JPS5833641B2 - Vulcanized ethylene-propylene rubber insulated wire - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel vulcanized insulated wire that has good adhesion between an external semiconductive layer and an insulating layer, and the semiconductive layer can be easily peeled off.

If a gap exists between the outer semiconducting layer and the insulating layer, corona discharge will occur in the gap when the electric wire is used. It is necessary to maintain good adhesion.

On the other hand, for electrical wire connection work, both layers must be easy to separate.

Also, the material making up the outer semiconducting layer must be resistant to scorch.

Conventionally, technologies that can satisfy the above three requirements have been proposed for cross-linked polyethylene insulated wires, but no satisfactory technology has yet been proposed for vulcanized ethylene-propylene rubber insulated wires. In view of this, the present invention proposes a vulcanized ethylene-propylene rubber insulated wire that uses a material constituting the outer semiconducting layer that is difficult to scorch and has excellent adhesion and peelability between the outer semiconducting layer and the insulating layer. It is.

The gist of this is that a semiconductive material mainly composed of an olefin polymer containing 60 to 70% by weight of vinyl acetate is placed on an insulating layer made of vulcanized ethylene-propylene rubber. It is characterized by having a semiconductive layer formed by extrusion molding and heat vulcanization.

In the present invention, the olefin polymer used as a constituent material of the outer semiconductive layer has a vinyl acetate content of 60 to 60%.
70% by weight ethylene-vinyl acetate copolymer, or a mixture of a copolymer with a higher vinyl acetate content than such ethylene-vinyl acetate copolymer and a polyolefin (e.g., polyethylene, polypropylene, polybutene-1, etc.) is used.

The vinyl acetate content of the above-mentioned olefin polymer is extremely important, and if the content is greater or less than the above-mentioned range, it will be difficult to achieve the objects of the present invention.

The olefinic polymer used in the present invention is prepared by adding a conventional amount of a known vulcanizing agent such as an organic peroxide, Kayahexa YD (2.5 dimethyl-27,5/(tert-butylperoxy)hexyne-3), and It is extruded and heated and vulcanized.

In this case, an organic peroxide with a 5-hour half-life temperature of 100°C or higher, such as 2,5-dimethyl-27,5/(tert-butylperoxy)hexyne-3, is added to 100 parts by weight of the olefin polymer. using 0.5 to 5 parts by weight,
Preferably, the coating is applied under conditions of heat vulcanization at a temperature of 150 to 210°C for 120 minutes to 5 minutes.

The olefin polymer used in the present invention is made semiconductive by adding conductive materials such as carbon black and metal powder.

The amount of these conductive materials blended is about 15 to 100 parts by weight per 100 parts by weight of the polymer.

Note that, if necessary, fillers, anti-aging agents, crosslinking accelerators, processing aids, etc. may be blended into the above-mentioned olefin polymer in normal amounts.

In the present invention, the ethylene-propylene rubber used as a constituent material of the insulating layer includes an ethylene-propylene copolymer, an ethylene-propylene-diene terpolymer, or a mixture thereof.

Also, per 100 parts by weight of these ethylene-propylene rubbers, polyethylene, polypropylene, polybutene-11
Ethylene/ethyl acrylate copolymer, ethylene/
A mixture of 5 to 30 parts by weight of a vinyl acetate copolymer with an α-olefin homo or copolymer may also be used.

These ethylene-propylene rubbers can be applied to the conductor using conventional vulcanizing agents and conventional mold vulcanization methods.

In the present invention, an external semiconductive layer may be coated by extrusion on a vulcanized ethylene-propylene rubber insulating layer that has been molded and cured in advance and then heat-vulcanized. They may be molded at the same time, and then both layers may be heated and vulcanized at the same time.

However, in the present invention, it is preferable to construct both layers by simultaneous molding and simultaneous vulcanization because it is possible to obtain a product with even better adhesion between the two layers without impairing releasability.

As mentioned above, the external semiconductive layer can be molded and cured in various ways, but the object of the invention cannot be achieved by methods other than extrusion, such as covering, tape wrapping, etc.

The extrusion of the material forming the outer semiconducting layer may be a compression type extrusion or a tubing type extrusion.

The outer semiconducting layer is amenable to vulcanization at typical thicknesses, ie on the order of 0.05 to 1.0, and can be easily peeled off due to its relatively high mechanical strength and low adhesion with the insulating layer.

Next, the present invention will be explained in detail using Examples and Comparative Examples.

On a copper conductor with a cross section of 1257IL4, an internal semiconducting layer having the following composition (parts by weight, the same hereinafter) is extruded, and on top of that an insulating layer of vulcanizable ethylene-propylene rubber having the following composition is extruded to a thickness of 4.5 mm. Three external semiconductive layers having the composition shown in Table 1 were simultaneously coated on the insulating layer to a thickness of 0.8 mπ, and then heated and vulcanized with high pressure steam at 200°C for 6 minutes to obtain a 15KV version. Manufactures electrical wires.

