Clathrate compound, epoxy resin curing agent, and curable resin composition

Abstract

A clathrate compound that is obtained by mixing an (A) imidazole compound and a (B) polyvalent phenol compound, said clathrate compound having an average particle size (X) of 7 μm or less and a maximum particle size (Y) of 40 μm or less. The (A) imidazole compound is preferably at least one type of compound selected from among the compounds represented by formula (1). (In the formula, R1, R2, R3, and R4 each independently represent a hydrogen atom, a C1-20 alkyl group that may have a substituent, or a C6-20 aryl group that may have a substituent. At least one type of substitutent selected from a halogen atom, a hydroxy group, and a nitrile group serves as each such substituent.)

Description

Inclusion compound, epoxy resin curing agent and curable resin composition

[0001] The present invention relates to an inclusion compound, and more particularly to an inclusion compound having a specific particle size obtained by mixing an imidazole compound and a polyhydric phenol compound, an epoxy resin curing agent containing the same, and a curable resin composition containing the epoxy resin curing agent and an epoxy resin.

[0002] Epoxy resins are characterized by excellent chemical resistance, corrosion resistance, mechanical properties, thermal properties, excellent adhesion to various substrates, electrical properties, and workability in any environment, and are widely used in adhesives, paints, electrical metal materials, composite materials, etc.

[0003] Epoxy resin compositions are classified into one-component and two-component systems depending on the type of curing agent or curing catalyst used. Two-component systems have the advantage of being able to cure at room temperature or low temperatures, but on the other hand, they have the disadvantages of being required to be measured and mixed immediately before use, having a short pot life, making them difficult to use in automatic machines, and other limitations on their usage conditions. Due to these problems, one-component curable epoxy resin compositions are desired for many applications.

[0004] Patent Document 1 describes that the storage stability of a one-component curable epoxy resin composition can be improved by using an inclusion compound using tetrakisphenol as a curing agent for an epoxy resin.

[0005] EP001520867A2

[0006] However, in recent years, there has been an increasingly strong demand for curability in one-component curable epoxy resin compositions, but the clathrate compound described in Patent Document 1 does not fully address the demand for such high curability. Therefore, the problem that the present invention aims to solve is to provide a curing agent for epoxy resins that can provide a curable resin composition that is capable of being cured in a one-component manner and has better curability than conventional curable resins.

[0007] Therefore, the present inventors conducted extensive research and discovered that by adjusting the particle size of an inclusion compound obtained by mixing an imidazole compound and a polyhydric phenol compound to a specific value or less, a one-component curing type epoxy resin curing agent having better curing properties than conventional ones can be obtained, thereby arriving at the present invention.

[0008] That is, the present invention provides an inclusion compound obtained by mixing (A) an imidazole compound and (B) a polyhydric phenol compound, wherein the inclusion compound has an average particle size (X) of 7 μm or less and a maximum particle size (Y) of 40 μm or less.

[0009] The present invention also provides an epoxy resin curing agent containing the clathrate compound.

[0010] Furthermore, the present invention provides a curable resin composition containing an epoxy resin and the epoxy resin curing agent.

[0011] According to the present invention, an inclusion compound obtained by mixing (A) an imidazole compound and (B) a polyhydric phenol compound has excellent storage stability and curability, and therefore, an epoxy resin curing agent suitable for one-component curing epoxy resin compositions can be provided. Curable resin compositions using the inclusion compound of the present invention have good stability in the presence of a solvent. Such curable resin compositions of the present invention are suitable for applications such as adhesives for die attach films.

[0012] FIG. 1 shows the clathrate obtained in Example 1. 1 1 is a H-NMR chart. FIG. 2 is a DSC curve (1° C. / min) of Example 3 and Comparative Example 2. FIG. 3 is a DSC curve (1° C. / min) of Example 4 and Comparative Example 2. FIG. 4 is a DSC curve (3° C. / min) of Example 3 and Comparative Example 2. FIG. 5 is a DSC curve (3° C. / min) of Example 4 and Comparative Example 2.

[0013] The inclusion compound of the present invention will be described below. The inclusion compound of the present invention is an inclusion compound obtained by mixing (A) an imidazole compound and (B) a polyhydric phenol compound, and has an average particle size (X) of 7 μm or less and a maximum particle size (Y) of 40 μm or less. Hereinafter, the imidazole compound (A) may be referred to as "component (A)," and the polyhydric phenol compound (B) may be referred to as "component (B)."

[0014] Here, an inclusion compound is a compound obtained from two or more chemical species that can exist stably on their own, in which one of the chemical species creates a molecular-scale space and, with the primary requirement being that its shape and dimensions fit into that space, incorporates (includes) the other chemical species, forming a specific crystal structure. The chemical species that provides the space is called the host, and the chemical species that is included is called the guest. The host and guest are bonded by interactions such as hydrogen bonds, van der Waals forces, and ionic bonds. Ionic inclusion compounds are thought to form ionic crystals or salt structures.

[0015] As the imidazole compound used in the present invention, a compound represented by the following formula (1) is preferred in terms of curing performance and ease of forming an inclusion compound.

[0016] However, in the formula, R 1 ~R 4 are each independently a hydrogen atom, an alkyl group having 1 to 20 carbon atoms which may have a substituent, or an aryl group having 6 to 20 carbon atoms which may have a substituent. The substituents are halogen atoms and nitrile groups.

