Epoxy resin, curable resin composition, and cured product thereof

Abstract

To provide an epoxy resin and an epoxy resin composition, a cured product of which is excellent in low dielectric properties, low water absorbency, and flame retardancy.SOLUTION: The present invention discloses an epoxy resin represented by the following formula (1). (In the formula (1), n represents a number of repetition, with its average value being 1<n<20; R represents a benzyl group in which a hydrogen atom of a benzene ring may be substituted with a C1-6 hydrocarbon group; and each p represents a real number of 0-4 with an average value of p being 1.0-2.0).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an epoxy resin having a specific structure, a curable resin composition, and a cured product thereof. [Background technology]

[0002] Epoxy resins have excellent electrical properties (dielectric constant, dielectric dissipation factor, insulation), mechanical properties, adhesive properties, and thermal properties (heat resistance, etc.), and are therefore widely used in the electrical and electronic fields, such as in cast products, laminates, and IC encapsulation materials, as well as in structural materials, adhesives, paints, and other fields.

[0003] In recent years, in the electrical and electronic fields, there has been a demand for further improvements in various properties of resin compositions, such as improved flame retardancy, moisture resistance, adhesion, and dielectric properties, as well as higher purity, lower viscosity for higher filler (inorganic or organic filler) loading, and improved reactivity for shorter molding cycles (Patent Document 1). Furthermore, as structural materials, lightweight materials with excellent mechanical properties are required for aerospace applications and leisure and sports equipment applications. In particular, in the field of semiconductor encapsulation and substrates (the substrate itself or its peripheral materials), semiconductors are becoming increasingly complex, with thinner layers, stacked structures, systemization, and three-dimensional structures, requiring properties such as extremely high levels of heat resistance and high fluidity.

[0004] Properties that are particularly required for high functionality include moisture resistance (low water absorption) and flame retardancy. For example, in applications such as copper-clad laminates for semiconductor package substrates, materials that are prone to water absorption can cause problems during solder reflow. Furthermore, in flame retardancy, there is a demand for reducing the environmental impact by not using halogen-based flame retardants, and in recent years, phosphorus-based flame retardants have been considered (Non-Patent Document 1). However, with phosphorus-based flame retardants, increasing the amount added tends to impair various properties such as mechanical properties, electrical properties, and moisture resistance, making it important to impart flame retardancy to the matrix resin, such as epoxy resin or phenolic resin. [Prior art documents] [Patent documents]

[0005] Japanese Patent Application Laid-Open No. 2015-147854

Non-Patent Document

[0006]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] In view of the above problems, an object of the present invention is to provide an epoxy resin and an epoxy resin composition whose cured product is excellent in low dielectric properties, low water absorption, and flame retardancy.

Means for Solving the Problems

[0008] As a result of intensive studies to solve the above problems, the present inventors have completed the present invention. That is, the present invention relates to the following [1] to [7]. [1] An epoxy resin represented by the following formula (1).

[0009]

Chemical Formula

[0010] (In formula (1), n is the number of repetitions, and its average value is 1 < n < 20. R represents a substituent represented by the following formula (2). Each p represents a real number from 0 to 4, and the average value of p is 1.0 to 2.0.)

[0011]

Chemical Formula

[0012] (In formula (2), * represents the bonding part to the aromatic ring of formula (1). X represents a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms. q represents a real number from 0 to 5.)

[0013] [2] An epoxy resin represented by the following formula (3):

[0014] [ka]

[0015] (In equation (3), n is the number of repetitions, and its average value is 1 <n<20である。)

[0016] [3] The epoxy resin according to the above item [1] or [2], which has a weight average molecular weight of 400 to 3,000 as determined by gel permeation chromatography (GPC). [4] A curable resin composition containing the epoxy resin according to any one of the preceding items [1] to [3]. [5] The curable resin composition according to the above item [4], further comprising an amine-based curing agent. [6] A cured product obtained by curing the curable resin composition according to the above item [4] or [5]. [7] A method for producing an epoxy resin according to any one of items [1] to [3] above, comprising the steps of: reacting a polycondensate of a dicyclopentadiene compound and a phenolic compound with a benzylating agent to obtain a phenolic resin; and epoxidizing the phenolic resin. [Effects of the Invention]

[0017] The present invention relates to an epoxy resin having a specific structure, a curable resin composition, and a cured product thereof, and the cured product thereof has low water absorption, low dielectric properties, and flame retardancy. Therefore, the present invention is useful for insulating materials for electric and electronic parts (such as highly reliable semiconductor encapsulation materials), laminates (such as printed wiring boards and build-up substrates), various composite materials including CFRP, adhesives, paints, and the like. [Brief explanation of the drawings]

[0018] [Figure 1] The GPC chart of Synthesis Example 1 is shown. [Figure 2] The GPC chart of Example 1 is shown.

