reaction will not proceed sufficiently. On the other hand, if the alkali metal hydroxide is used in an excessive amount exceeding 2.5 mol per 1 mol of the amino group of the amine compound, unnecessary waste will be generated as a by-product.

In order to promote the reaction, a quaternary ammonium salt such as tetramethylammonium chloride, tetramethylammonium bromide, trimethylbenzylammonium chloride, etc. may be added as a catalyst. The amount of the quaternary ammonium salt used is usually 0.1 g to 15 g, preferably 0.2 g to 10 g, relative to 1 mol of the amino group of the amine compound. If the amount used is too small, the reaction promotion effect cannot be fully obtained. If the amount used is too large, the amount of residual quaternary ammonium salt in the epoxy resin increases, which may also become a cause of deterioration of electrical reliability.

In the epoxidation reaction, in terms of the reaction progress, it is preferred to add an alcohol such as methanol, ethanol, isopropanol, dimethyl sulfide, dimethyl sulfoxide, tetrahydrofuran, dioxane, and other aprotic polar solvents to carry out the reaction. When alcohols are used, the amount used is usually 2% to 50% by weight relative to the amount of epihalogenated alcohol, preferably 4% to 20% by weight. In addition, when an aprotic polar solvent is used, the amount used is usually 5% to 100% by weight relative to the amount of epihalogenated alcohol, preferably 10% to 80% by weight. The reaction temperature is usually 30°C to 90°C, preferably 35°C to 80°C. The reaction time is usually 0.5 hours to 100 hours, preferably 1 hour to 30 hours. After the reaction is completed, the reactants are washed with water, or the epihalogenated alcohol and the solvent are removed under heating and reduced pressure without washing. In addition, in order to produce an epoxy resin with less hydrolyzable halogen, the recovered epoxy resin can also be dissolved in a solvent such as toluene, methyl isobutyl ketone, and an aqueous solution of an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide is added to react, so that the ring closure is reliable. In this case, the amount of alkali metal hydroxide used is usually 0.01 mol to 0.3 mol, preferably 0.05 mol to 0.2 mol, relative to 1 mol of the amino group of the amine compound used in the glycidylation. The reaction temperature is usually 50°C to 120°C, and the reaction time is usually 0.5 hour to 24 hours. After the reaction is completed, the generated salt is removed by filtration, water washing, etc., and the solvent is further distilled off under heating and reduced pressure to obtain the epoxy resin of the present invention.

The epoxy resin of the present invention is usually in a liquid to solid resin state at room temperature, and its softening point is preferably below 100°C, more preferably below 80°C. When the softening point is higher than 100°C, the viscosity is high, and the fiber impregnation property is reduced when making a prepreg. In addition, its epoxy equivalent is preferably 142 g/eq to 1000 g/eq, more preferably 150 g/eq to 500 g/eq, particularly preferably 170 g/eq to 450 g/eq, and most preferably 180 g/eq to 400 g/eq.

The epoxy resin composition of the present invention is described below. In the epoxy resin composition of the present invention, the epoxy resin represented by formula (1) can be used alone or in combination with other epoxy resins. When used in combination, the proportion of the epoxy resin represented by formula (1) in all epoxy resins is preferably 10 wt% to 98 wt%, more preferably 20 wt% to 95 wt%, and further preferably 30 wt% to 95 wt%. By setting the addition amount to 10 wt% or more, an improvement in the elastic coefficient and low water absorption can be achieved.

Specific examples of other epoxy resins that can be used in combination with the epoxy resin of the present invention include: 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.) and various aldehydes (formaldehyde, acetaldehyde, alkyl aldehydes, benzene, etc.). condensation products of the phenols and various diene compounds (dicyclopentadiene, terpenes, vinylcyclohexene, norbornadiene, vinyl norbornene, tetrahydroindene, divinylbenzene, divinylbiphenyl, diisopropylbiphenyl, butadiene, isoprene, etc.); polycondensates of the phenols and ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, acetophenone, benzophenone, etc.); polycondensates of the phenols and aromatic dimethanols (benzenedimethanol, biphenyledimethanol, etc.); polycondensates of the phenols and aromatic dichloromethyls (α,α'-dichloroxylene, dichloromethylbiphenyl, etc.); polycondensates of the phenols and aromatic dialkoxymethyls Condensates of (bismethoxymethylbenzene, bismethoxymethylbiphenyl, bisphenoxymethylbiphenyl, etc.); condensates of the above-mentioned diphenols and various aldehydes or glycidyl ether epoxy resins, alicyclic epoxy resins, glycidylamine epoxy resins, glycidyl ester epoxy resins, etc. obtained by glycidylating alcohols, etc., 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.