[0017] In the above formula, R 1 ~R 4Examples of the alkyl group having 1 to 20 carbon atoms represented by the formula (I) include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tertiary butyl group, a pentyl group, an isopentyl group, a tertiary pentyl group, a hexyl group, an isohexyl group, an octyl group, a 2-ethylhexyl group, a tertiary octyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, a hexadecyl group, a heptadecyl group, an octadecyl group, an icosanyl group, a benzyl group, and a phenethyl group. These groups may be substituted with a halogen atom, a hydroxy group, a nitrile group, or the like. In this specification, examples of the halogen atom include a fluorine atom, a bromine atom, a chlorine atom, and an iodine atom.

[0018] In the above formula, R 1 ~R 4 Examples of the aryl group having 6 to 20 carbon atoms represented by the formula (I) include a phenyl group and a naphthyl group. These groups may be substituted with an alkyl group having 1 to 10 carbon atoms, a halogen atom, a hydroxy group, a nitrile group, etc. When the aryl group is substituted with an alkyl group, the number of carbon atoms, including the number of carbon atoms of the substituent, may be 6 to 20.

[0019] Among these imidazole compounds, R 1 is preferably an alkyl group having 1 to 20 carbon atoms, more preferably an alkyl group having 1 to 10 carbon atoms, and particularly preferably an alkyl group having 1 to 4 carbon atoms. 2 and R 3 is preferably a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, more preferably a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and particularly preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. 4 is preferably a hydrogen atom. 1 is an alkyl group having 1 to 4 carbon atoms, and R 2 and R 3 is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R 4is a hydrogen atom. From the viewpoint of ease of forming an inclusion compound, 2-ethyl-4-methylimidazole is the most preferred.

[0020] The polyhydric phenol compound, component (B) used in the present invention, is not particularly limited as long as it forms an inclusion compound when mixed with an imidazole compound. However, among polyhydric phenol compounds, it is preferable to use at least one selected from tetrakisphenols represented by the following formula (2), from the viewpoint that an inclusion compound can be easily obtained.

[0021] In the formula, R 11 ~R 18 each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms which may have a substituent, or an aryl group having 6 to 20 carbon atoms which may have a substituent, and X represents a single bond or a hydrocarbon group having 1 to 4 carbon atoms.

[0022] In the formula (2), R 11 ~R 18 Examples of the alkyl group having 1 to 20 carbon atoms represented by the formula (I) include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tertiary butyl group, a pentyl group, an isopentyl group, a tertiary pentyl group, a hexyl group, an isohexyl group, an octyl group, a 2-ethylhexyl group, a tertiary octyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, a hexadecyl group, a heptadecyl group, an octadecyl group, an icosanyl group, a benzyl group, a phenethyl group, etc. These groups may be substituted with a halogen atom, a hydroxy group, a nitrile group, etc.

[0023] In formula (2), R 11 ~R 18 Examples of the aryl group having 6 to 20 carbon atoms represented by the formula (I) include a phenyl group and a naphthyl group. These groups may be substituted with an alkyl group having 1 to 10 carbon atoms, a halogen atom, a hydroxy group, a nitrile group, etc. When the aryl group is substituted with an alkyl group, the number of carbon atoms, including the number of carbon atoms of the substituent, may be 6 to 20.

[0024] Examples of the hydrocarbon group having 1 to 4 carbon atoms represented by X include alkylene groups having 1 to 4 carbon atoms. Examples of the alkylene group having 1 to 4 carbon atoms include a methylene group, an ethylene group, an ethylidene group, an n-propylene group, a propylidene group, an isopropylidene group, a methylethylene group, an n-butylene group, a butylidene group, an isobutylidene group, a sec-butylidene group, a 1,2-dimethylethylene group, a 1-methylpropylene group, and a 2-methylpropylene group.

[0025] Among the compounds represented by the formula (2), R 11 ~R 18 are each independently at least one selected from a hydrogen atom, a lower alkyl group having 1 to 6 carbon atoms, and a halogen atom, it is preferable to use a compound in which the obtained inclusion compound is used as a curing agent for an epoxy resin, thereby providing a curable resin composition having excellent curability, and R 11 ~R 18 are each independently at least one selected from a hydrogen atom, a lower alkyl group having 1 to 3 carbon atoms, or a halogen atom. 11 ~R 18 The number of hydrogen atoms may be 1 or more, 2 or more, 3 or more, 4 or more, 5 or more, 6 or more, 7 or more, or 8. Furthermore, X is preferably a single bond or a hydrocarbon group having 1 to 3 carbon atoms, more preferably a single bond or a hydrocarbon group having 1 to 2 carbon atoms, and most preferably a single bond, from the viewpoint that a curable resin composition having excellent curability can be easily provided when used as a curing agent for an epoxy resin.

[0026] The ratio of component (A) and component (B) contained in the clathrate compound is not particularly limited as long as the clathrate compound can be formed, but from the viewpoint of obtaining good curability, the amount of component (A) compound per mole of component (B) compound is preferably 0.1 to 10 moles, and more preferably 0.5 to 5.0 moles. When the clathrate compound contains a component other than components (A) and (B) (hereinafter also referred to as the "third component"), the amount of the third component is preferably 40 mol% or less, more preferably 10 mol% or less, and more preferably 3 mol% or less, based on the total amount of the clathrate compound. In particular, it is most preferable that the clathrate compound does not contain the third component. Note that, when there are multiple third components, the upper limit of the preferred molar ratio of the third component referred to here can apply to the number of moles of each of the third components or the total number of moles of the third component.

