JP2006199851A - Thermosetting type epoxy resin composition and article having curable adhesive layer of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermosetting type liquid state epoxy resin composition capable of being cured at a low temperature in a short time, giving its cured material showing an excellent heat resistance and maintaining a good bonding function even under a poor condition such as at a high temperature and high humidity, and suitable as an adhesive for the precision parts of optical, electric and electronic parts, etc. <P>SOLUTION: This thermosetting type epoxy resin composition contains (A) an epoxy resin obtained by condensing an epoxy group-containing alkoxy silicon compound expressed by formula (1): R<SP>1</SP>Si(OR<SP>2</SP>)<SB>3</SB>[wherein, R<SB>1</SB>is an alkyl having an epoxy group; R<SB>2</SB>is a 1-4C alkyl] in the presence of a basic catalyst, (B) an epoxy resin other than the epoxy resin (A) and having ≥2 epoxy groups, (C) an imidazole compound and (D) a compound having a phenolic hydroxy group. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a heat-curable epoxy resin composition suitable for optical, electrical, and electronic components, and the composition is useful as an adhesive, and can be cured at a low temperature in a short time. High heat resistance and high temperature and humidity resistance.

Conventionally, heat-curable epoxy resin compositions have excellent electrical, mechanical and heat-resistant properties after curing, and also have good adhesion to glass, metals, inorganics, plastics, etc. Has been adopted.
With the advancement of optics, electricity, electronic parts, etc., the requirements for the epoxy resin composition are diversified. Especially in the adhesive application of precision parts such as optics, electricity, electronics, etc., it can be applied to minute areas and complex shapes. The demands for improving workability, such as low viscosity because it is necessary, and that low temperature and short time curing is possible in order to suppress the influence of the curing heat treatment on the peripheral parts as much as possible, were the main.
In recent years, in the adhesive field, reliability has become more important, and adhesives with excellent environmental resistance are required. Specifically, adhesives that can withstand use in high-temperature and high-humidity environments (85 ° C and 85% humidity) are required. However, the present situation is that there is still no adhesive having both the above workability.

  Mercapto compounds, aliphatic amine compounds, and the like are generally known as curing agents that can cope with the low temperature and short time curing. However, with mercapto compounds, the curing reaction rate is too fast under normal conditions of use and there are difficulties in workability. With aliphatic amine compounds, the heat resistance of the cured product is low and it is not a product that can sufficiently meet market demands.

Non-Patent Document 1 discloses that when bisphenol A liquid epoxy resin (100 parts) is used as an epoxy resin and 2-methylimidazole (4 parts added) is used as a curing agent, gelation takes place at 100 ° C. in 4 minutes. When -4-methylimidazole (4 parts added) is used, it is reported that gelation takes place at 100 ° C. in 6 minutes. By using these imidazole compounds, a low-temperature and short-time curing treatment at 100 ° C. and 30 to 60 minutes becomes possible. One of the characteristics is that the cured product has high heat resistance.
However, when the imidazole is used as a curing agent, although it is characterized by achieving low-temperature and short-time curing and high heat resistance of the cured product, in terms of its adhesion function, the recent severe environment resistance under high temperature and high humidity It is not able to withstand the test sufficiently, and the adhesion strength under high temperature and high humidity is remarkable.
Moreover, although the composition containing the alkoxy silicon compound which has an epoxy group is described in patent document 1, there is no description about the composition containing the compound which has a phenolic hydroxyl group, and it describes also the use as an adhesive agent. There is no.

Shikoku Chemical Industry Co., Ltd./Imidazole-based epoxy resin curing agent / Curesol catalog JP 2004-256609 A

  The object of the present invention is, in particular, an adhesive for precision parts, which can be cured in a short time (within 1 hour) at a low temperature (for example, 130 ° C. or less). An object of the present invention is to provide an adhesive for precision parts such as optics, electricity, and electronics that can maintain a good adhesion function even under conditions of poor humidity.

As a result of intensive studies to solve the above-mentioned problems, the present inventors have determined that an epoxy resin (A) having a specific structure and an epoxy resin (B) having two or more epoxy groups other than the epoxy resin (A). The present invention was completed by finding a thermosetting epoxy resin composition containing a imidazole compound (C) and a compound (D) having a phenolic hydroxyl group.
That is, the present invention

1) The following formula (1)

[Chemical 1]
R ¹ Si (OR ² ) ₃ (1)

[Wherein, R ¹ represents an alkyl group having an epoxy group, and R ² represents a (C1-C4) alkyl group. ]
An epoxy resin (A) obtained by condensing an epoxy group-containing alkoxysilicon compound represented by the following formula in the presence of a basic catalyst, an epoxy resin (B) having two or more epoxy groups other than the epoxy resin (A), A thermosetting epoxy resin composition containing an imidazole compound (C) and a compound (D) having a phenolic hydroxyl group;

2) The thermosetting epoxy resin composition according to 1) above, wherein the alkyl group having an epoxy group of R ¹ is a glycidoxy (C1-C3) alkyl group;
3) The epoxy resin (B) having two or more epoxy groups other than the epoxy resin (A) is a polyfunctional epoxy resin that is a glycidyl etherified product of a polyphenol compound, and the compound (D) having a phenolic hydroxyl group is bisphenol. The thermosetting epoxy resin composition according to 1) or 2) above, which is A, bisphenol F, resorcin, catechol or diallyl bisphenol A;
4) The heat-curable epoxy resin composition according to any one of 1) to 3) above, wherein the heat-curable epoxy resin composition is a heat-curable epoxy resin composition for adhesives;
5) An article having an adhesive layer obtained by applying or pouring the heat-curable epoxy resin composition according to any one of 1) to 4) above and then heat-curing;
6) The article according to 5) above, wherein the article is an optical fiber connector;
About.