Examples of the curing agent that can be used in the epoxy resin composition of the present invention include amine compounds, acid anhydride compounds, amide compounds, and phenol compounds. Specific examples of the curing agent that can be used include 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'-diaminodiphenylmethane, 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'-diamino Diphenyl 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, naphthalene diamine, benzidine, dimethylbenzidine, international Aromatic amine compounds such as those described in Synthesis Examples 1 and 2 of Publication No. 2017/170551; aliphatic amines such as 1,3-bis(aminomethyl)cyclohexane, isophoronediamine, 4,4'-methylenebis(cyclohexylamine), norbornanediamine, ethylenediamine, propylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, dimer diamine, triethylenetetramine, etc., but are not limited thereto and can be used appropriately according to the properties to be imparted to the composition. In order to ensure the pot life, it is preferred to use aromatic amines, and in the case of imparting instant curability, it is preferred to use aliphatic amines. By using an amine compound containing a bifunctional component as a main component as a curing agent, a highly linear network can be constructed during the curing reaction, thereby showing particularly excellent toughness. In addition, amide compounds such as dicyandiamide, polyamide resin synthesized from dimer of linolenic acid and ethylenediamine; anhydride compounds such as phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride; bisphenols (bisphenol A, bisphenol F, bisphenol S, biphenol , bisphenol AD, etc.) or condensation products of phenols (phenol, alkyl-substituted phenol, aromatic-substituted phenol, naphthol, alkyl-substituted naphthol, dihydroxybenzene, alkyl-substituted dihydroxybenzene, dihydroxynaphthalene, etc.) and various aldehydes (formaldehyde, acetaldehyde, alkyl aldehydes, benzaldehyde, alkyl-substituted benzaldehyde, hydroxybenzaldehyde, naphthaldehyde, glutaraldehyde, o-phthalaldehyde, crotonaldehyde, cinnamaldehyde, etc.), or polycondensation products of the phenols and various diene compounds (dicyclopentadiene, terpenes, etc.) Polymers of the phenols (such as vinylcyclohexene, norbornadiene, vinyl norbornene, tetrahydroindene, divinylbenzene, divinylbiphenyl, diisopropylbiphenyl, butadiene, isoprene, etc.), or condensation products of the phenols with ketones (such as acetone, methyl ethyl ketone, methyl isobutyl ketone, acetophenone, benzophenone, etc.), or condensation products of the phenols with aromatic dimethanols (such as benzyl alcohol, biphenyl dimethanol, etc.), or Condensates of the above phenols with aromatic dichloromethyls (α,α'-dichloroxylene, bischloromethylbiphenyl, etc.), or condensates of the above phenols with aromatic dialkoxymethyls (bismethoxymethylbenzene, bismethoxymethylbiphenyl, bisphenoxymethylbiphenyl, etc.), or condensates of the above bisphenols with various aldehydes, and modified products thereof; imidazole, trifluoroborane-amine complex, guanidine derivatives, etc., but not limited to these.

In the epoxy resin composition of the present invention, the amount of the curing agent used is preferably 0.5 to 1.5 equivalents, particularly preferably 0.6 to 1.2 equivalents, relative to 1 equivalent of epoxy group in the epoxy resin. By setting the amount to 0.5 to 1.5 equivalents, good curing properties can be obtained.

