JPH08295765A - Resin composition excellent in adhesiveness and insulating material - Google Patents

Abstract

PURPOSE: To obtain a resin excellent in adhesiveness to an epoxy resin by blending a specified amount of an ethylene-acrylic ester copolymer having carboxyl or epoxy groups on its side chain with an ethylene-propylene rubber. CONSTITUTION: This resin composition is produced by blending 5-30 pts.wt. ethylene-acrylic ester copolymer (A) containing carboxyl or epoxy groups on its side chain with 100 pts.wt. ethylene-propylene rubber (EP rubber) (B). The component A is a copolymer containing 30-60wt.% ethylene units, 30-60wt.% acrylic ester units, and 1-10 pts.wt. crosslinking monomer having carboxyl or epoxy groups on its side chain. Because of good compatibility of the component A with the component B, various insulating materials can be produced by using this composition. Particularly, this composition is suitable for the production of premolded parts, such as an insulator, since it has good adhesiveness to an epoxy resin and good mold release properties and is free from crack of a molding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition and an insulating material having excellent adhesiveness, and more particularly to a resin composition and an insulating material having excellent adhesiveness to an epoxy resin.

[0002]

2. Description of the Related Art Ethylene-propylene rubber (hereinafter referred to as EP
Abbreviated) is excellent in ozone resistance, weather resistance, electrical properties, etc., and is widely used as an insulating material for captyre cables, high voltage cables, insulating parts for insulators and the like. For example, E, which is an EP blended with an inorganic filler,
The P compound molded product is adhered with an epoxy resin and used as a bushing for an insulator.

[0003]

However, since the adhesive strength between the EP rubber and the epoxy resin is not sufficiently large, if the epoxy resin is selected incorrectly, peeling will occur from the adhesive interface between the molded article of the EP compound and the epoxy resin. However, there is a problem that the electrical insulation is impaired. For example, when it is used as the bushing 13 of the insulator 11 as shown in FIG. 1, if it is peeled off from the adhesive interface 14 between the bushing and the epoxy resin, the watertightness is impaired, and the current is transmitted through the peeled surface of the bushing material to expose it. There was a problem of doing. On the other hand, when the composition having a high adhesive strength with the epoxy resin is used, the tear strength of the molded article of the EP compound is lowered, or the mold releasing property is deteriorated and the molded article is cracked when the molded article is separated from the molding die. There was also.

The present invention has been made in view of the above circumstances, and the range of selection of the type of epoxy resin is sufficiently wide, it does not peel off from the adhesive interface, so the electrical insulation is not impaired, and the molded product is peeled from the molding die. It is an object of the present invention to provide an ethylene-propylene rubber composition which has an advantage that a molded product does not crack sometimes and an insulating material using the composition.

[0005]

The resin composition having excellent adhesiveness of the present invention has an ethylene-acrylic acid ester copolymer having a carboxyl group or an epoxy group in the side chain in an amount of 100 parts by weight of ethylene-propylene rubber. 5 for department
-30 parts by weight. Further, the insulating material of the present invention is an insulating material using the resin composition.

Ethylene-propylene rubber is a copolymer mainly composed of ethylene units and propylene units. Typical examples thereof include a copolymer of ethylene and propylene and a diene monomer such as ethylene, propylene and dicyclopentadiene. Terpolymer (hereinafter referred to as EPDM) and the like. As the ethylene-propylene rubber, commercially available products can be used.

