Epoxy resin, hardening resin composition, and hardened product thereof

Abstract

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

Description

Technical Field

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

[0002] Epoxy resins, through curing with various hardeners, form cured products with excellent mechanical properties, water resistance, chemical resistance, heat resistance, and electrical properties, and are used in a wide range of fields such as adhesives, coatings, laminates, molding materials, and casting materials. Carbon fiber reinforced plastic (CFRP), a composite material made by impregnating reinforcing fibers with epoxy resin and hardeners as matrix resins and then curing them, has been widely adopted in recent years for applications such as aircraft structural components, windmill blades, automobile exterior panels, integrated circuit (IC) trays, and notebook computer housings, particularly utilizing its lightweight and high-strength properties as a matrix resin in aircraft applications.

[0003] Generally, the resins used as matrix resins in CFRP and other similar products are bisphenol A type epoxy resin, bisphenol F type epoxy resin, tetraglycidyl diaminodiphenylmethane, etc. In aircraft applications, glycidylamine type epoxy resin, tetraglycidyl diaminodiphenylmethane, etc. are used.

[0004] In recent years, the requirements for CFRP properties have become more stringent. For structural materials used in aerospace or automotive applications, heat resistance of over 180°C is required (Patent Document 1). Glycidyl amine-based materials possess high heat resistance, but their high water absorption rate leads to property degradation after water absorption. On the other hand, general glycidyl ether-type epoxy resins have relatively low water absorption, but their low elastic modulus is a concern. Therefore, there is a need for a material with high heat resistance, high elastic modulus, and low water absorption.

[0005] [Existing technical documents]

[0006] [Patent Literature]

[0007] Patent Document 1: International Publication No. 2010 / 204173 Summary of the Invention

[0008] [The problem the invention aims to solve]

[0009] In view of the aforementioned issues, the object of the present invention is to provide an epoxy resin and an epoxy resin composition, the cured of which has high heat resistance, high elastic modulus, and low water absorption.

[0010] [Technical means to solve the problem]

[0011] The inventors and others have conducted intensive research to solve the aforementioned problems, and as a result, the present invention has been completed. That is, the present invention relates to the following [1] to [8]. [1]

[0013] An epoxy resin is represented by the following formula (1), wherein,

[0014] The total content of epoxy resin represented by formulas (2) to (4) below is less than 80% of the area of ​​epoxy resin represented by formula (1) below.

[0015] [Chemistry 1]

[0016]

[0017] (In equation (1), n ​​is the number of repetitions, and its average value is 1 < n < 5.)

[0018] [Chemistry 2]

[0019] [2]

[0021] According to the epoxy resin described in the preceding item [1], wherein the component with n=1 in the formula (1) is less than 80% of area. [3]

[0023] The epoxy resin described in the preceding item [1] or [2] is represented by the following formula (5).

[0024] [Chemistry 3]

[0025]

[0026] (In equation (5), n is the number of repetitions, and its average value is 1 < n < 5.) [4]

[0028] A curable resin composition comprising an epoxy resin according to any one of the preceding items [1] to [3]. [5]

[0030] The curing resin composition according to the preceding item [4] also contains a curing agent. [6]

[0032] A hardened material formed by hardening a hardening resin composition according to the preceding paragraph [4] or [5].

[0033] [The effects of the invention]

[0034] This 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 elastic modulus, and low water absorption.

[0035] Therefore, this invention can be effectively used in insulating materials (such as high-reliability semiconductor sealing materials) and laminates (such as printed wiring boards and add-on substrates) for electrical and electronic components, or in various composite materials, adhesives, coatings, etc., represented by CFRP. Attached Figure Description

[0036] Figure 1 The image shows the gel permeation chromatography (GPC) chromatogram of Synthesis Example 1.

[0037] Figure 2 The image shows the 1H-NMR spectrum of Synthesis Example 1.

[0038] Figure 3 The image shows the high performance liquid chromatography (HPLC) chromatogram of Synthesis Example 1.

[0039] Figure 4 The GPC diagram represents Example 1.

[0040] Figure 5 The image shows the 1H-NMR spectrum of Example 1.

[0041] Figure 6 The HPLC chromatogram for Example 1 is shown below.

[0042] Figure 7 This refers to the GPC diagram in Example 1.

[0043] Figure 8 This shows the 1H-NMR spectrum of Reference Example 1.

[0044] Figure 9 This shows the HPLC chromatogram of Reference Example 1. Detailed Implementation

[0045] The present invention will now be described in detail.

