JPH0912683A - Epoxy resin composition and curing agent therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an epoxy resin compsn. excellent in adhesion. SOLUTION: This epoxy resin compsn. contains an imidazolylsilane of the general formula I, II or III, or a mixture thereof as a curing agent. In the formulae, R<1> is hydrogen, a vinyl group, or a 1-5C alkyl group; R<2> is hydrogen or a 1-20C alkyl group; R<3> and R<4> are each a 1-3C alkyl group; and (n) is 1 to 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an epoxy resin material containing a novel curing agent excellent in curability and adhesiveness, and a curing agent therefor.

[0002]

2. Description of the Related Art Epoxy resins having excellent mechanical properties, heat resistance, chemical resistance and adhesiveness have been used for adhesives, encapsulating materials, paints, laminated materials, molding materials and the like. In various fields in recent years, there has been an increasing demand for improved properties of epoxy resin cured products, and in particular, epoxy resin cured products with higher adhesive strength are required. Therefore, the following proposals have been made for the purpose of increasing the adhesive strength of the cured epoxy resin product. That is, there is a method of adding a silane coupling agent disclosed in JP-A-57-185371 and JP-A-60-18562. In other words, a coupling agent having a part having reactivity with an inorganic substance and a part having reactivity with an organic substance in one molecule is caused to act as an adhesion aid for the interface.

[0003]

However, although the conventionally known coupling agent improves the adhesive performance, its effect is not sufficient.

An object of the present invention is to provide a curing agent for a curable epoxy resin composition having excellent adhesiveness, and
It is intended to provide a curable epoxy resin composition containing the same.

[0005]

As a result of intensive studies, the present inventor has found that an imidazolesilane compound having a specific chemical structure is suitable as a curing agent for an epoxy resin, and has completed the present invention.

That is, the present invention provides (1) a curing agent represented by the following general formula (1), (2) or (3)
An epoxy resin composition characterized by containing an imidazole silane or a mixture thereof,

[0007]

Embedded image

(However, R ¹ is hydrogen, a vinyl group or an alkyl group having 1 to 5 carbon atoms, and R ² is hydrogen or 1 carbon atom.
To 20 alkyl groups, R ³ and R ⁴ are alkyl groups having 1 to 3 carbon atoms, and n is 1 to 3) (2) Imidazolesilane represented by the above formula (1), (2) or (3) or The present invention relates to a curing agent for epoxy resin, which is composed of the mixture.

R ^{1 to} R ⁴ in the above formulas (1) to (3) have the meanings as defined above, but R is particularly easy to synthesize.
¹ is preferably hydrogen, methyl, ethyl, undecyl or heptadecyl, R ² is preferably hydrogen, methyl or vinyl,
Further, R ³ and R ⁴ are preferably methyl and ethyl.

Regarding these synthesizing methods, JP-A-5-18
No. 6479. Even when it is obtained by this synthetic method as a mixture of imidazolesilanes represented by the above formulas (1) to (3), it is advantageous to use it in the form of a mixture without any need for separation. The epoxy resin is not particularly limited, and a curable epoxy compound or epoxy polycondensate having more than one epoxy group in one molecule can be used.

Examples of such epoxy resins include diglycidyl ethers of bisphenols such as bisphenol A and bisphenol F (bisphenol type epoxy resins), diglycidyl ethers of polyalkylene oxides such as polyethylene oxide and polypropylene oxide (aliphatic compounds). Epoxy resin) or side chain or main chain modified with flexible resin such as rubber, urethane, polyether, polyester, phenol novolac,
Examples thereof include glycidyl ether compounds (novolac type epoxy resins) such as cresol novolac, and epoxidized compounds of conjugated diene polymers such as polybutadiene.

In the epoxy resin composition of the present invention, it is important to use the above-mentioned specific imidazole silane as a curing agent, but other curing agents and curing accelerators known as curing agents for epoxy resins are also used. Can be used together.

Examples of such curing agents or curing accelerators include guanidine curing agents such as dicyandiamide as curing agents for epoxy resins, dihydrazide curing agents such as adipic acid dihydrazide, isophthalic acid dihydrazide and dodecanoic acid dihydrazide. It is possible to use a phenolic hardener such as phenol novolac, an acid anhydride hardener such as methyltetrahydrophthalic anhydride, an amine hardener such as diaminodiphenylmethane, or an imidazole hardener such as 2-ethyl-4-methylimidazole. it can. Further, as a curing accelerator, imidazoles such as 2-ethyl-4-methylimidazole, tertiary amines such as benzyldimethylamine, aromatic phosphines such as triphenylphosphine, and Lewis acids such as boron trifluoride monoethylamine. Is mentioned.

The amount of the above-mentioned curing agent of the present invention and other curing agents used is not particularly limited, but the epoxy resin 100 is used.
Usually 1 to 25 parts by weight, preferably 4 to 1 part by weight.
0 parts by weight, and similarly for the curing accelerator, 0.
It is used in an amount of 1 to 5 parts by weight, preferably 0.1 to 2.0 parts by weight.