The ethylene-acrylic acid ester copolymer having a carboxyl group or an epoxy group in the side chain is mainly composed of ethylene, an acrylic acid ester, and a crosslinking site monomer having a carboxyl group or an epoxy group in the side chain. It is a polymerized copolymer. More specifically, 30 to 60% by weight of ethylene units, 30 to 60% by weight of acrylate ester units such as methyl acrylate, ethyl acrylate, and butyl acrylate, and a carboxyl group on the side chain of acrylic acid, methacrylic acid, and the like. 1 to 10% by weight of a cross-linking site monomer unit having a cross-linking site monomer unit having an epoxy group in the side chain such as glycidyl acrylate or allyl glycidyl ether. Since the above-mentioned carboxyl group and epoxy group are active and a crosslinking point can be introduced into the ethylene-acrylic acid ester copolymer, the monomer containing a carboxyl group or an epoxy group in the side chain is referred to as a crosslinking site monomer. ing. The carboxyl groups and epoxy groups on the side chains of the copolymer are also extremely active with respect to the epoxy resin, and thus easily cross-link with the epoxy resin at the time of adhesion to give a large adhesive force. Since the ethylene-acrylic acid ester copolymer mainly contains ethylene units and acrylic acid ester units, it has good compatibility with ethylene-propylene rubber. A commercially available ethylene-acrylic acid ester copolymer can be used.

The blending amount of the ethylene-acrylic acid ester copolymer is 5 to 30 parts by weight, preferably 10 to 20 parts by weight, based on 100 parts by weight of ethylene-propylene rubber. If the amount is less than 5 parts by weight, there is no compounding effect such that the adhesive strength with the epoxy resin is not improved. If the amount is more than 30 parts by weight, the volume resistivity of the composition decreases and it becomes unsuitable as an insulating material.

The resin composition of the present invention contains ethylene-propylene rubber and an ethylene-acrylic acid ester copolymer having a carboxyl group or an epoxy group in a side chain as essential components, but other additives may be added as necessary. Can be further added. Examples of such additives include dyes, pigments, processing aids such as lubricants, fillers, antioxidants, ultraviolet absorbers, vulcanization accelerators, vulcanizing agents and the like. When an insulating material is manufactured using the resin composition of the present invention, heat resistance is improved by adding 20 to 120 parts by weight of an inorganic filler such as aluminum silicate to 100 parts by weight of the resin composition of the present invention.
It is preferable to improve the shape stability and the adhesiveness with the epoxy resin.

Various insulating materials can be manufactured using the resin composition of the present invention. For example, electrical insulating materials such as captyre cables, high voltage cables, premolded components for insulators and the like can be manufactured. The pre-molded component is a rubber molded product that has been thermoformed in advance, and is an electrical insulating component used for assembly at the site of overhead wire construction. Specifically, it is a bushing, a stress relief cone, or the like used in combination with an insulator. Since the resin composition of the present invention is particularly excellent in mold releasability at the time of molding and adhesiveness to an epoxy resin, an insulating material adhered by the epoxy resin, for example, bushings for insulators, pre-molds for stress relief cones, etc. It is particularly suitable as the manufactured component.

[0011]

In the resin composition of the present invention, an ethylene-acrylic acid ester copolymer having an active carboxyl group or epoxy group that easily cross-links with an epoxy resin is blended in a specific ratio. The adhesive strength between the resin composition and the epoxy resin is high. Since the ethylene-acrylic acid ester copolymer has a good compatibility with the ethylene-propylene rubber, the resin composition of the present invention has excellent mechanical properties such as tear strength. Therefore, when peeling the molded product from the mold, there is no problem that the molded product is broken. Since the blending amount of the ethylene-acrylic acid ester copolymer is set in an appropriate range, there is almost no decrease in the volume resistivity, so the composition is suitable as an insulating material.
Since the resin composition of the present invention is mainly composed of ethylene-propylene rubber and ethylene-acrylic acid ester copolymer, it has excellent ozone resistance, weather resistance, electrical properties, etc. give.