[0046] The epoxy resin of the present invention may use an aromatic amine resin represented by the following formula (6) as a precursor.

[0047] [Chemistry 4]

[0048]

[0049] (In equation (6), n is the number of repetitions, and its average value is 1 < n < 5.)

[0050] The aromatic amine resin represented by formula (6) is more preferably represented by formula (7) below. This is because the crystallinity is reduced compared to when the isopropylidene bonds in formula (6) are substituted at ortho or para positions relative to the unbonded amino group on the benzene ring. Reduced crystallinity increases solvent stability, making the preparation of the resin solution easier. Furthermore, the crystallinity of the derived compounds can also be reduced. Therefore, crystallization can be suppressed during storage after the composition is formed.

[0051] [Chemistry 5]

[0052]

[0053] (In equation (7), n is the number of repetitions, and its average value is 1 < n < 5.)

[0054] The method for preparing the aromatic amine resin represented by formula (6) or formula (7) is not particularly limited. For example, in Japanese Patent Application 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 of formula (4) can be obtained as the main component, but it includes three isomers: 1,3-bis(p-aminocumyl)benzene, 1-(o-aminocumyl)-3-(p-aminocumyl)benzene, and 1,3-bis(o-aminocumyl)benzene. Furthermore, n=2 to 5 isomers are also generated as secondary components, but in Japanese Patent Application Publication No. 61-000044, these are purified by crystallization to obtain 1,3-bis(p-aminocumyl)benzene with a purity of 98%.

[0055] In this invention, focusing on the isomers and polymeric components in aromatic amine resins that were previously removed as useless components, an epoxy resin exhibiting high heat resistance, low water absorption, high elastic modulus, and low viscosity was developed by epoxidizing these components instead of removing them.

[0056] That is, the amine resin used as a raw material for the epoxy resin of the present invention does not require purification processes such as crystallization, and therefore can be manufactured in a short time and at low cost, thereby improving industrial availability.

[0057] Examples of acidic catalysts used in the synthesis of the aromatic amine resin represented by formula (6) include: 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 catalyst used relative to the aniline used is 0.1% to 50% by weight, preferably 1% to 30% by weight. If too much catalyst is used, the viscosity of the reaction solution will be too high, making stirring difficult; if too little catalyst is used, the reaction will proceed slowly.

[0058] The reaction can be carried out using organic solvents such as toluene and xylene, or in a solvent-free environment, depending on the requirements. For example, after adding an acidic catalyst to a mixed solution of aniline and solvent, if the catalyst contains water, it is preferable to remove the water from the system by azeotropic extraction. Then, diisopropylbenzene or di(α-hydroxyisopropyl)benzene is added, and the temperature is increased 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 to 50 hours, preferably 5 to 30 hours. When using di(α-hydroxyisopropyl)benzene, water is generated as a byproduct, so it is removed from the system while azeotropically extracting the solvent during heating. After the reaction is complete, the acidic catalyst is neutralized with an alkaline aqueous solution, and a non-water-soluble organic solvent is added to the oil layer. The mixture is repeatedly washed with water until the wastewater becomes neutral, and then the solvent and excess aniline derivatives are removed under reduced pressure by heating. When using activated clay or ion exchange resin, the reaction solution is filtered after the reaction to remove the catalyst.

[0059] Furthermore, since diphenylamine is generated as a byproduct 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 means of steam distillation.

[0060] The epoxy resin of the present invention is represented by the following formula (1), and the total content of the epoxy resin represented by the following formulas (2) to (4) is 80% or less of the area of ​​the epoxy resin represented by the following formula (1).

[0061] [Chemistry 6]

[0062]

[0063] (In equation (1), n ​​is the number of repetitions, and its average value is 1 < n < 5.)

[0064] [Chemistry 7]

[0065]

[0066] In equation (1), n ​​is preferably 1 < n < 5, and more preferably 1 < n < 3.

[0067] The total content of epoxy resin represented by formulas (2) to (4) in the epoxy resin represented by formula (1) can be determined by using both gel permeation chromatography and high performance liquid chromatography. In this invention, the analysis was performed under the following conditions.

[0068] GPC (Gel Permeation Chromatography) Analysis

[0069] Tubing strings: Showa (SHODEX) GPC KF-601 (two), KF-602, KF-602.5, KF-603

[0070] Flow rate: 0.5 ml / min.