[0027] The method for mixing the inclusion compound of the present invention is not particularly limited. For example, a solution obtained by dissolving an imidazole compound (component (A)) in a solvent can be added dropwise to a solution obtained by dissolving a phenol compound (component (B)) in a solvent, and the mixture can be mixed at room temperature to 100°C during or after the dropwise addition, followed by cooling and pulverization. Mixing is preferably performed while heating at a temperature of 40 to 85°C. Examples of solvents that can be used to dissolve component (A) and component (B) include, independently, alcohol-based solvents such as methanol and 2-propanol; ester-based solvents such as ethyl acetate and butyl acetate; ketone-based solvents such as methyl ethyl ketone and acetone; aliphatic hydrocarbon solvents such as hexane, heptane, and cyclohexane; and aromatic hydrocarbon solvents such as benzene, toluene, and xylene. The solvents used to dissolve component (A) and component (B) may be the same or different. Furthermore, they can also be used as a mixed solvent. Among these solvents, ester-based solvents, especially ethyl acetate, are preferred for successful production of the clathrate compound. The concentration of the solution in which component (A) and component (B) are dissolved is not particularly limited, but can be, for example, 5 to 45% by mass, or can also be 10 to 35% by mass. The pulverizer used in the pulverization step can be, for example, a jet mill.

[0028] The clathrate compound of the present invention has an average particle size (X) of 7 μm or less and a maximum particle size (Y) of 40 μm or less, thereby achieving good low-temperature curing properties when used as an epoxy resin curing agent. The average particle size (X) of the clathrate compound is preferably 0.5 μm or more in terms of storage stability. Furthermore, the maximum particle size (Y) of the clathrate compound is preferably 1 μm or more in terms of storage stability. From the viewpoint of low-temperature curing properties, the average particle size (X) is more preferably 3 μm or less. Furthermore, from the viewpoint of low-temperature curing properties, the maximum particle size (Y) is even more preferably 10 μm or less. From these viewpoints, the average particle size (X) is particularly preferably 0.5 to 3 μm. Furthermore, the maximum particle size (Y) is particularly preferably 1 to 10 μm. Furthermore, from the viewpoint of further improving low-temperature curing properties, the ratio of the average particle size (X):maximum particle size (Y) is preferably 1:20 or less, and more preferably 1:5 or less. The ratio of the average particle size (X):maximum particle size (Y) is usually 1:1 or more, and may be 1:1.5 or more. Here, the average particle size (X) and maximum particle size (Y) are median diameters (average particle size: D50, maximum particle size: D100) measured by volume using a particle size distribution measuring device based on a laser light diffraction method.

[0029] The epoxy resin curing agent of the present invention essentially contains the inclusion compound of the present invention. The epoxy resin curing agent of the present invention may contain components other than the inclusion compound of the present invention, but preferably contains 30 mass % or more, and more preferably 80 mass % or more, of the inclusion compound of the present invention.

[0030] The curable resin composition of the present invention contains an epoxy resin and an epoxy resin curing agent essentially containing the inclusion compound of the present invention. The amount of the inclusion compound of the present invention added per 100 parts by mass of the epoxy resin is, for example, preferably 5 parts by mass or more and 40 parts by mass or less, and more preferably 10 parts by mass or more and 30 parts by mass or less.

[0031] The epoxy resin has at least two epoxy groups in the molecule, and can be used without any particular limitation on the molecular structure, molecular weight, etc.

[0032] Specific examples of the epoxy resin include polyglycidyl ether compounds of mononuclear polyhydric phenol compounds such as hydroquinone, resorcinol, pyrocatechol, and phloroglucinol; dihydroxynaphthalene, biphenol, methylenebisphenol (bisphenol F), methylenebis(ortho-cresol), ethylidenebisphenol, isopropylidenebisphenol (bisphenol A), isopropylidenebis(ortho-cresol), tetrabromobisphenol A, 1,3-bis(4-hydroxycumylbenzene), 1,4-bis(4-hydroxycumylbenzene), 1,1,3-tris(4-hydroxyphenyl)butane, 1,1,2,2-tetra(4-hydroxyphenyl)ethane, thiobisphenol, sulfobisphenol, oxybisphenol, phenol novolac, orthocresol novolac, ethylphenol novolac, butylphenol novolac, octylphenol novolac, resorcinol novolac, and terpene phenols. Polyglycidyl ether compounds of polynuclear polyhydric phenol compounds; polyglycidyl ether compounds of polyhydric alcohol compounds such as ethylene glycol, propylene glycol, butylene glycol, hexanediol, polyethylene glycol, polypropylene glycol, thioglycol, dicyclopentadiene dimethanol, 2,2-bis(4-hydroxycyclohexyl)propane (hydrogenated bisphenol A), glycerin, trimethylolpropane, pentaerythritol, sorbitol, and bisphenol A-alkylene oxide adducts; glycidyl ester compounds of aliphatic, aromatic, or alicyclic polybasic acids such as maleic acid, fumaric acid, itaconic acid, succinic acid, glutaric acid, suberic acid, adipic acid, azelaic acid, sebacic acid, dimer acid, trimer acid, phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, trimesic acid, pyromellitic acid, tetrahydrophthalic acid, and endomethylenetetrahydrophthalic acid, and homopolymers or copolymers of glycidyl methacrylate;Epoxy compounds having a glycidylamino group such as N,N-diglycidylaniline, bis(4-(N-methyl-N-glycidylamino)phenyl)methane, diglycidyl orthotoluidine, N,N-bis(2,3-epoxypropyl)-4-(2,3-epoxypropoxy)-2-methylaniline, N,N-bis(2,3-epoxypropyl)-4-(2,3-epoxypropoxy)aniline, and N,N,N',N'-tetra(2,3-epoxypropyl)-4,4-diaminodiphenylmethane; vinylcyclohexene diepoxide, Examples of epoxy resins include epoxidized cyclic olefin compounds such as cyclopentanediene diepoxide, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, 3,4-epoxy-6-methylcyclohexylmethyl-6-methylcyclohexanecarboxylate, and bis(3,4-epoxy-6-methylcyclohexylmethyl)adipate; epoxidized conjugated diene polymers such as epoxidized polybutadiene and epoxidized styrene-butadiene copolymers; and heterocyclic compounds such as triglycidyl isocyanurate. These epoxy resins may be internally crosslinked with a terminal isocyanate prepolymer or may be polymerized with a polyvalent active hydrogen compound (such as a polyphenol, a polyamine, a carbonyl group-containing compound, or a polyphosphate ester). These epoxy resins may be used alone or in combination of two or more. The amount of the epoxy resin is preferably 20 to 97% by mass, more preferably 30 to 94% by mass, and may be 40% by mass or more, or 50% by mass or more, based on the total amount of components other than the solvent in the curable resin composition.

