JPS5936651B2 - thermosetting resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a combination comprising an ester resin useful as a resin for casting or impregnation, a specific epoxidized poly-12-ptahone resin, a monomer having radical polymerizability, and an acid anhydride curing agent for epoxy resin. It relates to commercial products.

Conventionally, thermosetting resin compositions made of epoxy resins, unsaturated polyester resins, phenolic resins, silicone resins, etc. have been used as coating materials for electrical equipment and insulation.

Among them, epoxy resin compositions have excellent properties such as electrical properties and mechanical properties, and the range of their applications is rapidly expanding. However, when this epoxy resin composition is used, for example, as an electrical insulating material, it has the disadvantage that the cured product deteriorates due to mechanical dressing, distortion during hook curing, thermal shock, etc.

Such drawbacks polyethylene glycol, Dibutyl phthalate, polyglycol Noshinore etc. are allowed Ether, organic fatty acid glycidyl ester Can be used in combination as a flexibility imparting agent. ing.

However, when such a flexibility imparting agent is added to an epoxy resin, the electrical properties and mechanical properties of the cured product generally deteriorate, which limits its practical use.

As a result of various studies conducted by the present inventors in order to improve such drawbacks, the present inventors found that an epoxy resin has a specific epoxidized poly-1,2-butadiene resin that has an epoxy group and an unsaturated double bond in its molecule, and has radical polymerizability. An epoxy resin composition that improves crack resistance, arc resistance, and tracking resistance by blending a monomer and an acid anhydride curing agent for epoxy resin, while hardly deteriorating other electrical properties and mechanical properties. We aim to provide the following.

That is, the present invention deals with epoxy resins having the general formula CH2CHCH2-CH \ / (In the formula, n is an integer of 2 to 28, and m is an integer of 7 to 48.

), a monomer having radical polymerizability, and an acid anhydride curing agent for epoxy resins. The epoxy resin used in the present invention is usually one before being cured with a curing agent or the like, and a low molecular weight liquid epoxy resin is preferable. Further, it is particularly preferable to use the general formula (wherein R1, R2, and R3 are hydrogen or an alkyl group, and 1 is an integer of 0 to 10.

). Specifically, Epicron 80
0, Epiclon 850, Epiclon 1000 (all manufactured by Dainippon Ink & Chemicals Co., Ltd.), Epicort 828
, Epicote 1001 (all manufactured by Ciel Co., Ltd.),
Products that are commercially available under the trade names of Syodyne 500, Syodyne 508, Syodyne 540 (all manufactured by Showa Denko K.K.), Araldite GY-250, Araldite GY-252 (all manufactured by Ciba Corporation), etc. Can be mentioned. These epoxy resins may be used alone or in an appropriate mixture. The epoxidized poly 1,2-butadiene resin in the present invention has the general formula (where n is 2 to 2
8, m is an integer from 7 to 48.

). This epoxidized poly 1/2
- The terminal end of the butadiene resin is usually hydrogen. Such a butadiene resin preferably has a number average molecular weight of about 1000 to 3000 and an oxirane oxygen content of 3 to 15% by weight. Those having a molecular weight exceeding 3,000 and those having an oxirane oxygen content exceeding 15% by weight are difficult to handle because of their extremely high viscosity. Further, those containing less than 3% by weight of oxirane oxygen are not preferred because of insufficient compatibility with epoxy resins. This epoxidized poly-1,2-butadiene resin is more preferably one with a molecular weight of 1000 to 1500 and an oxirane oxygen content of 6 to 9% by weight, considering handling and compatibility with the epoxy resin. For example, NissO- PBBF-1
000 (product of Nippon Soda Co., Ltd.) is commercially available. The amount of epoxidized poly-1,2-butadiene resin used in the present invention is usually 20 to 40 parts by weight per 100 parts by weight of the epoxy resin.
It is used in a range of 0 parts by weight.

If the amount used is less than 20 parts by weight, there is little effect on crack resistance, while if it exceeds 400 parts by weight, cracks tend to occur. The composition of the present invention contains a polymerizable monomer as a crosslinker and thinner for the double bonds in the epoxidized poly-1-2-butadiene resin.

The rate of polymerization of double bonds in this epoxidized poly-1,2-butadiene resin is practically low and is therefore increased by adding polymerizable monomers. Furthermore, the polymerizable monomer plays an important role not only as a crosslinking agent but also as a viscosity reducing agent, making the casting process easier. Examples of compounds used as such polymerizable monomers include those shown below. Of course, it is not limited to only these compounds. (1) Styrene; Nucleically substituted alkylstyrenes such as methylstyrene, dimethylstyrene, ethylstyrene, diethylstyrene, and isopropylstyrene; Nuclearly substituted alkoxystyrenes such as methoxystyrene and ethoxystyrene; Styrenic compounds such as α-methylstyrene, divinylbenzene (2) (meth)acrylic acid, methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, cyclohexyl (meth)acrylate, (meth)acrylate (Meth)acrylic acid compounds (3 ) Allyl compounds such as diallyl phthalate, trimethylolpropane monoallyl ether, trimethylolpropane diallyl ether, trimethylolpropane triallyl ether, pentaerythritol diallyl ether, pentaerythritol triallyl ether, etc. used in mixtures.