  The thermosetting epoxy resin composition of the present invention can be cured at a low temperature in a short time when used as an adhesive for precision parts, and the cured product has high heat resistance and excellent high temperature and humidity resistance. It is possible to improve the environmental reliability of precision parts such as electricity and electronics.

  The present invention will be described in detail. In the following, “%” and “parts” mean “% by weight” and “parts by weight” unless otherwise specified.

The heat-curable epoxy resin composition of the present invention has the above formula (1) [wherein R ¹ represents an alkyl group having an epoxy group, and R ² represents a (C1-C4) alkyl group. An epoxy resin (B) obtained by condensing an epoxy group-containing alkoxysilicon compound represented by the formula (B) in the presence of a basic catalyst, an epoxy resin having two or more epoxy groups (B) other than the epoxy resin (A) ), An imidazole compound (C), and a compound (D) having a phenolic hydroxyl group.

Although R ¹ in the epoxy group-containing alkoxysilicon compound used for the production of the epoxy resin (A) contained in the heat-curable epoxy resin composition of the present invention is not particularly limited as long as it is an alkyl group having an epoxy group, For example, glycidyl group; glycidoxy (C1-C4) alkyl group such as β-glycidoxyethyl group, γ-glycidoxypropyl group, γ-glycidoxybutyl group, or β- (3,4-epoxycyclohexyl) Ethyl group, γ- (3,4-epoxycyclohexyl) propyl group, β- (3,4-epoxycycloheptyl) ethyl group, β- (3,4-epoxycyclohexyl) propyl group, β- (3,4- (C5-C8) cyclo having an epoxy group such as (epoxycyclohexyl) butyl group and β- (3,4-epoxycyclohexyl) pentyl group Examples thereof include an alkyl group substituted with an alkyl group, a glycidoxy (C1-C3) alkyl group is preferable, and a β-glycidoxyethyl group and a γ-glycidoxypropyl group are particularly preferable.

R ² is a (C1-C4) alkyl group, and specific examples include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, and the like. A methyl group and an ethyl group are preferable from the viewpoint of reactivity.

Examples of the epoxy group-containing alkoxysilicon compound represented by the formula (1) include a combination of compounds selected from the above R ¹ and R ^2. Specifically, for example, β-glycidoxyethyl tri Methoxysilane, β-glycidoxyethyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltriethoxysilane and the like, β-glycidoxyethyltrimethoxysilane, β-glycidoxyethyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycyl Sidoxypropyltriethoxysilane is preferred.

The manufacturing method of the epoxy resin (A) contained in the heat-curable epoxy resin composition of the present invention will be described. The epoxy resin (A) is obtained by condensing the epoxy group-containing alkoxysilicon compound of the formula (1) in the presence of a basic catalyst.
In order to accelerate the condensation, water may be added as necessary. When adding water, the addition amount is about 0.05-1.5 mol normally with respect to 1 mol of alkoxy groups of all the reaction mixtures, Preferably it is about 0.07-1.2 mol.

The basic catalyst used for the condensation reaction is not particularly limited. For example, inorganic catalysts such as ammonia, sodium hydroxide, potassium hydroxide, lithium hydroxide, cesium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, etc. Examples include bases, organic bases such as triethylamine, diethylenetriamine, n-butylamine, dimethylaminoethanol, triethanolamine, and tetramethylammonium hydroxide, and inorganic bases are preferred because they can be easily removed from the product.
The addition amount of the catalyst is usually 5 × 10 ^{−4 to} 7.5% by weight, preferably 1 × 10 ^{−3 to} 5% by weight, based on the epoxy group-containing alkoxysilicon compound of the formula (1).
While the reaction temperature depends on the amount of catalyst, it is generally 20 to 160 ° C, preferably 40 to 140 ° C. The reaction time is usually 1 to 12 hours.

The condensation reaction can be performed without a solvent or in an organic solvent. The solvent is not particularly limited as long as it is a solvent in which the epoxy group-containing alkoxysilicon compound of the formula (1) is dissolved, and specific examples thereof include dimethylformamide, dimethylacetamide, tetrahydrofuran, methyl ethyl ketone, methyl isobutyl ketone, and the like. Examples include aprotic polar solvents and aromatic hydrocarbons such as toluene and xylene.
The molecular weight of the epoxy resin (A) of the present invention thus obtained is preferably about 400 to 50000, more preferably about 750 to 30000 in terms of weight average molecular weight. When the weight average molecular weight is less than 400, the effect of improving the heat resistance is poor, and when it is more than 50,000, the physical properties such as compatibility and viscosity increase as the composition are not preferable.