Embodiments for Carrying Out the Invention

[0019] Hereinafter, the present invention will be described in detail.

[0020] The epoxy resin of the present invention is represented by the following formula (1).

[0021]

Chemical formula

[0022] (In formula (1), n is the number of repetitions, and its average value is 1 < n < 20. R represents a substituent represented by the following formula (2). p represents a real number from 0 to 4, and the average value of p is 1.0 to 2.0.)

[0023]

Chemical formula

[0024] (In formula (2), * represents the bonding part to the aromatic ring of formula (1). X represents a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms. q represents a real number from 0 to 5.)

[0025] In the above formula (1), the average value of n can be determined by the number average molecular weight measured by gel permeation chromatography (GPC, detector: RI), or calculated from the area ratio of each separated peak. The average value of n is more preferably 1 < n < 10, and particularly preferably 1 < n < 5.

[0026] The substituent R of the epoxy resin represented by the above formula (1) is the one represented by the above formula (2), and it is more preferable that X is a hydrogen atom.

[0027] In the above formula (1), each p represents a real number from 0 to 4, and the average value of p is preferably from 0.5 to 4.0, more preferably from 0.8 to 2.0, particularly preferably from 1.0 to 2.0, and most preferably from 1.0 to 1.5. When the average value of p is 0.5 or more, it is likely to exhibit high flame retardancy, and when it is 4.0 or less, a significant increase in viscosity can be suppressed.

[0028] As an example of a preferred structure of the epoxy resin represented by the above formula (1), an epoxy resin represented by the following formula (3) can be cited.

[0029]

Chemical formula

[0030] (In formula (3), n is the number of repetitions, and its average value is 1 < n < 20.)

[0031] The preferred range of n in the above formula (3) is the same as that of the above formula (1).

[0032] The production method of the epoxy resin of the present invention is not particularly limited. For example, it can be obtained by subjecting a phenol resin represented by the following formula (4) and epihalohydrin to an addition or ring-closing reaction in the presence of a solvent and a catalyst.

[0033]

Chemical formula

[0034] (In formula (4), n is the number of repetitions, and its average value is 1 < n < 20. R represents a substituent represented by the following formula (5). Each p represents a real number from 0 to 4, and the average value of p is 1.0 to 2.0.)

[0035]

Chemical formula

[0036] (In formula (5), * represents the bonding site to the aromatic ring in formula (4). X represents a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms. q represents a real number of 0 to 5.)

[0037] The preferred ranges of n, p, q, R, and X in the formulas (4) and (5) are the same as those in the formulas (1) and (2).

[0038] Here, a method for producing the phenolic resin represented by the formula (4) will be described. The method for producing the phenolic resin represented by the formula (4) is not particularly limited. For example, the target phenolic resin can be obtained by reacting a dicyclopentadiene-type phenolic resin (a polycondensate of a dicyclopentadiene compound and a phenolic compound) with a benzylating agent such as benzyl alcohol or benzyl chloride in the presence of an acid catalyst.

[0039] Examples of acidic catalysts used in synthesizing the phenolic resin represented by formula (4) include hydrochloric acid, phosphoric acid, sulfuric acid, formic acid, zinc chloride, ferric chloride, aluminum chloride, p-toluenesulfonic acid, methanesulfonic acid, activated clay, and ion exchange resins. These may be used alone or in combination. The amount of catalyst used is 0.1 to 50% by weight, preferably 1 to 30% by weight, based on the phenolic hydroxyl groups used. If the amount is too high, waste increases, and if the amount is too low, the reaction proceeds slowly.