[0033] In the curable resin composition of the present invention, a commonly known epoxy resin curing agent can be used in combination with the epoxy resin curing agent. Examples of the curing agent include acid anhydride-based curing agents, phenol-based curing agents, amine-based curing agents, and polythiol-based curing agents.

[0034] Examples of the acid anhydride curing agent include himic anhydride, phthalic anhydride, maleic anhydride, methyl himic anhydride, succinic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, trialkyltetrahydrophthalic anhydride-maleic anhydride adduct, benzophenonetetracarboxylic anhydride, trimellitic anhydride, pyromellitic anhydride, and hydrogenated methylnadic anhydride.

[0035] Examples of the phenol-based curing agent include polyhydric phenol compounds such as phenol novolac resins, cresol novolac resins, aromatic hydrocarbon formaldehyde resin-modified phenolic resins, dicyclopentadiene phenol adduct resins, phenol aralkyl resins (Xyloc resins), naphthol aralkyl resins, trisphenylolmethane resins, tetraphenylolethane resins, naphthol novolac resins, naphthol-phenol co-condensed novolac resins, naphthol-cresol co-condensed novolac resins, biphenyl-modified phenolic resins (polyhydric phenol compounds in which phenol nuclei are linked via bismethylene groups), biphenyl-modified naphthol resins (polyhydric naphthol compounds in which phenol nuclei are linked via bismethylene groups), aminotriazine-modified phenolic resins (compounds having a phenol skeleton, a triazine ring, and a primary amino group in the molecular structure), and alkoxy group-containing aromatic ring-modified novolac resins (polyhydric phenol compounds in which phenol nuclei and alkoxy group-containing aromatic rings are linked via formaldehyde).