  As the epoxy resin (B) having two or more epoxy groups other than the epoxy resin (A) contained in the heat-curable epoxy resin composition of the present invention, a polyfunctional epoxy resin which is a glycidyl etherified product of a polyphenol compound Polyfunctional epoxy resins, alicyclic polyfunctional epoxy resins, aliphatic polyfunctional epoxy resins, heterocyclic polyfunctional epoxy resins, glycidyl ester polyfunctional epoxy resins, glycidyl amines, which are glycidyl etherified products of various novolak resins Examples include polyfunctional epoxy resins, polyfunctional epoxy resins obtained by glycidylation of halogenated phenols.

  The polyphenolic compound in the polyfunctional epoxy resin that is a glycidyl etherified product of a polyphenolic compound is not particularly limited as long as it is a compound having a plurality of phenolic hydroxyl groups. Specifically, for example, 2- [4- (2,3 -Hydroxyphenyl) -2- [4- [1,1-bis [4- (2,3-hydroxy) phenyl] ethyl] phenyl] propane, bisphenol A, bisphenol F, bisphenol S, 4,4′-biphenol, Tetramethyl bisphenol A, dimethyl bisphenol A, tetramethyl bisphenol F, dimethyl bisphenol F, tetramethyl bisphenol S, dimethyl bisphenol S, tetramethyl-4,4′-biphenol, dimethyl-4,4′-biphenol, 1- (4 -Hydroxyphenyl)- -[4- (1,1-bis- (4-hydroxyphenyl) ethyl) phenyl] propane, 2,2'-methylene-bis (4-methyl-6-tert-butylphenol), 4,4'-butylidene- Phenols having a fluorene skeleton such as bis (3-methyl-6-tert-butylphenol), trishydroxyphenylmethane, resorcinol, hydroquinone, pyrogallol, phloroglicinol, 1,1-di-4-hydroxyphenylfluorene, phenolization Examples thereof include polyphenol compounds such as polybutadiene and phenols having mono- or diallyl groups bonded thereto, such as diallylated bisphenol A. By subjecting these polyphenol compounds to a normal substitution reaction with a halogenated glycidyl compound, glycidyl etherified products of the polyphenol compounds can be obtained.

  Polyfunctional epoxy resins that are glycidyl etherified products of various novolak resins include various types such as phenol, cresols, ethylphenols, butylphenols, octylphenols, bisphenols (bisphenol A, bisphenol F, bisphenol S, etc.), naphthols, etc. Examples include novolak resins using phenol as a raw material; xylylene skeleton-containing phenol novolak resins; dicyclopentadiene skeleton-containing phenol novolak resins; biphenyl skeleton-containing phenol novolak resins;

Examples of the alicyclic polyfunctional epoxy resin include polyfunctional epoxy resins of alicyclic compounds such as cyclohexane. Examples thereof include Celoxide 2080, Celoxide 3000, and Celoxide 2021 manufactured by Daicel Chemical Industries.
Examples of the aliphatic polyfunctional epoxy resin include glycidyl etherified products of polyhydric alcohols such as 1,4-butanediol, 1,6-hexanediol, polyethylene glycol, and pentaerythritol.
The heterocyclic polyfunctional epoxy resin includes a heterocyclic polyfunctional epoxy resin having a heterocyclic ring such as an isocyanuric ring or a hydantoin ring. For example, triglycidyl isocyanuric acid.

Examples of the glycidyl ester epoxy resin include carboxylic acid esters such as hexahydrophthalic acid diglycidyl ester.
Examples of the glycidylamine-based polyfunctional epoxy resin include epoxy resins obtained by glycidylating amines such as aniline and toluidine.
Examples of the polyfunctional epoxy resin obtained by glycidylation of halogenated phenols include brominated bisphenol A, brominated bisphenol F, brominated bisphenol S, brominated phenol novolak, brominated cresol novolak, chlorinated bisphenol S, and chlorinated bisphenol. An epoxy resin obtained by glycidylating a phenolic hydroxyl group of a halogenated phenol such as A can be mentioned.

  Among these resins, the epoxy resin (B) is preferably a polyfunctional epoxy resin which is a glycidyl etherified product of a polyphenol compound from the viewpoint of liquid, curing at low temperature in a short time, heat resistance after curing, and moisture resistance. Specifically, for example, glycidyl etherified compounds of compounds such as bisphenol A, bisphenol F, resorcinol, and allylated bisphenol A are preferable.

  As the epoxy resin (B), the above polyfunctional epoxy resin may be used alone or in combination of two or more in view of curing conditions and viscosity depending on the application.

In the heat-curable epoxy resin composition of the present invention, the proportion of the epoxy resin (A) in the total epoxy resin of the composition is about 10 to 70% in order to prevent a decrease in adhesive strength under high temperature and high humidity. Preferably it is about 30-70%, More preferably, it is about 40-70%. When it contains exceeding 70%, the initial adhesive force may be reduced.
In the thermosetting epoxy resin composition of the present invention, the proportion of the epoxy resin (A) in the composition is about 3 to 67%.