[0040] The reaction may be carried out using an organic solvent such as toluene or xylene, or without solvent, as needed. For example, after adding an acidic catalyst to a mixed solution of a phenolic resin obtained by polycondensation of a dicyclopentadiene compound and a phenolic compound and a benzylating agent, if the catalyst contains water, it is preferable to remove the water from the system by azeotropy. The reaction is then carried out while removing the solvent from the system, by raising the temperature to 100 to 220°C, preferably 120 to 180°C, for 1 to 50 hours, preferably 2 to 20 hours. When an alcohol-based benzylating agent is used, water is by-produced and removed from the system by azeotropy with the solvent during the temperature increase. After the reaction is complete, the acidic catalyst is neutralized with an alkaline aqueous solution, etc., and the oil layer is added with a water-insoluble organic solvent and repeatedly washed with water until the wastewater becomes neutral. The solvent and excess benzylating agent are then removed under reduced pressure and heating. When activated clay or ion exchange resin is used, the reaction solution is filtered after the reaction to remove the catalyst.

[0041] Next, the method for producing the epoxy resin of the present invention will be described. As described above, the method for producing the epoxy resin of the present invention is not particularly limited. For example, the epoxy resin can be obtained by subjecting a phenolic resin represented by the formula (4) to an addition or ring-closing reaction with epihalohydrin in the presence of a solvent and a catalyst. The amount of epihalohydrin used is usually 1.0 to 20.0 mol, preferably 1.5 to 10.0 mol, per mol of the phenolic hydroxyl group of the phenolic resin.

[0042] Examples of alkali metal hydroxides that can be used in the epoxidation reaction include sodium hydroxide and potassium hydroxide. The alkali metal hydroxide may be a solid or an aqueous solution. When an aqueous solution is used, the alkali metal hydroxide may be continuously added to the reaction system while continuously distilling water and epihalohydrin under reduced pressure or normal pressure, followed by liquid separation to remove water and continuously returning the epihalohydrin to the reaction system. The amount of alkali metal hydroxide used is typically 0.9 to 2.5 mol, preferably 0.95 to 1.5 mol, per mol of phenolic hydroxyl groups in the phenolic resin. If the amount of alkali metal hydroxide used is too small, the reaction will not proceed sufficiently. On the other hand, excessive use of more than 2.5 mol of alkali metal hydroxide per mol of phenolic hydroxyl groups in the phenolic resin will result in the production of unnecessary waste by-products.

[0043] To accelerate the reaction, a quaternary ammonium salt such as tetramethylammonium chloride, tetramethylammonium bromide, or trimethylbenzylammonium chloride may be added as a catalyst. The amount of quaternary ammonium salt used is typically 0.1 to 15 g, and preferably 0.2 to 10 g, per mole of phenolic hydroxyl groups in the phenolic resin. If the amount used is too small, a sufficient reaction acceleration effect cannot be obtained, while if the amount used is too large, the amount of quaternary ammonium salt remaining in the epoxy resin increases, which may cause a deterioration in electrical reliability.

[0044] In order to advance the epoxidation reaction, it is preferable to add an alcohol such as methanol, ethanol, or isopropyl alcohol, or an aprotic polar solvent such as dimethyl sulfone, dimethyl sulfoxide, tetrahydrofuran, or dioxane. When an alcohol is used, the amount used is usually 2 to 50% by weight, preferably 4 to 20% by weight, based on the amount of epihalohydrin used. When an aprotic polar solvent is used, the amount used is usually 5 to 100% by weight, preferably 10 to 80% by weight, based on the amount of epihalohydrin used. The reaction temperature is usually 30 to 90°C, preferably 35 to 80°C. The reaction time is usually 0.5 to 100 hours, preferably 1 to 30 hours. After the reaction is complete, the reaction product is washed with water, or heated under reduced pressure to remove the epihalohydrin and solvent. To further reduce the hydrolyzable halogen content of the epoxy resin, the recovered epoxy resin can be dissolved in a solvent such as toluene or methyl isobutyl ketone, and an aqueous solution of an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide can be added to the reaction mixture to ensure ring closure. In this case, the amount of alkali metal hydroxide used is typically 0.01 to 0.3 mol, preferably 0.05 to 0.2 mol, per mol of amino group in the amine compound used for glycidylation. The reaction temperature is typically 50 to 120°C, and the reaction time is typically 0.5 to 24 hours. After the reaction is complete, the resulting salt is removed by filtration, washing with water, or the like, and the solvent is then distilled off under reduced pressure with heating to obtain the epoxy resin of the present invention.