[0071] Column temperature: 40℃

[0072] Solvent used: Tetrahydrofuran (THF)

[0073] Detector: RI (Refractive Index) (Differential Refraction Detector)

[0074] HPLC (High Performance Liquid Chromatography) analysis

[0075] Column: Inertsil ODS-2

[0076] Flow rate: 1.0 ml / min.

[0077] Column temperature: 40℃

[0078] Solvent used: Acetonitrile / 10 mmol / L aqueous phosphoric acid solution

[0079] Detector: Photodiode array (274nm)

[0080] Specifically, by gel permeation chromatography, the content (α) of the n=1 component in the epoxy resin represented by formula (1) can be determined. By high performance liquid chromatography, the content (β2~β4) of the epoxy resin represented by formulas (2) to (4) contained in the n=1 component can be determined. Therefore, for example, the product of α and β2 becomes the content of the epoxy resin represented by formula (2) contained in the epoxy resin represented by formula (1).

[0081] In the epoxy resin of the present invention, the total content of the epoxy resin represented by formula (2) to (4) in the epoxy resin represented by formula (1) is preferably 80 area % or less, more preferably 70 area % or less, and most preferably 60 area % or less. This is because if it is 80 area % or less, orientation and molecular weight distribution can be controlled, thus obtaining an epoxy resin that possesses properties that are difficult to exhibit simultaneously, namely high heat resistance, low water absorption, and high elastic modulus. Furthermore, the lower limit can be 0 area %, but is preferably 20 area % or more, more preferably 40 area % or more.

[0082] Furthermore, in the epoxy resin of the present invention, the component with n=1 in formula (1) is preferably 80 area % or less, more preferably 70 area % or less, and most preferably 65 area % or less. This is because if it is 80 area % or less, the molecular rigidity becomes higher, thus easily exhibiting high elastic modulus and low water absorption. Additionally, the lower limit can be 0 area %, but is preferably 20 area % or more, more preferably 40 area % or more.

[0083] The epoxy resin represented by formula (1) is more preferably represented by formula (5) below. The reason is that by further abutting each other through the isopropylidene structure or crosslinking points, the rigidity of the molecules is increased due to their steric hindrance, which makes it easy to exhibit high elastic modulus and low water absorption.

[0084] [Chemistry 8]

[0085]

[0086] In equation (5), the value of n and the preferred range are the same as in equation (1).

[0087] The method for preparing the epoxy resin of the present invention is not particularly limited. For example, it can be obtained by reacting the aromatic amine resin represented by formula (6) with a epihalool in the presence of a solvent and a catalyst through an addition or ring-closing reaction. The amount of epihalool used is typically 3.0 mol to 20.0 mol relative to 1 mol of the amino group of the amine compound, preferably 3.5 mol to 10.0 mol.

[0088] Examples of alkali metal hydroxides that can be used in epoxidation reactions include sodium hydroxide and potassium hydroxide. Alkali metal hydroxides can be solids or aqueous solutions. When using an aqueous solution, the following method can be employed: the aqueous solution of the alkali metal hydroxide is continuously added to the reaction system, and water and epihaloalcohol are continuously distilled off under reduced pressure or normal pressure, followed by separation to remove water and continuously returning the epihaloalcohol to the reaction system. The amount of alkali metal hydroxide used is typically 0.9 to 2.5 moles relative to 1 mole of the amino group of the amine compound, preferably 0.95 to 1.5 moles. If the amount of alkali metal hydroxide used is too small, the reaction will not proceed sufficiently. On the other hand, using more than 2.5 moles of alkali metal hydroxide relative to 1 mole of the amino group of the amine compound will result in the generation of unnecessary waste byproducts.

[0089] To promote the reaction, quaternary ammonium salts such as tetramethylammonium chloride, tetramethylammonium bromide, and trimethylbenzylammonium chloride can be added as catalysts. The amount of quaternary ammonium salt used is typically 0.1 g to 15 g, preferably 0.2 g to 10 g, relative to 1 mole of the amino group of the amine compound. If the amount used is too small, sufficient reaction promotion will not be achieved; if the amount used is too large, the amount of quaternary ammonium salt remaining in the epoxy resin will increase, which may also contribute to the deterioration of electrical reliability.

[0090] In the epoxidation reaction, it is preferable to add alcohols such as methanol, ethanol, and isopropanol, or a nonprotic polar solvent such as dimethyl sulfone, dimethyl sulfoxide, tetrahydrofuran, or dioxane to carry out the reaction. When using alcohols, the amount used is typically 2% to 50% by weight relative to the amount of epihaloalcohol, preferably 4% to 20% by weight. Furthermore, when using a nonprotic polar solvent, the amount used is typically 5% to 100% by weight relative to the amount of epihaloalcohol, preferably 10% to 80% by weight. The reaction temperature is typically 30°C to 90°C, preferably 35°C to 80°C. The reaction time is typically 0.5 hours to 100 hours, preferably 1 hour to 30 hours.

