JPH02260326A - Power cable - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a power cable such as a cross-linked polyethylene insulated cable, and the semiconductive layer thereof has improved peelability.

[Conventional technology]

For power cables such as cross-linked polyethylene insulated cables (CV cables), insulating layers made of cross-linked polyethylene or cross-linked ethylene propylene rubber, etc. It is necessary to make the conductive layer easy to peel off. Furthermore, it is also necessary that interfacial peeling between the insulating layer and the semiconducting layer does not occur when an external bending force is applied to the power cable. Therefore, the semiconducting layer needs to have both appropriate releasability and appropriate adhesion to the insulating layer.

For this reason, conventionally, polyvinyl chloride, chlorinated polyethylene, ethylene-vinyl acetate copolymers, polar polymers, fluororesins, silicone resins, etc. are blended with an appropriate amount of polyolefin resins such as polyethylene to form a base polymer, and this is made into a base polymer. The semiconductive layer is made of a resin composition containing carbon black, and is designed to have appropriate peelability and adhesion to an insulating layer made of a polyolefin resin such as crosslinked polyethylene or crosslinked ethylene propylene rubber.

[Problem to be solved by the invention]

However, in the case of a semiconducting layer made of the above-mentioned resin composition, since this resin composition is a blend of a polyolefin resin and a polar polymer that is inherently poor in compatibility with this polyolefin resin, it is difficult to uniformly conduct wires when cross-wired. It is difficult to disperse, and therefore, when the semiconducting layer obtained from this resin composition is peeled from the insulating layer, directionality is exhibited,
There was a problem in that the cable could not be peeled off in any direction, making it difficult to easily process the ends of the power cable.

[Means to solve the problem]

In this invention, the resin composition forming the semiconductive layer includes 30 to 80 parts by weight of conductive carbon black and 0.00 parts by weight of fatty acid ester based on 100 parts by weight of the polyolefin polymer.
The above problem was solved by using a blend of 1 to 10 parts by weight.

The present invention will be described in detail below.

FIG. 1 shows an example of the power cable of the present invention, and reference numeral 1 in the figure indicates a conductor. The outer periphery of this conductor l is coated with an internal semiconducting layer 2. This internal semiconducting layer 2 is
This is a bond type semiconductive layer, and the type is different from the one with good peelability in the present invention. Furthermore, this internal semiconducting layer 2 is coated with an insulating layer 3. This insulating layer 3 is made of a resin composition obtained by extruding and coating a polyolefin resin such as crosslinked polyethylene or crosslinked ethylene propylene rubber, and then heating and crosslinking it. Furthermore, the insulating layer 3 is coated with an outer semiconducting layer 4, a sheathing layer 5, and a sheath 6 in this order to form a power cable. The outer semiconductive layer 4 is formed by extrusion coating on the insulating layer 3 a resin composition containing 30 to 80 parts by weight of conductive carbon black and 0.1 to 10 parts by weight of fatty acid ester to 100 parts by weight of a polyolefin polymer. It was formed by

The polyolefin polymer used here is
Homopolymers of α-olefins such as polyethylene, polypropylene, polybutene-1, ethylene-ethyl acrylate copolymers (EEA), ethylene-vinyl acetate copolymers (EVA), ethylene-propylene copolymers, ethylene- Examples include ethylene copolymers such as butene-1 copolymers, and single or blended polymers of these polymers may be used. Among these, ethylene-vinyl acetate copolymer and ethylene-ethyl acrylate copolymer are particularly preferably used.

Conductive carbon blacks for imparting conductivity to such base polymers include acetylene black,
Well-known carbon blacks such as furnace black can be used. The amount of conductive carbon black to be mixed with the base polymer is determined in consideration of the conductivity required for the outer semiconductive layer 4, and is determined in the range of 30 to 80 parts by weight based on 100 parts by weight of the base polymer.

In addition, fatty acid esters added to obtain appropriate release properties include caprylic acid, pelargonic acid, capric acid, undecylic acid, lauric acid, tridecylic acid, myristic acid, pentadecylic acid, stearic acid, nonadecanoic acid,
Fatty acids such as arachidic acid, behenic acid, oleic acid, linoleic acid, sorbic acid, lylunic acid, butyl alcohol, amyl alcohol, hexyl alcohol, heptyl alcohol, octyl alcohol, caprylic alcohol,
Nonyl alcohol, allyl alcohol, myristyl alcohol, stearyl alcohol, cetyl alcohol,
One or a mixture of two or more of esters with monohydric alcohols such as allyl alcohol or alcohols such as diethylene glycol and polyhydric alcohols such as glycerin are used, preferably having a molecular weight of 50 to 800,
Those with a melting point of 10 to 90°C are used, and specific examples thereof include rKOL-101J, rKOL-102'', r
Examples include KOL-103J (product name, Kao Corporation). The blending amount of the fatty acid ester is in the range of 01 to 10 parts by weight based on 100 parts by weight of the base polymer. If the amount is less than 0.1 part by weight, it will be difficult to peel it off from the insulating layer, and if it exceeds 510 parts by weight, the mechanical properties will deteriorate significantly and it is also uneconomical.