  The imidazole compound (C) contained in the heat-curable epoxy resin composition of the present invention is used as a curing agent when the epoxy resin undergoes a crosslinking reaction. Examples of the imidazole compound (C) include imidazole, 2-methylimidazole (2MZ), 2-ethyl-4-methylimidazole (2E4MZ), 2-phenylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2 -Phenyl-4-methylimidazole, 1-benzyl-2-phenylimidazole (1B2PZ), 1-benzyl-2-methylimidazole (1B2MZ), 1-cyanoethyl-2-ethyl-4-methylimidazole (2E4MZ-CN), 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole, 2,3-dihydro-1H-pyrrolo- [1,2-a] benzimidazole, 2, 4-diamino-6- (2 ' -Methylimidazole (1 ')) ethyl-s-triazine, 2,4-diamino-6- (2'-undecylimidazole (1')) ethyl-s-triazine, 2,4-diamino-6- (2 '-Ethyl-4-methylimidazole (1')) ethyl-s-triazine, 2,4-diamino-6- (2'-methylimidazole (1 ')) ethyl-s-triazine isocyanuric acid adduct, 2 -2: 3 adduct of methylimidazole / isocyanuric acid, 2-phenylimidazole / isocyanuric acid adduct, 2-phenyl-3,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole or 1 -Cyanoethyl-2-phenyl-3,5-dicyanoethoxymethylimidazole and the like, and these imidazole compounds are used alone You may use it by mixing 2 or more types.

  Among the imidazole compounds, 2MZ, 2E4MZ, 2E4MZ-CN, and 1B2PZ are preferable, and a mixture of 2E4MZ and 1B2PZ, or a mixture of 2E4MZ-CN and 1B2PZ is preferable in terms of a balance between viscosity and reactivity.

  It is also possible to use a solid imidazole compound as a liquefied imidazole compound master batch by dissolving it in a liquid resin or the like. For example, a liquid resin to be dissolved means an alicyclic epoxy resin (for example, Celoxide 2080, Celoxide 3000, Celoxide 2021, etc. manufactured by Daicel Chemical Industries, Ltd.), a liquid acid anhydride (for example, 4-methylhexahydrophthalic anhydride, etc. ), Liquid amine compounds (for example, hexamethylene diamine), and high boiling point solvents (for example, propylene glycol monomethyl ether) of 130 ° C. or higher.

In the heat curable epoxy resin composition of the present invention, the amount of the imidazole compound added can be adjusted depending on the curing conditions for each application. For example, under the curing conditions at 100 ° C. for 30 minutes, the total epoxy resin 100 in the composition is 100%. The total amount of imidazole compound is 1 to 15 parts by weight, preferably 5 to 15 parts by weight based on parts by weight. If it is less than 1 part by weight, it takes a long time to cure at a low temperature, and the heat resistance tends to be lacking in practical use. On the other hand, if it exceeds 15 parts by weight, the usable time after mixing with the epoxy resin is shortened, and the workability tends to be lowered.
Furthermore, low-temperature short-time curing may be realized in combination with an additive that accelerates the ring-opening reaction of a normal epoxy resin within a range not impairing heat resistance. Examples of such additives include tertiary amines such as 2- (dimethylaminomethyl) phenol, 1,8-diazabicyclo [5,4,0] undecene-7 (DBU), and triphenylphosphine. Examples include phosphines.

  Moreover, if it is a grade which does not affect the characteristics of the thermosetting epoxy resin composition of the present invention, such as low temperature short time curing, heat resistance, and adhesion retention after high temperature and high humidity, curing other than imidazole compound (C). An agent may be used in combination. Examples of the curing agent include an acid anhydride curing agent, a carboxylic acid curing agent, an amine curing agent, and a hydrazide curing agent.

  Examples of the acid anhydride-based curing agent include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenone tetracarboxylic anhydride, ethylene glycol trimellitic anhydride, biphenyltetracarboxylic anhydride. Aromatic carboxylic anhydrides such as azelaic acid, sebacic acid, dodecanedioic acid, etc .; tetrahydrophthalic anhydride, hexahydrophthalic anhydride, nadic acid anhydride, het acid anhydride, Examples include alicyclic carboxylic acid anhydrides such as highmic acid anhydrides. Especially, a liquid acid anhydride is more preferable from the point which prevents the viscosity rise of a composition.

  Examples of the carboxylic acid-based curing agent include aliphatic polycarboxylic acids having 2 to 22 carbon atoms such as succinic acid, adipic acid, azelaic acid, and sebacic acid; phthalic acid, isophthalic acid, terephthalic acid, 1,2,4- Aromatic polycarboxylic acids such as benzenetricarboxylic acid, 1,2,4,5-benzenetetracarboxylic acid and naphthalenedi (or tetra) carboxylic acid; fats such as tetrahydrophthalic acid, hexahydrophthalic acid and methylhexahydrophthalic acid And cyclic polycarboxylic acid.

  Examples of the amine curing agent include aromatics such as diaminodiphenylmethane, diaminodiphenylsulfone, diaminodiphenyl ether, p-phenylenediamine, m-phenylenediamine, o-phenylenediamine, 1,5-diaminonaphthalene, and m-xylylenediamine. Amines; Aliphatic amines such as ethylenediamine, diethylenediamine, isophoronediamine, bis (4-amino-3-methyldicyclohexyl) methane, and polyetherdiamine; and guanidines such as dicyandiamide and 1- (o-tolyl) biguanide.