If the amount of the curing agent is less than 1 part by weight, the curability is lowered, and if it exceeds 25 parts by weight, the brittleness of the cured product itself is increased and neither is sufficient adhesive strength, which is not preferable. On the other hand, if the curing accelerator is less than 0.1 parts by weight, sufficient adhesive strength cannot be obtained, and if it exceeds 5 parts by weight, the shear strength is lowered.

If desired, a silane coupling agent can be added to the epoxy resin composition of the present invention as an adhesion improver. By adding a silane coupling agent, the adhesive strength to a metal can be particularly improved. Examples of such silane coupling agents include γ-glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, and N-β. (Aminoethyl) γ-aminopropylmethyldimethoxysilane, γ-chloropropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, N-β- (N-vinylbenzylaminoethyl)
Examples include -γ-aminopropyltrimethoxysilane and hydrochloride.

The epoxy resin composition of the present invention contains the above-mentioned epoxy resin and curing agent as essential components, and optionally other curing agent, curing accelerator and silane coupling agent,
Further, if necessary, other epoxy resin, a reactive diluent composed of a monoepoxy compound, a flame retardant, a coloring agent, a stress reducing agent, a filler and the like can be added.

When used together with other curing agents, curing accelerators, adhesion promoters, etc., the curing agent of the present invention acts as a curing agent, and also as a curing accelerator and adhesion promoter. Is also playing at the same time.

The epoxy resin composition of the present invention can be similarly used in the fields where general curable epoxy resins can be used, but it is suitable for adhesives, especially for metal.

[0020]

The present invention will be specifically described below with reference to examples, but the present invention is not limited to the examples. The "parts" and "%" in the examples mean "parts by weight" and "% by weight".

Examples 1 and 2 and Comparative Examples 1 to 8 After sufficiently kneading the components shown in Table 1, a stainless plate (SUS304) was laminated using the composition obtained, 100 ° C. × 1 hour, 150 Cured under conditions of ℃ × 1 hour,
The tensile shear strength was evaluated. The measurement conditions are JIS
According to K 6850. Table 1 shows the obtained results.

[0022]

[Table 1]

* 1 Bisphenol A type epoxy resin (Product name: Epicoat 828; manufactured by Yuka Shell Co., Ltd., epoxy equivalent: 190) * 2 R ¹ = R ² = H in the general formulas (1) to (3); R ³ = CH ₃ ;
Imidazolesilane with n = 3 (mixed composition ratio of each formula)
(1): (2): (3) = 45:22:33 mixture) * 3 R ¹ = C ₂ H _{5 in the} general formulas (1) to (3); R ² = CH ₃ ;
R ₃ ═CH ₃ ; imidazole silane where n = 3 (mixture composition ratio (1) :( 2) :( 3) = 5: 2: 3 mixture of each formula) * 4 N-β (aminoethyl) γ -Aminopropyltrimethoxysilane (KBM608; Shin-Etsu Chemical Co., Ltd.)
* 5 γ-glycidoxypropyltrimethoxysilane (KBM403; manufactured by Shin-Etsu Chemical Co., Ltd.) * 6 Dicyandiamide (product name: AH-154; manufactured by Ajinomoto Co., Inc.) * 7 2-Ethyl-4-methylimidazole (Product name: 2
E4MZ; manufactured by Shikoku Chemicals Co., Ltd. Table 1 shows that the epoxy resin composition containing the curing agent of the present invention improves the adhesive strength without lowering the glass transition point of the cured product.

Examples 3 and 4 and Comparative Examples 4 to 6 After thoroughly kneading the components shown in Table 2, copper alloy (Zn about 30%, Cu balance) plates were laminated using the composition obtained. It was cured under the conditions of 100 ° C. × 1 hour and 150 ° C. × 1 hour, and the tensile shear strength was evaluated. The measurement conditions were in accordance with JIS K 6850. Table 2 shows the obtained results.
Shown in

[0025]

[Table 2]

* 1 Bisphenol A type epoxy resin (Product name: Epicoat 828; manufactured by Yuka Shell Co., Ltd., epoxy equivalent: 190) * 2 R ¹ = R ² = H in the general formulas (1) to (3); R ³ = CH ₃ ;
Imidazolesilane with n = 3 (mixed composition ratio of each formula)
(1): (2): (3) = 45:22:33 mixture) * 3 R ¹ = C ₂ H _{5 in the} general formulas (1) to (3); R ² = CH ₃ ;
R ₃ ═CH ₃ ; imidazole silane where n = 3 (mixture composition ratio (1) :( 2) :( 3) = 5: 2: 3 mixture of each formula) * 4 N-β (aminoethyl) γ -Aminopropyltrimethoxysilane (KBM603; Shin-Etsu Chemical Co., Ltd.)
* 5 γ-glycidoxypropyltrimethoxysilane (KBM403; manufactured by Shin-Etsu Chemical Co., Ltd.) * 6 Dicyandiamide (product name: AH-154; manufactured by Ajinomoto Co., Inc.) * 7 2-Ethyl-4-methylimidazole (Product name: 2
E4MZ; manufactured by Shikoku Kasei Co., Ltd. Examples 5 and 6 and Comparative Examples 7 to 9 After sufficiently kneading the components shown in Table 3, an aluminum alloy (Cu3.8) was prepared using the composition obtained. ~ 4.9%,
0.8 to 0.9% of Mn, 1.2 to 1.8% of Mg, and the balance of Al) Plates were laminated and cured under the conditions of 100 ° C. × 1 hour and 150 ° C. × 1 hour to evaluate the tensile shear strength. The measurement conditions were in accordance with JIS K 6850. Table 3 shows the obtained results.

