JPS6231734B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to epoxy resin compositions. Epoxy resins are widely used in electrical insulation materials, adhesives, molding materials, etc. because they provide cured products with excellent mechanical, electrical, and chemical properties when cured with acid anhydrides or amines. However, when an acid anhydride curing agent is added, the epoxy resin composition is relatively stable at room temperature;
On the other hand, it has the disadvantage that it requires heating at a fairly high temperature for a long time during curing. Therefore, tertiary amine, quaternary amine
Curing time has been shortened by using a curing accelerator such as an ammonium compound or an organic metal complex salt. However, the addition of these curing accelerators improves curability but has the disadvantage that storage stability is significantly impaired. Therefore, there is a strong demand for a curing agent having so-called latent properties, which exhibits excellent storage stability as the composition hardly reacts at around room temperature, and which reacts rapidly even at relatively low temperatures when heated. By the way, several kinds of boron complex compound-based curing agents have been commercially available as latent curing agents, but they have the disadvantage of having a negative effect on the properties of cured products due to their high hygroscopicity. It was also insufficient in some respects. The present invention was made in view of the above points, and its purpose is to rapidly accelerate the curing reaction only when heated without accelerating curing near room temperature, and to improve various properties, especially good adhesive strength. An object of the present invention is to provide an epoxy resin composition. That is, the present invention provides an epoxy resin composition containing an epoxy resin and a curing agent as essential components, in which the curing agent is contained in an amount of 0.5 to 100 parts by weight based on 100 parts by weight of the epoxy resin.
0.05 to 10 parts by weight of azine derivatives of imidazoles and 1 equivalent of epoxy group of epoxy resin
The present invention relates to an epoxy resin composition that essentially contains two components, 0.2 equivalents of phthalic anhydride and/or tetrahydrophthalic anhydride, and does not contain an amine curing agent. The epoxy resins used in the present invention include bisphenol type epoxy resins, resorcin type epoxy resins, novolac type epoxy resins, halogenated epoxy resins thereof, hydantoin type, epoxy resins having a heterocycle such as a triazine ring, and an isocyanurate ring. can be mentioned. Moreover, as these epoxy resins, those having an epoxy equivalent of 400 to 1000 and a molecular weight of about 800 to 2500 are generally used. The azine derivative of imidazole used in the present invention is generally represented by the following formula. In the above general formula, _R1 to _R5 are hydrogen atoms, alkyl groups, alkenyl groups, acyl groups, allyl groups, aryl groups, cycloalkyl groups, cycloalkenyl groups,
These include aldehyde groups, amino groups, cyano groups, etc., and they may be the same or different. More specifically, imidazoles, such as imidazole, 2-methylimidazole, 2-undecylimidazole, 2-heptadecyl imidazole, 2-phenylimidazole, 2-ethyl-4
-Methylimidazole, 1-benzyl-2-methylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-ethyl-
4-methylimidazole, 1-cyanoethyl-2
-Undecylimidazole, 1-cyanoethyl-
Examples include derivatives represented by the above general formula [1] derived from 2-phenylimidazole and the like. The amount of the azine derivative of imidazoles added is 0.5 as described above per 100 parts by weight of the epoxy resin.
~10 parts by weight, which provides good curing of the epoxy resin by catalytic curing reaction of the derivative. That is, if the amount added is less than 0.5 parts by weight, the curability based on the above-mentioned curing system will be insufficient, and if it is more than 10 parts by weight, problems such as poor storage stability will occur. The amount of phthalic anhydride and/or tetrahydrophthalic anhydride used in the present invention ranges from 0.05 to 1 equivalent of epoxy group in the epoxy resin.
The reason why the amount is limited to 0.2 equivalent is that if the amount is less than 0.05 equivalent, there is hardly any effect of improving storage stability, whereas if it is more than 0.2 equivalent, it has the disadvantage that it takes a long time to completely cure. The composition of the present invention can be produced by uniformly heating and mixing the above three components and cooling the mixture. When heating and mixing the three components, inorganic fillers, pigments, deterioration inhibitors, etc. may be added as necessary. As mentioned above, the curing agent component in the composition of the present invention essentially includes two components: an azine derivative of imidazoles and phthalic anhydride and/or tetrahydrophthalic anhydride, and an amine curing agent, e.g. It does not contain various aliphatic or aromatic amines such as polymethylene diamine, menthanediamine, tetrachloro-p-xylene diamine, m-phenylene diamine, or dicyandiamide. These amine curing agents perform an amine curing reaction that is inferior in curability to the catalytic curing reaction using the azine derivatives of imidazoles, so when such amine curing agents are used in combination with the above two components, the curability decreases. It is unsuitable because it lowers the temperature and makes it impossible to cure at low temperature and in a short time. The composition of the present invention described above has excellent storage stability at room temperature and cures in a relatively short time. The present invention will be specifically explained below using examples. Note that parts in the examples are parts by weight. Example 1 Epoxy resin (Epicoat 1002 manufactured by Ciel)
100 parts, 2.0 parts of an azine derivative of imidazoles (Kyuazol 2MZ-AZINE manufactured by Shikoku Kasei Co., Ltd.), and 3.0 parts of phthalic anhydride were kneaded for 5 minutes with a heated roll at 70°C, then cooled to obtain a lump, which was crushed. Then, 30 mesh passes of epoxy resin composition powder was obtained. Its properties are shown in Table 1 below. Example 2 100 parts of Epicote 1002 (mentioned above), Cyuazol
5 parts of 2MZ-AZINE (mentioned above) and 10 parts of tetrahydrophthalic anhydride were treated in the same manner as in Example 1.
A 30 mesh pass of epoxy resin composition powder was obtained. Its properties are shown in Table 1 below. Comparative Example 100 parts of Epicote #1002 (described above) and 2 parts of Kyuazol 2MZ-AZINE were treated in the same manner as in Example 1 to obtain 200 mesh passes of epoxy resin composition powder. Its properties are listed in Table 1 below. The shelf life of each composition powder is 10 mm in diameter.
mm, weight 300 mg, and this is 45
The material was placed on a slanted plate and cured in an atmosphere of 120°C, the distance it traveled until it cured was measured, and the number of storage days until the value (distance) reached 50% of the initial value was determined. be. In addition, the adhesive strength is shown by the shear adhesive strength of the test piece obtained by bonding clean aluminum plates together using the obtained composition powder (120°C, 30 minutes, 1 Kg/cm ² conditions). There is. 【table】

Claims (1)

[Claims] 1. In an epoxy resin composition containing an epoxy resin and a curing agent as essential components, the curing agent is
Two components: 0.5 to 10 parts by weight of an azine derivative of imidazole based on 100 parts by weight of epoxy resin, and 0.05 to 0.2 equivalents of phthalic anhydride and/or tetrahydrophthalic anhydride based on 1 equivalent of epoxy group in the epoxy resin. An epoxy resin composition characterized in that it essentially contains the following and does not contain an amine-based curing agent.