  Examples of hydrazide-based curing agents include carbodihydrazide, oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide, adipic acid dihydrazide, pimelic acid dihydrazide, suberic acid dihydrazide, azelaic acid dihydrazide diacid Hydrazide, hexadecandiohydrazide, terephthalic acid dihydrazide, isophthalic acid dihydrazide, 2,6-naphthoic acid dihydrazide, 4,4′-bisbenzenedihydrazide, 1,4-naphthoic acid dihydrazide, 2,6-pyridinedihydrazide, 1,4- Cyclohexane dihydrazide, tartaric acid dihydrazide, malic acid dihydrazide, iminodiacetic acid dihydrazide, N, N'-hexamethylenebissemicarbazide, itaconic acid dihydrazide Dihydrazide compounds of; pyromellitic acid trihydrazide, ethylenediaminetetraacetic acid tetrahydrazide, polyhydrazide compounds such as 1,2,4-benzenetricarboxylic hydrazide.

  When a curing agent other than the above-mentioned imidazole compound (C) is added, the amount added is a functional group involved in the curing of the curing agent with respect to the epoxy groups of all epoxy resins in the heat-curable epoxy resin composition of the present invention. The equivalent ratio is usually preferably in the range of 0.1 to 0.5. If it exceeds 0.5, properties such as low-temperature short-time curing and heat resistance may be impaired.

  The compound (D) having a phenolic hydroxyl group contained in the heat-curable epoxy resin composition of the present invention serves to shorten the curing reaction time, not as a curing agent that is usually used. For example, bisphenol A, bisphenol F, bisphenol S, 4,4′-biphenylphenol, tetramethyl bisphenol A, dimethyl bisphenol A, tetramethyl bisphenol F, dimethyl bisphenol F, tetramethyl bisphenol S, dimethyl bisphenol S, tetramethyl-4 , 4′-biphenol, dimethyl-4,4′-biphenol, 1- (4-hydroxyphenyl) -2- [4- (1,1-bis- (4-hydroxyphenyl) ethyl) phenyl] propane, 2, 2′-methylene-bis (4-methyl-6-tert-butylphenol), 4,4′-butylidene-bis (3-methyl-6-tert-butylphenol), trishydroxyphenylmethane, resorcinol, hydroquinone, pyrogallol, di Phenols having a sopropylidene skeleton; phenols having a fluorene skeleton such as 1,1-di-4-hydroxyphenylfluorene; phenolized polybutadiene, phenol, cresols, ethylphenols, butylphenols, octylphenols, bisphenol A, bisphenol Novolak resins made from various phenols such as F, bisphenol S, and naphthols; xylylene skeleton-containing phenol novolak resins; dicyclopentadiene skeleton-containing phenol novolac resins; biphenyl skeleton-containing phenol novolac resins; fluorene skeleton-containing phenol novolak resins; Containing phenol novolac resin: allylated low melting point or liquefied phenol compound such as diallyl bisphenol A I can get lost.

As the compound (D) having a phenolic hydroxyl group, the above compounds may be used alone or a plurality of compounds may be mixed and used.
When the compound (D) having a phenolic hydroxyl group is solid at room temperature, it may be dissolved in a liquid resin or the like and used as a master batch. For example, as a liquid resin, an alicyclic epoxy resin (for example, Celoxide 2080, Celoxide 3000, Celoxide 2021, etc. manufactured by Daicel Chemical Industries), a liquid acid anhydride (for example, 4-methylhexahydrophthalic anhydride, etc.) , Liquid imidazole compounds (for example, 2E4MZ, 2E4MZ-CN, etc.), and high boiling point solvents having a temperature of 130 ° C. or higher (for example, propylene glycol monomethyl ether).
The addition amount of the compound (D) having a phenolic hydroxyl group can be adjusted depending on the curing conditions in each application. For example, the total amount in the thermosetting epoxy resin composition of the present invention can be adjusted at 100 ° C. for 30 minutes. The amount of the compound (D) having a phenolic hydroxyl group is 5 to 40 parts by weight, preferably 10 to 30 parts by weight, and more preferably 10 to 20 parts by weight with respect to 100 parts by weight of the epoxy resin. If it is less than 5 parts by weight, the curing time at low temperature becomes long, and if it exceeds 40 parts by weight, the viscosity of the liquid epoxy resin composition is remarkably increased and the workability tends to be lowered.

  Among the compounds having a phenolic hydroxyl group, bisphenol A, bisphenol F, resorcin, catechol, or allylated, low-melting or liquid phenolic compounds (for example, diallyl), which are bifunctional and have a relatively low melting point, from the viewpoint of suppressing an increase in viscosity. Bisphenol A) and the like are preferred.

  Furthermore, the thermosetting epoxy resin composition of the present invention includes a coupling agent, a surfactant, a filler, an oxidation stabilizer, a light stabilizer, a moisture resistance improver, a thixotropy imparting agent, an antifoaming agent as necessary. Additives such as an agent, a tackifier, an antistatic agent, a lubricant, and an ultraviolet absorber can also be blended.

