CN115052928A

CN115052928A - Epoxy resin composition and cured resin

Info

Publication number: CN115052928A
Application number: CN202180012958.0A
Authority: CN
Inventors: 小林文明; 斋藤亚希
Original assignee: Soken Chemical and Engineering Co Ltd
Current assignee: Soken Chemical and Engineering Co Ltd
Priority date: 2020-02-05
Filing date: 2021-01-05
Publication date: 2022-09-13
Also published as: JP7445687B2; TW202136354A; WO2021157265A1; JPWO2021157265A1; KR20220123259A

Abstract

The present invention addresses the problem of providing 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

Epoxy resin composition and cured resin

Technical Field

The present invention relates to an epoxy resin composition and a cured resin product.

Background

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 to 2). Epoxy resins are generally cured and used as cured resin products.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2002-080696

Patent document 2: international publication No. 2017/195902

Disclosure of Invention

Technical problem to be solved by the invention

A cured resin product obtained from an epoxy resin may have poor impact resistance. For example, patent document 2 discloses that an acrylic polymer is added to an epoxy resin, but according to the study of the present inventors, it is found that the impact resistance of the resin cured product obtained in this way is insufficient.

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

Technical scheme for solving technical problem

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

[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.

[2] The epoxy resin composition according to the above [1], wherein the (meth) acrylic polymer (B) is contained in an amount of 0.1 to 70 parts by mass based on 100 parts by mass of the epoxy resin (A).

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

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

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

[6] A cured resin material comprising the epoxy resin composition according to any one of the above [1] to [5 ].

[7] A resin cured product 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 an average dispersion diameter of island phases of 0.01 to 0.84 [ mu ] m.

[8] The cured resin product according to the above [7], wherein the tensile modulus (X) of the cured resin product and the tensile modulus (Y) of the cured resin product in the case where the (meth) acrylic polymer is not contained satisfy the following formula (2).

0.6≤X/Y≤1.1…(2)

ADVANTAGEOUS EFFECTS OF INVENTION

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

Detailed Description

The present invention will be described in detail below. In the present specification, (meth) acrylic acid is used as a generic term for acrylic acid and methacrylic acid, and acrylic acid may be acrylic acid or methacrylic acid, and (meth) acrylate is used as a generic term for acrylic acid ester and methacrylic acid ester, and acrylic acid ester may be methacrylic acid ester.

[ epoxy resin composition]

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, which are described below, respectively. Here, the (meth) acrylic polymer (B) is a reaction product of the carboxyl group-containing (meth) acrylic polymer (B1) and the epoxy compound (B2).

(solubility parameter (SP value))

The solubility parameter (SP value) is used to indicate, for example, the degree of dissolution or lack thereof between different kinds of macromolecules. When the difference between the SP value of the (meth) acrylic polymer (B) and the SP value of the epoxy resin (a) is within an appropriate range, the average dispersion diameter of the island phase in the resin cured product having a sea-island phase separation structure, which will be described later, tends to be controlled to an appropriate value.

The SP values of the epoxy resin (a), (meth) acrylic POLYMER (B), carboxyl group-containing (meth) acrylic POLYMER (B1), and epoxy compound (B2) in the present specification can be calculated from the sum (Δ H) of the molar heat of vaporization (Δ ei) of atomic groups described in Robert f.fedors, "POLYMER ENGINEERING AND SCIENCE", 1974, volume 14, No.2, p151 to 153, and the sum (V) of the molar volume (Δ vi).

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

Examples of the epoxy resin (a) include epoxy compounds having 2 or more epoxy groups in 1 molecule.

Examples of the epoxy resin (A) include

Bisphenol type epoxy resins such as bisphenol a type epoxy resin, bisphenol E type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol O type epoxy resin, bisphenol AD type epoxy resin, hydrogenated bisphenol type epoxy resin, alkyl-substituted bisphenol type epoxy resin, alkylene oxide-modified bisphenol type epoxy resin, biphenyl type epoxy resin, resorcinol type epoxy resin, thioether type epoxy resin, diphenyl ether type epoxy resin, dicyclopentadiene type epoxy resin, naphthalene type epoxy resin, phenol novolac type epoxy resin, n-cresol novolac type epoxy resin, dicyclopentadiene novolac type epoxy resin, biphenol novolac type epoxy resin, naphthol novolac type epoxy resin, glycidyl amine type epoxy resin;

diglycidyl ethers of bisphenols such as bisphenol a, bisphenol E, bisphenol F, bisphenol S, bisphenol O, and bisphenol AD, or 4, 4-dihydroxybiphenyl (here, the bisphenols and biphenyls may be hydrogenated (example: hydrogenated bisphenols), may have an alkyl substituent (example: alkyl-substituted bisphenols), or may be modified with alkylene oxides such as ethylene oxide-modified and propylene oxide-modified (example: alkylene oxide-modified bisphenols)); alkylene glycol diglycidyl ethers such as ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, 1, 4-butanediol diglycidyl ether, 1, 6-hexanediol diglycidyl ether, 1, 8-octanediol diglycidyl ether, 1, 10-decanediol diglycidyl ether, and 2, 2-dimethyl-1, 3-propanediol 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-containing dimethanol, e.g., 1, 4-cyclohexanedimethanol diglycidyl ether;

glycerol triglycidyl ether, 1, 3-bis (N, N-diglycidylaminomethyl) cyclohexane, N, N, N ', N' -tetraglycidyliedim-xylylenediamine, N, N, N ', N' -tetraglycidylaminophenylmethane, triglycidyl isocyanurate, m-N, N-diglycidylaminophenylglycidyl ether, N, N-diglycidyltoluidine, N, N-diglycidylaniline, 3', 4' -epoxycyclohexylmethyl-3, 4-epoxycyclohexanecarboxylate, epsilon-caprolactone-modified 3', 4' -epoxycyclohexylmethyl-3, 4-epoxycyclohexanecarboxylate.