[0091] After the reaction is complete, the epihaloalcohol and solvent are removed by washing the reactants with water, or by heating under reduced pressure without washing with water. Alternatively, to produce an epoxy resin with fewer hydrolyzable halogens, the recovered epoxy resin can be dissolved in solvents such as toluene or methyl isobutyl ketone, and an aqueous solution of alkali metal hydroxides such as sodium hydroxide or potassium hydroxide can be added to carry out the reaction, thus ensuring reliable ring closure. In this case, the amount of alkali metal hydroxide used is typically 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 glycidylation. The reaction temperature is typically 50°C to 120°C, and the reaction time is typically 0.5 hours to 24 hours. After the reaction is complete, the generated salt is removed by filtration, washing with water, etc., and then the solvent is removed by distillation under reduced pressure, thereby obtaining the epoxy resin of the present invention.

[0092] The epoxy resin of the present invention is typically a liquid to solid resin at room temperature, and its softening point is preferably below 100°C, more preferably below 80°C. When the softening point is above 100°C, the viscosity is high, resulting in reduced fiber impregnation when making the prepreg. Furthermore, 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.

[0093] The epoxy resin composition of the present invention will be described below.

[0094] 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 epoxy resin represented by formula (1) accounts for a proportion of 10% to 98% by weight of all epoxy resins, more preferably 20% to 95% by weight, and even more preferably 30% to 95% by weight. By setting the addition amount to 10% by weight or more, an increase in elastic modulus and low water absorption can be achieved.

[0095] Specific examples of other epoxy resins that can be used in conjunction with the epoxy resin of the present invention include: condensation polymers of bisphenols (bisphenol A, bisphenol F, bisphenol S, biphenol, bisphenol AD, etc.) or phenols (phenol, alkyl-substituted phenols, aromatic-substituted phenols, naphthol, alkyl-substituted naphthols, dihydroxybenzene, alkyl-substituted dihydroxybenzene, dihydroxynaphthalene, etc.) with various aldehydes (formaldehyde, acetaldehyde, alkyl aldehydes, benzaldehyde, alkyl-substituted benzaldehyde, hydroxybenzene, naphthal, glutaraldehyde, o-phthalaldehyde, crotonaldehyde, cinnamaldehyde, etc.); and condensation polymers of the phenols with various diene compounds (dicyclopentadiene, terpenes, vinylcyclohexene, norbornene, vinylnorbornene, tetrahydroindene, divinylbenzene, divinylbiphenyl, diisopropenylbiphenyl, butadiene, isoprene, etc.). The epoxy resins include: condensation polymers of phenols and ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, acetophenone, benzophenone, etc.); condensation polymers of phenols and aromatic dimethyl alcohols (benzenedimethanol, biphenyl dimethylethanol, etc.); condensation polymers of phenols and aromatic dichloromethyl alcohols (α,α'-dichloroxylene, dichloromethylbiphenyl, etc.); condensation polymers of phenols and aromatic diekoxymethyl alcohols (dimethoxymethylbenzene, dimethoxymethylbiphenyl, diphenoxymethylbiphenyl, etc.); condensation polymers of bisphenols and various aldehydes; or glycidyl ether epoxy resins, alicyclic epoxy resins, glycidyl amine epoxy resins, glycidyl ester epoxy resins, etc., obtained by glycidylating alcohols, etc. These are not limited to any commonly used epoxy resin. These can be used alone or in combination.