Examples of the coupling agent include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, N- (2-amino Ethyl) 3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, vinyltrimethoxysilane, N Silanes such as-(2- (vinylbenzylamino) ethyl) -3-aminopropyltrimethoxysilane hydrochloride, 3-methacryloxypropyltrimethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane Coupling agent; Isopropyl (N-ethylaminoethylamino) titanate, isopropyl triisostearoyl titanate, titanium di (dioctyl pyrophosphate) oxyacetate, tetraisopropyl di (dioctyl phosphite) titanate, neoalkoxy tri (p-N- (β-aminoethyl) ) Titanium coupling agents such as aminophenyl) titanate; zirconium acetylacetonate, zirconium methacrylate, zirconium propionate, neoalkoxyzirconate, neoalkoxytrisneodecanoylzirconate, neoalkoxytris (dodecanoyl) benzenesulfonylzirconate, neo Alkoxytris (ethylenediaminoethyl) zirconate, neoalkoxytris (m-aminophenyl) zirconate DOO, zirconium coupling agents such as ammonium zirconium carbonate; aluminum acetylacetonate, aluminum methacrylate, aluminum-based coupling agents such as aluminum propionate, and the like.
Of these, silane coupling agents are preferred, and silane coupling agents having an epoxy group are more preferred. When a coupling agent is used, the adhesiveness with the base material is improved, and a more excellent adhesive layer is obtained in terms of moisture resistance reliability.

  When a coupling agent is used, the amount used is about 0.1 to 5 parts, preferably about 0.5 to 5 parts, with respect to 100 parts of the total epoxy resin in the heat-curable epoxy resin composition of the present invention. .

Examples of the inorganic filler include fused crushed silica, crystal crushed silica, spherical silica, silicon carbide, silicon nitride, boron nitride, calcium carbonate, magnesium carbonate, barium sulfate, calcium sulfate, mica, talc, clay, aluminum oxide, Magnesium oxide, zirconium oxide, aluminum hydroxide, magnesium hydroxide, calcium silicate, aluminum silicate, lithium aluminum silicate, zirconium silicate, barium titanate, glass fiber, carbon fiber, molybdenum disulfide, etc., preferably fused crushed silica , Crushed silica, spherical silica, calcium carbonate, aluminum oxide, aluminum hydroxide, calcium silicate, and further considering crack resistance, fused crushed silica, crystal crushed silica, spherical silica, calcium carbonate, hydroxide Aluminum is particularly preferred.
These inorganic fillers may be used alone or in combination of two or more. When an inorganic filler is used, the amount used should be such that it does not affect the viscosity required for the thermosetting epoxy resin composition, and is 5% to 50% by weight of the composition, preferably 5%. % By weight to 30% by weight, more preferably 5% by weight to 20% by weight. If it exceeds 50% by weight, the viscosity of the composition of the present invention increases, which may cause problems on the work surface. In addition, it is also possible to use the filler which has been surface-treated with the above coupling agent.

  The particle size of the inorganic filler is not particularly limited, but in order that the heat curable epoxy resin composition of the present invention oozes out and does not generate bleed or the like, it is preferable to use a particle having a particle size of 500 microns or less. Good, preferably less than 100 microns.

When the thermosetting epoxy resin composition obtained from the above components is in liquid form, it may be used as it is or after diluting with a solvent. When the composition is solid, it should be diluted with a solvent. Is preferred. The solvent is not particularly limited as long as the composition is soluble, and examples thereof include ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone, and glycol solvents such as propylene glycol monomethyl ether.
Further, a surfactant may be used in order to improve the coating property to the substrate. As the surfactant, for example, a silicon-based surfactant, a fluorine-based surfactant, or the like is used, and when added, the addition amount is usually 0 with respect to 100 parts of the thermosetting epoxy resin composition of the present invention. About 0.001 to 0.5 part, preferably about 0.08 to 0.3 part.
When using the thermosetting epoxy resin composition of the present invention, the components to be contained may be blended in advance, and the pot life (the time that can be normally used after blending the curing agent) In consideration of the time until use, the epoxy resins and the curing agents may be separated, and both may be mixed and used immediately before use.

  The heat-curable epoxy resin composition of the present invention has excellent adhesion to various materials such as glass, metal, inorganic material, and plastic, and has excellent properties as an adhesive. In particular, adhesion in optical components (specifically, fixing of lenses, fixing of optical fibers and connectors, fixing of fibers to V-grooves, etc.) or display devices (specifically, flat panels such as liquid crystal panels and EL panels) When it is used for adhesion or the like in (Related), it is possible to maintain adhesion even under poor conditions such as high temperature and high humidity. In addition, when used for adhesion of film (specifically polyimide, polyamide, PET) and glass, film and metal, etc., it can be bonded in a short time of 130 ° C or less, and can be bonded even under poor conditions such as high temperature and high humidity. Hold power.

