JP2732432B2 - Method for producing heat-resistant resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a low-viscosity, one-pack type heat-resistant resin composition having excellent heat resistance and storage stability for use in impregnating materials and the like. The present invention relates to a method for manufacturing a product.

(Prior Art) Conventionally, as a heat-resistant impregnating material of the H class regarding electric equipment insulation, a bismaleimide compound containing a bismaleimide compound synthesized from a diamine such as diaminodiphenylmethane and maleic anhydride-epoxy compound- An acid anhydride-curing accelerator-based resin composition is often used.

(Problems to be Solved by the Invention) However, the viscosity of this impregnated material increases even during storage at room temperature when all components are blended. Therefore, a bismaleimide compound-epoxy compound and an acid anhydride-curing accelerator are usually used. And a two-pack impregnating material. Therefore, when impregnating,
A step of mixing the two liquids each time is required, which is very troublesome. Further, the impregnated material mixed with the two components has a disadvantage that the bismaleimide compound crystallizes during storage and precipitates and separates. Furthermore, since this impregnated material has a relatively high viscosity at room temperature, it must be used by impregnating it by heating it to reduce its viscosity, and since the heating is repeated every time the impregnation work is performed, it gradually increases. There was a disadvantage that it could not be used due to stickiness. Thus, the conventional impregnating material is
Due to poor storage stability, it becomes a two-pack type, and there are drawbacks such as a short pot life and a large loss of material economically due to thickening after mixing of the two packs.

The present invention has been made in view of the above circumstances, and is a one-pack type, which has excellent heat resistance, excellent storage stability, low viscosity and long pot life, and can reduce the total cost of the impregnation material and the impregnation process. It is intended to provide a method for producing a heat-resistant resin composition of the present invention.

[Constitution of the Invention] (Means for Solving the Problems) As a result of intensive studies to achieve the above object, the present inventor has heat resistance of H class or higher and excellent storage stability. It has been found that a one-pack type heat-resistant resin composition having a low viscosity and which can be easily impregnated can be obtained, and the present invention has been completed. That is, the present invention relates to (A) a bismaleimide compound and (B) an epoxy resin that is liquid at room temperature by heating and reacting at a temperature of 130 to 190 ° C.
After cooling to (C), a liquid acid anhydride is blended at room temperature,
A method for producing a heat-resistant resin composition, comprising adding and blending one or more selected from (D) peroxide and (E) latent curing accelerator at a temperature of 70 ° C. or lower. .

 Hereinafter, the present invention will be described in detail.

As the bismaleimide compound (A) used in the present invention, a compound represented by the following general formula is used.

(Where R ¹ is a hydrogen atom or an alkyl group, R ² is an aliphatic divalent or And the like. As specific compounds, for example, N, N'-ethylenebismaleimide, N, N'-hexamethylenebismaleimide, N, N'-m-phenylenebismaleimide, N, N'-4,
4'-diphenylmethane bismaleimide, N, N'-4,4 '
-Diphenyl ether bismaleimide, N, N'-methylenebis (3-chloro-p-phenylene) bismaleimide, N, N'-4,4'-dicyclohexylmethanebismaleimide and the like, alone or in combination of two or more To use. N, N'-methylenebis (N-phenyl)
A monomaleimide such as a monomaleimide can be used in combination.

The epoxy resin (B) which is liquid at ordinary temperature used in the present invention is selected from bisphenol F-type and cycloaliphatic epoxy resins obtained by reacting bisphenol F with epichlorohydrin for the purpose of lowering the viscosity of the resin composition. And a liquid is selected. Specific examples of the bisphenol F type include XJ4100, PY306 (trade name, manufactured by Ciba-Geigy), Epicron S129, and Epicron 830 (trade name, manufactured by Dainippon Ink Co., Ltd.). Examples include Celloxide 2021 (manufactured by Daicel, trade name),
ERL4221 (manufactured by Union Carbide, trade name) and the like. These epoxy resins can be used alone or in combination of two or more.

The compounding ratio of (A) the bismaleimide compound and (B) the epoxy resin liquid at room temperature is the total amount of these ([A) +
(B)], the bismaleimide compound is desirably blended in an amount of 10 to 60% by weight. This amount
If it is less than 10% by weight, the heat resistance is not effective.

Specific examples of the (C) acid anhydride which is liquid at room temperature used in the present invention include monomethylhexahydrophthalic anhydride, monomethyltetrahydrophthalic anhydride, dodecynyl succinic anhydride, and the like. Mix and use. The compounding ratio of the acid anhydride is determined by the equivalent of the compounding amount of the epoxy resin described above. The equivalent ratio of acid anhydride / epoxy resin is desirably 0.7 to 1.1. If the equivalent ratio is less than 0.7, a hard and brittle cured product is likely to be formed, and if the equivalent ratio exceeds 1.1, heat loss is increased and heat resistance is lowered, which is not preferable.