When the curing agent is used for the curing reaction, a curing accelerator may also be used. Examples of the curing accelerator include: imidazoles such as 2-methylimidazole, 2-ethylimidazole, 2-phenylimidazole, and 2-ethyl-4-methylimidazole; tertiary amines such as 2-(dimethylaminomethyl)phenol, triethylenediamine, triethanolamine, and 1,8-diazabicyclo(5,4,0)undecene-7; organic phosphines such as triphenylphosphine, diphenylphosphine, and tributylphosphine; The curing accelerator may be a metal compound such as tin tin; a tetrasubstituted phosphonium-tetrasubstituted borate such as tetraphenylphosphonium-tetraphenylborate and tetraphenylphosphonium-ethyltriphenylborate; a tetraphenyl borate such as 2-ethyl-4-methylimidazolium-tetraphenylborate and N-methylmorpholine-tetraphenylborate; a carboxylic acid compound such as benzoic acid, phthalic acid, isophthalic acid, terephthalic acid, naphthoic acid, and salicylic acid. From the viewpoint of promoting the curing reaction of the amine compound and the epoxy resin, a carboxylic acid compound such as salicylic acid is preferred. The curing accelerator may be used in an amount of 0.01 to 15 parts by weight relative to 100 parts by weight of the epoxy resin as needed.

Furthermore, an inorganic filler may be added to the epoxy resin composition of the present invention as needed. Examples of the inorganic filler include, but are not limited to, powders of crystalline silica, fused silica, alumina, zircon, calcium silicate, calcium carbonate, silicon carbide, silicon nitride, boron nitride, zirconium oxide, forsterite, steatite, spinel, titanium dioxide, talc, or beads obtained by sphering these. These 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 sealant for semiconductors, in terms of heat resistance, moisture resistance, mechanical properties, flame retardancy, etc. of the cured epoxy resin composition, it is preferably used in a ratio of 20% by weight or more, more preferably 30% by weight or more, and particularly in order to increase the linear expansion rate relative to the lead frame, it is more preferably used in a ratio of 70% by weight to 95% by weight.

In the epoxy resin composition of the present invention, a release agent may be formulated to facilitate demolding from a mold during molding. As a release agent, any previously known one may be used, for example: ester waxes such as carnauba wax and montan wax; fatty acids such as stearic acid and palmitic acid and their metal salts; polyolefin waxes such as oxidized polyethylene and non-oxidized polyethylene, etc. These may be used alone or in combination of two or more. The formulation amount of these release agents is preferably 0.5 wt% to 3 wt% relative to all organic components. If it is too little, demolding from the mold will be poor, and if it is too much, adhesion to the lead frame, etc. will be poor.

In the epoxy resin composition of the present invention, a coupling agent may be added to improve the adhesion between the inorganic filler and the resin component. As the coupling agent, any previously known coupling agent may be used, for example, various alkoxysilane compounds such as vinyl alkoxysilane, epoxy alkoxysilane, styryl alkoxysilane, methacryloxy alkoxysilane, acryloxy alkoxysilane, amino alkoxysilane, alkyl alkoxysilane, isocyanate alkoxysilane, alkoxy titanium compounds, aluminum chelates, etc. may be listed. These may be used alone or in combination of two or more. The coupling agent can be added by treating the surface of the inorganic filler with the coupling agent before mixing with the resin, or by mixing the coupling agent in the resin before mixing with the inorganic filler.

Furthermore, in the epoxy resin composition of the present invention, known additives can be formulated as needed. Specific examples of usable additives include: polybutadiene and its modified products, modified products of acrylonitrile copolymers, polyphenylene ether, polystyrene, polyethylene, polyimide, fluororesin, maleimide compounds, cyanate compounds, silicone gel, silicone oil, and coloring agents such as carbon black, phthalocyanine blue, and phthalocyanine green.

The epoxy resin composition of the present invention is obtained by uniformly mixing the above-mentioned components. The epoxy resin composition of the present invention can be easily made into a hardened product by the same method as the previously known method. For example, the epoxy resin and the hardener, and the hardening accelerator, inorganic filler, mold release agent, silane coupling agent and additives are fully mixed to be uniform by using an extruder, a kneader, a roller, etc. as needed to obtain the epoxy resin composition of the present invention, and the epoxy resin composition is molded by melt casting, transfer molding, injection molding, compression molding, etc., and then heated at 80°C to 200°C for 2 hours to 10 hours to obtain a hardened product.