The amount of these polymerizable monomers used is usually 1 part of the epoxy resin.
If the amount is less than 10 parts by weight, there will be no effect of increasing the radical polymerization rate of the epoxidized poly-1,2-butadiene resin, and there will be no effect of reducing the viscosity of the composition. will also become scarce. Furthermore, the composition of the present invention contains an acid anhydride curing agent for epoxy resins (hereinafter simply referred to as epoxy resin curing agent), and such epoxy resin curing agents include, for example, phthalic anhydride, methyl anhydride, etc. Examples thereof include acid anhydride compounds commonly used for epoxy resins, such as tetrahydrophthalic anhydride, hexahydrophthalic anhydride, and succinic anhydride.

The amount used is usually approximately the same as the amount of epoxy groups in the composition, more specifically 100 to 500 parts by weight (based on 100 parts by weight of the epoxy resin). Then,
The resulting composition of the present invention is cured by a curing reaction of epoxy groups and a curing reaction of radically polymerizable unsaturated groups.

Among these, the curing reaction of the epoxy group is carried out by the epoxy group and the acid anhydride group of the acid anhydride, but a tertiary amine can be used in combination as an accelerator. Examples of such tertiary amines include tris (dimethylaminomethylphenol) and benzylmethylaniline. The amount used is usually 0 relative to the amount of epoxy resin curing agent.
．． A suitable amount is 5 to 2% by weight, and in the composition of the present invention, it is 0.5 to 10 parts by weight per 100 parts by weight of the epoxy resin. On the other hand, the curing reaction of radically polymerizable unsaturated groups is carried out by the unsaturated double bonds in the epoxidized poly-1,2-butadiene resin and the radically polymerizable monomer. It is desirable to use peroxide in combination. In the case of a casting operation, such organic peroxides are precured at a temperature of about 80 to 100°C as a first step to prevent cracks from occurring due to heat generated during curing, and then a second step of complete curing at a high temperature is performed. Therefore, it is desirable to use a substance that decomposes at a low temperature, specifically, 1,1-bis(t-butylbaroxy)-3,5
- 5-Trimethylcyclohexane, benzoyl peroxide, cyclohexane peroxide, t-butyl peroxylaurate, etc. can be mentioned. The amount used is usually 0.5 to 2% by weight of the total amount of the epoxidized poly-1,2-butadiene resin and the polymerizable monomer, and in the composition of the present invention, it is based on 100 parts by weight of the epoxy resin. The amount is 0.5 to 10 parts by weight. The composition of the present invention is in the form of a transparent liquid, and operations such as casting and impregnation can be carried out satisfactorily even at room temperature, but operations can be carried out more easily by heating to about 50°C.

The method for curing the composition of the present invention is usually carried out by heating. That is, the composition is precured by heat treatment at 80 to 100°C for 2 to 5 hours, and then heated to 100 to 180°C.
Heat treatment for 5 to 20 hours to completely cure. Additionally, the composition of the present invention may contain reinforcing agents such as glass fibers, synthetic fibers, and asbestos, fillers such as tankar and metal powder, pigments, lubricants, retardant agents, processing aids, and mold release agents. can.

Therefore, the composition of the present invention is particularly useful for electric insulation applications such as transformers, insulating encapsulation of busbars, insulators, insulators, switching devices, etc., and is also useful due to improved arc resistance and tracking resistance. It can also be used for outdoor equipment.

Hereinafter, the present invention will be explained in detail with reference to Examples and Comparative Examples.

Note that "parts" in the examples mean "parts by weight."
Examples 1 to 4, Comparative Examples 1 to 3 Each of the formulations shown in Table 1 was mixed at room temperature and heated at 80°C for 5 hours and then at 160°C for 6 hours to obtain test beads.

The resulting test beads were measured for crack resistance, arc resistance, tracking resistance, dielectric constant, dielectric loss tangent, bending strength, and tensile strength. The results are shown in Table 1. Examples 5-6, Comparative Examples 4-6 The raw materials shown in Table 2 were blended in the same manner as in Example 1 and reacted.

Claims (1)

[Claims] 1 Epoxy resin, epoxidized poly 1 represented by the general formula ▲ There are numerical formulas, chemical formulas, tables, etc. - A thermosetting resin composition comprising a 2-butadiene resin, a radically polymerizable monomer, and an acid anhydride curing agent for epoxy resins.