The epoxy resin (A) may be used alone in 1 kind, or may be used in 2 or more kinds.

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 preferable from the viewpoint of the sea-island phase separation structure in which the epoxy resin (a) and the (meth) acrylic polymer (B) constitute island phases having an average dispersion diameter of an appropriate size.

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. When the absolute value of the difference in SP values is within the above range, the sea-island phase separation structure is easily formed after curing of the resin composition, and the average dispersion diameter of the island phases is appropriate, so that the impact resistance of the cured resin tends to be further improved.

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, more preferably 0 to 2.5, from the viewpoint of forming a sea-island phase separation structure having 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.

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

<(meth) acrylic acid Polymer (B)>

The (meth) acrylic polymer (B) is a reaction product of the carboxyl group-containing (meth) acrylic polymer (B1) and the epoxy compound (B2), and is preferably an addition reaction product of the carboxyl group-containing (meth) acrylic polymer (B1) and the 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).

[ solution 1]

By using the (meth) acrylic polymer (B) as a modifier for the epoxy resin (a), a resin cured product obtained from the epoxy resin composition of the present embodiment exhibits high impact resistance, as compared with a case where the modifier is not used. The cured resin product has improved impact resistance without greatly changing the elastic modulus inherent in the epoxy resin. Further, the epoxy resin composition of the present embodiment exhibits high adhesiveness to a metal adherend.

Although the reason why such an effect is exhibited is not clear, it is considered that appropriate compatibility between the epoxy resin and the modifier is important for forming a sea-island structure including island phases having an average dispersion diameter of an appropriate size. It is presumed that the (meth) acrylic polymer (B) which is the reaction product is used as a modifier for the epoxy resin (a), and by setting the SP value and the SP value difference of both within an appropriate range, both are appropriately compatible with each other, and a sea-island structure including island phases having an average dispersion diameter of an appropriate size is formed, whereby the impact resistance of a resin cured product obtained from the epoxy resin composition is improved.

Carboxyl-containing (meth) acrylic acid Polymer (B1)

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.

The monomer having a carboxyl group includes a compound obtained by hydrolyzing a monomer having an acid anhydride group and opening the ring.

Examples of the monomer having a carboxyl group include carboxyl group-containing monomers other than carboxyl group-containing (meth) acrylates such as (meth) acrylic acid, itaconic acid, crotonic acid, maleic acid, and fumaric acid; (meth) acrylates having 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.

Examples of the monomer having an acid anhydride group include maleic anhydride, dodecenylsuccinic anhydride, chlorendic anhydride, sebacic anhydride, phthalic anhydride, pyromellitic anhydride, trimellitic anhydride, cyclopentanetetracarboxylic dianhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, tetramethylene maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, endomethylenetetrahydrophthalic anhydride, methylendomethylenetetrahydrophthalic anhydride, 5- (2, 5-dioxotetrahydroxyfuranyl) -3-methyl-3-cyclohexene-1, 2-dicarboxylic anhydride, and methylendomethylenetetrahydrophthalic anhydride. Among them, (meth) acrylic acid is preferable.

The proportion of the monomer having a carboxyl group in the polymerizable unsaturated group-containing monomer used for obtaining the polymer (B1) is preferably 0.8 to 15% by mass, more preferably 1 to 10% by mass.

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

Examples of the (meth) acrylic acid ester include,

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, alkyl (meth) acrylates such as 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;

(meth) acrylic esters containing alicyclic hydrocarbon groups or aromatic hydrocarbon groups, such as cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, adamantyl (meth) acrylate, benzyl (meth) acrylate, phenyl (meth) acrylate, and phenoxyethyl (meth) acrylate;

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;

alkoxypolyalkylene 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;

n, N-dialkylaminoalkyl (meth) acrylates such as N, N-dimethylaminoethyl (meth) acrylate and N, N-diethylaminoethyl (meth) acrylate;

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;

hydroxyl group-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 (4-hydroxymethylcyclohexyl) methyl acrylate.

From the viewpoint of setting the appropriate SP value of the (meth) acrylic polymer (B), the total proportion of the alkyl (meth) acrylate, the alicyclic hydrocarbon group-or aromatic hydrocarbon group-containing (meth) acrylate, and the alkoxyalkyl (meth) acrylate in the polymerizable unsaturated group-containing monomer used for obtaining the polymer (B1) is preferably 30 to 99% by mass, and more preferably 70 to 99% by mass.

The polymer (B1) may have a constitutional unit derived from the above-mentioned monomer having a carboxyl group and a monomer other than the (meth) acrylate (at least 1 selected from the group consisting of a hydroxyl group-containing monomer, an amide group-containing monomer, a cyano group-containing monomer, a nitrogen-containing heterocyclic monomer, a styrene-based monomer, and a vinyl ether-based monomer).