In addition, the epoxy resin composition of the present invention may also contain a solvent as needed. The epoxy resin composition (epoxy resin varnish) containing a solvent is impregnated in a fibrous material (substrate) such as glass fiber, carbon fiber, polyester fiber, polyamide fiber, alumina fiber, paper, etc. and heated and dried to obtain a prepreg, and the obtained prepreg is hot-pressed to produce a cured product of the epoxy resin composition of the present invention. The solvent content of the epoxy resin composition is usually 10% to 70% by weight, preferably about 15% to 70% by weight, based on the internal ratio. As the solvent, for example, there can be listed: γ-butyrolactone; 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 (carbon number 1-3) alkyl ethers of lower (carbon number 1-3) alkanediols; ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone, more preferably di-lower (carbon number 1-3) alkyl ketones in which two alkyl groups may be the same or different; aromatic solvents such as toluene and xylene, etc. These can be used alone or as a mixed solvent of two or more.

Furthermore, by applying the epoxy resin varnish on the release film and removing the solvent under heating to perform B-stage, a sheet-shaped adhesive (sheet of the present invention) can be obtained. The sheet-shaped adhesive can be used as an interlayer insulating layer in a multilayer substrate or the like.

The hardened material obtained in the present invention can be used for various purposes. Specifically, general uses of thermosetting resins such as epoxy resins can be listed, for example, adhesives, coatings, coatings, molding materials (including sheets, films, FRP, etc.), insulating materials (including printed circuit boards, wire coatings, etc.), sealants, and additives to other resins, etc.

Examples of adhesives include adhesives for civil engineering, construction, automobiles, general affairs, and medical applications, as well as adhesives for electronic materials. Among these, examples of adhesives for electronic materials include: interlayer adhesives for multi-layer substrates such as build-up substrates, die bonding agents, underfill agents, and other semiconductor adhesives; underfill agents for ball grid array (BGA) enhancement, anisotropic conductive film (ACF), anisotropic conductive paste (ACP), and other mounting adhesives.

As sealants, there are: potting seals, immersion seals, and transfer mold seals for capacitors, transistors, diodes, LEDs, ICs, large scale integrated circuits (LSIs), etc.; potting seals for ICs and LSIs such as chip on board (COB), chip on film (COF), and tape automated bonding (TAB); bottom fillers for flip chips; sealing during installation of IC packages such as quad flat package (QFP), ball grid array (BGA), and chip size package (CSP) (including enhanced bottom fillers), etc. [Examples]

Next, the present invention is described in more detail by way of examples. Unless otherwise specified, parts are parts by weight. Furthermore, the present invention is not limited to these examples. In addition, in the examples, the epoxy equivalent is measured by a method in accordance with Japanese Industrial Standards (JIS) K-7236, and the softening point is measured by a method in accordance with JIS K-7234.

･GPC (Gel Permeation Chromatography) Analysis Column: Showa (SHODEX) GPC KF-601 (two), KF-602, KF-602.5, KF-603 Flow rate: 0.5 ml/min. Column temperature: 40℃ Solvent used: THF (tetrahydrofuran) Detector: RI (differential refractometer)

･HPLC (High Performance Liquid Chromatography) Analysis Column: Inertsil ODS-2 Flow rate: 1.0 ml/min. Column temperature: 40°C Solvent used: Acetonitrile/10 mmol/L phosphoric acid aqueous solution Detector: Photodiode array (274 nm)

[Synthesis Example 1] While nitrogen was purged into a flask equipped with a thermometer, cooling tube, distillation tube, and stirrer, 559 parts of aniline, 291 parts of α,α,α',α'-tetramethylbenzenedimethanol (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.), and 360 parts of toluene were added, and 63 parts of a 35% aqueous solution of hydrochloric acid were added and stirring was started. While the water generated by dehydration was extracted together with the toluene, the internal temperature was raised to 160°C and the reaction was carried out for 15 hours. The mixture was cooled to room temperature, the extracted toluene and water were returned to the system, and 88 parts of a 30% aqueous solution of sodium hydroxide were added for neutralization. Thereafter, the organic layer was washed with water until the waste liquid became neutral and then concentrated to obtain 458 parts of an aromatic amine resin (A1). The amine equivalent of the aromatic amine resin (A1) was 185 g/eq and the softening point was 58.7°C. According to GPC analysis (RI), the n=1 isomer was 61% by area. According to HPLC analysis, the 4,4'-(1,3-phenylenediisopropylidene)bisaniline in the n=1 isomer was 16.7% by area. Therefore, the 4,4'-(1,3-phenylenediisopropylidene)bisaniline in the aromatic amine resin was 10.2% by area. The GPC chart of the obtained amine resin (A1) is shown in FIG1 , ^{the 1} H-NMR chart (heavy chloroform) is shown in FIG2 , and the HPLC chart is shown in FIG3 . Signals derived from amine groups were observed at 3.05 ppm-3.65 ppm in the ¹ H-NMR spectrum.