Articles having a cured adhesive layer obtained by applying or injecting and injecting the heat-curable epoxy resin composition of the present invention and heating, particularly optical fiber connectors, are also included in the present invention. For example, in the case of bonding of an optical fiber connector, which is an optical component, after injecting the thermosetting epoxy resin composition of the present invention into the center of the connector, the optical fiber is inserted and heat-treated at 100 ° C. for 30 minutes in a heating furnace. Thus, an optical component fixed by the adhesive layer can be obtained.
Further, the thermosetting epoxy resin composition of the present invention may be used by impregnating glass cloth, polyamide fiber, polyester fiber, paper, unemployed cloth or the like.

  Hereinafter, the present invention will be described in more detail with reference to examples. The present invention is not limited to these examples. Moreover, unless otherwise indicated in an Example, a part shows a weight part. The epoxy equivalent was measured by a method according to JIS K-7236.

Reference Example Preparation of Epoxy Resin A 94.4 parts of γ-glycidoxypropyltrimethoxysilane and 94.4 parts of methyl isobutyl ketone were charged in a reaction vessel and heated to 80 ° C. After the temperature increase, 21.6 parts of a 0.1 wt% aqueous potassium hydroxide solution was continuously added dropwise over 30 minutes. After completion of the dropping, the reaction was carried out at 80 ° C. for 5 hours while removing the produced methanol. After completion of the reaction, washing with water was repeated until the washing solution became neutral. Subsequently, the solvent was removed under reduced pressure to obtain 67 g of the epoxy resin (A) of the present invention. The epoxy equivalent of the obtained compound was 170 g / eq. From the ¹ H-NMR (CDCl ₃ solution) of the epoxy resin (A), the presence of an epoxy ring methine peak (near 3.2 ppm) and the disappearance of the methoxy group peak (near 3.6 ppm) were confirmed.

Example 1
The epoxy resin (A) obtained in the reference example, the epoxy resin (B2), and the phenol compound (D1) are weighed and mixed in advance at the blending ratio shown in Table 1, and heated in a 150 ° C. oven for 20 to 30 minutes. Thereafter, it is taken out and stirred while hot to dissolve the phenol compound (D1). It was allowed to cool to obtain an epoxy resin / phenol compound master batch (hereinafter referred to as epoxy MB).
The imidazole compound (C1) and the imidazole compound (C2) are weighed and mixed at the blending ratio shown in Table 1, dissolved by heating in a 100 ° C. oven for 10 to 20 minutes, taken out, allowed to cool after stirring. An imidazole compound master batch (hereinafter referred to as curing agent MB) was obtained.
The epoxy MB and the curing agent MB were blended at room temperature in the ratio shown in Table 1 and then stirred to obtain the heat curable epoxy resin composition of the present invention.
Examples 2 and 3
In the same manner as in Example 1, a thermosetting epoxy resin composition was produced from the epoxy MB having the composition shown in Table 1 and the curing agent MB.
Comparative Examples 1, 2, 3, 4
The same curing agent MB as in Example 1 was used. The other components and the curing agent MB were blended at room temperature in the composition shown in Table 1 and then stirred to obtain a comparative thermosetting epoxy resin composition.

Table 1
Example 1 Example 2 Example 3
Epoxy resin (A) 50 50 50
Epoxy resin (B)
B1-50
B2 50-50
Imidazole compound (C)
C1 5 5 5
C2 5 5 5
Phenol compound (D)
D1 10 10 −
D2 − − 12

Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4
Epoxy resin (A) 50 100 − −
Epoxy resin (B)
B1 50-100 100
B2 − − − −
Imidazole compound (C)
C1 5 5 5 5
C2 5 5 5 5
Phenol compound (D)
D1 − − − 10
D2 − − − −

Epoxy resin A: epoxy resin obtained by condensing γ-glycidoxypropyltrimethoxysilane in the presence of a basic catalyst (epoxy equivalent: about 170 g / eq)
Epoxy resin B1: bisphenol A type liquid epoxy resin (epoxy equivalent: about 185 g / eq, trade name Epicoat 828, manufactured by Nippon Epoxy Resin Co., Ltd.)
Epoxy resin B2: bisphenol F type liquid epoxy resin (epoxy equivalent: about 170 g / eq, trade name Epicoat 807, manufactured by Nippon Epoxy Resin Co., Ltd.)
Imidazole compound C1: 2E4MZ (2-ethyl-4-methylimidazole, liquid at room temperature, manufactured by Shikoku Kasei Co., Ltd.)
Imidazole compound C2: 1B2PZ (1-benzyl-2-phenylimidazole, semi-solid at room temperature, manufactured by Shikoku Kasei Co., Ltd.)
Phenol compound D1: bisphenol A (melting point 105 ° C., reagent product)
Phenol compound D2: Phloroglucinol (melting point: 217 ° C., reagent product)

The performance evaluation about the composition obtained by the said Example and the comparative example is shown below.
The reactivity was evaluated at 100 ° C. gel time, the heat resistance was evaluated by dynamic viscoelasticity measurement, and the adhesiveness was evaluated by a glass / glass chip adhesion test. The results are shown in Table 2. The evaluation method is as follows.