[0036] Examples of the amine-based curing agent include alkylenediamines such as ethylenediamine, 1,2-diaminopropane, 1,3-diaminopropane, 1,3-diaminobutane, 1,4-diaminobutane, hexamethylenediamine, and metaxylenediamine; polyalkylpolyamines such as diethylenetriamine, triethylenetriamine, and tetraethylenepentamine; 1,4-diaminocyclohexane, 1,3-diaminocyclohexane, 1,3-diaminomethylcyclohexane, 1,2-diaminocyclohexane, 1,4-diamino-3,6-diethylcyclohexane, 4,4'-diaminodicyclohexylmethane, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 4,4'-diaminodicyclohexylmethane, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 4,4'-diaminodicyclohexylmethane, 1,3-bis(aminomethyl)cyclohexane, 4,4' ... alicyclic polyamines such as 4,4'-diaminodicyclohexylpropane, bis(4-aminocyclohexyl)sulfone, 4,4'-diaminodicyclohexyl ether, 2,2'-dimethyl-4,4'-diaminodicyclohexylmethane, isophoronediamine, and norbornenediamine; aromatic polyamines such as diaminodiphenylmethane, diaminodiphenylsulfone, diethyltoluenediamine, 1-methyl-3,5-diethyl-2,4-diaminebenzene, 1-methyl-3,5-diethyl-2,6-diaminobenzene, 1,3,5-triethyl-2,6-diaminobenzene, 3,3'-diethyl-4,4'-diaminodiphenylmethane, and 3,5,3',5'-tetramethyl-4,4'-diaminodiphenylmethane;N,N-dimethylaminoethylamine, N,N-diethylaminoethylamine, N,N-diisopropylaminoethylamine, N,N-diallylaminoethylamine, N,N-benzylmethylaminoethylamine, N,N-dibenzylaminoethylamine, N,N-cyclohexylmethylaminoethylamine, N,N-dicyclohexylaminoethylamine, N-(2-aminoethyl)pyrrolidine, N-(2-aminoethyl)piperidine, N-(2-aminoethyl)morpholine, N-(2-aminoethyl)piperazine, N-(2-aminoethyl)-N'-methylpiperazine, N,N-dimethylaminopropylamine, N,N-diethylaminopropylamine, N,N-diisopropylaminopropylamine, N,N-diallylaminopropylamine, N,N-benzylmethylaminopropylamine, N,N-dibenzylaminopropylamine, N,N-cyclohexylmethylaminopropylamine, N,N-dicyclohexylaminopropylamine, N-(3-aminopropyl)pyrrolidine, N-(3-aminopropyl)piperidine, N-(3-aminopropyl)morpholine, N-(3-aminopropyl)piperazine, N-(3-aminopropyl)-N'-methylpiperidine, 4-(N,N-dimethylamino)benzylamine, 4-(N,N-diethylamino)benzylamine, 4-(N,N-diisopropylamino)benzylamine, N,N,-dimethylisophoronediamine, N,N-dimethylbisaminocyclohexane, N,N,N'-trimethylethylenediamine, N'-ethyl-N,N-dimethylethylenediamine, N,N,N'-trimethylethylenediamine, N'-ethyl-N,N-dimethylpropanediamine, N'-ethyl-N,N-dibenzylaminopropylamine;N,N-(bisaminopropyl)-N-methylamine, N,N-bisaminopropylethylamine, N,N-bisaminopropylpropylamine, N,N-bisaminopropylbutylamine, N,N-bisaminopropylpentylamine, N,N-bisaminopropylhexylamine, N,N-bisaminopropyl-2-ethylhexylamine, N,N-bisaminopropylcyclohexylamine, N,N-bisaminopropylbenzylamine, N,N-bisaminopropylallylamine, bis[3-(N,N-dimethylaminopropyl)]amine dibasic acid dihydrazides such as oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide, adipic acid dihydrazide, suberic acid dihydrazide, azelaic acid dihydrazide, sebacic acid dihydrazide, and phthalic acid dihydrazide; guanidine compounds such as dicyandiamide, benzoguanamine, and acetoguanamine; melamine;2-Methylimidazole, 2-ethyl-4-methylimidazole, 2-isopropylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-aminopropylimidazole, 1-phenylmethyl-2-imidazole, 1-phenylmethyl-2-ethyl-4-methylimidazole, 1-phenylmethyl-2-phenylimidazole, 1-butoxycarbonylethyl-2-methylimidazole, 1-butoxycarbonylethyl-2- Ethyl-4-methylimidazole, 1-butoxycarbonylethyl-2-phenylimidazole, 1-(2-ethylhexyl)carbonylethyl-2-methylimidazole, 1-(2-ethylhexyl)carbonylethyl-2-ethyl-4-methylimidazole, 1-(2-ethylhexyl)carbonylethyl-2-phenylimidazole, 1-octyloxycarbonylethyl-2-methylimidazole, 1-octyloxycarbonylethyl-2-ethyl-4-methylimidazole, 1-octyloxycarbonylethyl- 2-Phenylimidazole, hexanediol bis(2-methylimidazolyl ethanoate), hexanediol bis(2-ethyl-4-methylimidazolyl ethanoate), hexanediol bis(2-phenylimidazolyl ethanoate), decanediol bis(2-methylimidazolyl ethanoate), decanediol bis(2-ethyl-4-methylimidazolyl ethanoate), decanediol bis(2-phenylimidazolyl ethanoate), tricyclopentane dimethanol Bis(2-methylimidazolyl ethanoic acid) ester, tricyclopentane dimethanol bis(2-ethyl-4-methylimidazolyl ethanoic acid) ester, tricyclopentane dimethanol bis(2-phenylimidazolyl ethanoic acid) ester, 1-(2-hydroxynaphthylmethyl)-2-methylimidazole, 1-(2-hydroxynaphthylmethyl)-2-ethyl-4-methylimidazole, 1-(2-hydroxynaphthylmethyl)-2-phenylimidazole, imidazole silane (for example, manufactured by Shikoku Chemical Industry Co., Ltd.);2MUSIZ), etc. Modified products of these amines may also be used, and the modification method may include dehydration condensation with carboxylic acid, addition reaction with an epoxy compound, addition reaction with an isocyanate compound, Michael addition reaction, Mannich reaction, condensation reaction with urea, condensation reaction with ketone, etc.;

[0037] Examples of carboxylic acids that can be used in the modified amine curing agent include aliphatic, aromatic, or alicyclic polybasic acids such as maleic acid, fumaric acid, itaconic acid, succinic acid, glutaric acid, suberic acid, adipic acid, azelaic acid, sebacic acid, dimer acid, trimer acid, phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, trimesic acid, pyromellitic acid, tetrahydrophthalic acid, hexahydrophthalic acid, and endomethylenetetrahydrophthalic acid.

[0038] Examples of epoxy compounds that can be used in the modified amine-based curing agent include polyglycidyl ether compounds of mononuclear polyhydric phenol compounds such as hydroquinone, resorcinol, pyrocatechol, and phloroglucinol; dihydroxynaphthalene, biphenol, methylene bisphenol (bisphenol F), methylene bis(ortho-cresol), ethylidene bisphenol, isopropylidene bisphenol (bisphenol A), isopropylidene bis(ortho-cresol), tetrabromobisphenol A, 1,3-bis(4-hydroxycumylbenzene), 1,4-bis(4-hydroxycumylbenzene), 1,1,3-tris(4-hydroxyphenyl)butane, 1,1,2,2-tetra(4-hydroxyphenyl)ethane, thiobisphenol, sulfonyl bisphenol, oxybisphenol, phenol novolac, orthocresol novolac, ethylphenol novolac, butylphenol novolac, octylphenol novolac, resorcinol novolac, and terpene phenols. Polyglycidyl ether compounds of polynuclear polyhydric phenol compounds such as ethylene glycol, propylene glycol, butylene glycol, hexanediol, polyglycol, thiodiglycol, glycerin, trimethylolpropane, pentaerythritol, sorbitol, bisphenol A-alkylene oxide adducts, and other polyhydric alcohols; polyglycidyl ethers of maleic acid, fumaric acid, itaconic acid, succinic acid, glutaric acid, suberic acid, adipic acid, azelaic acid, sebacic acid, dimer acid, triglyceride, glycerol ... Glycidyl esters of aliphatic, aromatic, or alicyclic polybasic acids, such as phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, trimesic acid, pyromellitic acid, tetrahydrophthalic acid, hexahydrophthalic acid, and endomethylenetetrahydrophthalic acid, and homopolymers or copolymers of glycidyl methacrylate; epoxy compounds having a glycidylamino group, such as N,N-diglycidylaniline, bis(4-(N-methyl-N-glycidylamino)phenyl)methane, and diglycidyl orthotoluidine;Examples include epoxidized products of cyclic olefin compounds such as vinylcyclohexene diepoxide, dicyclopentanediene diepoxide, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, 3,4-epoxy-6-methylcyclohexylmethyl-6-methylcyclohexanecarboxylate, and bis(3,4-epoxy-6-methylcyclohexylmethyl)adipate; epoxidized conjugated diene polymers such as epoxidized polybutadiene and epoxidized styrene-butadiene copolymers; and heterocyclic compounds such as triglycidyl isocyanurate.