[0045] The epoxy resin of the present invention is usually in a semi-solid to solid resin state at room temperature, and its softening point is preferably 100°C or lower, more preferably 80°C or lower. If the softening point is higher than 100°C, the viscosity will be high and fiber impregnation will be poor during prepreg production. The epoxy equivalent is preferably 200 to 1000 g / eq, more preferably 300 to 800 g / eq, particularly preferably 300 to 700 g / eq, and most preferably 330 to 600 g / eq.

[0046] The epoxy resin composition of the present invention will be 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 the total epoxy resin is preferably 10 to 98% by weight, more preferably 20 to 95% by weight, and even more preferably 30 to 95% by weight. By adding an amount of 10% or more, it is possible to achieve improved elastic modulus and low water absorption.

[0047] Specific examples of other epoxy resins that can be used in combination with the epoxy resin of the present invention 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 above phenols with various diene compounds (dicyclopentadiene, terpenes, vinylcyclohexene, norbornadiene, vinylnorbornene, tetrahydroindene, divinylbenzene, divinylbiphenyl, disopropenyl, etc.); Examples of epoxy resins include 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.); and glycidyl ether epoxy resins, alicyclic epoxy resins, glycidylamine epoxy resins, and glycidyl ester epoxy resins obtained by glycidylating polycondensates of the bisphenols and various aldehydes or alcohols, but 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.

[0048] Curing agents that can be used in the epoxy resin composition of the present invention include amine-based curing agents, acid anhydride-based curing agents, amide-based curing agents, phenol-based curing agents, etc. Specific examples of curing agents that can be used include o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 4,4'-diaminodiphenylsulfone, 3,4'-diaminodiphenylsulfone, 3,3'-diaminodiphenylsulfone, 2,2'-diaminodiphenylsulfone, diethyltoluenediamine, dimethylthiotoluenediamine, diaminodiphenylmethane, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 3,3'-diethyl-4,4'-diaminodiphenylmethane, ... ,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, naphthalenediamine, benzidine, dimethylbenzidine, WO 2017 / 170551 Examples of suitable amines include aromatic amine compounds such as the aromatic amine compounds described in Synthesis Examples 1 and 2, and aliphatic amines such as 1,3-bis(aminomethyl)cyclohexane, isophoronediamine, 4,4'-methylenebis(cyclohexylamine), norbornanediamine, ethylenediamine, propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, dimer diamine, and triethylenetetramine, but are not limited to these. Suitable amines can be used depending on the properties desired to be imparted to the composition.To ensure a long pot life, it is preferable to use an aromatic amine, and to impart quick-curing properties, it is preferable to use an aliphatic amine. By using an amine compound containing a bifunctional component as the main component as a curing agent, a highly linear network can be constructed during the curing reaction, and particularly excellent toughness can be achieved.Further, amide compounds such as polyamide resins synthesized from dicyandiamide and a dimer of linolenic acid 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; bisphenols (bisphenol A, bisphenol F, bisphenol S, biphenol, bisphenol AD, etc.) or phenols (phenol polycondensates of phenols (e.g., alkyl-substituted phenols, aromatic-substituted phenols, naphthol, alkyl-substituted naphthols, dihydroxybenzenes, alkyl-substituted dihydroxybenzenes, dihydroxynaphthalenes) with various aldehydes (e.g., formaldehyde, acetaldehyde, alkyl aldehydes, benzaldehyde, alkyl-substituted benzaldehydes, hydroxybenzaldehyde, naphthaldehyde, glutaraldehyde, phthalaldehyde, crotonaldehyde, cinnamaldehyde), or polycondensates of the above phenols with various diene compounds (e.g., methyl phenols, alkyl-substituted phenols, aromatic-substituted phenols, naphthols, alkyl-substituted naphthols, dihydroxybenzenes, alkyl-substituted dihydroxybenzenes, dihydroxynaphthalenes, etc.) with various aldehydes (e.g., formaldehyde, acetaldehyde, alkyl aldehydes, benzaldehyde, alkyl-substituted benzaldehydes, hydroxybenzaldehyde, naphthaldehyde, glutaraldehyde, phthalaldehyde, crotonaldehyde, cinnamaldehyde, etc.); dicyclopentadiene, terpenes, vinylcyclohexene, norbornadiene, vinylnorbornene, tetrahydroindene, divinylbenzene, divinylbiphenyl, disopropenylbiphenyl, butadiene, isoprene, etc.), or polycondensates of the above phenols with ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, acetophenone, benzophenone, etc.), or polycondensates of the above phenols with aromatic dimethanols (benzenedimethanol, biphenyldimethanol, etc.), or Examples of the phenolic compounds include, but are not limited to, polycondensates of 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; imidazole, trifluoroborane-amine complexes, guanidine derivatives, etc.