A predetermined amount (about 1 g) of this composition is placed on a hot plate set at 100 ° C. gel time and surface temperature 100 ° C., and a timer is started and stirred with a spatula. Gelation is promoted over time, changing from a liquid to a viscous liquid, and finally the thread is not pulled. The time until the yarn was not pulled was recorded as the gel time (gel time).
Dynamic viscoelasticity (hereinafter referred to as DMA)
-A predetermined amount of this composition is taken in an aluminum cup and cured in an oven at 100 ° C for 30 minutes. The cured product was cut into a thin plate having a thickness of about 0.5 mm, a width of about 5 mm, and a length of about 4 cm to obtain a DMA sample. Using a DMA device (TA Instruments, DMA 2980, measurement conditions: amplitude 15 μm, frequency 10 Hz, temperature rising rate 2 ° C./min), the tan δ peak value was DMA-Tg (glass transition point) to evaluate the heat resistance.
Glass / glass chip adhesion test-A small amount of this composition was applied on a glass substrate (5 cm x 5 cm x 1 mm). A glass chip (1.5 mm × 1.5 mm × 0.7 mm) is placed on the applied resin composition and pressure is applied thereto. The adhered glass substrate was placed on a tray, placed in a 100 ° C. oven, cured for 60 minutes, and allowed to cool to obtain an adhesive sample. An external force is applied from the lateral direction of the glass chip using a SS-30WD bond tester manufactured by Seishin Shoji Co., Ltd. (speed: 0.166 mm / s), and the shear bond strength (unit / kgf) is measured. (Adhesive strength test 1)
Furthermore, after applying the high temperature and high humidity conditions (processed at a temperature of 85 ° C. and a humidity of 85% for 53 hours) to the adhesive sample, the shear adhesive strength (unit / kgf) was measured in the same manner. (Adhesive strength test 2)

Table 2
Example 1 Example 2 Example 3
100 ° C
Gel time 5 minutes 4 minutes and a half 5 minutes DMA-Tg 157 ° C 167 ° C 171 ° C
Adhesive strength test 1 8.7 11.2 10.8
Adhesive strength test 2 5.3 6.3 8.2

Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4
100 ° C
Gel time 11 minutes> 15 minutes 6 minutes 4 minutes DMA-Tg
93 ° C ^{* 2)} - ^{* 1)} 154 ° C 141 ° C
173 ° C ^{* 2)}
Adhesive strength test 1 4.5 2.3 5.8 7.5
Adhesive strength test 2 3.7 1.8 2.8 2.4

^{* 1)} Due to insufficient curing, the sample is brittle and cannot be measured.
^{* 2)} Due to insufficient curing, ^two Tg points appeared at 93 ° C and 173 ° C.
The bond strength test 1 shows the bond strength value after predetermined curing.
Adhesive strength test 2 shows the adhesive strength after the test is performed at 85 ° C., 85% for 53 hours.

From the results of Table 2, only the epoxy resin (A) not containing the epoxy resin (B) (Comparative Example 2) has insufficient adhesive strength. When the epoxy resin (A) is not included (Comparative Example 3 and Comparative Example 4), the adhesive strength after high temperature and high humidity is low as shown in the adhesive strength test 2. When the epoxy resin (A) and the epoxy resin (B) are included but the phenol compound (D) is not included (Comparative Example 1), two points of Tg appear, heat resistance is insufficient, and adhesive strength is low.
On the other hand, the thermosetting epoxy resin composition of the present invention comprising the epoxy resin (A), the epoxy resin (B), the imidazole compound (C), and the phenolic compound (D) as a component is cured under conditions of low temperature and short time curing. In addition, the cured product has high heat resistance and sufficient initial adhesive strength shown in the adhesive strength test 1, and also has high adhesive strength after high temperature and high humidity as shown in the adhesive strength test 2. It was confirmed that the adhesive function was maintained.

Claims (6)

Following formula (1)
[Chemical 1]
R ¹ Si (OR ² ) ₃ (1)
[Wherein, R ¹ represents an alkyl group having an epoxy group, and R ² represents a (C1-C4) alkyl group. ]
An epoxy resin (A) obtained by condensing an epoxy group-containing alkoxysilicon compound represented by the following formula in the presence of a basic catalyst, an epoxy resin (B) having two or more epoxy groups other than the epoxy resin (A), A thermosetting epoxy resin composition containing an imidazole compound (C) and a compound (D) having a phenolic hydroxyl group. The heat-curable epoxy resin composition according to claim 1, wherein the alkyl group having an epoxy group of R ¹ is a glycidoxy (C1-C3) alkyl group. The epoxy resin (B) having two or more epoxy groups other than the epoxy resin (A) is a polyfunctional epoxy resin that is a glycidyl etherified product of a polyphenol compound, and the compound (D) having a phenolic hydroxyl group is bisphenol A, The thermosetting epoxy resin composition according to claim 1 or 2, which is bisphenol F, resorcin, catechol, or diallyl bisphenol A. The heat-curable epoxy resin composition according to any one of claims 1 to 3, wherein the heat-curable epoxy resin composition is a heat-curable epoxy resin composition for an adhesive. An article having an adhesive layer obtained by heat-curing after applying or pouring the heat-curable epoxy resin composition according to any one of claims 1 to 4. The article according to claim 5, wherein the article is an optical fiber connector.