JPS63213541A - Electrical insulating composition - Google Patents

Abstract

PURPOSE:To obtain an electrical insulating composition, having excellent gas blocking properties and obtained by adding a silane coupling agent to a composition containing ethylene propylene rubber and/or ethylene-propylene-diene copolymer as a base polymer. CONSTITUTION:An electrical insulating composition, obtained by blending (B) a coupling agent containing any of vinyl groups, epoxy groups, methacryl groups, amino groups and mercapto groups in organic functional groups (e.g. vinyltriethoxysilane or gamma-mercaptopropyltrimethoxysilane) in an amount of 0.05-5pts.wt. based on 100pts.wt. base polymer with (A) a composition containing ethylene propylene rubber and/or ethylene-propylene-diene copolymer as the base polymer, a filler, crosslinking agent and crosslinking assistant. Since the component (B) having adhesive properties to both metal and insulator components is blended, the above-mentioned composition has excellent gas blocking properties.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to an electrical insulating composition that is used under extreme conditions such as high temperature and high pressure, and is exposed to an atmosphere containing oil, water, etc. In particular, the present invention relates to a composition that improves gas blocking properties by increasing the adhesion between a conductor and an insulator.

<Prior art> Conventionally, synthetic polymers of olefins have been used as thermoplastic insulators in various fields of electrical materials, but in particular, ethylene propylene rubber (EPM) and ethylene-propylene-diene copolymers ( Due to its good extrudability and electrical properties, EPDM has been widely used as the primary insulation material for electric wires and cables.

In addition to being used under normal conditions, such electrical insulators are sometimes used under extreme conditions such as high temperature and high pressure, and in an atmosphere containing oil, water, and the like.

Electrical insulators used under such harsh conditions not only have excellent electrical properties, ease of formulation, and extrudability, but also have high resistance to high temperatures, high pressures, and rapid changes. It must be durable and also have excellent oil resistance and water resistance.

In particular, electric wires and cables used under such conditions have good adhesion between the conductor and insulator, and have gas blocking properties that prevent gas movement in the lengthwise direction of the wire. is required.

Conventionally, as a general method for improving the adhesion between a conductor and an insulator, a method using a vulcanized adhesive that has high adhesion to both the insulator and the conductor metal has been employed.

However, this method using a vulcanized adhesive has the following drawbacks.

(2) If the environment in which it is used is at a high temperature of about 120 to 200°C, the heat resistance limit of the vulcanized adhesive will be exceeded, resulting in a significant decrease in adhesion.

■When conducting a bending test on electric wires and cables that have a conductor-adhesive-insulator structure in an atmosphere of about 80°C, cracks (cracks) appear in the insulator. This crack occurs from inside the insulator, and the reason for this is presumed to be that the heat-cured vulcanizable adhesive cracks when bent, and stress concentrates in this area.

(2) If the insulator is coated with the vulcanized adhesive on the conductor until the solvent has not been completely removed, the insulator will be peeled off by the gasified solvent.

(2) Also, as a matter of course, adhesive application and solvent drying steps are required.

The present invention was completed in view of such conventional drawbacks.

Means for solving problems and their effects〉In other words,
The present invention achieves good gas blocking properties and eliminates the need for an adhesive layer by incorporating a silane coupling agent that has high adhesion to both metal and insulator components directly into the insulator. This is what I did.

More specifically, the present invention relates to ethylene propylene rubber (EPM) and/or ethylene-propylene-diene copolymer (EPDM) t-based polymers, fillers, crosslinking agents, crosslinking aids, and processing aids. An electrically insulating composition is prepared by adding a silane coupling agent to a composition containing the necessary parts by weight of 0.05 to 5 parts by weight based on 100 parts by weight of the base polymer.