The peroxide (D) used in the present invention serves as a polymerization catalyst for the bismaleimide compound and has a decomposition temperature of 100 ° C. or higher for the purpose of increasing storage stability and pot life during impregnation. Is valid. Specific compounds include dicumyl peroxide, α, α'-bis (t-butylperoxyisopropyl) benzene, p-menthane hydroperoxide and the like. These are used alone or together with (E) a latent curing accelerator described later.
The mixing ratio of the peroxide is (A) + the total amount of the bismaleimide compound and (B) the epoxy resin liquid at normal temperature [(A) +
(B)], it is desirable to add 0.01 to 1.0% by weight. If the compounding amount is less than 0.01% by weight, the curing time of the resin composition is prolonged, and if it exceeds 1.0% by weight, the heat generation temperature during curing is high, the curing shrinkage is large, and cracks in the cured product are likely to occur. Not preferred.

The (E) latent curing accelerator used in the present invention is a curing accelerator for an epoxy resin and an acid anhydride, which improves the properties and storage stability of the cured product and prolongs the pot life during impregnation. Activated above 70 ° C. For example, amine compounds are microencapsulated with a particle size of 10 μm or less, and specifically commercially available HX-3741, HX-3742, HX
And HX-3727 (trade name, manufactured by Asahi Kasei Kogyo Co., Ltd.), and these are used alone or in combination with the above-mentioned peroxide (D). The compounding ratio of the latent curing accelerator is 0.01 to 10.0% by weight based on the total amount of the (A) bismaleimide compound and (B) the epoxy resin liquid at room temperature [(A) + (B)]. It is desirable. If the compounding amount is less than 0.01% by weight, the curing time of the resin composition is prolonged, and if it exceeds 10.0% by weight, the heat generation temperature during curing is high, so that the curing shrinkage becomes large and the cured product is liable to crack. Not preferred. The above (D) peroxide and (E) latent curing accelerator can be used alone or in combination of two or more.

The method for producing a heat-resistant resin composition of the present invention comprises: first, a bismaleimide compound and an epoxy resin that is
The solution is heated and reacted at a temperature of 190190 ° C. to form a homogeneous solution, which is cooled to 100 ° C. Then, add a liquid acid anhydride at room temperature and cool down. When the temperature reaches 70 ° C. or lower, add a peroxide and / or a latent curing accelerator and mix well to obtain a brown heat-resistant resin composition. . The composition thus produced is used as an impregnating material for class H of electrical equipment insulation.

(Function) The above object has been achieved by the method for producing a heat-resistant resin composition of the present invention. That is, the bismaleimide compound and the epoxy resin which is liquid at room temperature are heated and reacted at 130 to 190 ° C., whereby the bismaleimide compound is homopolymerized, the solubility with the epoxy resin is improved, and the bismaleimide compound is uniformly dissolved. Therefore, it has the heat resistance of the H class, prevents the bismaleimide compound from crystallizing out, and can improve the storage stability. The viscosity is reduced by using epoxy resin which is liquid at room temperature and acid anhydride which is liquid at room temperature.
By using the above peroxide and a latent curing accelerator that activates at 70 ° C or higher, storage stability and pot life are lengthened, and the one-pack type impregnation process is shortened and workability is improved. Things.

(Examples) Next, the present invention will be described with reference to examples, but the present invention is not limited to these examples. In the following Examples and Comparative Examples, “parts” means “parts by weight”.

Example 1 15 parts of N, N'-4,4'-diphenylmethanebismaleimide and 85 parts of a bisphenol F type epoxy resin were added to a container, and heated and mixed at 170 ° C for 2 hours to obtain a uniform resin liquid. 100
After cooling to ℃, monomethyltetrahydrophthalic anhydride
Add 75 parts and cool to below 60 ° C. Thereafter, 0.5 parts of a latent curing accelerator HX-3742 (trade name, manufactured by Asahi Kasei Kogyo Co., Ltd.) was added and uniformly mixed to produce a brown heat-resistant resin composition. The composition was tested for viscosity at 40 ° C, gel time at 150 ° C, and storage stability at 40 ° C. Using this composition, a casting plate having a thickness of 1 mm was prepared by heating and curing at 180 ° C. for 10 hours, and its volume resistivity and loss on heating were tested. The results are shown in Table 1. In each case, the composition of the present invention was excellent, and the effect of the present invention could be confirmed.

Examples 2 to 4 Heat-resistant resin compositions were produced in the same manner as in Example 1 using the compositions shown in Table 1. In addition, these compositions were tested in the same manner as in Example 1, and the results are shown in Table 1. In each case, the composition of the present invention was excellent, and the effect of the present invention could be confirmed.

Comparative Example A heat-resistant resin composition was produced according to the composition shown in Table 1 in the same manner as in Example 1. The composition was tested in the same manner as in Example 1, and the results are shown in Table 1.

[Effects of the Invention] As is clear from the above description and Table 1, according to the method for producing a heat-resistant resin composition of the present invention, heat resistance and storage stability are excellent, and low viscosity and impregnation workability are also obtained. It is possible to obtain a one-pack type heat-resistant resin composition having a long working life. By using this composition, it is possible to sufficiently cope with the miniaturization of the electrical equipment of class H and to manufacture electrical equipment that contributes to a reduction in the total cost.

Claims (1)

(57) [Claims] 1. A bismaleimide compound (A) and an epoxy resin (B) which are liquid at room temperature are heated and reacted at a temperature of 130 to 190 ° C. and cooled to 100 ° C., and then (C) an acid anhydride which is liquid at room temperature A heat-resistant resin composition characterized by adding one or more selected from (D) peroxide and (E) latent curing accelerator at a temperature of 70 ° C. or less. Manufacturing method.