[0096] Examples of curing agents that can be used in the epoxy resin compositions of the present invention include amine compounds, acid anhydride compounds, amide compounds, and phenolic compounds. Specific examples of usable curing agents 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, naphthyldiamine, benzidine, dimethylbenzidine, international Aromatic amine compounds, such as those described in Synthetic Examples 1 and 2 of Publication No. 2017 / 170551, and aliphatic amines such as 1,3-bis(aminomethyl)cyclohexane, isophorone diamine, 4,4'-methylenebis(cyclohexylamine), norbornene diamine, ethylenediamine, propylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, dimerized diamine, and triethylenetetramine, are used, but are not limited to these. Appropriate amines can be used depending on the desired properties imparted to the composition. To ensure a good working life, aromatic amines are preferred; when immediate curing is desired, aliphatic amines are preferred. By using an amine compound containing a difunctional component as the main component as a curing agent, a highly linear network can be constructed during the curing reaction, thereby exhibiting particularly excellent strength and toughness.In addition, examples include amide compounds such as dicyandiamine, polyamide resins synthesized from dimers 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, and methylhexahydrophthalic anhydride; and bisphenols (bisphenol A, bisphenol F, bisphenol S, biphenol). Condensation polymers of phenols (such as bisphenol A, alkyl-substituted phenols, aromatic-substituted phenols, naphthol, alkyl-substituted naphthols, dihydroxybenzene, alkyl-substituted dihydroxybenzene, dihydroxynaphthalene, etc.) with various aldehydes (formaldehyde, acetaldehyde, alkyl aldehydes, benzaldehyde, alkyl-substituted benzaldehyde, hydroxybenzene, naphthal, glutaraldehyde, o-phthalaldehyde, crotonaldehyde, cinnamaldehyde, etc.), or phenols with various dienes (dicyclopentadiene, terpenes, etc.). Polymers of phenols and ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, acetophenone, benzophenone, etc.), polymers of phenols and aromatic dimethyl alcohols (benzenedimethanol, biphenyl dimethyl alcohol, etc.), polymers of phenols and aromatic dichloromethyl alcohols (α,α'-dichloroxylene, dichloromethyl biphenyl, etc.), polymers of phenols and aromatic dialkoxymethyl alcohols (dimethoxymethylbenzene, dimethoxymethyl biphenyl, diphenoxymethyl biphenyl, etc.), polymers of bisphenols and various aldehydes, and modified forms thereof, etc.; imidazoles, trifluoroborane-amine complexes, guanidine derivatives, etc., but not limited to these.

[0097] In the epoxy resin composition of the present invention, the amount of curing agent used is preferably 0.5 to 1.5 equivalents, and particularly preferably 0.6 to 1.2 equivalents, relative to the epoxy group 1 of the epoxy resin. By setting it to 0.5 to 1.5 equivalents, good cured properties can be obtained.

[0098] When using the aforementioned hardener for the hardening reaction, a hardening accelerator may also be used in conjunction. Examples of usable hardening 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; organophosphorus compounds such as triphenylphosphine, diphenylphosphine, and tributylphosphine; metal compounds such as tin octoate; tetrasubstituted phosphine-tetrasubstituted borates such as tetraphenylphosphine-tetraphenylborate and tetraphenylphosphine-ethyltriphenylborate; tetraphenylborates 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, naphtholic acid, and salicylic acid. From the viewpoint of promoting the curing reaction between amine compounds and epoxy resin, carboxylic acid compounds such as salicylic acid are preferred. The curing accelerator can be used in quantities of 0.01 to 15 parts by weight relative to 100 parts by weight of epoxy resin, as needed.

[0099] Furthermore, inorganic fillers may be added to the epoxy resin composition of the present invention as needed. Examples of inorganic fillers include 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, etc., or beads formed by spheroidizing these, but are not limited to these. These fillers may be used alone or in combination. The amount of these inorganic fillers used varies depending on the application, but for example, when used as a sealant for semiconductors, it is preferable to use them at a proportion of 20% by weight or more, more preferably 30% by weight or more, in terms of the heat resistance, moisture resistance, mechanical properties, and flame retardancy of the cured epoxy resin composition. In particular, it is preferable to use them at a proportion of 70% to 95% by weight to improve the linear expansion rate relative to the lead frame.

[0100] In the epoxy resin composition of the present invention, a release agent may be formulated to ensure good demolding from the mold during molding. Any of the conventionally known release agents 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. These may be used alone or in combination of two or more. The amount of these release agents formulated relative to all organic components is preferably 0.5% to 3% by weight. If this amount is too small, demolding from the mold will be poor; if this amount is too large, adhesion to the lead frame, etc., will be poor.

[0101] In the epoxy resin composition of the present invention, a coupling agent can be adjusted to improve the adhesion between the inorganic filler and the resin components. Any known coupling agent can be used, such as: vinylalkoxysilanes, epoxyalkoxysilanes, styrylalkoxysilanes, methacryloxyalkoxysilanes, acryloxyalkoxysilanes, aminoalkoxysilanes, mercaptoalkoxysilanes, isocyanoalkoxysilanes, and various alkoxysilane compounds, alkoxytitanium compounds, aluminum chelates, etc. These can be used alone or in combination of two or more. The coupling agent can be added by pre-treating the surface of the inorganic filler with the coupling agent and then mixing it with the resin, or by mixing the coupling agent into the resin and then mixing the inorganic filler.

[0102] Furthermore, in the epoxy resin composition of the present invention, known additives can be formulated as needed. Specific examples of additives that can be used include: polybutadiene and its modified forms, modified acrylonitrile copolymers, polyphenylene ether, polystyrene, polyethylene, polyimide, fluoropolymers, maleimide compounds, cyanate ester compounds, silicone gels, silicone oils, and colorants such as carbon black, phthalocyanine blue, and phthalocyanine green.

[0103] 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 readily cured using methods similar to those known in the prior art. For example, the epoxy resin composition of the present invention is obtained by thoroughly mixing epoxy resin with a hardener, and optionally a curing accelerator, inorganic filler, release agent, silane coupling agent, and additives until homogeneous using an extruder, kneader, roller, etc., and then molding it by melt casting, transfer molding, injection molding, compression molding, etc., followed by heating at 80°C to 200°C for 2 to 10 hours, thereby obtaining a cured product.

[0104] In addition, the epoxy resin composition of the present invention may also contain a solvent as needed. A prepreg is obtained by impregnating a solvent-containing epoxy resin composition (epoxy resin varnish) into a fibrous material (substrate) such as glass fiber, carbon fiber, polyester fiber, polyamide fiber, alumina fiber, or paper, and then heating and drying it. The resulting prepreg is then 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 typically 10% to 70% by weight, preferably about 15% to 70% by weight, based on internal proportions. Examples of solvents include: γ-butyrolactones; amide solvents such as N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, and N,N-dimethylimidazolium ketone; 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 (1-3 carbon) alkyl ethers of lower (1-3 carbon) alkyl diols; ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone, more preferably di-lower (1-3 carbon) alkyl ketones in which the two alkyl groups may be the same or different; aromatic solvents such as toluene and xylene. These can be used alone or in mixtures of two or more solvents.

[0105] Furthermore, by coating the release film with the epoxy resin varnish and removing the solvent under heating to perform B-stage processing, a sheet-like adhesive (the sheet of the present invention) can be obtained. This sheet-like adhesive can be used as an interlayer insulating layer in multilayer substrates, etc.

[0106] The cured product obtained in this invention can be used for a variety of applications. In detail, common uses of thermosetting resins such as epoxy resins can be listed, for example: adhesives, coatings, coating agents, molding materials (including sheets, films, FRP, etc.), insulating materials (including printed circuit boards, wire sheathing, etc.), sealants, and other additives to other resins, etc.

[0107] Examples of adhesives include those used in civil engineering, construction, automotive, general office, and medical applications, as well as adhesives used in electronic materials. Among these, adhesives used in electronic materials include: interlayer adhesives for multilayer substrates such as build-up substrates, die bonding agents, underfills, and other semiconductor adhesives; underfills for ball grid array (BGA) reinforcement, anisotropic conductive film (ACF), anisotropic conductive paste (ACP), and other mounting adhesives.

[0108] As a sealant, examples include: potting seals, impregnation seals, and transfer mold seals for capacitors, transistors, diodes, light-emitting diodes, ICs, and large-scale integration circuits (LSIs); potting seals for ICs and LSIs such as chip-on-board (COB), chip-on-film (COF), and tape-automated bonding (TAB); underfills for flip-chip devices; and seals (including reinforcing underfills) for IC packages such as quad flat packages (QFPs), ball grid arrays (BGAs), and chip size packages (CSPs) during installation.

[0109] [Example]

[0110] The present invention will now be described in more detail through examples. Unless otherwise specified, all parts are parts by weight. Furthermore, the present invention is not limited to these examples. In the examples, the epoxy equivalent was determined according to the method of Japanese Industrial Standards (JIS) K-7236, and the softening point was determined according to the method of JIS K-7234.

[0111] GPC (Gel Permeation Chromatography) Analysis

[0112] Tubing strings: Showa (SHODEX) GPC KF-601 (two), KF-602, KF-602.5, KF-603

[0113] Flow rate: 0.5 ml / min.

[0114] Column temperature: 40℃

[0115] Solvent used: THF (tetrahydrofuran)

[0116] Detector: RI (Differential Refraction Detector)

[0117] HPLC (High Performance Liquid Chromatography) analysis

[0118] Column: Inertsil ODS-2

[0119] Flow rate: 1.0 ml / min.