[0049] In the epoxy resin composition of the present invention, the amount of curing agent used is preferably 0.5 to 1.5 equivalents, particularly preferably 0.6 to 1.2 equivalents, per equivalent of epoxy group in the epoxy resin. By using an amount of 0.5 to 1.5 equivalents, good curing properties can be obtained.

[0050] When the curing reaction is carried out using the above curing agent, a curing accelerator may be used in combination. Examples of usable curing accelerators 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; metal compounds such as tin octoate; tetra-substituted phosphonium tetra-substituted borates such as tetraphenylphosphonium tetraphenylborate and tetraphenylphosphonium ethyltriphenylborate; tetraphenylboron salts such as 2-ethyl-4-methylimidazole tetraphenylborate and N-methylmorpholine tetraphenylborate; and carboxylic acid compounds such as benzoic acid, phthalic acid, isophthalic acid, terephthalic acid, naphthoic acid, and salicylic acid. From the viewpoint of accelerating the curing reaction between the amine compound and the epoxy resin, a carboxylic acid compound such as salicylic acid is preferred. The curing accelerator is used as needed in an amount of 0.01 to 15 parts by weight per 100 parts by weight of the epoxy resin.

[0051] Furthermore, inorganic fillers can be added to the epoxy resin composition of the present invention 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 inorganic filler used varies depending on the application. For example, when used as a semiconductor sealant, the inorganic filler is preferably used in an amount of 20% by weight or more of the epoxy resin composition, more preferably 30% by weight or more, in terms of the heat resistance, moisture resistance, mechanical properties, and flame retardancy of the cured product of the epoxy resin composition. Furthermore, it is even more preferable to use the inorganic filler in an amount of 70 to 95% by weight, particularly to improve the linear expansion coefficient with the lead frame.

[0052] The epoxy resin composition of the present invention can be blended with a release agent to improve release from the mold during molding. Any of the conventionally known release agents 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. The amount of these release agents blended is preferably 0.5 to 3% by weight of the total organic components. If the amount is less than this, release from the mold will be poor, and if the amount is too high, adhesion to a lead frame or the like will be poor.

[0053] The epoxy resin composition of the present invention can contain a coupling agent to enhance adhesion between the inorganic filler and the resin component. Any conventionally known coupling agent can be used, including various alkoxysilane compounds such as vinylalkoxysilane, epoxyalkoxysilane, styrylalkoxysilane, methacryloxyalkoxysilane, acryloxyalkoxysilane, aminoalkoxysilane, mercaptoalkoxysilane, and isocyanatoalkoxysilane; alkoxytitanium compounds; and aluminum chelates. These can be used alone or in combination of two or more. The coupling agent can 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.

[0054] Furthermore, known additives can be blended into the epoxy resin composition of the present invention as needed. Specific examples of usable additives include polybutadiene and modified polybutadiene, modified acrylonitrile copolymers, polyphenylene ether, polystyrene, polyethylene, polyimide, fluororesin, maleimide compounds, cyanate ester compounds, silicone gel, silicone oil, and colorants such as carbon black, phthalocyanine blue, and phthalocyanine green.

[0055] The epoxy resin composition of the present invention can be obtained by uniformly mixing the above-mentioned components. The epoxy resin composition of the present invention can be easily cured by methods similar to those known in the art. For example, the epoxy resin and curing agent, and optionally a curing accelerator, inorganic filler, mold release agent, silane coupling agent, and additives, are thoroughly mixed until uniform using an extruder, kneader, roll, or the like, to obtain the epoxy resin composition of the present invention. This composition can then be molded by melt casting, transfer molding, injection molding, compression molding, or the like, and further heated at 80 to 200°C for 2 to 10 hours to obtain a cured product.