Internal semiconducting EPDM composition EPDM (product name JSREP-21) to.

Dicumyl peroxide 2.7P, P'
Dibenzoylquinone dioxime 3.5 Conductive carbon black (product name Denka Acetylene Black) 70 Anti-aging agent 1.0 Zinc oxide
5.0 stearic acid
EPDM insulation layer composition EPDM (trade name Nisprene 301) 100 dicumyl peroxide 2.7P, P'
Dibenzoylquinone dioxime 3.5 Anti-aging agent
l zinc oxide
5 stearic acid
l Water immersion charging improver 5D-91010 Calcined clay 110 Process oil 10 Peel strength is AEIC
The following method was used according to the standard.

Cut the cable to a length of 15 inches and cut the outer semiconducting layer with a knife to the insulation at 0.5 inch width.
Peel the 2 inch semiconducting layer from the insulator on both ends at a 0.00 angle.

Holding the sample horizontally by supporting both ends, peel the outer semiconducting layer from the insulator at an angle of 900 degrees at a speed of 0.5 inches/second.
Measure the peeling force.

Note that the displayed data is the value of 10 samples.

The AEIC standards required for cable peel tests are 1.
8kg to 8kg.

Table 1 shows the volume resistivity of the composition constituting the outer semiconducting layer,
It also exhibits scorch properties, which were measured by the following method.

The volume resistivity is Lm press-cured at 160°C for 30 minutes.
Ando Electric metal plate electrode (main electrode area 2
After applying electricity for 1 minute at 23°C and 5KV DC, the value is measured.

The scorch time is 5 mrcX cut from an unvulcanized sheet.
Sections of 5 mm x 1 mm were subjected to a Brabender Plast rice-grafting machine at 100°C and 100 rpm.
Measured under the conditions of 500
The time required for the scorch to rise by 9-m is defined as the scorch time, and is shown as the average value of 3 samples.

Example 1 Engineered tyrene-vinyl acetate copolymer with vinyl acetate content of 60% [Soabrene CH from Japan Synthetic Rubber] Conductive carbon black Stearic acid Antioxidant Crosslinking aid Crosslinking agent Example 2 The polymer of Example 1 was converted into vinyl acetate. Example 3 Replacing the polymer of Example 1 with an ethylene-vinyl acetate copolymer (Dainippon Ink @) Evasurene 450-P) with a 65% content of vinyl acetate [Japan Synthetic Rubber ■ Soabrene] DH) Replacement Example 4 Ethylene-vinyl acetate copolymer with vinyl acetate content of 65% O 0 [Dainippon Ink at Evathren 450-P) Ethylene-propylene diene terpolymer conductive carbon black Stearic acid anti-aging agent Cross-linked Auxiliary crosslinking agent Example 5 Ethylene-vinyl acetate copolymer with vinyl acetate content of 70% (Japan Synthetic Rubber ■ Soablen DH) Polyethylene conductive carbon black Stearic acid anti-aging crosslinking agent Crosslinking agent Example 6 Vinyl acetate content 65% Ethylene-vinyl acetate copolymer [Dainippon Ink QD Everthrene 450-P] Butyl rubber O 0 0 0 Conductive carbon black 5゜Stearic acid l Anti-aging agent
2 Crosslinking aid
2 Crosslinking agent
l Example 7 90 engineering tyrene vinyl acetate copolymer with vinyl acetate content of 70% [Japan Synthetic Rubber OD Soarblen DH) Ethylene ethyl acrylate resin 10 Conductive carbon black 50 Stearic acid l Anti-aging agent
2 Crosslinking aid
2 Crosslinking agent
Example 8 80-engineering tyrene-vinyl acetate copolymer with a vinyl acetate content of 70% [Nippon Taipei rR-f DH] 20-engineering tyrene-vinyl acetate copolymer with a vinyl acetate content of 9% [Mitsui Polychemical OD Eva] Flex P-1705)
Conductive carbon black 50 Stearic acid anti-aging agent Cross-linking agent Comparative example 1 Ethylene-vinyl acetate copolymer with vinyl acetate content of 25% (Sumitomo Chemical ■ Evatate 2010) Conductive carbon black Stearic acid anti-aging agent Cross-linking agent Crosslinking agent comparative example 2 Ethylene-vinyl acetate copolymer with vinyl acetate content of 45% [Bayer [F] D Lebuff 0 Ren 45o] Conductive carbon black Stearic acid Antioxidant Crosslinking aid Crosslinking agent 00 O0

Claims (1)

[Claims] 1 A semiconductive material whose main component is an olefin polymer containing 60 to 70% vinyl acetate is extruded and heated and mudded onto an insulating layer made of vulcanized ethylene-propylene rubber. 1. A vulcanized ethylene-propylene rubber insulated wire characterized by being coated with a semiconductive layer consisting of: