Epoxy resin composition and cured resin

Abstract

The present invention aims to provide an epoxy resin composition capable of forming a resin cured product having excellent impact resistance. The epoxy resin composition of the present invention is an epoxy resin composition comprising an epoxy resin (A) having a solubility parameter (SP value) of 11 to 15 and a (meth) acrylic polymer (B) having an SP value of 9.5 to 11, wherein the (meth) acrylic polymer (B) is a reaction product of a carboxyl group-containing (meth) acrylic polymer (B1) and an epoxy compound (B2), and the absolute value of the difference between the SP value of the (meth) acrylic polymer (B) and the SP value of the epoxy resin (A) is 0.1 to 3.3.

Description

Technical Field

[0001] The present invention relates to an epoxy resin composition and a cured resin. Background Art

[0002] Epoxy resins are used in a wide range of fields such as adhesives and sealants due to their excellent physical properties (see, for example, Patent Documents 1 and 2). Epoxy resins are generally cured and used as cured resins.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2002-080696

[0006] Patent Document 2: International Publication No. 2017 / 195902 Summary of the invention

[0007] Technical problem to be solved by the invention

[0008] A cured resin obtained from an epoxy resin may have poor impact resistance. For example, in Patent Document 2, an acrylic polymer is added to an epoxy resin, but according to the research of the present inventors, it is known that the cured resin obtained in this way has insufficient impact resistance.

[0009] An object of one embodiment of the present invention is to provide an epoxy resin composition capable of forming a cured resin product having excellent impact resistance, and a cured resin product composed of the epoxy resin composition.

[0010] Technical solutions adopted to solve technical problems

[0011] The present invention is, for example, the inventions of the following [1] to [8].

[0012] [1] An epoxy resin composition comprising an epoxy resin (A) having a solubility parameter (SP value) of 11 to 15 and a (meth)acrylic polymer (B) having an SP value of 9.5 to 11, wherein the (meth)acrylic polymer (B) is a reaction product of a carboxyl group-containing (meth)acrylic polymer (B1) and an epoxy compound (B2), and the absolute value of the difference between the SP value of the (meth)acrylic polymer (B) and the SP value of the epoxy resin (A) is 0.1 to 3.3.

[0013] [2] The epoxy resin composition according to [1] above, comprising 0.1 to 70 parts by mass of the (meth)acrylic polymer (B) based on 100 parts by mass of the epoxy resin (A).

[0014] [3] The epoxy resin composition according to [1] or [2] above, wherein the absolute value of the difference between the SP value of the carboxyl group-containing (meth)acrylic polymer (B1) and the SP value of the epoxy compound (B2) is 1.3 to 4.5.

[0015] [4] The epoxy resin composition according to any one of [1] to [3] above, wherein the (meth)acrylic polymer (B) has a weight average molecular weight of 3,000 to 100,000.

[0016] [5] The epoxy resin composition according to any one of [1] to [4] above, further comprising a curing agent (C).

[0017] [6] A cured resin product comprising the epoxy resin composition described in [1] to [5] above.

[0018] [7] A cured resin obtained by curing an epoxy resin composition containing an epoxy resin and a (meth)acrylic polymer, the cured resin having a sea-island phase separation structure, wherein the average dispersion diameter of the island phase is 0.01 to 0.84 μm.

[0019] [8] The cured resin material according to [7] above, wherein the tensile modulus (X) of the cured resin material and the tensile modulus (Y) of the cured resin material without the (meth)acrylic polymer satisfy the following formula (2).

[0020] 0.6≤X / Y≤1.1…(2)

[0021] Effects of the Invention

[0022] According to the present invention, by using an epoxy resin composition in which a specific (meth)acrylic polymer is blended as a modifier into an epoxy resin, a cured resin having excellent impact resistance can be provided. DETAILED DESCRIPTION

[0023] Hereinafter, the present invention will be described in detail. In this specification, (meth)acrylic acid is used as a general term for acrylic acid and methacrylic acid, and may be either acrylic acid or methacrylic acid, and (meth)acrylate is used as a general term for acrylate and methacrylate, and may be either acrylate or methacrylate.

[0024] Epoxy resin composition

[0025] One embodiment of the epoxy resin composition of the present invention (hereinafter also referred to as "the epoxy resin composition of the present embodiment") contains an epoxy resin (A) having a solubility parameter (SP value) of 11 to 15 and a (meth)acrylic polymer (B) having an SP value of 9.5 to 11, respectively. Here, the (meth)acrylic polymer (B) is a reaction product of a carboxyl group-containing (meth)acrylic polymer (B1) and an epoxy compound (B2).

[0026] (Solubility parameter (SP value))

[0027] The solubility parameter (SP value) is used to indicate, for example, the degree of solubility between different types of polymers. By setting the difference between the SP value of the (meth)acrylic polymer (B) and the SP value of the epoxy resin (A) within an appropriate range, there is a tendency that the average dispersion diameter of the island phase in the cured resin having a sea-island phase separation structure described later can be controlled to an appropriate value.

[0028] In addition, the SP value of the epoxy resin (A), the (meth)acrylic polymer (B), the carboxyl group-containing (meth)acrylic polymer (B1), and the epoxy compound (B2) in this specification can be calculated based on the sum (ΔH) of the molar heat of vaporization (Δei) and the sum (V) of the molar volume (Δvi) of the atomic group described in Robert F. Fedors., "POLYMER ENGINEERING AND SCIENCE", 1974, Vol. 14, No. 2, pp. 151 to 153.

[0029] <Epoxy resin (A)>

[0030] The epoxy resin composition of the present embodiment contains an epoxy resin (A). However, the epoxy resin (A) excludes the polymer having an epoxy group which is a reaction product of the carboxyl group-containing (meth)acrylic polymer (B1) and the epoxy compound (B2) described above.

[0031] As the epoxy resin (A), for example, an epoxy compound having two or more epoxy groups in one molecule may be mentioned.

[0032] Examples of the epoxy resin (A) include

[0033] Bisphenol-type epoxy resins such as bisphenol A epoxy resin, bisphenol E epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, bisphenol O epoxy resin, bisphenol AD ​​epoxy resin, hydrogenated bisphenol epoxy resin, alkyl-substituted bisphenol epoxy resin, alkylene oxide-modified bisphenol epoxy resin, biphenyl epoxy resin, resorcinol epoxy resin, thioether epoxy resin, diphenyl ether epoxy resin, dicyclopentadiene epoxy resin, naphthalene epoxy resin, phenol novolac epoxy resin, orthocresol novolac epoxy resin, dicyclopentadiene novolac epoxy resin, biphenyl novolac epoxy resin, naphthol novolac epoxy resin, and glycidylamine epoxy resin;

[0034] Diglycidyl ethers of bisphenols such as bisphenol A, bisphenol E, bisphenol F, bisphenol S, bisphenol O, and bisphenol AD, or 4,4-dihydroxybiphenyl (herein, the above bisphenols and the above biphenyls may be hydrogenated (e.g., hydrogenated bisphenols), may have an alkyl substituent (e.g., alkyl-substituted bisphenols), or may be modified with alkylene oxides such as ethylene oxide and propylene oxide (e.g., alkylene oxide-modified bisphenols)); ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, 1, Alkanediol diglycidyl ethers such as 8-octanediol diglycidyl ether, 1,10-decanediol diglycidyl ether, and 2,2-dimethyl-1,3-propylene glycol diglycidyl ether; alkanetriol diglycidyl ethers such as glycerol diglycidyl ether; polyalkylene glycol diglycidyl ethers such as diethylene glycol diglycidyl ether, triethylene glycol diglycidyl ether, tetraethylene glycol diglycidyl ether, and hexaethylene glycol diglycidyl ether; diglycidyl ether compounds such as diglycidyl ethers of alicyclic dimethanols such as 1,4-cyclohexanedimethanol diglycidyl ether;

[0035] Glycerol triglycidyl ether, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, N,N,N',N'-tetraglycidyl m-xylylenediamine, N,N,N',N'-tetraglycidylaminophenylmethane, triglycidyl isocyanurate, m-N,N-diglycidylaminophenyl glycidyl ether, N,N-diglycidyl toluidine, N,N-diglycidyl aniline, 3',4'-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, ε-caprolactone-modified 3',4'-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate.

[0036] The epoxy resin (A) may be used alone or in combination of two or more.

[0037] The SP value of the epoxy resin (A) is 11 to 15, preferably 11 to 13.5. The SP value in the above range is preferred from the viewpoint that the epoxy resin (A) and the (meth)acrylic polymer (B) form a sea-island phase separation structure having an island phase with an average dispersion diameter of an appropriate size.

[0038] In the epoxy resin composition of the present embodiment, the absolute value of the difference between the SP value of the (meth)acrylic polymer (B) and the SP value of the epoxy resin (A) is 0.1 to 3.3, preferably 1.5 to 3.3. If the absolute value of the difference in SP value is within the above range, after the resin composition is cured, the sea-island phase separation structure is easily formed, and the average dispersion diameter of the island phase is appropriate, which tends to further improve the impact resistance of the cured resin.

[0039] The absolute value of the difference between the SP value of the epoxy resin (A) and the SP value of the epoxy compound (B2) is preferably 0 to 2.7, and more preferably 0 to 2.5, from the viewpoint of forming a sea-island phase separation structure with an average dispersion diameter of an appropriate size. In one embodiment, the value obtained by subtracting the SP value of the epoxy compound (B2) from the SP value of the epoxy resin (A) is preferably -2.7 to 1.2, and more preferably -2.5 to 1.1.

[0040] The epoxy equivalent of the epoxy resin (A) is not particularly limited, but is preferably 100 to 3000 g / eq., more preferably 100 to 1000 g / eq.

[0041] <(Meth)acrylic polymer (B)>

[0042] The (meth)acrylic polymer (B) is a reaction product of a carboxyl group-containing (meth)acrylic polymer (B1) and an epoxy compound (B2), and is preferably an addition reaction product of a carboxyl group-containing (meth)acrylic polymer (B1) and an epoxy compound (B2). That is, the (meth)acrylic polymer (B) is preferably a compound having a structure represented by the following formula (1) obtained by reacting a carboxyl group of the carboxyl group-containing (meth)acrylic polymer (B1) with an epoxy group of the epoxy compound (B2).

[0043] [Chemistry 1]

[0044]

[0045] By using (meth) acrylic polymer (B) as a modifier for epoxy resin (A), the cured resin obtained from the epoxy resin composition of the present embodiment exhibits high impact resistance compared to the case where the above-mentioned modifier is not used. In addition, the above-mentioned cured resin has improved impact resistance when the elastic modulus originally possessed by the epoxy resin does not change significantly. Moreover, the epoxy resin composition of the present embodiment exhibits high adhesion to metal adherends.

[0046] Although the reason for such an effect is not clear, it is believed that the appropriate compatibility of the epoxy resin and the modifier is important for forming a sea-island structure including an island phase having an average dispersion diameter of an appropriate size. It is speculated that by using the (meth)acrylic polymer (B) as the above-mentioned reaction product as a modifier for the epoxy resin (A), the SP value and the SP value difference of the two are set within an appropriate range, and the two are appropriately compatible, forming a sea-island structure including an island phase having an average dispersion diameter of an appropriate size, thereby improving the impact resistance of the resin cured product obtained from the epoxy resin composition.

[0047] 《(Meth)acrylic polymer (B1) containing carboxyl group》

[0048] The carboxyl group-containing (meth)acrylic polymer (B1) (hereinafter, also referred to as “polymer (B1)”) contains a structural unit derived from a monomer having a carboxyl group.

[0049] The monomer having a carboxyl group includes a compound obtained by hydrolyzing and ring-opening a monomer having an acid anhydride group.

[0050] Examples of the monomer having a carboxyl group include carboxyl-containing monomers other than (meth)acrylates containing a carboxyl group such as (meth)acrylic acid, itaconic acid, crotonic acid, maleic acid, and fumaric acid; and (meth)acrylates containing a carboxyl group such as β-carboxyethyl (meth)acrylate, 5-carboxypentyl (meth)acrylate, mono(meth)acryloyloxyethyl succinate, ω-carboxypolycaprolactone mono(meth)acrylate, and p-carboxybenzyl (meth)acrylate.

[0051] Examples of the monomer containing anhydride groups include maleic anhydride, dodecenylsuccinic anhydride, chlorendic anhydride, sebacic anhydride, phthalic anhydride, pyromellitic anhydride, trimellitic anhydride, cyclopentanetetracarboxylic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, tetramethylene maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, endomethylenetetrahydrophthalic anhydride, methylendomethylenetetrahydrophthalic anhydride, 5-(2,5-dioxytetrahydroxyfuranyl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, and methylendomethylenetetrahydrophthalic anhydride. Among them, (meth)acrylic acid is preferred.

[0052] The ratio of the monomer having a carboxyl group in the polymerizable unsaturated group-containing monomer used to obtain the polymer (B1) is preferably 0.8 to 15% by mass, more preferably 1 to 10% by mass.

[0053] The polymer (B1) is preferably a polymer having a repeating structural unit derived from a (meth)acrylate. In one embodiment, the polymer (B1) is a polymer containing preferably 40% by mass or more, more preferably 50% by mass or more, and even more preferably 60% by mass or more of a (meth)acrylate-containing monomer having a polymerizable unsaturated group.

[0054] As (meth)acrylate, for example,

[0055] Alkyl (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, lauryl (meth)acrylate, oleyl (meth)acrylate, n-stearyl (meth)acrylate, and isostearyl (meth)acrylate, particularly alkyl (meth)acrylates having an alkyl group having 1 to 20 carbon atoms;

[0056] (Meth)acrylates containing an alicyclic hydrocarbon group or an aromatic hydrocarbon group, such as cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, adamantyl (meth)acrylate, benzyl (meth)acrylate, phenyl (meth)acrylate, and phenoxyethyl (meth)acrylate;

[0057] Alkoxyalkyl (meth)acrylates such as methoxymethyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 3-methoxypropyl (meth)acrylate, 3-ethoxypropyl (meth)acrylate, 4-methoxybutyl (meth)acrylate, and 4-ethoxybutyl (meth)acrylate;

[0058] Alkoxy polyalkylene glycol mono(meth)acrylates such as methoxydiethylene glycol mono(meth)acrylate, methoxydipropylene glycol mono(meth)acrylate, ethoxytriethylene glycol mono(meth)acrylate, and methoxytriethylene glycol mono(meth)acrylate;

[0059] N,N-dialkylaminoalkyl (meth)acrylates such as N,N-dimethylaminoethyl (meth)acrylate and N,N-diethylaminoethyl (meth)acrylate;

[0060] Hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, and 8-hydroxyoctyl (meth)acrylate;

[0061] Hydroxyl-containing (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, and (4-hydroxymethylcyclohexyl)methyl acrylate.

[0062] From the viewpoint of making the (meth)acrylic polymer (B) have an appropriate SP value, the total proportion of the (meth)acrylic acid alkyl ester, the alicyclic hydrocarbon group- or aromatic hydrocarbon group-containing (meth)acrylic acid ester, and the (meth)acrylic acid alkoxyalkyl ester in the polymerizable unsaturated group-containing monomer used to obtain the polymer (B1) is preferably 30 to 99% by mass, and more preferably 70 to 99% by mass.

[0063] The polymer (B1) may have structural units derived from other monomers (at least one selected from the group consisting of hydroxyl group-containing monomers, amide group-containing monomers, cyano group-containing monomers, nitrogen-containing heterocyclic monomers, styrene-based monomers, and vinyl ether-based monomers) other than the above-mentioned monomers having a carboxyl group and (meth)acrylates.

[0064] Examples of the hydroxyl group-containing monomer include vinyl alcohol, allyl alcohol, 2-hydroxyethyl vinyl ether and 4-hydroxybutyl vinyl ether.

[0065] Examples of the amide group-containing monomer include (meth)acrylamide, N-methyl(meth)acrylamide, N-propyl(meth)acrylamide, N-hexyl(meth)acrylamide and other N-alkyl(meth)acrylamide; and N,N-dimethyl(meth)acrylamide, N,N-dipropyl(meth)acrylamide and other N,N-dialkyl(meth)acrylamide.

[0066] As a cyano group-containing monomer, (meth)acrylonitrile may be mentioned, for example.

[0067] Examples of the nitrogen-containing heterocyclic monomer include N-vinylpyrrolidone, N-vinylcaprolactam and (meth)acryloylmorpholine.

[0068] Examples of the styrene monomers include styrene, α-methylstyrene; alkylstyrenes such as 4-methylstyrene, 3,5-diethylstyrene, trimethylstyrene, propylstyrene, butylstyrene, hexylstyrene, heptylstyrene, octylstyrene, and 3,5-dimethylstyrene; halogenated styrenes such as 4-fluorostyrene, 4-chlorostyrene, 4-bromostyrene, and 3,5-dibromostyrene; and functionalized styrenes such as 4-nitrostyrene, 4-acetylstyrene, and 4-methoxystyrene.

[0069] Examples of the vinyl ether monomer include vinyl acetate; and alkyl vinyl ethers such as methyl vinyl ether, n-propyl vinyl ether and n-butyl vinyl ether.

[0070] The ratio of other monomers in the polymerizable unsaturated group-containing monomer used to obtain the polymer (B1) is 20% by mass or less, preferably 10% by mass or less.

[0071] 《Epoxy compound (B2)》

[0072] As an epoxy compound (B2), the number of epoxy groups in 1 molecule may be 2 or more, for example.

[0073] Examples of the epoxy compound (B2) include

[0074] Bisphenol-type epoxy resins such as bisphenol A epoxy resin, bisphenol E epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, bisphenol O epoxy resin, bisphenol AD ​​epoxy resin, hydrogenated bisphenol epoxy resin, alkyl-substituted bisphenol epoxy resin, alkylene oxide-modified bisphenol epoxy resin, biphenyl epoxy resin, resorcinol epoxy resin, thioether epoxy resin, diphenyl ether epoxy resin, dicyclopentadiene epoxy resin, naphthalene epoxy resin, phenol novolac epoxy resin, orthocresol novolac epoxy resin, dicyclopentadiene novolac epoxy resin, biphenyl novolac epoxy resin, naphthol novolac epoxy resin, and glycidylamine epoxy resin;

[0075] Diglycidyl ethers of bisphenols such as bisphenol A, bisphenol E, bisphenol F, bisphenol S, bisphenol O, and bisphenol AD, or 4,4-dihydroxybiphenyl (herein, the above bisphenols and the above biphenyls may be hydrogenated (e.g., hydrogenated bisphenols), may have an alkyl substituent (e.g., alkyl-substituted bisphenols), or may be modified with alkylene oxides such as ethylene oxide and propylene oxide (e.g., alkylene oxide-modified bisphenols)); ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, 1, Alkanediol diglycidyl ethers such as 8-octanediol diglycidyl ether, 1,10-decanediol diglycidyl ether, and 2,2-dimethyl-1,3-propylene glycol diglycidyl ether; alkanetriol diglycidyl ethers such as glycerol diglycidyl ether; polyalkylene glycol diglycidyl ethers such as diethylene glycol diglycidyl ether, triethylene glycol diglycidyl ether, tetraethylene glycol diglycidyl ether, and hexaethylene glycol diglycidyl ether; diglycidyl ether compounds such as diglycidyl ethers of alicyclic dimethanols such as 1,4-cyclohexanedimethanol diglycidyl ether;

[0076] Glycerol triglycidyl ether, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, N,N,N',N'-tetraglycidyl m-xylylenediamine, N,N,N',N'-tetraglycidylaminophenylmethane, triglycidyl isocyanurate, m-N,N-diglycidylaminophenyl glycidyl ether, N,N-diglycidyl toluidine, N,N-diglycidyl aniline, 3',4'-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, ε-caprolactone-modified 3',4'-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate.

[0077] The epoxy equivalent of the epoxy compound (B2) is not particularly limited, but is preferably 100 to 3000 g / eq., more preferably 100 to 1000 g / eq.

[0078] The SP value of the carboxyl group-containing (meth)acrylic polymer (B1) is preferably 9.0 to 11.5, and more preferably 9.0 to 11. The SP value of the epoxy compound (B2) is preferably 10 to 15, and more preferably 11 to 13.5.

[0079] The absolute value of the difference between the SP value of the carboxyl group-containing (meth)acrylic polymer (B1) and the SP value of the epoxy compound (B2) is preferably 1.3 to 4.5, and more preferably 1.3 to 3.7, from the viewpoint of forming a sea-island phase separation structure having an island phase with an average dispersion diameter of an appropriate size. In one embodiment, the value obtained by subtracting the SP value of the epoxy compound (B2) from the SP value of the carboxyl group-containing (meth)acrylic polymer (B1) is preferably -4.5 to -1.3, and more preferably -3.6 to -1.3.

[0080] Among these epoxy compounds (B2), from the viewpoint of forming a sea-island phase separation structure of an appropriate size, preferred are bisphenol-type epoxy resins such as bisphenol A-type epoxy resin, diglycidyl ethers of bisphenol or 4,4-dihydroxybiphenyl [herein, the above-mentioned bisphenol and the above-mentioned biphenyl may be hydrogenated, may have an alkyl substituent, or may be modified with an alkylene oxide], and polyalkylene glycol diglycidyl ethers such as diethylene glycol diglycidyl ether.

[0081] 《Manufacture of (Meth)acrylic polymer (B)》

[0082] The (meth)acrylic polymer (B) can be produced by a known method, and can be obtained by reacting a carboxyl group-containing (meth)acrylic polymer (B1) and an epoxy compound (B2).

[0083] The carboxyl-containing (meth) acrylic polymer (B1) is not particularly limited, and is preferably produced by bulk polymerization from the viewpoint of removing impurities. Specifically, a monomer containing a polymerizable unsaturated group, a polymerization initiator, and a chain transfer agent and a polymerization solvent used as needed are added to a reaction vessel, and the reaction temperature is heated to about 50 to 150° C. under an inert gas atmosphere such as nitrogen, and the reaction is allowed to react for 2 to 20 hours. In addition, a monomer containing a polymerizable unsaturated group, a polymerization initiator, a chain transfer agent, and a polymerization solvent may be appropriately added during the polymerization reaction.

[0084] As the polymerization initiator, for example, a common organic polymerization initiator may be mentioned, and specifically, a peroxide compound or an azo compound may be mentioned.

[0085] Examples of the peroxide compound include 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, t-hexyl peroxy-2-ethylhexanoate, t-amyl peroxy-2-ethylhexanoate, t-butyl peroxy-2-ethylhexanoate, cumyl peroxyneodecanoate, 1,1,3,3-tetramethylbutyl peroxyneodecanoate, t-hexyl peroxyneodecanoate, t-butyl peroxyneodecanoate, t-butyl peroxyneoheptanoate, t-hexyl peroxypivalate, t-butyl peroxypivalate, 2,5-dimethyl-2,5-di(2-ethylhexanoylperoxy)hexane, 2,5-dimethyl-2,5-di(2-benzoylperoxy)hexane, t-butyl peroxy-3,3,5-trimethylhexanoate, t-butyl peroxylaurate, and t-hexyl peroxybenzoate.

[0086] Examples of the azo compound include 2,2'-azobisisobutyronitrile, 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis(2-cyclopropylpropionitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2-methylbutyronitrile), 1,1'-azobis(cyclohexane-1-carbonitrile), 2-(carbamoylazo)isobutyronitrile, 2-phenylazo-4-methoxy-2,4-dimethylvaleronitrile, 2,2'-azobis(2-cyclopropylpropionitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2-methylbutyronitrile), 1,1'-azobis(cyclohexane-1-carbonitrile), 2-(carbamoylazo)isobutyronitrile, (2-amidinopropane) dihydrochloride, 2,2'-azobis(N,N'-dimethyleneisobutylamidine), 2,2'-azobis[2-methyl-N-(2-hydroxyethyl)-propionamide], 2,2'-azobis(isobutylamide) dihydrate, 4,4'-azobis(4-cyanovaleric acid), 2,2'-azobis(2-cyanopropanol), 2,2'-azobis(2-methylpropionic acid) dimethyl ester, 2,2'-azobis[2-methyl-N-(2-hydroxyethyl)propionamide].

[0087] The polymerization initiator may be used alone or in combination of two or more.

[0088] The amount of the polymerization initiator used is usually 0.01 to 5 parts by mass based on 100 parts by mass of the polymerizable unsaturated group-containing monomer. In such a form, the number average molecular weight (Mn) of the (meth)acrylic polymer (B) can be adjusted within an appropriate range.

[0089] When polymer (B1) is produced, the monomer containing a polymerizable unsaturated group is preferably polymerized in the presence of a chain transfer agent. From the viewpoint of suppressing the foaming generated when the epoxy resin is cured, in order to suppress the residual low molecular weight components such as residual monomers, it is more preferable to perform the polymerization in the presence of a chain transfer agent having a highly reactive polar group.

[0090] As a chain transfer agent having a polar group in the molecule, a thiol chain transfer agent having a polar group in the molecule is preferred. As a thiol chain transfer agent having a polar group in the molecule, a thiol chain transfer agent having one or more polar groups such as carboxyl, hydroxyl, amino, sulfonic acid group in the molecule can be cited. Among these polar groups, a carboxyl group or a hydroxyl group is preferred. As such a thiol chain transfer agent having a polar group in the molecule, for example, carboxyl-containing thiol compounds such as α-mercaptopropionic acid and β-mercaptopropionic acid; hydroxyl-containing thiol compounds such as 1-mercaptoethanol, 2-mercaptoethanol, and 1-mercaptopropanol can be cited. In addition, as a chain transfer agent, for example, alkylthiol compounds such as n-octyl mercaptan and n-dodecyl mercaptan can be cited.

[0091] The chain transfer agent may be used alone or in combination of two or more.

[0092] The amount of the chain transfer agent used is preferably 0.1 to 10 parts by mass, more preferably 3 to 8 parts by mass, based on 100 parts by mass of the polymerizable unsaturated group-containing monomer. In this form, the weight average molecular weight and number average molecular weight of the (meth)acrylic polymer (B) can be adjusted within appropriate ranges.

[0093] In the solution polymerization, the polymerization solvent may be, for example, aromatic hydrocarbons such as benzene, toluene, and xylene; aliphatic hydrocarbons such as n-pentane, n-hexane, n-heptane, and n-octane; alicyclic hydrocarbons such as cyclopentane, cyclohexane, cycloheptane, and cyclooctane; diethyl ether, diisopropyl ether, 1,2-dimethoxyethane, dibutyl ether, tetrahydrofuran, dimethoxyethane, diisopropyl ether ... Ethers such as alkane, anisole, phenethyl ether, and diphenyl ether; halogenated hydrocarbons such as chloroform, carbon tetrachloride, 1,2-dichloroethane, and chlorobenzene; esters such as ethyl acetate, propyl acetate, butyl acetate, and methyl propionate; ketones such as acetone, methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, and cyclohexanone; amides such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone; nitriles such as acetonitrile and benzonitrile; sulfoxides such as dimethyl sulfoxide and cyclopentane.

[0094] The polymerization solvent may be used alone or in combination of two or more.

[0095] The (meth)acrylic polymer (B) is a polymer obtained by reacting an epoxy compound (B2) in an amount preferably in the range of 0.1 to 500 parts by mass, more preferably 5 to 300 parts by mass, further preferably 10 to 200 parts by mass, and further preferably 15 to 100 parts by mass, relative to 100 parts by mass of the carboxyl group-containing (meth)acrylic polymer (B1). The cured resin of the polymer obtained by reacting the epoxy compound (B2) in the above range forms a sea-island phase separation structure of an appropriate size and has excellent impact resistance. In addition, when reacting the carboxyl group-containing (meth)acrylic polymer (B1) and the epoxy compound (B2), a known epoxy curing catalyst may also be used.

[0096] The (meth)acrylic polymer (B) is preferably a polymer obtained by reacting the carboxyl group in the carboxyl group-containing (meth)acrylic polymer (B1) and the epoxy group in the epoxy compound (B2) in a molar ratio (B1 / B2) of preferably 0.1 to 1, more preferably 0.3 to 1.

[0097] 《Content of (Meth)acrylic polymer (B)》

[0098] The epoxy resin composition of the present embodiment preferably contains 0.1 to 70 parts by mass, more preferably 10 to 70 parts by mass, and still more preferably 10 to 40 parts by mass of the (meth)acrylic polymer (B) relative to 100 parts by mass of the epoxy resin (A). Such a form is preferred from the viewpoint of imparting impact resistance without damaging the original properties of the epoxy resin.

[0099] The epoxy resin composition of the present embodiment preferably contains 30% by mass or more of the epoxy resin (A) and the (meth) acrylic polymer (B) in total, more preferably 50% by mass or more, and further preferably 70% by mass or more, in its solid content 100% by mass, from the viewpoint of obtaining excellent bonding strength with a metal adherend. The solid content refers to components other than the solvent described later.

[0100] 《Physical properties of (Meth)acrylic polymer (B)》

[0101] The SP value of the (meth)acrylic polymer (B) is 9.5 to 11, preferably 9.7 to 10.7. The SP value within the above range is preferred from the viewpoint that the epoxy resin (A) and the (meth)acrylic polymer (B) form a sea-island phase separation structure having an island phase with an average dispersion diameter of an appropriate size.

[0102] The epoxy equivalent of the (meth)acrylic polymer (B) is not particularly limited, but is preferably 100 to 10,000 g / eq., more preferably 500 to 8,000 g / eq. The SP value within the above range is preferred from the viewpoint of excellent compatibility between the epoxy resin and the (meth)acrylic polymer (B).

[0103] The weight average molecular weight (Mw) of the (meth)acrylic polymer (B) is preferably 3,000 to 100,000, more preferably 3,500 to 80,000.

[0104] In addition, the number average molecular weight (Mn) of the (meth)acrylic polymer (B) is preferably 1,500 to 15,000, and more preferably 1,500 to 8,000. If the above molecular weight satisfies such conditions, the (meth)acrylic polymer (B) has a moderate viscosity, excellent workability, and is preferably compatible with the epoxy resin (A) and has excellent durability of the obtained resin cured product. The weight average molecular weight (Mw) and the number average molecular weight (Mn) are measured by gel permeation chromatography (GPC). The details of the measurement conditions of the GPC method are described in the examples described below.

[0105] The viscosity of the (meth)acrylic polymer (B) measured using an E-type viscometer at a liquid temperature of 25° C. and a rotation speed of 6 rpm is preferably 150 Pa·s or less, more preferably 100 Pa·s or less. The lower limit of the viscosity is not particularly limited, but in one embodiment is 1 Pa·s.

[0106] <Curing agent (C)>

[0107] The epoxy resin composition of the present embodiment preferably contains the epoxy resin (A) and the (meth)acrylic polymer (B) together with a curing agent (C). The curing agent (C) is, for example, a compound that cures the epoxy resin composition by reacting with the epoxy resin (A).

[0108] Examples of the curing agent (C) include polyamines, polycarboxylic acids, acid anhydrides and phenols, and in addition thereto, imidazoles, polythiols and organic acid hydrazides may be mentioned.

[0109] Examples of the polyamine include aliphatic polyamines such as diethylenetriamine, dipropylenetriamine, triethylenetetramine, tetraethylenepentamine, dimethylaminopropylamine, diethylaminopropylamine, dibutylaminopropylamine, hexamethylenediamine, N-aminoethylpiperazine, trimethylhexamethylenediamine, bis(hexamethylene)triamine, and polyoxypropylenediamine; and 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane, 3-amino-1-cyclohexylaminopropane, 4,4'-diaminodicyclohexylmethane, isophoronediamine, 1,3-bis(aminomethyl)cyclohexane, N-dimethylcyclohexylaminopropane, and 4,4'-diaminodicyclohexylmethane. Alicyclic polyamines such as a mixture of aminodicyclohexylaminopropane; aromatic polyamines such as 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, diaminodiphenyl sulfone, meta-phenylenediamine, 2,4-toluenediamine, 2,6-toluenediamine, 2,3-toluenediamine, 3,4-toluenediamine, meta-xylylenediamine, and xylylenediamine; heterocyclic polyamines such as N-aminoethylpiperazine; amide curing agents such as dicyandiamide and diacetone acrylamide; and modified products thereof (e.g., epoxy adducts, acrylonitrile adducts, ethylene oxide adducts, Mannich reaction products, Michael reaction products, thiourea reaction products, and modified aromatic amines).

[0110] Examples of the polycarboxylic acid include phthalic acid, hydroxyisophthalic acid, succinic acid, sebacic acid, maleic acid, dodecenylsuccinic acid, chlorendic acid, pyromellitic acid, trimellitic acid, hexahydrophthalic acid, methylhexahydrophthalic acid, tetrahydrophthalic acid, methyltetrahydrophthalic acid and methylnadic acid.

[0111] Examples of the acid anhydride include maleic anhydride, dodecenylsuccinic anhydride, chlorendic anhydride, sebacic anhydride, phthalic anhydride, pyromellitic anhydride, trimellitic anhydride, cyclopentanetetracarboxylic dianhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, tetramethylenemaleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, endomethylenetetrahydrophthalic anhydride, methylendomethylenetetrahydrophthalic anhydride, 5-(2,5-dioxytetrahydroxyfuranyl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride and methylendomethylenetetrahydrophthalic anhydride.

[0112] Examples of the phenols include bisphenol A, bisphenol F, bisphenol S, bisphenol AD, hydroquinone, resorcinol, methylresorcinol, biphenol, tetramethylbiphenol, dihydroxynaphthalene, dihydroxydiphenyl ether, thiodiphenols, phenol novolac resins, cresol novolac resins, phenol aralkyl resins, biphenyl aralkyl resins, naphthol aralkyl resins, terpene phenol resins, dicyclopentadiene phenol resins, bisphenol A novolac resins, trisphenol methane type resins, naphthol novolac resins, brominated bisphenol A, brominated phenol novolac resins, and the like. Various polyphenols, and polyphenol resins obtained by condensation reaction of various phenols with various aldehydes such as benzaldehyde, hydroxybenzaldehyde, crotonaldehyde, glyoxal, etc., polyphenol resins obtained by condensation reaction of xylene resin and phenols, co-condensation resins of heavy oil or asphalt with phenols and formaldehydes, phenol·benzaldehyde·xylene dimethanol condensation products, phenol·benzaldehyde·xylene dihalide condensation products, phenol·benzaldehyde·4,4'-dimethoxybiphenyl condensation products, phenol·benzaldehyde·4,4'-dihalobiphenyl condensation products and other phenolic resins.

[0113] Examples of the imidazoles include 2-phenylimidazole, 2-ethyl-4-methylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyano-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole trimer, 1-cyanoethyl-2-phenylimidazole trimer, 2,4-diamino-6-[2'-methylimidazole] 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1'))]-ethyl-s-triazine, 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1'))]-ethyl-s-triazine, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole.

[0114] Among these curing agents (C), in one embodiment, polyamines, amide-based curing agents, and imidazoles are preferred, and aliphatic polyamines and modified products of aliphatic polyamines are more preferred.

[0115] The curing agent (C) may be used alone or in combination of two or more.

[0116] In one embodiment, the epoxy resin composition of the present embodiment preferably contains 0.01 to 10 equivalents of the curing agent (C), more preferably 0.1 to 5 equivalents, and even more preferably 0.5 to 2 equivalents, based on the equivalent ratio to the epoxy resin (A). Such a form is preferred from the viewpoint of curability.

[0117] <Cationic or anionic polymerization initiator>

[0118] The epoxy resin composition of this embodiment may contain a cationic or anionic polymerization initiator instead of the curing agent (C) or together with the curing agent (C). The cationic or anionic polymerization initiator is a compound that initiates and / or accelerates the curing reaction of the epoxy resin (A) by heating or light.

[0119] The cationic polymerization initiator may be any polymerization initiator that generates cationic species such as Bronsted acid or Lewis acid by heating or light, and examples thereof include onium salts, protonic acid esters, and Lewis acid-amine complexes. The cationic polymerization initiator may be used alone or in combination of two or more.

[0120] As the anionic polymerization initiator, any one can be used as long as it generates anionic species such as Bronsted base or Lewis base by heating or light, and examples thereof include imidazoles and tertiary amines. The anionic polymerization initiator may be used alone or in combination of two or more.

[0121] In one embodiment, the epoxy resin composition of the present embodiment preferably contains 0.001 to 50 parts by mass of a cationic or anionic polymerization initiator, more preferably 0.01 to 30 parts by mass, and even more preferably 0.1 to 10 parts by mass, relative to 100 parts by mass of the epoxy resin (A). Such a form is preferred from the viewpoint of curability.

[0122] <Additive>

[0123] The epoxy resin composition of the present embodiment may also contain at least one additive selected from ultraviolet absorbers, antioxidants, preservatives, rust inhibitors, pigments, tackifiers, surface lubricants, glossing agents, water repellents, photosensitizers, organic and inorganic fibers, plasticizers, conductive fillers, inorganic fillers, flame retardants, antistatic agents, foam stabilizers, release agents, colorants, and foaming agents as needed. The additives may be used alone or in combination of two or more.

[0124] <Solvent>

[0125] The epoxy resin composition of the present embodiment may contain a solvent. Examples of the solvent include the solvents listed as the polymerization solvent in the method for producing the (meth)acrylic polymer (B) or reactive diluents such as epoxy compounds having one epoxy group in one molecule.

[0126] The solvent may be used alone or in combination of two or more.

[0127] The content ratio of the solvent in the epoxy resin composition of the present embodiment is usually 70% by mass or less, preferably 30% by mass or less, and more preferably 20% by mass or less.

[0128] [Use of epoxy resin composition]

[0129] By using the epoxy resin composition of this embodiment, a cured resin material having sufficient elastic modulus and impact resistance can be formed.

[0130] Since the epoxy resin composition of the present embodiment has the above-mentioned characteristics, it can be used for electronic materials, adhesives, coatings, adhesives and the like. Specifically, base substrates for electronic components such as semiconductor packages, laminated films, solder resist inks, bottom filling materials, solid sealing materials for packages, paving adhesives, adhesives for carbon fiber reinforced plastics (CFRP), cationic electrodeposition coating agents, heavy anticorrosive coatings, powder coatings, adhesives for infrastructure maintenance / reinforcement, and general household / industrial adhesives can be cited. The epoxy resin composition of the present embodiment is suitable for these uses.

[0131] [Resin cured product]

[0132] One embodiment of the cured resin material of the present invention (hereinafter referred to as “cured resin material of the present embodiment”) is obtained by curing the epoxy resin composition of the present embodiment.

[0133] The cured resin material of the present embodiment preferably has a sea-island phase separation structure.

[0134] Preferably, the sea-island phase separation structure is a structure in which a component derived from the (meth)acrylic polymer (B) as an island phase (dispersed phase) is dispersed in a component derived from the epoxy resin (A) as a sea phase (continuous phase).

[0135] In the sea-island phase separation structure of the cured resin of the present embodiment, the average dispersion diameter of the island phase is preferably 0.01 to 0.84 μm, more preferably 0.03 to 0.80 μm. If the average dispersion diameter of the island phase is within the above range, the impact resistance of the cured resin can be improved while maintaining the original elastic modulus of the epoxy resin. If the average dispersion diameter of the island phase is less than 0.01 μm or exceeds 0.84 μm, the original elastic modulus of the epoxy resin tends to decrease.

[0136] That the cured resin obtained by curing the epoxy resin composition of the present embodiment has a sea-island phase separation structure can be confirmed by, for example, cutting the cured resin with a razor or a microtome and observing the cut surface with a transmission electron microscope, a scanning electron microscope, an atomic force microscope, or the like.

[0137] The tensile modulus (X) of the cured resin of the present embodiment and the tensile modulus (Y) of the cured resin when the (meth)acrylic polymer (B) of the present embodiment is not included preferably satisfy the following formula (2).

[0138] 0.6≤X / Y≤1.1…(2)

[0139] The lower limit of the formula (2) is preferably 0.7 or more, more preferably 0.75 or more, and further preferably 0.8 or more. The upper limit of the formula (2) is more preferably 1.08 or less, and further preferably 1.05 or less.

[0140] When a modifier is added to a curable composition obtained from an epoxy resin in order to improve impact resistance, the elastic modulus inherent in the epoxy resin changes. Therefore, in a system in which the modifier is added, it is necessary to readjust the elastic modulus.

[0141] In the cured resin of the present embodiment, even when a modifier ((meth)acrylic polymer (B)) is blended, since the above formula (2) is satisfied, the impact resistance can be improved without readjusting the elastic modulus of the cured product.

[0142] As a method for curing the epoxy resin composition of the present embodiment, for example, a method of mixing the components to prepare the epoxy resin composition of the present embodiment and then performing a curing reaction by heating with light may be mentioned.

[0143] The mixing is performed using, for example, a mixer, a blender or a roll.

[0144] In the case of thermal curing, the heating temperature during curing (curing temperature) is usually 20 to 300° C., preferably 40 to 250° C., and more preferably 60 to 200° C. In addition, the heating time during curing (curing time) is usually 10 to 1440 minutes, preferably 30 to 900 minutes, and more preferably 60 to 480 minutes. The above heating may also be performed in multiple stages.

[0145] In the case of photocuring, light such as ultraviolet light, visible light, infrared light, etc. may be used, and ultraviolet light is preferred. The exposure amount is preferably 1 to 10000 mJ / cm 2 , more preferably 10 to 3000 mJ / cm 2 Examples of the light source include a low-pressure mercury lamp, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a carbon arc lamp, a xenon lamp, a metal halide lamp, a chemical lamp, a black light fluorescent lamp, and an electrodeless UV lamp.

[0146] The curing reaction can be carried out by applying the epoxy resin composition of the present embodiment on a substrate, or by injecting the composition into a mold.

[0147] The shape of the cured resin product of the present embodiment is not particularly limited, and may be, for example, a plate, a sheet, or a film. The thickness thereof is, for example, usually 0.01 to 1000 mm, preferably 0.1 to 100 mm.

[0148] In addition, another embodiment of the cured resin of the present invention is a cured resin obtained by curing an epoxy resin composition containing an epoxy resin and a (meth) acrylic polymer, which has a sea-island phase separation structure, and the average dispersion diameter of the island phase is 0.01 to 0.84 μm. Here, as the epoxy resin composition containing an epoxy resin and a (meth) acrylic polymer, the epoxy resin composition of the present embodiment described above is preferably used.

[0149] The tensile modulus (X) of the cured resin of the above-mentioned other embodiment and the tensile modulus (Y) of the cured resin in the case of not containing a (meth)acrylic polymer preferably satisfy the following formula (2).

[0150] 0.6≤X / Y≤1.1…(2)

[0151] The lower limit of the formula (2) is preferably 0.7 or more, more preferably 0.75 or more, and further preferably 0.8 or more. The upper limit of the formula (2) is more preferably 1.08 or less, and further preferably 1.05 or less.

[0152] Example

[0153] The present invention will be described in more detail below based on Examples, but the present invention is not limited to these Examples. In the following Examples and the like, "parts" means "parts by mass" unless otherwise specified.

[0154] <SP value>

[0155] The SP value of each component was calculated from the sum (ΔH) of the molar heat of vaporization (Δei) and the sum (V) of the molar volume (Δvi) of the atomic group described in Robert F. Fedors, "POLYMER ENGINEERING AND SCIENCE", 1974, Vol. 14, No. 2, pp. 151-153.

[0156] <Weight average molecular weight (Mw), number average molecular weight (Mn)>

[0157] The weight average molecular weight (Mw) and number average molecular weight (Mn) of the polymer were analyzed by gel permeation chromatography (GPC) and calculated in terms of polystyrene under the following conditions.

[0158] ·Device: GPC-8220 (manufactured by Tosoh Corporation)

[0159] Column: G7000HXL / 7.8mmID×1+

[0160] GMHXL / 7.8mmID×2pcs+

[0161] G2500HXL / 7.8mmID×1

[0162] Medium: Tetrahydrofuran

[0163] Flow rate: 1.0mL / min

[0164] Concentration: 1.5 mg / mL

[0165] Injection volume: 300μL

[0166] Column temperature: 40℃

[0167] <Viscosity>

[0168] The viscosity of each polymer was measured under the conditions of a liquid temperature of 25° C. and a rotation speed of 6 rpm using an E-type viscometer VISCONIC EHD (manufactured by Tokyo Keiki Co., Ltd.).

[0169] <Epoxy equivalent>

[0170] The epoxy equivalent of the polymer is determined based on JIS K7236.

[0171] [Production Example 1]

[0172] In a flask equipped with a stirring device, a nitrogen inlet pipe, a thermometer, and a reflux cooling tube, 62.1 parts of 2-ethylhexyl acrylate, 2.5 parts of acrylic acid, and 4.3 parts of β-mercaptopropionic acid were added, and nitrogen was introduced into the flask while stirring for 30 minutes to perform nitrogen substitution, and then the content of the flask was heated to 60°C. Next, while the content in the flask was maintained at 60°C, 0.06 parts of azobisisobutyronitrile was added to initiate the reaction. Thereafter, 0.06 parts of azobisisobutyronitrile was added 6 times every 1 hour to allow the reaction to proceed, and then the reaction was carried out at 100°C to 125°C for 3 hours, and the volatile components in the product were distilled off under reduced pressure to obtain a carboxyl group-containing (meth)acrylic polymer (B1-1). Next, 31.1 parts of bisphenol A epoxy resin ("jER828", manufactured by Mitsubishi Chemical Corporation, SP value = 12.8) and an appropriate amount of epoxy curing catalyst (triphenylphosphine, "HOKKO TPP", manufactured by Hokko Chemical Co., Ltd.) were added to the flask as an epoxy compound (B2), and stirred at 110°C for 8 hours. Thereafter, the mixture was cooled to room temperature to obtain a (meth)acrylic polymer (B-1). The (meth)acrylic polymer (B-1) had an SP value of 10.2, an Mw of 5814, an Mn of 3342, a viscosity of 40.2 Pa·s, and an epoxy equivalent of 2316 g / eq.

[0173] [Production Examples 2 to 15, 20, 21]

[0174] (Meth)acrylic polymers (B-2) to (B-15), (cB-5), and (cB-6) were obtained in the same manner as in Production Example 1 except that the compositions were changed to those shown in Table 1. The SP value, Mw, Mn, viscosity, and epoxy equivalent of each polymer are shown in Table 1.

[0175] [Production Example 16]

[0176] In a flask equipped with a stirring device, a nitrogen inlet tube, a thermometer, and a reflux cooling tube, 100 parts of methyl ethyl ketone, 92 parts of 2-ethylhexyl acrylate, 6 parts of glycidyl methacrylate, and 2 parts of n-dodecyl mercaptan were added, and nitrogen was introduced into the flask while stirring for 30 minutes to perform nitrogen substitution, and then the contents of the flask were heated to 60°C. Next, while the contents in the flask were maintained at 60°C, 0.2 parts of azobisisobutyronitrile were added to initiate the reaction. After reacting for 3 hours, 0.2 parts of azobisisobutyronitrile was further added, and then reacted at 75 to 80°C for 5 hours to obtain an epoxy-containing (meth)acrylic polymer (cB-1). The (meth)acrylic polymer (cB-1) had an SP value of 9.4, an Mw of 14588, an Mn of 7521, a viscosity of 42.1 Pa·s, and an epoxy equivalent of 1872 g / eq.

[0177] [Production Examples 17 to 19]

[0178] Except for changing the composition to that shown in Table 1, the reaction was carried out under the same conditions as in Preparation Example 16 to obtain epoxy-containing (meth)acrylic polymers (cB-2), (cB-3), and (cB-4). The SP value, molecular weight, viscosity, and epoxy equivalent are shown in Table 1.

[0179] [Table 1]

[0180]

[0181] (※1) In Table 1, in the case of (meth)acrylic polymers (cB-1) to (cB-4), these are polymers obtained by comparison using epoxy group-containing (meth)acrylates instead of components B1 and B2, but are collectively described in the "B1" column for convenience.

[0182] The abbreviations of the monomers, chain transfer agents, and epoxy compounds have the following meanings.

[0183] BA: n-butyl acrylate

[0184] ·2EHA: 2-Ethylhexyl acrylate

[0185] ·GMA: Glycidyl Methacrylate

[0186] AA: Acrylic acid

[0187] MAA: Methacrylic acid

[0188] BMPA: beta-mercaptopropionic acid

[0189] ·NOM: n-octyl mercaptan

[0190] ·NDM: n-dodecyl mercaptan

[0191] ·jER828: Bisphenol A type epoxy resin (manufactured by Mitsubishi Chemical Corporation)

[0192] EPOLITE 100E: Diethylene glycol diglycidyl ether (manufactured by Kyoeisha Chemical Co., Ltd.)

[0193] EPOLITE 3002N: Bisphenol A PO (propylene oxide) 2 mol adduct diglycidyl ether (manufactured by Kyoeisha Chemical Co., Ltd.)

[0194] Table 1 shows these SP values.

[0195] [Example 1]

[0196] 100 parts of bisphenol A epoxy resin (trade name "jER828", manufactured by Mitsubishi Chemical Corporation), 40 parts of (meth)acrylic polymer (B-1), and 50 parts of aliphatic polyamine curing agent (trade name "ST12", manufactured by Mitsubishi Chemical Corporation) were mixed using a rotation / revolution mixer (trade name "Defoam Rentaro") to obtain an epoxy resin composition.

[0197] [Examples 2 to 18, Comparative Examples 1 to 6, Reference Examples 1 to 3]

[0198] Except for changing the blending composition described in Table 2-1 and Table 2-2 (hereinafter, these are also collectively referred to as "Table 2"), the epoxy resin composition was obtained in the same manner as in Example 1. The composition conditions and the evaluation results are described in Table 2. In Table 2, "113" is jRE QURE 113 (modified alicyclic amine, manufactured by Mitsubishi Chemical Corporation), "DICY15" is jERQURE DICY15 (dicyandiamide fine powder, manufactured by Mitsubishi Chemical Corporation), and "2E4MZ" is CUREZOL 2E4MZ (imidazole, manufactured by Shikoku Chemicals Co., Ltd.).

[0199] [Table 2-1]

[0200] Table 2-1

[0201]

[0202] [Table 2-2]

[0203] Table 2-2

[0204]

[0205] (※2) In Table 2, in the case of Comparative Examples 1 to 4, for convenience, the SP values ​​of polymers (cB-1) to (cB-4) for comparison using epoxy-containing (meth)acrylates instead of components B1 and B2 are described as the SP values ​​of "component (B)". Similarly, the SP values ​​"absolute values ​​of the differences between components (A) and (B)" in the case of Comparative Examples 1 to 4 are calculated together with the SP values ​​of (cB-1) to (cB-4).

[0206] [Evaluation]

[0207] <Tensile modulus of dumbbell test piece>

[0208] The epoxy resin compositions obtained in the examples, comparative examples and reference examples were poured into a SUS mold, and cured at 80°C for 3 hours for Examples 1 to 13, Reference Examples 1 and 2, and Comparative Examples 1 to 6, and at 150°C for 1 hour for Examples 14 to 18 and Reference Example 3, to prepare dumbbell test pieces. The tensile modulus was measured under the following conditions in accordance with JIS-K7161.

[0209] Specimen size: dumbbell specification 1A

[0210] Test speed: 10mm / min

[0211] ·Measurement environment: temperature 23℃, humidity 50%RH

[0212] Number of measurements: 3 times, calculated from the average value

[0213] In addition, the ratio of the tensile modulus (X) to the tensile modulus (Y) was calculated as an index of change in the elastic modulus of the curable composition blended with the modifier, together with the tensile modulus (X) of the dumbbell test pieces obtained in the examples and comparative examples and the tensile modulus (Y) of the resin cured product of reference example 1 or 2. In addition, in each example and comparative example, the blending composition of the epoxy resin (A) and the curing agent (C) was based on the same reference example.

[0214] <Shear adhesion strength>

[0215] Based on JIS-K6850, the epoxy resin composition obtained in each example, comparative example and reference example was applied to a test piece with a thickness of 0.2 mm so that the respective ends of the two test pieces (between SUS plates or between Fe plates) overlapped by 12.5 mm, and the layers of the resin composition were clamped with the test pieces so that they overlapped. Examples 1 to 13, Reference Examples 1 and 2, and Comparative Examples 1 to 6 were dried at 80° C. for 3 hours, and Examples 14 to 18 and Reference Example 3 were dried at 150° C. for 1 hour to obtain an adhesive test piece for evaluation after the epoxy resin composition was fixed.

[0216] The tensile shear adhesion test was performed using the above-mentioned adhesion test piece for evaluation. As the tensile testing machine, a universal tensile testing machine AG-X manufactured by Shimadzu Corporation (Shimadzu) was used.

[0217] · Sample size: According to JIS-K6850

[0218] Test speed: 200mm / min

[0219] ·Measurement environment: temperature 23℃, humidity 50%RH

[0220] ·Measured value: 3 times measured, calculated from the average value

[0221] <Average dispersion diameter of island phase>

[0222] The sea-island structure of the fracture surface of the above-mentioned dumbbell test piece that broke in the tensile modulus test was observed at a magnification of 10,000 times using SEM (product name "S-4800", manufactured by Hitachi High-Technologies Corporation). The observed SEM image was analyzed using average particle size analysis software (product name "Fine-View", manufactured by Astron Corporation), and the Fret diameter of the island phase (dispersed phase) in the captured SEM image (9.2 μm × 12.7 μm) was measured. Specifically, the island phase (dispersed phase) was sandwiched between parallel lines in a certain direction, and the distance between the parallel lines was measured. The number average of the above-mentioned Fret diameters of the measured island phase was taken as the average dispersed diameter of the island phase.

[0223] <Viscosity of cured product>

[0224] After the dumbbell test piece was left to stand on the PET film at 25°C and 50% RH for 24 hours, the surface of the PET film on which the dumbbell test piece was placed and the portion of the PET film on which the dumbbell test piece was placed were visually observed and evaluated according to the following evaluation criteria.

[0225] AA: There was no change in the appearance of the test piece surface, and no transferred matter was confirmed on the PET film.

[0226] BB: Bleeding was observed from part of the surface of the test piece toward the PET film.

[0227] CC: Bleeding was observed from the entire surface of the test piece to the PET film.

[0228] [Impact resistance test]

[0229] Based on JIS-K6850, the epoxy resin composition obtained in each example, comparative example and reference example was applied to a test piece with a thickness of 0.2 mm so that the respective ends of the two test pieces overlapped by 12.5 mm, and the layers of the resin composition were clamped with the test pieces so that they overlapped. Examples 1 to 13, Reference Examples 1 and 2, and Comparative Examples 1 to 6 were dried at 80° C. for 3 hours, and Examples 14 to 18 and Reference Example 3 were dried at 150° C. for 1 hour to obtain adhesive test pieces for evaluation after the epoxy resin composition was fixed.

[0230] The drop impact test was performed using the above-mentioned evaluation adhesive test piece. The test type was DuPont type. The test piece was set so that the distance from the support to the adhesive layer of the epoxy resin composition was 50 mm, and a 1 kg weight was dropped on the evaluation adhesive test piece in a range of 10 to 30 cm in height at a height change of 10 cm. Confirm whether the adhesive surface was damaged, and evaluate the impact resistance based on the height of the weight according to the following evaluation criteria.

[0231] AA: Even 30cm is not damaged.

[0232] BB: No damage at 20 cm, but damage at 30 cm.

[0233] CC: No damage at 10 cm, but damage at 20 cm.

[0234] DD: Destroyed at a height of 10 cm.

[0235] <Discussion>

[0236] In Comparative Examples 1 to 4, epoxy-containing (meth)acrylic polymers were used as modifiers for epoxy resins. In these epoxy-containing (meth)acrylic polymers, epoxy groups were introduced into the polymers by using glycidyl methacrylate as a monomer component. These are not polymers obtained by reacting carboxyl-containing (meth)acrylic polymers with epoxy compounds. In Comparative Examples 1 to 4, the impact resistance of the obtained cured resins was not sufficiently improved.

[0237] In Comparative Examples 5 and 6, a polymer obtained by reacting a carboxyl group-containing (meth)acrylic polymer with an epoxy compound was used as a modifier for epoxy resin. However, since the SP value was as low as 9.4 or as high as 11.8, the impact resistance of the obtained cured resin was not sufficiently improved.

[0238] In contrast, in the examples, a polymer having an SP value within a specific range obtained by reacting a carboxyl group-containing (meth) acrylic polymer with an epoxy compound is used as a modifier for epoxy resin. In addition, the difference in SP value between the epoxy resin and the modifier is also within a specific range. In the examples, a resin cured product having excellent impact resistance can be obtained.

Claims

1. An epoxy resin composition comprising An epoxy resin (A) having a solubility parameter (SP value) of 11 to 15, and An epoxy resin composition comprising a (meth)acrylic polymer (B) having an SP value of 9.5 to 11, The number average molecular weight (Mn) of the (meth)acrylic polymer (B) is 1,500 to 15,000, The (meth)acrylic polymer (B) is a reaction product of a carboxyl group-containing (meth)acrylic polymer (B1) and an epoxy compound (B2), and The absolute value of the difference between the SP value of the (meth)acrylic polymer (B) and the SP value of the epoxy resin (A) is 0.1 to 3.3, The (meth)acrylic polymer (B) is contained in an amount of 0.1 to 70 parts by mass relative to 100 parts by mass of the epoxy resin (A). The epoxy resin composition is used for applications selected from electronic materials, adhesives, coatings, and bonding agents.

2. The epoxy resin composition according to claim 1, wherein The absolute value of the difference between the SP value of the carboxyl group-containing (meth)acrylic polymer (B1) and the SP value of the epoxy compound (B2) is 1.3 to 4.

5.

3. The epoxy resin composition according to claim 1 or 2, characterized in that The weight average molecular weight of the (meth)acrylic polymer (B) is 3,000 to 100,000.

4. The epoxy resin composition according to claim 1 or 2, characterized in that It also contains a curing agent (C).

5. The epoxy resin composition according to claim 3, characterized in that It also contains a curing agent (C).

6. A cured resin product, characterized in that: The epoxy resin composition according to any one of claims 1 to 5.

7. A cured resin product, characterized in that: The epoxy resin composition containing 10 to 65 parts by mass of a (meth)acrylic polymer and a curing agent is cured relative to 100 parts by mass of the epoxy resin. The (meth)acrylic polymer is a reaction product of a carboxyl group-containing (meth)acrylic polymer (B1) and an epoxy compound (B2) having two or more epoxy groups in one molecule, wherein the (meth)acrylic polymer is obtained by reacting 15 to 100 parts by mass of the epoxy compound (B2) with respect to 100 parts by mass of the carboxyl group-containing (meth)acrylic polymer (B1). It has a sea-island phase separation structure in which a component derived from a (meth)acrylic polymer as an island phase is dispersed in a component derived from an epoxy resin as a sea phase, and the average dispersion diameter of the island phase is 0.01 to 0.84 μm.

8. The cured resin material according to claim 7, wherein The tensile modulus (X) of the cured resin and the tensile modulus (Y) of the cured resin without the (meth)acrylic polymer satisfy the following formula (2): 0.6≤X / Y≤1.1…(2).

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