[0039] Examples of the isocyanate compound that can be used in the modified amine-based curing agent include aromatic diisocyanates such as 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, diphenylmethane-4,4'-diisocyanate, phenylene diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, 1,5-naphthylene diisocyanate, 1,5-tetrahydronaphthalene diisocyanate, 3,3'-dimethyldiphenyl-4,4'-diisocyanate, dianisidine diisocyanate, and tetramethylxylylene diisocyanate; isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate; Examples of suitable isocyanate compounds include alicyclic diisocyanates such as diisocyanate, trans-1,4-cyclohexyl diisocyanate, and norbornene diisocyanate; aliphatic diisocyanates such as tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, 2,2,4 and / or (2,4,4)-trimethylhexamethylene diisocyanate, and lysine diisocyanate; isocyanurate trimerization products, biuret trimerization products, and trimethylolpropane adducts of the above-exemplified diisocyanates; triphenylmethane triisocyanate, 1-methylbenzene-2,4,6-triisocyanate, and dimethyltriphenylmethane tetraisocyanate. Furthermore, these isocyanate compounds may be used in a carbodiimide-modified, isocyanurate-modified, biuret-modified, or other modified form, or may be used in the form of a blocked isocyanate blocked with various blocking agents.

[0040] Examples of the polythiol curing agent include pentaerythritol tetrakis(3-mercaptopropionate), pentaerythritol tetrakis(thioglycolate), dipentaerythritol hexakis(3-mercaptopropionate), and dipentaerythritol. It is preferable to use hexakis(3-mercaptobutyrate), 1,3,4,6-tetrakis(2-mercaptoethyl)-1,3,4,6-tetraazaochydropentalene-2,5-dione, 1,3,5-tris(3-mercaptopropyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane, 4,8-, 4,7-, or 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, or 1,3,4,6-tetrakis(2-mercaptoethyl)glycoluril, since they have an excellent balance between storage stability and curability. Commercially available products of these preferred thiol compounds include, for example, TS-G manufactured by Shikoku Chemical Industry Co., Ltd., DPMP and PEMP manufactured by SC Organic Chemical Co., Ltd., and PETG manufactured by Yodo Chemical Co., Ltd.

[0041] Commercially available products of the curing agent include, for example, ADEKA HARDNER EH-3636AS (manufactured by ADEKA Corporation; dicyandiamide type latent curing agent), ADEKA HARDNER EH-4351S (manufactured by ADEKA Corporation; dicyandiamide type latent curing agent), ADEKA HARDNER EH-5011S (manufactured by ADEKA Corporation; imidazole type latent curing agent), ADEKA HARDNER EH-5046S (manufactured by ADEKA Corporation; imidazole type latent curing agent), ADEKA HARDNER EH-4357S (manufactured by ADEKA Corporation; polyamine type latent curing agent), ADEKA HARDNER EH-5057P (manufactured by ADEKA Corporation; polyamine type latent curing agent), and ADEKA HARDNER Examples include EH-5057PK (manufactured by ADEKA Corporation; polyamine-type latent curing agent), Amicure PN-23 (manufactured by Ajinomoto Fine-Techno Co., Ltd.; amine adduct-based latent curing agent), Amicure PN-40 (manufactured by Ajinomoto Fine-Techno Co., Ltd.; amine adduct-based latent curing agent), Amicure VDH (manufactured by Ajinomoto Fine-Techno Co., Ltd.; hydrazide-based latent curing agent), Fujicure FXR-1020 (manufactured by T&K TOKA Corporation; latent curing agent), and Curesol (imidazole-based curing agent manufactured by Shikoku Kasei Co., Ltd.). These can be used alone or in appropriate combination.

[0042] The blending amount of the curing agent other than the inclusion compound of the present invention is not particularly limited, but is preferably 10 parts by mass or more and 500 parts by mass or less, more preferably 100 parts by mass or more and 300 parts by mass or less, and even more preferably 30 parts by mass or less, relative to 100 parts by mass of the inclusion compound of the present invention.

[0043] In the curable resin composition of the present invention, a known epoxy resin curing accelerator can be used in combination as needed. Specific examples of these curing accelerators include phosphines such as triphenylphosphine; phosphonium salts such as tetraphenylphosphonium bromide; amines such as benzyldimethylamine and 2,4,6-tris(dimethylaminomethyl)phenol; quaternary ammonium salts such as trimethylammonium chloride; ureas such as 3-(p-chlorophenyl)-1,1-dimethylurea, 3-(3,4-dichlorophenyl)-1,1-dimethylurea, 3-phenyl-1,1-dimethylurea, isophorone diisocyanate-dimethylurea, and tolylene diisocyanate-dimethylurea; and complex compounds of boron trifluoride with amines, ether compounds, or the like. These curing accelerators may be used alone or in combination of two or more. The content of the epoxy resin curing accelerator in the curable resin composition of the present invention is not particularly limited and can be appropriately set depending on the application of the curable resin composition.

[0044] A silane coupling agent can be used in the curable resin composition of the present invention. Examples of the silane coupling agent include γ-aminopropyltriethoxysilane, N-β-(aminoethyl)-γ-aminopropyltriethoxysilane, N-β-(aminoethyl)-N'-β-(aminoethyl)-γ-aminopropyltriethoxysilane, γ-anilinopropyltriethoxysilane, γ-glycidoxypropyltriethoxysilane, β-(3,4-epoxycyclohexyl)ethyltriethoxysilane, vinyltriethoxysilane, N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, and γ-mercaptopropyltrimethoxysilane.

[0045] The curable resin composition of the present invention may contain a filler, such as silica (e.g., fused silica, crystalline silica, etc.), powders (e.g., magnesium hydroxide, aluminum hydroxide, zinc molybdate, calcium carbonate, silicon carbonate, calcium silicate, potassium titanate, beryllium, zirconia, zircon, fosterite, steatite, spinel, mullite, titania, etc.), or spherical beads thereof, glass fiber, pulp fiber, synthetic fiber, ceramic fiber, etc.

[0046] The curable resin composition of the present invention can be used by dissolving it in various solvents, preferably organic solvents, and examples thereof include ethers such as tetrahydrofuran, 1,2-dimethoxyethane, and 1,2-diethoxyethane; alcohols such as iso- or n-butanol, iso- or n-propanol, amyl alcohol, benzyl alcohol, furfuryl alcohol, and tetrahydrofurfuryl alcohol; ketones such as methyl ethyl ketone, methyl isopropyl ketone, and methyl butyl ketone; aromatic hydrocarbons such as benzene, toluene, and xylene; triethylamine, pyridine, dioxane, and acetonitrile.

[0047] Furthermore, the curable resin composition of the present invention may further contain various other additives as necessary. Examples of the additives include antioxidants (phenolic, phosphorus-based, sulfur-based), hindered amine light stabilizers, ultraviolet absorbers, phenolic compounds such as biphenol; reactive diluents such as monoalkyl glycidyl ether; non-reactive diluents (plasticizers) such as dioctyl phthalate, dibutyl phthalate, benzyl alcohol, and coal tar; reinforcing materials such as glass cloth, aramid cloth, and carbon fiber; pigments; lubricants such as candelilla wax, carnauba wax, Japan wax, Ibota wax, beeswax, lanolin, spermaceti, montan wax, petroleum wax, aliphatic wax, aliphatic esters, aliphatic ethers, aromatic esters, and aromatic ethers; thickeners; thixotropic agents; antifoaming agents; rust inhibitors; colloidal silica, colloidal alumina, and other commonly used additives. In the present invention, adhesive resins such as cyanate ester resins, xylene resins, and petroleum resins can also be used in combination.

[0048] The curable resin composition of the present invention has excellent curability and storage stability, and can therefore be used as a one-component curable resin composition. Its applications are not particularly limited, and it can be suitably used, for example, as a semiconductor encapsulating material, a laminating agent for printed wiring boards, an electronic component adhesive, an electronic component encapsulating material, a casting material, a varnish, a paint, a structural adhesive, a fiber-reinforced composite material, and the like.

[0049] Next, the present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to these examples. In the following examples, percentages are by mass unless otherwise specified.

[0050] Example 1 [Production of Inclusion Compound] 30.0 g (0.272 mol) of 2-ethyl-4-methylimidazole and 138 g of ethyl acetate were added and stirred at 40°C for 2 hours to prepare a solution of 2-ethyl-4-methylimidazole in ethyl acetate (2E4MZ solution). 53.8 g (0.135 mol) of tetrakis(4-hydroxyphenyl)ethane and 138 g of ethyl acetate were added to a reaction vessel to obtain a solution. The 2E4MZ solution was added dropwise to the obtained solution at 22-23°C over 15 minutes, and the mixture was then heated to 75°C over 1 hour, mixed at 75-77°C for 2 hours, and then cooled to less than 30°C over 1 hour. The mixture was then filtered, heated and dried at 80°C, pulverized using a jet mill, and sieved using a 20 μm mesh sieve to obtain pulverized product A-1 with an average particle size of 2.52 μm and a maximum particle size of 6.54 μm. The average particle size and maximum particle size were measured using a Microtrac MT-3000II (a particle size distribution analyzer manufactured by Microtrac Bell) with a wet measurement method and hexane as the measurement solvent. A sample of 0.01 g was placed in 30 ml of hexane (containing 0.5% nonionic surfactant), which was the sample dispersion solvent, and subjected to ultrasonic waves (160 W) for 3 minutes before being placed in the analyzer and measured. The H of the obtained inclusion compound was 1 The NMR data is shown in Figure 1. NMR was measured using a JEOL ECX-NMR and a JEOL ECX-400. Deuterated DMSO was used as the measurement solvent. The amine value was 183 mg KOH / g. The amine value was measured by the TEAB method. As shown in Figure 1, the NMR measurement results confirmed that the molar ratio of tetrakis(4-hydroxyphenyl)ethane to 2-ethyl-4-methylimidazole was 1:2. In this example, it is presumed that imidazole is the guest and tetrakis(4-hydroxyphenyl)ethane is the host.