[Example 1] While nitrogen was purged into a flask equipped with a thermometer, a cooling tube, a distillation tube, and a stirrer, 186 parts of the aromatic amine resin (A1) obtained in Synthesis Example 1, 555 parts of epichlorohydrin, 55 parts of methanol, and 5.5 parts of water were added, and the mixture was reacted at 77°C for 8 hours. The internal temperature was cooled to 65°C, and 81 parts of sodium hydroxide were added in batches over 90 minutes. The reaction was continued at 65°C for 3 hours, and 500 parts of water was added to remove the sodium chloride in the organic layer, and then the mixture was concentrated under reduced pressure at 120°C. 300 parts of methyl isobutyl ketone (MIBK) and 40 parts of a 30% aqueous sodium hydroxide solution were added, and the reaction was continued at 70°C for 6 hours. The organic layer was washed until the drainage became neutral, and then concentrated under reduced pressure at 120°C to obtain 235 parts of a semi-solid epoxy resin (EP1). The epoxy equivalent was 209.7 g/eq. The GPC chart of the obtained epoxy resin (EP1) is shown in Figure 4, the ¹ H-NMR chart (heavy chloroform) is shown in Figure 5, and the HPLC chart is shown in Figure 6. Signals derived from epoxy groups were observed at 2.50 ppm-3.80 ppm in the ¹ H-NMR chart. According to GPC analysis (RI), the n=1 body accounted for 61% by area. According to HPLC analysis (measurement wavelength: 274 nm), the n=1 body accounted for 31.2% by area of 2,2'-(1,3-phenylenediisopropylidene)bis(diglycidylaniline), 32.3% by area of 2,4'-(1,3-phenylenediisopropylidene)bis(diglycidylaniline), and 33.0% by area of 4,4'-(1,3-phenylenediisopropylidene)bis(diglycidylaniline). According to the above, the 2,2'-(1,3-phenylene diisopropylidene)bis(diglycidylaniline) (in the epoxy resin represented by formula (2) where each isopropylidene bond is substituted at the meta position) contained in EP1 is 19.0% by area, and the 2,4'-(1,3-phenylene diisopropylidene)bis(diglycidylaniline) is 19.0% by area. The area percentage of 4,4'-(1,3-phenylenediisopropylidene)bis(diglycidylaniline) (the area percentage of the epoxy resin represented by formula (4) in which each isopropylidene bond is substituted at the meta-position) is 19.7%, and the area percentage of 4,4'-(1,3-phenylenediisopropylidene)bis(diglycidylaniline) (the area percentage of the epoxy resin represented by formula (4) in which each isopropylidene bond is substituted at the meta-position) is 20.1%.

[Reference Example 1] While nitrogen was purged into a flask equipped with a thermometer, cooling tube, distillation tube, and stirrer, 150 parts of 4,4'-(1,3-phenylenediisopropyl)bisaniline (manufactured by Tokyo Chemical Industry Co., Ltd.), 483 parts of epichlorohydrin, 17 parts of methanol, and 5 parts of water were added, and the mixture was reacted at 80°C for 3 hours. The internal temperature was cooled to 65°C, and 70.3 parts of sodium hydroxide were added in portions over 90 minutes. The reaction was continued at 65°C for 3 hours, and 400 parts of water were added to remove the sodium chloride in the organic layer, and then the mixture was concentrated under reduced pressure at 120°C. 300 parts of MIBK and 40 parts of a 30% aqueous sodium hydroxide solution were added, and the reaction was continued at 70°C for 20 hours. The organic layer was washed until the drainage became neutral, and then concentrated under reduced pressure at 120°C to obtain 213 parts of a liquid epoxy resin (EP2). The epoxy equivalent was 160.3 g/eq. The GPC chart of the obtained epoxy resin (EP2) is shown in Figure 7, the ¹ H-NMR chart (heavy chloroform) is shown in Figure 8, and the HPLC chart is shown in Figure 9. Signals derived from epoxy groups were observed at 2.50 ppm-3.80 ppm in the ¹ H-NMR chart. According to GPC analysis (RI), the n=1 isomer is 90.2% by area, and according to HPLC analysis (measurement wavelength: 274 nm), the 4,4'-(1,3-phenylene diisopropylidene)bis(diglycidylaniline) in the n=1 isomer is 100% by area. Based on the above, the 4,4'-(1,3-phenylene diisopropylidene)bis(diglycidylaniline) (in which each isopropylidene bond in the epoxy resin represented by formula (4) is substituted at the meta position) contained in EP2 is 90.2% by area.