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

Examples of the amide group-containing monomer include N-alkyl (meth) acrylamides such as (meth) acrylamide, N-methyl (meth) acrylamide, N-propyl (meth) acrylamide and N-hexyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide and N, N-dialkyl (meth) acrylamides such as N, N-dipropyl (meth) acrylamide.

The cyano group-containing monomer may, for example, be (meth) acrylonitrile.

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

Examples of the styrene-based monomer 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, 3, 5-dibromostyrene, and the like; functionalized styrenes such as 4-nitrostyrene, 4-acetyl styrene, 4-methoxy styrene, and the like.

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

The proportion of the other monomer in the polymerizable unsaturated group-containing monomer used for obtaining the polymer (B1) is 20 mass% or less, preferably 10 mass% or less.

Epoxy Compound (B2)

Examples of the epoxy compound (B2) include epoxy compounds having 2 or more epoxy groups in 1 molecule.

Examples of the epoxy compound (B2) include

Bisphenol type epoxy resins such as bisphenol a type epoxy resins, bisphenol E type epoxy resins, bisphenol F type epoxy resins, bisphenol S type epoxy resins, bisphenol O type epoxy resins, bisphenol AD type epoxy resins, hydrogenated bisphenol type epoxy resins, alkyl-substituted bisphenol type epoxy resins, alkylene oxide-modified bisphenol type epoxy resins, biphenyl type epoxy resins, resorcinol type epoxy resins, thioether type epoxy resins, diphenyl ether type epoxy resins, dicyclopentadiene type epoxy resins, naphthalene type epoxy resins, phenol novolac type epoxy resins, n-cresol novolac type epoxy resins, dicyclopentadiene novolac type epoxy resins, biphenyl phenol novolac type epoxy resins, naphthol novolac type epoxy resins, glycidyl amine type epoxy resins;

diglycidyl ethers of bisphenols such as bisphenol a, bisphenol E, bisphenol F, bisphenol S, bisphenol O and bisphenol AD, or 4, 4-dihydroxybiphenyl (here, the bisphenols and biphenyls may be hydrogenated (example: hydrogenated bisphenol), may have an alkyl substituent (example: alkyl-substituted bisphenol), or may be modified with alkylene oxides such as ethylene oxide-modified and propylene oxide-modified (example: alkylene oxide-modified bisphenol)); alkylene glycol diglycidyl ethers such as ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, 1, 4-butanediol diglycidyl ether, 1, 6-hexanediol diglycidyl ether, 1, 8-octanediol diglycidyl ether, 1, 10-decanediol diglycidyl ether, and 2, 2-dimethyl-1, 3-propanediol 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-containing dimethanol, e.g., 1, 4-cyclohexanedimethanol diglycidyl ether;

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-diglycidylaminophenylglycidyl ether, N, N-diglycidyltoluidine, N, N-diglycidylaniline, 3', 4' -epoxycyclohexylmethyl-3, 4-epoxycyclohexanecarboxylate, epsilon-caprolactone-modified 3', 4' -epoxycyclohexylmethyl-3, 4-epoxycyclohexanecarboxylate.

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

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

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, more preferably 1.3 to 3.7, from the viewpoint of forming a sea-island phase separation structure having island phases 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, more preferably-3.6 to-1.3.

Among these epoxy compounds (B2), bisphenol type epoxy resins such as bisphenol a type epoxy resins, diglycidyl ethers of bisphenol or 4, 4-dihydroxybiphenyl [ here, 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 are preferable from the viewpoint of forming a sea-island phase separation structure with an appropriate size.

Production of (meth) acrylic acid Polymer (B)

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

The carboxyl group-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 optionally a chain transfer agent and a polymerization solvent are charged into a reaction vessel, and the reaction is carried out for 2 to 20 hours by heating the reaction vessel to a temperature of about 50 to 150 ℃ in an inert gas atmosphere such as nitrogen. In addition, a monomer containing a polymerizable unsaturated group, a polymerization initiator, a chain transfer agent, and a polymerization solvent may be added to the polymerization reaction as appropriate.

The polymerization initiator may, for example, be a conventional organic polymerization initiator, and specifically, may, for example, be a peroxide compound or an azo compound.

Examples of the peroxide compounds include 1,1,3, 3-tetramethylbutyl peroxy-2-ethylhexanoate, tert-hexyl peroxy-2-ethylhexanoate, tert-amyl peroxy-2-ethylhexanoate, tert-butyl peroxy-2-ethylhexanoate, cumyl peroxyneodecanoate, 1,3, 3-tetramethylbutyl peroxyneodecanoate, tert-hexyl peroxyneodecanoate, tert-butyl peroxyneoheptanoate, tert-hexyl peroxypivalate, tert-butyl peroxypivalate, 2, 5-dimethyl-2, 5-bis (2-ethylhexanoylperoxy) hexane, 2, 5-dimethyl-2, 5-bis (2-benzoylperoxy) hexane, peroxy-3, tert-butyl 3, 5-trimethylhexanoate, tert-butyl peroxylaurate and tert-hexyl peroxybenzoate.

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

The polymerization initiator may be used alone in 1 kind, or may be used in 2 or more kinds.

The amount of the polymerization initiator used is usually 0.01 to 5 parts by mass per 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.

In the production of the polymer (B1), the polymerizable unsaturated group-containing monomer is preferably polymerized in the presence of a chain transfer agent, and from the viewpoint of suppressing foaming during curing of the epoxy resin, the polymerization is more preferably carried out in the presence of a chain transfer agent having a polar group with high reactivity in order to suppress the residual of low-molecular components such as residual monomers.

As the chain transfer agent having a polar group in a molecule, a thiol chain transfer agent having a polar group in a molecule is preferable. Examples of the thiol chain transfer agent having a polar group in a molecule include thiol chain transfer agents having 1 or more polar groups in a molecule, such as a carboxyl group, a hydroxyl group, an amino group, and a sulfonic acid group. Among these polar groups, a carboxyl group or a hydroxyl group is preferable. Examples of such thiol chain transfer agents having a polar group in the molecule include thiol compounds having a carboxyl group such as α -mercaptopropionic acid and β -mercaptopropionic acid; hydroxyl group-containing thiol compounds such as 1-mercaptoethanol, 2-mercaptoethanol, and 1-mercaptopropanol. The chain transfer agent may, for example, be an alkyl mercaptan compound such as n-octyl mercaptan or n-dodecyl mercaptan.

The chain transfer agent may be used in 1 kind or 2 or more kinds.

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

In the solution polymerization, the polymerization solvent may, for example, be an aromatic hydrocarbon such as benzene, toluene or 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 and dibutyl ether

Alkane, anisole, benzeneEthers such as diethyl ether and diphenyl ether; halogenated hydrocarbons such as chloroform, carbon tetrachloride, 1, 2-dichloroethane, chlorobenzene, and the like; 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-dimethylacetamide and N-methylpyrrolidone; nitriles such as acetonitrile and benzonitrile; sulfoxides such as dimethyl sulfoxide and sulfolane.

The polymerization solvent may be used alone in 1 kind, or may be used in 2 or more kinds.

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

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

(meth) acrylic acid Polymer (B) content

The epoxy resin composition of the present embodiment preferably contains the (meth) acrylic polymer (B) in an amount of 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, based on 100 parts by mass of the epoxy resin (a). Such a form is preferable from the viewpoint of imparting impact resistance without impairing the inherent properties of the epoxy resin.

The epoxy resin composition of the present embodiment preferably contains the total of the epoxy resin (a) and the (meth) acrylic polymer (B) in an amount of 30 mass% or more, more preferably 50 mass% or more, and still more preferably 70 mass% or more, based on 100 mass% of the solid content, from the viewpoint of obtaining excellent adhesive strength with a metal adherend. The solid component means a component other than the solvent described later.

Properties of (meth) acrylic acid Polymer (B)

The SP value of the (meth) acrylic polymer (B) is 9.5 to 11, preferably 9.7 to 10.7. An SP value within the above range is preferable from the viewpoint of a sea-island phase separation structure in which the epoxy resin (a) and the (meth) acrylic polymer (B) constitute island phases having an average dispersion diameter of an appropriate size.

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. An SP value within the above range is preferable from the viewpoint of excellent compatibility between the epoxy resin and the (meth) acrylic polymer (B).

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.

Further, the number average molecular weight (Mn) of the (meth) acrylic polymer (B) is preferably 1, 500 to 15,000, more preferably 1, 500 to 8,000. When the molecular weight satisfies such a condition, the (meth) acrylic polymer (B) is preferably suitable in that it has an appropriate viscosity and excellent handling properties, and is excellent in compatibility with the epoxy resin (a) and durability of the resulting resin cured product. The weight average molecular weight (Mw) and the number average molecular weight (Mn) were measured by a Gel Permeation Chromatography (GPC) method. The details of the measurement conditions of the GPC method are described in examples described later.

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

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

Examples of the curing agent (C) include polyamines, polycarboxylic acids, acid anhydrides and phenols, and in addition, imidazoles, polythiols and organic acid hydrazides.

Examples of the polyamine include aliphatic polyamines such as diethylenetriamine, dipropylenetriamine, triethylenetetramine, tetraethylenepentamine, dimethylaminopropylamine, diethylaminopropylamine, dibutylaminopropylamine, hexamethylenediamine, N-aminoethylpiperazine, trimethylhexamethylenediamine, bis (hexamethylene) triamine and polyoxypropylene diamine; alicyclic polyamines such as a mixture with 3,3 '-dimethyl-4, 4' -diaminodicyclohexylmethane, 3-amino-1-cyclohexylaminopropane, 4 '-diaminodicyclohexylmethane, isophoronediamine, 1, 3-bis (aminomethyl) cyclohexane, N-dimethylcyclohexylaminopropane and 4,4' -diaminodicyclohexylaminopropane; aromatic polyamines such as 4,4 '-diaminodiphenylmethane, 4' -diaminodiphenyl ether, diaminodiphenylsulfone, m-phenylenediamine, 2, 4-tolylenediamine, 2, 6-tolylenediamine, 2, 3-tolylenediamine, 3, 4-tolylenediamine, m-xylylenediamine, and xylylenediamine; heterocyclic polyamines such as N-aminoethylpiperazine; amide-based curing agents such as dicyandiamide and diacetone acrylamide; modifications thereof (e.g., epoxy adducts, acrylonitrile adducts, ethylene oxide adducts, Mannich reaction products, Michael reaction products, thiourea reaction products, modified aromatic amines).

Examples of the polycarboxylic acid include phthalic acid, hydroxyisophthalic acid, succinic acid, sebacic acid, maleic acid, dodecenylsuccinic acid, chlorendic acid (クロレンデック acid), pyromellitic acid, trimellitic acid, hexahydrophthalic acid, methylhexahydrophthalic acid, tetrahydrophthalic acid, methyltetrahydrophthalic acid, and methylnadic acid.

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, tetramethylene maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, endomethylenetetrahydrophthalic anhydride, methylendomethylenetetrahydrophthalic anhydride, 5- (2, 5-dioxotetrahydroxyfuranyl) -3-methyl-3-cyclohexene-1, 2-dicarboxylic anhydride, and methylendomethylenetetrahydrophthalic anhydride.

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, triphenol methane resins, naphthol novolac resins, brominated bisphenol A, brominated phenol novolac resins, and the like, and polyhydric phenol resins obtained by condensation reaction of various phenols with various aldehydes such as benzaldehyde, hydroxybenzaldehyde, crotonaldehyde, glyoxal, and the like, polyhydric phenol resins obtained by condensation reaction of xylene resin with phenols, heavy oil, or co-condensation resins of asphalts with phenols and formaldehydes, heavy oil, and phenol co-condensation resins, Phenol resins such as phenol benzaldehyde xylene dimethanol polycondensate, phenol benzaldehyde xylene dihalide polycondensate, phenol benzaldehyde 4,4 '-dimethoxybiphenyl polycondensate, and phenol benzaldehyde 4,4' -dihalobiphenyl polycondensate.

Examples of the imidazoles include 2-phenylimidazole, 2-ethyl-4-methylimidazole, 2-phenyl-4-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' -methylimidazolyl- (1') ] -ethyl-s-triazine, 2, 4-diamino-6- [2' -ethyl-4 ' -methylimidazolyl- (1') ] -ethyl-s-triazine, and mixtures thereof, 2, 4-diamino-6- [2 '-methylimidazolyl- (1') ] -ethyl-s-triazine isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct, 2-phenyl-4, 5-dimethyloimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole.

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

The curing agent (C) may be used alone in 1 kind, or may be used in 2 or more kinds.

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 still more preferably 0.5 to 2 equivalents, based on the equivalent ratio of the epoxy resin (a). Such an embodiment is preferable from the viewpoint of curability.

The epoxy resin composition of the present embodiment may contain a cationic or anionic polymerization initiator in place of the curing agent (C) or in addition to the curing agent (C). The cationic or anionic polymerization initiator is a compound which initiates and/or accelerates the curing reaction of the epoxy resin (a) by heat or light.

The cationic polymerization initiator may be any polymerization initiator which generates a cationic species such as a bronsted acid or a 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 in 1 kind, or may be used in 2 or more kinds.

The anionic polymerization initiator may be any polymerization initiator which generates an anionic species such as a bronsted base or a lewis base by heating or light, and examples thereof include imidazoles and tertiary amines. The anionic polymerization initiator may be used alone in 1 kind, or may be used in 2 or more kinds.

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 still more preferably 0.1 to 10 parts by mass, based on 100 parts by mass of the epoxy resin (a). Such an embodiment is preferable from the viewpoint of curability.

The epoxy resin composition of the present embodiment may contain, if necessary, at least 1 additive selected from the group consisting of an ultraviolet absorber, an antioxidant, an antiseptic, a rust preventive, a pigment, a thickener, a surface lubricant, a gloss agent, a water repellent, a photosensitizer, organic and inorganic fibers, a plasticizer, a conductive filler, an inorganic filler, a flame retardant, an antistatic agent, a foam stabilizer, a mold release agent, a colorant, and a foaming agent. The additive may be used alone in 1 kind, or in 2 or more kinds.

<Solvent(s)>

The epoxy resin composition of the present embodiment may contain a solvent. Examples of the solvent include solvents listed as the polymerization solvent in the process for producing the (meth) acrylic polymer (B), and reactive diluents such as epoxy compounds having 1 epoxy group in 1 molecule.

The solvent may be used alone in 1 kind, or may be used in 2 or more kinds.

The content 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.

[ use of an epoxy resin composition]

By using the epoxy resin composition of the present embodiment, a resin cured product having sufficient elastic modulus and impact resistance can be formed.

The epoxy resin composition of the present embodiment has the above-described characteristics, and thus can be used for applications such as electronic materials, adhesives, paints, and adhesives. Specifically, the substrate for electronic components such as semiconductor packages, a laminate film, a solder resist ink, an underfill material, a solid sealing material for packages, a paving adhesive, an adhesive for Carbon Fiber Reinforced Plastics (CFRP), a cationic electrodeposition coating agent, a heavy duty coating, a powder coating, an adhesive for infrastructure maintenance/reinforcement, and an adhesive for general household/industrial use may be mentioned. The epoxy resin composition of the present embodiment is suitable for these uses.

[ cured resin product]

One embodiment of the cured resin product of the present invention (hereinafter referred to as "cured resin product of the present embodiment") is obtained by curing the epoxy resin composition of the present embodiment.

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

The sea-island phase separation structure is preferably a structure in which a component derived from the (meth) acrylic polymer (B) is dispersed as an island phase (dispersed phase) in a component derived from the epoxy resin (a) as a sea phase (continuous phase).

In the sea-island phase separation structure of the cured resin of the present embodiment, the average dispersion diameter of the island phases is preferably 0.01 to 0.84. mu.m, more preferably 0.03 to 0.80. mu.m. When 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. mu.m, the inherent elastic modulus of the epoxy resin tends to be lowered.

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

The tensile modulus (X) of the cured resin material of the present embodiment and the tensile modulus (Y) of the cured resin material in the case where the (meth) acrylic polymer (B) of the present embodiment is not contained preferably satisfy the following formula (2).

0.6≤X/Y≤1.1…(2)

The lower limit of the formula (2) is preferably 0.7 or more, more preferably 0.75 or more, and still more preferably 0.8 or more. The upper limit value of formula (2) is more preferably 1.08 or less, and still more preferably 1.05 or less.

In a curable composition obtained from an epoxy resin, if a modifier is blended in order to improve impact resistance, the inherent elastic modulus of the epoxy resin changes, and therefore, in a system in which the modifier is blended, it is necessary to readjust the elastic modulus.

Even when the modifier ((meth) acrylic polymer (B)) is blended in the cured resin material of the present embodiment, the impact resistance can be improved without readjusting the elastic modulus of the cured material because the above formula (2) is satisfied.

The method of curing the epoxy resin composition of the present embodiment may, for example, be a method of mixing the respective components to prepare the epoxy resin composition of the present embodiment, and then performing a curing reaction by heating light.

The mixing may be carried out by, for example, a mixer, a blender or a roll.

In the case of thermal curing, the heating temperature (curing temperature) at the time of curing is usually 20 to 300 ℃, preferably 40 to 250 ℃, and more preferably 60 to 200 ℃. The heating time (curing time) during curing is usually 10 to 1440 minutes, preferably 30 to 900 minutes, and more preferably 60 to 480 minutes. The heating may be performed in multiple stages.

In the case of photocuring, light such as ultraviolet light, visible light, infrared light, and the like may be mentioned, and ultraviolet light is preferable. The exposure is preferably 1 to 10000mJ/cm ² More preferably 10 to 3000mJ/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.

The curing reaction may be performed by coating the epoxy resin composition of the present embodiment on a substrate or may be performed in an injection molding machine.

The shape of the cured resin of the present embodiment is not particularly limited, and examples thereof include a plate shape, a sheet shape, and a film shape. The thickness of these is, for example, usually 0.01 to 1000mm, preferably 0.1 to 100 mm.

Another embodiment of the cured resin material of the present invention is a cured resin material obtained by curing an epoxy resin composition containing an epoxy resin and a (meth) acrylic polymer, the cured resin material having a sea-island phase separation structure, wherein the average dispersion diameter of the island phases is 0.01 to 0.84. mu.m. 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.

The tensile modulus (X) of the cured resin material according to the other embodiment described above and the tensile modulus (Y) of the cured resin material in the case where the (meth) acrylic polymer is not contained preferably satisfy the following formula (2).

0.6≤X/Y≤1.1…(2)

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 value of formula (2) is more preferably 1.08 or less, and still more preferably 1.05 or less.

Examples

The present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. In the following description of examples and the like, "part" means "part by mass" unless otherwise specified.

The SP value of each component was calculated from the sum (Δ H) of the molar heat of vaporization (Δ ei) of the atomic group and the sum (V) of the molar volume (Δ vi) described in Robert f.fedors., "POLYMER ENGINEERING AND SCIENCE", 1974, volume 14, No.2, p151 to 153.

The weight average molecular weight (Mw) and the number average molecular weight (Mn) of the polymer were analyzed by Gel Permeation Chromatography (GPC) and calculated from polystyrene conversion under the following conditions.

An apparatus: GPC-8220 (manufactured by Tosoh corporation of imperial China ソー)

Column: g7000HXL/7.8mmID × 1 root +

GMHXL/7.8mmID multiplied by 2 roots +

G2500HXL/7.8mmID X1 root

The medium: tetrahydrofuran (THF)

Flow rate: 1.0 mL/min

Concentration: 1.5mg/mL

Injection amount: 300 mu L

Column temperature: 40 deg.C

The viscosity of each polymer was measured at a liquid temperature of 25 ℃ and a rotation speed of 6rpm by using an E-type viscometer VISCONIC EHD (manufactured by Tokyo Meter K.K., by imperial Tokyo ).

The epoxy equivalent of the polymer was determined in accordance with JIS K7236.

Production example 1]

Into a flask equipped with a stirrer, a nitrogen gas inlet tube, a thermometer, and a reflux condenser, 62.1 parts of 2-ethylhexyl acrylate, 2.5 parts of acrylic acid, and 4.3 parts of β -mercaptopropionic acid were charged, and after nitrogen substitution was performed by stirring for 30 minutes while introducing nitrogen gas into the flask, the content of the flask was heated to 60 ℃. Then, while maintaining the contents of the flask at 60 ℃, 0.06 part of azobisisobutyronitrile was added to initiate a reaction. Thereafter, azobisisobutyronitrile (0.06 part) was added every 1 hour for 6 times to react, and then the reaction was carried out at 100 to 125 ℃ for 3 hours, and volatile components in the product were distilled off under reduced pressure to obtain a carboxyl group-containing (meth) acrylic polymer (B1-1). Next, in the flask, as an epoxy compound (B2), 31.1 parts of a bisphenol a type epoxy resin ("jER 828", manufactured by mitsubishi chemical corporation (mitsubishi ケミカル), SP value 12.8) and an appropriate amount of an epoxy curing catalyst (triphenylphosphine, "HOKKO TPP", manufactured by beixing chemical corporation, north xingkong chemical) were charged, and the mixture was stirred at 110 ℃ for 8 hours. After that, the reaction mixture was cooled to room temperature to obtain (meth) acrylic polymer (B-1). The (meth) acrylic polymer (B-1) had an SP value of 10.2, Mw of 5814, Mn of 3342, viscosity of 40.2 pas and epoxy equivalent of 2316g/eq.

Production examples 2 to 15, 20 and 21]

(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 shown in Table 1 were changed. The SP value, Mw, Mn, viscosity and epoxy equivalent of each polymer are shown in Table 1.

Production example 16]

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 to a flask equipped with a stirrer, a nitrogen gas inlet tube, a thermometer, and a reflux condenser, and after nitrogen substitution was performed by stirring for 30 minutes while introducing nitrogen gas into the flask, the content of the flask was heated to 60 ℃. Then, while maintaining the contents of the flask at 60 ℃, 0.2 parts of azobisisobutyronitrile was added to initiate a reaction. After the reaction for 3 hours, 0.2 part of azobisisobutyronitrile was further added, and the mixture was reacted at 75 to 80 ℃ for 5 hours to obtain an epoxy group-containing (meth) acrylic polymer (cB-1). The (meth) acrylic polymer (cB-1) had an SP value of 9.4, Mw of 14588, Mn of 7521, viscosity of 42.1 pas and epoxy equivalent of 1872g/eq.

Production examples 17 to 19]

The reaction was carried out under the same conditions as in production example 16 except that the composition shown in Table 1 was changed to obtain epoxy group-containing (meth) acrylic polymers (cB-2), (cB-3) and (cB-4), respectively. The SP value, molecular weight, viscosity and epoxy equivalent are shown in Table 1.

[ Table 1]

In table 1, the (meth) acrylic polymers (cB-1) to (cB-4) are polymers obtained by comparing epoxy group-containing (meth) acrylates in place of the B1 component and the B2 component, but for convenience, they are collectively described in the column of "B1".

The meanings of the monomers, chain transfer agents and epoxy compounds are as follows.

BA: acrylic acid n-butyl ester

2 EHA: 2-ethylhexyl acrylate

The GMA: glycidyl methacrylate

AA: acrylic acid

MAA: methacrylic acid

BMPA: beta-mercaptopropionic acid

NOM: n-octyl mercaptan

NDM: n-dodecyl mercaptan

jER 828: bisphenol A type epoxy resin (Mitsubishi chemical corporation)

EPOLITE 100E: diethylene glycol diglycidyl ether (product of Eiken chemical Co., Ltd.)

EPOLITE 3002N: diglycidyl ether of bisphenol A PO (propylene oxide) 2mol adduct (available from Kyoeisha chemical Co., Ltd.)

The SP values of these are shown in table 1.

[ example 1]

100 parts of bisphenol A-type epoxy resin (trade name "Jer 828", manufactured by Mitsubishi chemical corporation), 40 parts of (meth) acrylic polymer (B-1), and 50 parts of aliphatic polyamine-based curing agent (trade name "ST 12", manufactured by Mitsubishi chemical corporation) were mixed in a rotation and revolution mixer (trade name "Kabushiki Kaisha" (あわとり Tailang)) to obtain an epoxy resin composition.

Examples 2 to 18, comparative examples 1 to 6, and reference examples 1 to 3]

An epoxy resin composition was obtained in the same manner as in example 1, except that the blend compositions shown in tables 2-1 and 2-2 (hereinafter, these are also collectively referred to as "table 2") were changed. The composition conditions are shown in Table 2 together with the evaluation results. In Table 2, "113" is jRE QURE 113 (modified alicyclic amine, manufactured by Mitsubishi chemical corporation), "DICY 15" is jER QURE DICY15 (dicyandiamide fine powder, manufactured by Mitsubishi chemical corporation), and "2E 4 MZ" is CUREZOL 2E4MZ (imidazole, manufactured by Siraitia Kasei ).

[ Table 2-1]

TABLE 2-1

[ tables 2-2]

Tables 2 to 2

In table 2, for comparative examples 1 to 4, the SP values of the polymers (cB-1) to (cB-4) compared with each other using an epoxy group-containing (meth) acrylate instead of the B1 component and the B2 component are described as the SP value of the "(B) component" for convenience. Similarly, the SP values in comparative examples 1 to 4 (the absolute value of the difference between component (A) and component (B)) were calculated together with the SP values of (cB-1) to (cB-4).

[ evaluation of]

The epoxy resin compositions obtained in examples, comparative examples and reference examples were poured into an SUS mold, and cured at 80 ℃ for 3 hours for examples 1 to 13, reference examples 1 and 2 and comparative examples 1 to 6 and at 150 ℃ 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.