Further, a crosslinking agent, a crosslinking aid, an anti-aging agent, etc. can be added to the resin composition made of the mixture of the base polymer, fatty acid ester, and carbon black, if necessary. As a crosslinking agent, dicumyl peroxide (DC
P), 2,5-dimethyl-2,5-di(1-butylperoxy)hexyne-3, and other conventional peroxide crosslinking agents can be suitably used. The amount of crosslinking agent is 10% of the pace polymer
It is approximately 0.2 to 3 parts by weight relative to 0 parts by weight.

In addition, as a crosslinking aid, triallyl isocyanurate, triallyl cyanurate, tetraallyloxyethane, N,N'-m-phenylenebismaleimide, p,p'
- Dibenzoylquinone dioxime, p-quinone dioxime, etc. can be used, and 0 parts by weight of the base polymer can be used.
．． It can be blended in an amount of about 5 to 3 parts by weight. These crosslinking agents and crosslinking aids may be used in combination, or either one may be used alone. When a crosslinking aid is used alone, a portion of the crosslinking agent in the insulator migrates to the semiconductive layer during crosslinking and reacts with the migrated crosslinking agent to cause crosslinking. In addition, as an anti-aging agent,
4,4°-thiobis(6-t-butyl-3-methylphenol) and the like can be used, and zinc stearate, zinc oxide, magnesia, etc. can also be added as required.

In order to form the outer semiconductive layer 4 using such a composition, an extrusion coating method can be applied in the same manner as the conventional method. During this extrusion coating (7) press 8 [degree is 12
It is said to be about 0 to 140°C.

In such a power cable, since the outer semiconductive layer 4 is made of a resin composition containing a polyolefin polymer and an appropriate amount of fatty acid ester, it is different from the insulating layer 3 made of crosslinked polyethylene or crosslinked ethylene propylene rubber. , has appropriate adhesion and appropriate releasability, and
The base polymer itself becomes a homogeneous system, and when peeling off the semiconducting layer, there are no problems such as easy peeling in a specific direction.
It can be easily peeled off in any direction as needed.

Hereinafter, the effects of this invention will be clarified by showing examples.

〔Example〕

A resin composition having the formulation shown in Table 1 was prepared as an outer semiconductive layer. On the conductor (500I! 1m”), an internal semiconducting layer (thickness IIIffi), an insulating layer (crosslinked polyethylene,
thickness 11 o++a), outer semiconducting layer (thickness 0, 5
Power cables were produced by coating the cables (mm) with a three-layer extrusion coating, followed by successive application of a shielding layer and a sheath.

Regarding the obtained power cable, the presence or absence of directionality during peeling of the outer semiconductive layer and the mechanical properties of the two-handed conductive layer were investigated. Separately, a sheet piece with a two-layer structure made of this resin composition and crosslinked polyethylene was extruded and its peel force was determined.

The results are also shown in Table 1.

Margin below -14'/ As is clear from Table 1, in the power cable of the present invention, there is no directionality when peeling the semiconducting layer, and it can be peeled off in any direction. It can be seen that the peeling force and adhesion force are well balanced.

〔Effect of the invention〕

As explained above, the power cable of the present invention contains 0.1-10 parts by weight of fatty acid ester and 30 parts by weight of conductive carbon black per 100 parts by weight of polyolefin polymer.
Since it has a semiconductive layer made of a resin composition containing ~80 parts by weight, it is possible to peel off the semiconductive layer as much as necessary in any direction when peeling the semiconductive layer from the insulating layer during terminal processing work, etc. , Therefore, terminal processing work can be easily performed. Further, this semiconductive layer has appropriate adhesiveness and appropriate releasability to an insulating layer made of crosslinked polyethylene or the like.

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view showing an example of the power cable of the present invention. 4...Outer semiconducting layer.

Claims (2)

[Claims] (1) A power cable having a semiconductive layer made of a resin composition containing 30 to 80 parts by weight of conductive carbon black and 0.1 to 10 parts by weight of fatty acid ester with respect to 100 parts by weight of a polyolefin polymer. (2) Fatty acid ester has a molecular weight of 50 to 800 and a melting point of 1
The power cable according to claim 1, which has a temperature of 0 to 90°C.