[0120] Column temperature: 40℃

[0121] Solvent used: Acetonitrile / 10 mmol / L aqueous phosphoric acid solution

[0122] Detector: Photodiode array (274nm)

[0123] [Synthesis example 1]

[0124] While purging the flask equipped with a thermometer, cooling pipe, fractionating pipe, and stirrer with nitrogen, 559 parts of aniline, 291 parts of α,α,α',α'-tetramethylbenzenedimethanol (manufactured by Fujifilm and Koko Pure Chemical Industries Co., Ltd.), 360 parts of toluene, and 63 parts of 35% hydrochloric acid aqueous solution were added, and stirring was initiated. While removing the water generated during dehydration along with the toluene, the internal temperature was raised to 160°C, and the reaction was carried out for 15 hours. After cooling to room temperature, the removed toluene and water were returned to the system, and 88 parts of 30% sodium hydroxide aqueous solution were added for neutralization. The organic layer was then washed with water until the waste liquid became neutral and concentrated to obtain 458 parts of 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 fraction had an area percentage of 61%. According to HPLC analysis, 4,4'-(1,3-phenylene diisopropylidene)bisphenylamine in the n=1 fraction had an area percentage of 16.7%, therefore, the 4,4'-(1,3-phenylene diisopropylidene)bisphenylamine in the aromatic amine resin had an area percentage of 10.2%. The GPC diagram of the obtained amine resin (A1) is shown in [image / ... Figure 1 ,Will 1 The H-NMR spectrum (dichloroform) is shown in Figure 2 HPLC chromatogram Figure 3 .exist 1 Signals originating from amino groups were observed in the 3.05 ppm–3.65 ppm range of the H-NMR spectrum.

[0125] [Example 1]

[0126] While purging the flask equipped with a thermometer, cooling pipe, fractionating pipe, and stirrer with nitrogen, 186 parts of 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 reaction was carried out at 77°C for 8 hours. The internal temperature was then 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 were added to remove sodium chloride from the organic layer. The mixture was then concentrated under reduced pressure at 120°C. 300 parts of methyl isobutyl ketone (MIBK) and 40 parts of a 30% sodium hydroxide aqueous solution were added, and the reaction was continued at 70°C for 6 hours. The organic layer was washed until the water was neutral, and then concentrated under reduced pressure at 120°C to obtain 235 parts of semi-solid epoxy resin (EP1). The epoxy equivalent was 209.7 g / eq. The GPC diagram of the obtained epoxy resin (EP1) is shown in the figure. Figure 4 ,Will1 The H-NMR spectrum (dichloroform) is shown in Figure 5 HPLC chromatogram Figure 6 .exist 1 Signals originating from epoxides were observed in the 2.50 ppm–3.80 ppm range of the ¹H NMR spectrum. According to GPC analysis (RI), the n=1 variant had an area percentage of 61%. According to HPLC analysis (measurement wavelength: 274 nm), 2,2'-(1,3-phenylene diisopropylidene)bis(diglycidylaniline) had an area percentage of 31.2%, 2,4'-(1,3-phenylene diisopropylidene)bis(diglycidylaniline) had an area percentage of 32.3%, and 4,4'-(1,3-phenylene diisopropylidene)bis(diglycidylaniline) had an area percentage of 33.0%. Based on the above, EP1 contains 19.0 area % of 2,2'-(1,3-phenylene diisopropylidene)bis(diglycidylaniline) (epoxy resin in which each isopropylidene bond is substituted at the meta position in the epoxy resin represented by formula (2)), 19.7 area % of 2,4'-(1,3-phenylene diisopropylidene)bis(diglycidylaniline) (epoxy resin in which each isopropylidene bond is substituted at the meta position in the epoxy resin represented by formula (3)), and 20.1 area % of 4,4'-(1,3-phenylene diisopropylidene)bis(diglycidylaniline) (epoxy resin in which each isopropylidene bond is substituted at the meta position in the epoxy resin represented by formula (4)).