[0012]

The present invention will be described in detail below. In the following description, examples and conventional examples, all parts are parts by weight. The test pieces required for the performance tests of Examples and Comparative Examples were prepared as follows. For 100 parts of EPDM,
The blending amounts of the ethylene-acrylic acid ester copolymer having a carboxyl group or an epoxy group in the side chain and the filler are as shown in Table 1. As other common additives, 15 parts of processing aid, 1 part of antioxidant, 4 parts of vulcanization accelerator and 4 parts of vulcanizing agent were further blended in each composition of Table 1. Next, each compound was mixed, masticated, molded into a rubber sheet, and vulcanized at a double bond portion of EPDM to obtain a test piece. The materials used in Table 1 are as follows. EPDM: Ethylene-propylene rubber, which is a copolymer of ethylene, propylene, and diene monomers (trade name: EPT3045, manufactured by Mitsui Petrochemical Co., Ltd.) Copolymer containing carboxyl group: Crosslinking site having ethylene and methyl acrylate and a carboxyl group in the side chain Copolymer with monomer (trade name: Baymac G: Showa Denko DuPont) Epoxy group-containing copolymer: 38% by weight of ethylene unit, 59% by weight of methyl acrylate unit and cross-linking site having epoxy group in side chain Copolymer with 2.3% by weight of monomer unit (trade name Esprene EMA: manufactured by Sumitomo Chemical Co., Ltd.) Filler: Aluminum silicate

The peel strength and volume resistivity measurement methods in Table 1 and the display of the measurement results are as follows. Peel strength: The rubber sheet having a thickness of 3 mm and a width of 10 mm was bonded to an insulator plate with an epoxy resin, and then heated at 80 ° C. for 4 hours to complete curing. Then, peeling was performed at 23 ° C., and the peeling strength and peeling state were examined. Cohesive peeling means that the rubber sheet was torn without peeling from the adhesive interface during peeling. Interfacial peeling means peeling at the adhesive interface between the insulator plate and the epoxy resin. Volume resistivity: Measured by the measuring method of JIS K 6723. Table 1 shows the measurement results of the peel strength and the volume resistivity of Examples and Comparative Examples.

[0014]

[Table 1]

Examples 1 to 4 and Comparative Examples 1 to 2 When an ethylene-acrylic acid ester copolymer having a carboxyl group in the side chain is blended, the peel strength becomes larger than that in Comparative Example, and the above copolymers are used. When the compounding amount was 10 parts, the peeling state was cohesive peeling. Also in the case of Example 4 in which 10 parts of the ethylene-acrylic acid ester copolymer having an epoxy group in the side chain was blended, cohesive peeling was observed. That is, it can be seen that the composition of the present invention has excellent adhesive strength by the epoxy resin. On the other hand, the volume resistivity is about 10 ¹² Ω · cm when the blending amount of the ethylene-acrylic acid ester copolymer having a carboxyl group in the side chain is 50 parts, which makes it unsuitable as an electrical insulating material.

A bushing for an insulator was compression-molded using the composition of Example 2 in Table 1 and vulcanized at the double bond portion to produce a bushing for an insulator. The mold releasability during compression molding was good. Then, as shown in FIG. 1, the electric wire 10 was supported by the insulator 11 through the bushing 13 which was fitted into the end portion of the insulator 11 by an overhead wire construction and the fitting portion of which was adhered to the insulator by an epoxy resin. After using for 6 months, the watertightness of the bushing was good and there was no exposure of the electric current.

[0017]

As described above, since the resin composition of the present invention has an active carboxyl group or epoxy group that easily reacts with the epoxy resin, it has a high adhesive strength to the epoxy resin. Moreover, since the resin composition of the present invention is excellent in mechanical properties such as tear strength, ozone resistance, weather resistance, and electrical properties, it is used as an insulating material for outdoor use, for example, pre-molded parts for insulators. Especially suitable as

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an insulator part equipped with a bushing for an insulator, which is one application of the resin composition of the present invention.

[Explanation of symbols]

10 electric wire, 11 insulator, 12 adhesive layer, 13 bushing, 14 adhesive interface

Claims (2)

[Claims] 1. A blending amount of an ethylene-acrylic acid ester copolymer having a carboxyl group or an epoxy group in a side chain, based on 100 parts by weight of ethylene-propylene rubber.
A resin composition having excellent adhesiveness, which is 5 to 30 parts by weight. 2. An insulating material using the resin composition according to claim 1.