Examples of the silane coupling agent used in the present invention include coupling agents containing any one of a vinyl group, an epoxy group, a methacrylic group, an amino group, and a mercapto group as an organic functional group. For example, vinylsilanes such as vinyltriethoxysilane, vinyltriacetylsilane, vinyltris(β-methoxyethoxy)silane, epoxysilanes such as β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-[N-(β -methacryloxyethyl)
-N,N-dimethylammonium (chloride)] Methacrylsilane such as propyltrimethoxysilane, aminosilane such as γ-aminopropyltrimethoxysilane, T-ureidopropyltriethoxysilane, mercaptosilane such as γ-mercaptopropyltrimethoxysilane There is. The blending amount is 0.05 to 5 parts by weight per 100 parts by weight of the base polymer (EPM and/or EPDM).
It is necessary to express it in parts by weight. This is because if it is less than 0.05 parts by weight, a sufficient adhesive effect cannot be obtained, and if it exceeds 5 parts by weight, the adhesive effect will not be improved so much that it will become uneconomical and the extrusion processability will deteriorate. .

<Example> Various electrical insulation compositions (Examples 1 to 6, Comparative Examples 1 to 3) were prepared according to the formulations shown in Table 1, and sample electric wires were manufactured using the compositions as insulators. Various property tests were conducted, including extrusion processability, adhesion of the composition to metal, and gas-tightness. The results are also listed in Table 1.

The tests in the table were conducted as follows.

(2) Extrusion processability test Each composition was extruded onto a copper conductor (3 mm diameter copper wire) using an extruder, and its quality was determined. Here, ◎ is good, ○ is good, ×
indicates defective.

■ Adhesion test The above compounded composition was adhered to a tin-plated copper tape (thickness 1 mm) by press vulcanization at 160°C for 40 minutes, and then
The adhesive force was determined by cutting into small pieces with a width of 15 mm and measuring the strength when peeling the composition portion from the small pieces. Here, the unit is kg/15mm+width.

■Gas Tightness Test One end of a 30 cm test cable core was immersed in water, an air pressure of 0.5) cg/awl was applied to the other end, and the airtightness was evaluated by the appearance of bubbles in the water.

Here, ◎ indicates a case where there is no bubbles after 3 hours or more.
In other words, it is good, ○ is a case where bubbles appear for less than 1 to 3 hours,
In other words, "good" and "x" represent cases in which bubbles appear in less than 1 hour, ie, failure.

From Table 1 above, it can be seen that the electrical insulation composition of the present invention is superior to the comparative example.

In particular, a great effect can be obtained with aminosilane, and if the amount of silane coupling agent added is small, the adhesive strength will decrease and the gas tightness will also deteriorate, but if the amount added is too large, extrusion processability may deteriorate. I understand.

Note that the use of the electrical insulation composition of the present invention is not limited to insulators for electric wires and cables.

<Effects of the Invention> As is clear from the above description, according to the present invention, a silane coupling agent having high adhesiveness to both the metal and the rubber or copolymer of the insulator component is directly blended into the insulator. Therefore, in the case of electric wires and cables, for example, it is possible to obtain an electrically insulating composition that does not require the provision of an adhesive layer between a conductor and an insulator as in the past. Therefore, as a matter of course, an adhesive application process and a solvent drying process are unnecessary, and manufacturing costs can be gradually reduced. Additionally, by eliminating the need for this adhesive layer, the heat resistance of wires and cables is not affected by the heat resistance limit of the adhesive, the occurrence of cranks that are assumed to be caused by the adhesive layer is eliminated, and there is no need for solvents. Excellent advantages such as no peeling of the insulator due to solvent gasification can be obtained. Furthermore, in the case of electric wires and cables, excellent gas blocking properties can be obtained.

Claims (2)

[Claims] (1) A composition using ethylene propylene rubber (EPM) and/or ethylene-propylene-diene copolymer (EPDM) as a base polymer and containing the necessary parts by weight of a filler, a crosslinking agent, a crosslinking aid, and a processing aid, Add 0.05 to 5 silane coupling agent to 100 parts by weight of the base polymer.
Electrical insulation composition added in parts by weight. (2) The electrical insulation composition according to claim 1, wherein the silane coupling agent is a coupling agent containing any one of a vinyl group, an epoxy group, a methacrylic group, an amino group, and a mercapto group as an organic functional group. .