[0056] The epoxy resin composition of the present invention may also contain a solvent, if necessary. The solvent-containing epoxy resin composition (epoxy resin 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 epoxy resin composition of the present invention. The solvent content of this epoxy resin composition is typically 10 to 70% by weight, preferably about 15 to 70% by weight. Examples of solvents include amide solvents such as γ-butyrolactones, 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 monoacetate, and propylene glycol monobutyl ether, preferably mono- or di-lower (1-3 carbon atoms) alkyl ethers of lower (1-3 carbon atoms) alkylene glycols; ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone, preferably in which the two alkyl groups are the same or different; di-lower (1-3 carbon atoms) alkyl ketones; and aromatic solvents such as toluene and xylene. These may be used alone or in a mixture of two or more.

[0057] Furthermore, a sheet-like adhesive (the sheet of the present invention) can be obtained by applying the epoxy resin varnish onto 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 layer in a multilayer substrate or the like.

[0058] The cured product obtained by the present invention can be used in various applications, including general applications in which thermosetting resins such as epoxy resins are used, such as adhesives, paints, coating agents, molding materials (including sheets, films, FRP, etc.), insulating materials (including printed circuit boards, electric wire coatings, etc.), sealants, and additives for other resins, etc.

[0059] 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 adhesives 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).

[0060] Examples of the sealing agent include potting, dipping, and transfer mold sealing for capacitors, transistors, diodes, light-emitting diodes, ICs, and LSIs; potting sealing for COB, COF, and TAB of ICs and LSIs; underfill for flip chips; and sealing (including reinforcing underfill) when mounting IC packages such as QFP, BGA, and CSP. [Example]

[0061] The present invention will now be described in more detail with reference to examples. In the following, "parts" are by weight unless otherwise specified. The present invention is not limited to these examples. In the examples, the epoxy equivalent was measured according to JIS K-7236, and the softening point was measured according to JIS K-7234.

[0062] GPC (gel permeation chromatography) analysis Columns: SHODEX GPC KF-601 (2 columns), KF-602, KF-602.5, KF-603 Flow rate: 0.5ml / min. Column temperature: 40℃ Solvent used: THF (tetrahydrofuran) Detector: RI (differential refractive index detector)

[0063] [Synthesis Example 1] 84 parts of dicyclopentadiene-type phenolic resin (hydroxyl equivalent: 168 g / eq.), 54.2 parts of benzyl alcohol, and 1.4 parts of paratoluenesulfonic acid monohydrate were added, and the mixture was heated to 150°C while distilling off the generated water, and reacted for 3 hours. 100 parts of toluene was added, and the organic layer was washed with water until the waste liquid became neutral, and then concentrated, yielding 95 parts of phenolic resin (P1). The number average molecular weight Mn was 699, the weight average molecular weight Mw was 769, and the hydroxyl equivalent was 258.1 g / eq. The GPC chart of phenolic resin (P1) is shown in Figure 1.

[0064] [Example 1] A flask equipped with a thermometer, a condenser, a fractionating column, and a stirrer was purged with nitrogen while adding 80 parts of the phenolic resin (P1) obtained in Example 1, 115 parts of epichlorohydrin, 28.7 parts of dimethyl sulfoxide, and 1.3 parts of water, and the internal temperature was raised to 45°C. 12.8 parts of sodium hydroxide were added in portions over 1.5 hours, and the mixture was reacted at 45°C for 2 hours and at 70°C for 1 hour. Unreacted epichlorohydrin and the solvent were distilled off under heating and reduced pressure. 146 parts of MIBK was added, and the organic layer was washed once with 100 parts of water. The organic layer was returned to the reaction vessel, and 15 parts of a 30 wt% aqueous sodium hydroxide solution was added. The mixture was reacted at 70°C for 2 hours. After cooling, the organic layer was washed three times with 100 parts of water, and the solvent was distilled off under heating and reduced pressure, yielding the target compound (E1) as a brown solid resin. The number average molecular weight Mn was 698, the weight average molecular weight Mw was 824, the epoxy equivalent was 332.1 g / eq., the ICI viscosity (150°C) was 0.08 Pa·s, and the softening point was 59.8°C. The GPC chart of epoxy resin (E1) is shown in Figure 2.