[0027]

[Table 3]

* 1 Bisphenol A type epoxy resin (Product name: Epicoat 828; manufactured by Yuka Shell Co., Ltd., epoxy equivalent: 190) * 2 R ¹ = R ² = H in the general formulas (1) to (3); R ³ = CH ₃ ;
Imidazolesilane with n = 3 (mixed composition ratio of each formula)
(1): (2): (3) = 45:22:33 mixture) * 3 R ¹ = C ₂ H _{5 in the} general formulas (1) to (3); R ² = CH ₃ ;
R ₃ ═CH ₃ ; imidazole silane where n = 3 (mixture composition ratio (1) :( 2) :( 3) = 5: 2: 3 mixture of each formula) * 4 N-β (aminoethyl) γ -Aminopropyltrimethoxysilane (KBM608; Shin-Etsu Chemical Co., Ltd.)
* 5 γ-glycidoxypropyltrimethoxysilane (KBM403; manufactured by Shin-Etsu Chemical Co., Ltd.) * 6 Dicyandiamide (product name: AH-154; manufactured by Ajinomoto Co., Inc.) * 7 2-Ethyl-4-methylimidazole (Product name: 2
E4MZ; manufactured by Shikoku Kasei Co., Ltd. Examples 7-9, Comparative Examples 10-12 After thoroughly kneading the components shown in Table 4, a stainless plate (SUS304) was laminated using the composition obtained. The evaluation was performed in the same manner as in Example 1. The results are shown in Table 4.

[0029]

[Table 4]

* 1 Bisphenol A type epoxy resin (Product name: Epicoat 828; manufactured by Yuka Shell Co., Ltd., epoxy equivalent: 190) * 2 R ¹ = R ² = H in the general formulas (1) to (3); R ³ = CH ₃ ;
Imidazolesilane with n = 3 (mixed composition ratio of each formula)
(1): (2): (3) = 45:22:33 mixture) * 3 Dicyandiamide (Product name: AH-154; Ajinomoto Co., Inc.) * 4 Methyltetrahydrophthalic anhydride (Product name: AH-
2; Sumitomo Chemical Co., Ltd.) * 5 2-Ethyl-4-methylimidazole (Product name: 2
E4MZ; manufactured by Shikoku Chemicals Co., Ltd.)

[0031]

INDUSTRIAL APPLICABILITY As described above, in the epoxy resin composition of the present invention, the imidazole silane effectively functions without lowering the glass transition point of the cured product thereof, and exhibits high adhesive strength on various base materials. Therefore, it is useful as an adhesive, a sealing material, a coating material, a laminated material, a molding material, etc., which requires adhesiveness.

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[Procedure amendment]

[Submission date] January 26, 1996

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

Embedded image (However, R ¹ is hydrogen, a vinyl group or an alkyl group having 1 to 5 carbon atoms, R ² is hydrogen or an alkyl group having 1 to 20 carbon atoms, and R ³ and R ⁴ are alkyl groups having 1 to 3 carbon atoms. Group, n is 1-3)

Embedded image (However, R ¹ is hydrogen, a vinyl group or an alkyl group having 1 to 5 carbon atoms, R ² is hydrogen or an alkyl group having 1 to 20 carbon atoms, and R ³ and R ⁴ are alkyl groups having 1 to 3 carbon atoms. Group, n is 1-3)

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction contents]

[0007]

Embedded image

Claims (4)

[Claims] 1. An epoxy resin composition comprising an imidazole silane represented by the following general formula (1), (2) or (3) or a mixture thereof as a curing agent. Embedded image (However, R ¹ is hydrogen, a vinyl group or an alkyl group having 1 to 5 carbon atoms, R ² is hydrogen or an alkyl group having 1 to 20 carbon atoms, and R ³ and R ⁴ are alkyl groups having 1 to 3 carbon atoms. Group, n is 1-3) 2. The epoxy resin composition according to claim 1, which further contains another curing agent. 3. The epoxy resin composition according to claim 1, further comprising a curing accelerator. 4. A curing agent for an epoxy resin comprising an imidazole silane represented by the following general formula (1), (2) or (3) or a mixture thereof. Embedded image (However, R ¹ is hydrogen, a vinyl group or an alkyl group having 1 to 5 carbon atoms, R ² is hydrogen or an alkyl group having 1 to 20 carbon atoms, and R ³ and R ⁴ are alkyl groups having 1 to 3 carbon atoms. Group, n is 1-3)