[0051] Example 2 [Production of inclusion compound] The inclusion compound (before jet mill pulverization) obtained in the same manner as in Example 1 was pulverized using a jet mill and then sieved using a 10 μm mesh sieve to obtain a pulverized product A-2 having an average particle size of 1.16 μm and a maximum particle size of 2.31 μm.

[0052] Comparative Example 1 [Production of Inclusion Compound] The inclusion compound obtained in the same manner as in Example 1 [before jet mill pulverization] was pulverized using a jet mill to obtain a pulverized product B-1 having an average particle size of 7.31 μm and a maximum particle size of 44.00 μm.

[0053] Examples 3 and 4, Comparative Example 2 [Curability] An evaluation sample was prepared by mixing 11 parts by mass of the inclusion compounds obtained in Examples 1 and 2 and Comparative Example 1 with 100 parts by mass of a bisphenol A-type epoxy resin (ADEKA Corporation; ADEKA RESIN EP-4100E). Differential scanning calorimetry (DSC) was performed under the following conditions. Table 1 shows the average particle size, maximum particle size, peak top, and total heat release (total amount of reaction heat generated until the curing reaction is complete using an uncured compound as a sample). Figures 2 to 5 show portions of the DSC curves obtained by differential scanning calorimetry (DSC) near the peak. Figure 2 shows the results of heating from 40°C to 300°C at a heating rate of 1°C / min. Figure 3 shows the results of heating from 40°C to 300°C at a heating rate of 1°C / min. Fig. 4 shows the results of increasing the temperature from 40°C to 300°C at a rate of 3°C / min. Fig. 5 shows the results of increasing the temperature from 40°C to 300°C at a rate of 3°C / min.

[0054]

[0055] As shown in Table 1, the clathrate compounds of the examples each had an average particle size (X) of 7 μm or less and a maximum particle size (Y) of 40 μm or less, and therefore the peak top temperature was lower than that of Comparative Example 2, and the total heat generation amount (amount of heat required for curing) was also effectively reduced. This clearly demonstrates that the resin composition obtained using the clathrate compound of the present invention has excellent curability at low temperatures.

[0056] Example 5 and Comparative Example 3 [Stability of Curable Resin Composition in the Presence of Solvent] Bisphenol A epoxy resin (ADEKA Corporation; ADEKA RESIN EP-4100E), the inclusion compound A-1 or 2-ethyl-4-methylimidazole produced in Example 1, and methyl ethyl ketone were placed in a flask in the amounts shown in Table 2 and stirred with a spatula to prepare a clear solution. The amount of 2-ethyl-4-methylimidazole used in Comparative Example 3 was approximately the same as the amount of 2-ethyl-4-methylimidazole in the inclusion compound A-1 used in Example 5. The amount of methyl ethyl ketone was adjusted to 30% by mass in the mixture. The resulting solution was allowed to stand at 25°C. The viscosity at 25°C on days 0, 1, 3, and 7 after preparation was measured using a Brookfield viscometer (rotor No. 1 or 2, rotation speed 60 rpm, viscosity 5 minutes after the start of measurement). In Comparative Example 3, the viscosity on the 7th day could not be measured.

[0057]

[0058] As shown in Table 2, the curable resin composition of the present invention did not gel and maintained a low viscosity even when coexisting with an epoxy resin for a long period of time under conditions containing 30% by mass of solvent. Therefore, it is clear that the curable resin composition of the present invention has excellent stability in the presence of a solvent and can be suitably used in applications requiring the epoxy resin composition to be made into a varnish, such as an adhesive for die attach films.

[0059] According to the present invention, it is possible to provide a curable resin composition that has excellent curing properties, particularly at low temperatures, and the composition can be suitably used, for example, as an adhesive for electronic components such as an adhesive for die attach films, an electronic component encapsulant, a casting material, a paint, a structural adhesive, and the like.​

Claims

1. An inclusion compound obtained by mixing (A) an imidazole compound and (B) a polyhydric phenol compound, wherein the inclusion compound has an average particle size (X) of 7 μm or less and a maximum particle size (Y) of 40 μm or less.

2. 2. The clathrate compound according to claim 1, wherein the imidazole compound (A) is at least one selected from compounds represented by the following formula (1): 【Chemical 1】 In the formula, R 1 , R 2 , R 3 and R 4 are each independently a hydrogen atom, an alkyl group having 1 to 20 carbon atoms which may have a substituent, or an aryl group having 6 to 20 carbon atoms which may have a substituent. The substituent is at least one selected from a halogen atom, a hydroxy group, and a nitrile group.

3. 2. The inclusion compound according to claim 1, wherein the imidazole compound (A) is 2-ethyl-4-methylimidazole.

4. 2. The clathrate compound according to claim 1, wherein the polyhydric phenol compound (B) is at least one selected from tetrakisphenols represented by the following formula (2): 【Chemistry 2】 In the formula, R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 and R 18 are each independently at least one selected from a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms which may have a substituent, and an aryl group having 6 to 20 carbon atoms which may have a substituent, and X is a single bond or a hydrocarbon group having 1 to 4 carbon atoms. The substituent is at least one selected from a halogen atom, a hydroxy group, and a nitrile group.

5. 2. The clathrate compound according to claim 1, wherein the clathrate compound has an average particle size (X) of 0.5 μm or more and a maximum particle size (Y) of 1 μm or more.

6. An epoxy resin curing agent containing the inclusion compound according to any one of claims 1 to 5.

7. A curable resin composition comprising an epoxy resin and the epoxy resin curing agent according to claim 6.

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