[0127] [Reference Example 1]

[0128] While purging a flask equipped with a thermometer, cooling pipe, fractionating tube, and stirrer with nitrogen, 150 parts of 4,4'-(1,3-phenylene diisopropylidene)biphenylamine (manufactured by Tokyo Chemical Co., Ltd.), 483 parts of epichlorohydrin, 17 parts of methanol, and 5 parts of water were added, and the reaction was carried out at 80°C for 3 hours. The internal temperature was then cooled to 65°C, and 70.3 parts of sodium hydroxide were added in batches over 90 minutes. The reaction was continued at 65°C for 3 hours, and 400 parts of water were added to remove sodium chloride from the organic layer. The mixture was then concentrated under reduced pressure at 120°C. 300 parts of MIBK and 40 parts of a 30% sodium hydroxide aqueous solution were added, and the reaction was continued at 70°C for 20 hours. The organic layer was washed until the water was neutral, and then concentrated under reduced pressure at 120°C to obtain 213 parts of liquid epoxy resin (EP2). The epoxy equivalent was 160.3 g / eq. The GPC diagram of the obtained epoxy resin (EP2) is shown in the figure. Figure 7 ,Will 1 The H-NMR spectrum (dichloroform) is shown in Figure 8 HPLC chromatogram Figure 9 .exist 1Signals originating from epoxy groups were observed in the 2.50 ppm–3.80 ppm range of the H-NMR spectrum. According to GPC analysis (RI), the n=1 variant had an area percentage of 90.2%, and according to HPLC analysis (measurement wavelength: 274 nm), the 4,4'-(1,3-phenylene diisopropylidene)bis(diglycidylaniline) in the n=1 variant had an area percentage of 100%. Based on the above, the 4,4'-(1,3-phenylene diisopropylidene)bis(diglycidylaniline) contained in EP2 (the epoxy resin represented by formula (4) in which each isopropylidene bond is substituted at the meta position) had an area percentage of 90.2%.

[0129] [Example 2, Comparative Example 1, Comparative Example 2]

[0130] 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'-methylene-bis(2,6-diethylaniline) (manufactured by Tokyo Kasei Co., Ltd., abbreviated as MDEA) as a curing agent were mixed in the proportions (parts by weight) in Table 1. The mixtures were uniformly mixed / kneaded using a mixing roller, and then demolded. The mixtures were then cured at 160°C for 2 hours and at 180°C for 6 hours to obtain test pieces for evaluation.

[0131] <Determination of Hardening Properties>

[0132] The results obtained by measuring the test pieces for evaluation under the following conditions are shown in Table 1.

[0133] <Glass transition temperature>

[0134] The determination was performed according to JIS K-7244. The peak temperature of tanδ was set as Tg.

[0135] • Dynamic viscoelasticity measuring instrument: TA-instruments, dynamic thermomechanical analyzer (DMA)-2980

[0136] Sample size: 20mm × 5mm × 1mm

[0137] • Heating rate: 10℃ / min

[0138] <Flexural strength, flexural elasticity>

[0139] The determination was carried out according to JIS K-6911.

[0140] • Tensilon: RTG-1310 (manufactured by A&D Company, Limited)

[0141] • Measurement temperature: room temperature

[0142] <Water Absorption Rate>

[0143] The result was calculated based on the mass change of a disc-shaped test piece with a diameter of 5 cm and a thickness of 4 mm after being immersed in water at 100°C for 24 hours.

[0144] [Table 1]

[0145]

[0146] Based on the results in Table 1, it was confirmed that Example 2 has high heat resistance, high flexural strength, high elastic modulus, and low water absorption.

[0147] [Industry availability]

[0148] The epoxy resin of the present invention can be effectively used in insulating materials for electrical and electronic components (such as high-reliability semiconductor sealing materials), laminates (such as printed wiring boards, BGA substrates, and add-on substrates), adhesives (such as conductive adhesives), or various composite materials represented by CFRP, coatings, and other applications. In particular, it can be effectively used in various composite material applications represented by CFRP, which have strong requirements for high elastic modulus.

Claims

1. An epoxy resin, represented by the following formula (5), wherein, Let the area percentage of the component with n=1 in the epoxy resin, as represented by the following formula (5) obtained by gel permeation chromatography, be α area%. When the area percentage of epoxy resin represented by the following formulas (2), (3), and (4) in the component with n=1 obtained by high performance liquid chromatography is set as β2 area%, β3 area%, and β4 area%, respectively, in the epoxy resin represented by formula (5), the area percentage (α×(β2+β3+β4)) of the epoxy resin represented by formulas (2) to (4) is 40% to 80% area. In equation (5), n is the number of repetitions, and its average value is 1 < n < 5. 。 2. The epoxy resin according to claim 1, wherein, In the above formula (5), the component with n=1 is less than 80% of the area.

3. A curable resin composition comprising the epoxy resin as described in claim 1 or 2.

4. The curable resin composition according to claim 3, further comprising a curing agent.

5. A hardened compound formed by hardening the hardening resin composition as described in claim 3 or 4.

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