[Example 2, Comparative Example 1, Comparative Example 2] The epoxy resins (EP1, EP2) and epoxy resin (EP3; RE-304S, manufactured by Nippon Kayaku Co., Ltd.) obtained in Example 1 and Reference Example 1, and 4,4'-methylenebis(2,6-diethylaniline) (manufactured by Tokyo Chemical Industry Co., Ltd., abbreviated as MDEA (4,4'-methylene-bis(2,6-diethylaniline))) as a curing agent were prepared in the proportion (parts by weight) shown in Table 1, and mixed/kneaded uniformly using a mixing roller, and then demolded, and cured at 160°C for 2 hours and 180°C for 6 hours to obtain test pieces for evaluation.

<Measurement of curing properties> The results of the evaluation test pieces measured under the following conditions are shown in Table 1.

<Glass transition temperature> Measured in accordance with JIS K-7244. The peak temperature of tanδ is set as Tg. ･Dynamic viscoelasticity tester: TA-instruments, dynamic thermomechanical analyzer (DMA)-2980 ･Sample size: 20 mm×5 mm×1 mm ･Heating rate: 10℃/min

<Bending strength, bending elasticity> Measured in accordance with JIS K-6911. ･Tensilon: RTG-1310 (manufactured by A&D Company, Limited) ･Measurement temperature: room temperature

<Water absorption> Calculated based on the mass change of a disk-shaped test piece with a diameter of 5 cm and a thickness of 4 mm, immersed in water at 100°C for 24 hours.

[Table 1] Embodiment 2 Comparison Example 1 Comparison Example 2 Dispensing amount Epoxy EP1 100 EP2 100 EP3 100 Hardener MDEA 37 48 46 Evaluation results Glass transition temperature ℃ 182 206 155 Bending strength (30℃) MPa 95 113 94 Bending elastic modulus (30℃) GPa 3.2 2.6 2.3 Water absorption (100℃) % 0.8 1.3 1.2

According to the results in Table 1, it is confirmed that Example 2 has high heat resistance, high flexural strength, high modulus of elasticity, and low water absorption. [Industrial Applicability]

The epoxy resin of the present invention can be effectively used in insulating materials for electrical and electronic parts (high-reliability semiconductor sealing materials, etc.), laminates (printed wiring boards, BGA substrates, build-up substrates, etc.), adhesives (conductive adhesives, etc.), various composite materials represented by CFRP, coatings, etc., and can be particularly effectively used in various composite materials represented by CFRP that strongly require a high modulus of elasticity.

without

Figure 1 shows a gel permeation chromatography (GPC) chart of Synthesis Example 1. Figure 2 shows a ¹ H-nuclear magnetic resonance ( ¹ H-NMR) chart of Synthesis Example 1. Figure 3 shows a high performance liquid chromatography (HPLC) chart of Synthesis Example 1. Figure 4 shows a GPC chart of Example 1. Figure 5 shows a ¹ H-NMR chart of Example 1. Figure 6 shows a HPLC chart of Example 1. Figure 7 shows a GPC chart of Reference Example 1. Figure 8 shows a ¹ H-NMR chart of Reference Example 1. Figure 9 shows a HPLC chart of Reference Example 1.

Claims (5)

An epoxy resin is represented by the following formula (5), wherein the total content of the epoxy resins represented by the following formulas (2) to (4) in the epoxy resin represented by the following formula (5) is 80% by volume or less,

In formula (5), n is the number of repetitions, and its average value is 1<n<5;

The epoxy resin as described in claim 1, wherein the component where n=1 in the formula (5) is less than 80% by area. A curable resin composition comprising the epoxy resin as described in claim 1 or claim 2. The curable resin composition as described in claim 3 further contains a curing agent. A hardened material obtained by hardening the hardening resin composition as described in claim 3 or claim 4.