Sample size: dumbbell Specification 1A

Test speed: 10 mm/min

The assay environment: temperature 23 ℃ and humidity 50% RH

Number of measurements: 3 measurements, from the mean value

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

The epoxy resin compositions obtained in examples, comparative examples and reference examples were applied to test pieces with a thickness of 0.2mm in accordance with JIS-K6850 so that the respective ends of 2 test pieces (between SUS plates or between Fe plates) were overlapped by 12.5mm, and the layers of the resin compositions were sandwiched between the test pieces and overlapped, and examples 1 to 13, reference examples 1 and 2 and comparative examples 1 to 6 were dried at 80 ℃ for 3 hours and examples 14 to 18 and reference example 3 were dried at 150 ℃ for 1 hour to obtain adhesive test pieces for evaluation, in which the epoxy resin compositions were fixed.

Using the above adhesion test piece for evaluation, a tensile shear adhesion test was performed. A universal model tensile tester AG-X manufactured by shimadzu corporation (shimadzu) was used as the tensile tester.

Sample size: according to JIS-K6850

Test speed: 200 mm/min

The assay environment: temperature 23 ℃ and humidity 50% RH

Measured values: 3 measurements, from the mean value

The sea-island structure of the fracture surface of the test piece fractured in the tensile modulus test of the dumbbell test piece was observed at a magnification of 10000 times by using an SEM (product name "S-4800", manufactured by Hitachi high tech Co., Ltd. (Hitachi ハイテクノロジーズ)). The observed SEM image was analyzed using an average particle size analysis software (product name "Fine-View", manufactured by Asterian corporation (アストロン)), and the Feret diameter of the island phase (dispersed phase) in the captured SEM image (9.2 μm. times.12.7 μm) was measured. Specifically, the island phase (dispersed phase) was sandwiched between parallel lines in a fixed direction, and the distance between the parallel lines was measured. The number average of the above-mentioned Frett diameters of the island phases measured was defined as the average dispersion diameter of the island phases.

After the dumbbell test pieces were allowed to stand on the PET film at 25 ℃ and 50% RH for 24 hours, the surface of the PET film on which the dumbbell test pieces were mounted and the PET film of the portion on which the dumbbell test pieces were mounted were visually confirmed, and evaluation was performed according to the following evaluation criteria.

AA: the appearance of the test piece surface was not changed, and no transfer was observed on the PET film.

BB: the exudate from the part of the test piece surface facing the PET film was confirmed.

CC: an exudate from the entire surface of the test piece facing the PET film was confirmed.

The epoxy resin compositions obtained in examples, comparative examples and reference examples were applied to test pieces with a thickness of 0.2mm in accordance with JIS-K6850, so that the respective ends of 2 test pieces were overlapped by 12.5mm, and the layers of the resin compositions were sandwiched between the test pieces and overlapped, and then examples 1 to 13, reference examples 1 and 2 and comparative examples 1 to 6 were dried at 80 ℃ for 3 hours and examples 14 to 18 and reference example 3 were dried at 150 ℃ for 1 hour, to obtain adhesion test pieces for evaluation, in which the epoxy resin compositions were fixed.

The adhesive test piece for evaluation was used to perform a drop impact test. The type of test was DuPont. The test piece was set so that the distance from the support base to the adhesive layer of the epoxy resin composition was 50mm, and a 1kg weight was placed on the adhesive test piece for evaluation while changing the height per 10cm within the range of 10 to 30 cm. Whether or not the adhesive surface was broken was confirmed, and the impact resistance was evaluated based on the height of the weight according to the following evaluation criteria.

AA: even 30cm was not destroyed.

BB: there was no destruction at 20cm, but at 30 cm.

CC: there was no destruction at 10cm, but at 20 cm.

DD: failure was at a height of 10 cm.

< investigation >)

In comparative examples 1 to 4, epoxy group-containing (meth) acrylic polymers were used as modifiers for epoxy resins. In these epoxy group-containing (meth) acrylic polymers, an epoxy group is introduced into the polymer by using glycidyl methacrylate as a monomer component. These are not polymers obtained by reacting a carboxyl group-containing (meth) acrylic polymer with an epoxy compound. In comparative examples 1 to 4, the impact resistance of the resulting resin cured product was not sufficiently improved.

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

In contrast, in the examples, as a modifier for epoxy resin, a polymer having an SP value within a specific range obtained by reacting a carboxyl group-containing (meth) acrylic polymer with an epoxy compound was used. Further, the difference in SP value between the epoxy resin and the modifier is also within a specific range. In the examples, a cured resin having excellent impact resistance was 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 of a (meth) acrylic polymer (B) having an SP value of 9.5 to 11,

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.

2. The epoxy resin composition according to claim 1, wherein the (meth) acrylic polymer (B) is contained in an amount of 0.1 to 70 parts by mass based on 100 parts by mass of the epoxy resin (A).

3. The epoxy resin composition according to claim 1 or 2, 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.

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

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

6. A cured resin product comprising the epoxy resin composition according to any one of claims 1 to 5.

7. 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 has an average dispersion diameter of the island phase of 0.01 to 0.84 μm.

8. The cured resin material according to claim 7, wherein the tensile modulus (X) of the cured resin material and the tensile modulus (Y) of the cured resin material in the case where the (meth) acrylic polymer is not contained satisfy the following formula (2).

0.6≤X/Y≤1.1…(2)