[0065] [Example 2, Comparative Examples 1 and 2] The epoxy resin (E1) obtained in Example 1, bisphenol F epoxy resin (RE-304S, manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent: 169 g / eq.), dicyclopentadiene-type phenolic resin-derived epoxy resin (XD-1000-2L, manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent: 238 g / eq., ICI viscosity (150°C): 0.05, softening point: 55.4°C), and 4,4'-methylenebis(2,6-diethylaniline) (KAYABOND C-300S, manufactured by Nippon Kayaku Co., Ltd.) as a curing agent were used. These were compounded in the proportions (parts by weight) shown in Table 1, and the mixture was uniformly mixed and kneaded using a mixing roll. After demolding, the mixture was cured at 160°C for 2 hours and then at 180°C for 6 hours to obtain test specimens for evaluation.

[0066] <Measurement of cured physical properties> The evaluation test piece was measured under the following conditions, and the results are shown in Table 1.

[0067] <Flexural modulus> Measurement was carried out in accordance with JIS K-6911. Tensilon: RTG-1310 (manufactured by A&D Company, Limited) ·Measurement temperature: room temperature

[0068] <Water absorption rate> A disk-shaped test piece with a diameter of 5 cm and a thickness of 4 mm was immersed in water at 100°C for 24 hours and the mass change was calculated.

[0069] <Dielectric constant test / dielectric loss tangent test> · Tests were conducted using a 1GHz cavity resonator manufactured by AET Development Co., Ltd. using the cavity resonator perturbation method.

[0070] [Table 1]

[0071] From the results in Table 1, it was confirmed that Example 2 had a high elastic modulus, low water absorption, low dielectric constant, and low dielectric loss tangent.

[0072] [Example 3, Comparative Example 3] The epoxy resin (E1) obtained in Example 1, orthocresol novolac epoxy resin (EOCN-1020, manufactured by Nippon Kayaku Co., Ltd.), silica filler (MSR-2212), triphenylphosphine (TPP, manufactured by Tokyo Kasei Co., Ltd.) as a catalyst, and Zylok-type phenolic resin (MEHC-7800SS, manufactured by Meiwa Kasei Co., Ltd.) as a curing agent were blended in the proportions shown in Table 2 and uniformly mixed using a mixing roll to obtain a curable resin composition. These compositions were pulverized and then tableted using a tablet machine. The resulting tablets were molded using a transfer molding machine to form test specimens measuring 10 x 4 x 90 mm. These test specimens were post-cured by heating at 160°C for 2 hours and then at 180°C for 8 hours. The test specimen was held vertically in a clamp, and the burner flame was adjusted to a 19 mm blue flame. The flame was applied to the center of the lower end of the test specimen at 9.5 mm for 10 seconds. After application of the flame, the burner was removed and the duration of combustion was measured. After the flame has gone out, the flame is immediately applied for 10 seconds, the burner is then removed, and the duration of combustion is measured. The total combustion time for each sample for 10 times is shown in Table 2.

[0073] [Table 2]

[0074] From the results in Table 2, it was confirmed that Example 3 had high flame retardancy. [Industrial Applicability]

[0075] The epoxy resin of the present invention is useful for applications such as insulating materials for electric and electronic components (such as highly reliable semiconductor encapsulation materials), laminates (such as printed wiring boards, BGA substrates, and build-up substrates), adhesives (such as conductive adhesives), various composite materials including CFRP, and coating materials, and is particularly useful for applications in various composite materials including CFRP, which strongly require a high elastic modulus.

Claims

1. An epoxy resin represented by the following formula (1): 【Chemical 1】 (In formula (1), n is the number of repeating units, and the average value is 1<n<20. R represents a substituent represented by formula (2) below. p represents a real number of 0 to 4, and the average value of p is 1.0 to 2.0.) 【Chemistry 2】 (In formula (2), * represents the bonding site to the aromatic ring in formula (1). X represents a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms. q represents a real number of 0 to 5.)

2. An epoxy resin represented by the following formula (3): 【Chemistry 3】 (In formula (3), n is the number of repetitions, and the average value is 1<n<20.)

3. 3. The epoxy resin according to claim 1, which has a weight average molecular weight of 400 to 3,000 as determined by gel permeation chromatography (GPC).

4. A curable resin composition comprising the epoxy resin according to claim 1 .

5. The curable resin composition according to claim 4, further comprising an amine-based curing agent.

6. A cured product obtained by curing the curable resin composition according to claim 4 or 5.

7. 4. The method for producing an epoxy resin according to claim 1, comprising: a step of reacting a polycondensate of a dicyclopentadiene compound and a phenolic compound with a benzylating agent to obtain a phenolic resin; and a step of epoxidizing the phenolic resin.

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