JPH06275129A - Electric insulating composition and electric wire/cable - Google Patents

Abstract

PURPOSE:To provide an electric insulating composition and an electric wire/ cable which do not generate scorching by including a specific composition in a thermoplastic resin. CONSTITUTION:To provide an electric insulating composition, 3,4-dimethyl-3,4- diphenylhexane, or 3,3,6,6,9,9-hexamethyl-1,2,4,5-tetraoxacyclononane and multifunctional compound are included in a thermoplastic resin. A resin composition containing 0.5-5.0 parts wt. of 3,4-dimethyl-3,4-diphenylhexane or 3,3,6,6,9,9- hexamethyl-1,2,4,5-tetraoxacyclononane and 0.05-10 parts wt. of multifunctional compound added to 100 parts wt. of the thermoplastic resin is provided on a conductor or on the shield layer of the conductor, and is crosslinked, to form an electric cable.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric insulating composition and an electric wire / cable.

[0002]

2. Description of the Related Art Polyethylene, ethylene copolymers, polypropylene, polystyrene and other polyolefins, polyamides, etc.
Thermoplastic resins such as fluororesins are widely used.
When heat resistance and mechanical strength are required, these thermoplastic resins are used after being crosslinked. For the cross-linking, a method using an organic peroxide, a method of grafting a silane compound and cross-linking with water, a method of irradiating with an electron beam or γ-ray, and the like are used.

In the crosslinking method using an organic peroxide,
Dicumyl peroxide is generally used for crosslinking polyethylene and the like.
(Dicumyl peroxide) is used, and in the case of ordinary low density polyethylene, molding is usually performed at around 130 ° C.

Among the above-mentioned cross-linking methods, the method utilizing silane grafting has a slow cross-linking speed, and particularly it takes a long time to increase the cross-linking density inside the molded article. The method of irradiating with an electron beam or γ-ray also requires a large amount of irradiation for a long time in order to increase the crosslinking density inside the molded product. The method using a peroxide is more efficient than these two methods, and even a thick insulator can crosslink the inside to a high crosslink density.

[0005]

However, dicumyl peroxide (DCP) conventionally used as a cross-linking agent.
When the molding temperature is raised to shorten the molding time or speed up extrusion, part of the cross-linking agent decomposes during molding, causing scorch, which not only damages the appearance of the insulation, but also causes AC breakdown. The voltage drops. In particular, for high density polyethylene (molding temperature 145 ° C), linear extremely low density or extremely low density polyethylene (140 ° C or higher), medium density polyethylene, polypropylene, polyamide, fluororesin, etc., which have relatively high molding temperature, DCP When used as a cross-linking agent, scorch is large, and it is difficult to form an insulating material made of a cross-linked resin.

Further, since DCP is rapidly decomposed by heat, even if the molding temperature is not raised, premature crosslinking similarly occurs in a long-time operation, and it is difficult to stably perform the extrusion operation.

The object of the present invention is, without scorch generation,
An object of the present invention is to provide an electric insulating composition and a wire / cable which are composed of a crosslinked thermoplastic resin and which can be stably extruded.

[0008]

Means for Solving the Problems The gist of the present invention is to provide a thermoplastic resin with 3,4-dimethyl-3,4-diphenylhexane or
An electrically insulating composition containing 3,3,6,6,9,9-hexamethyl-1,2,4,5-tetraoxacyclononane and a polyfunctional compound, and 100 parts by weight of a thermoplastic resin. On the other hand, 3,4-dimethyl-3,4-diphenylhexane or 3,3,6,6,9,9-hexamethyl-1,2,4,5-tetraoxacyclononane was added to 0.5
It is an electric wire / cable formed by providing a resin composition containing 0.05 to 5.0 parts by weight and 0.05 to 10 parts by weight of a polyfunctional compound on a conductor or a conductor shielding layer and performing a crosslinking treatment.

[0009]

In the present invention, 3,4, dimethyl-3,4-diphenylhexane or 3,3,4-diphenylhexane is used as a cross-linking agent in order to realize an organic insulating material composed of a cross-linked thermoplastic resin that can be molded without the generation of scorch. 6,6,9,9-hexamethyl-1,2,4,5-tetraoxacyclononane is used. This 3,4, dimethyl-3,4-
Diphenylhexane or 3,3,6,6,9,9-hexamethyl-1,
The combination of 2,4,5-tetraoxacyclononane and the polyfunctional compound increases the crosslinking speed, and thus the crosslinking density can be easily increased.

3,4, Dimethyl-3,4-diphenylhexane or 3,3,6,6,9,9-hexamethyl-1,2,4,5-tetraoxacyclononane was added to the insulator in the form of 0. It is preferable to add 5 to 5.0 parts by weight. If it is less than 0.5 part by weight, crosslinking will be insufficient, and if it exceeds 5 parts by weight, precipitation (bloom) will occur on the surface after molding.

As the crosslinking aid, 3,4, dimethyl-3,4-diphenylhexane or 3,3,6,6,9,9-hexamethyl-1,2,4,5
Examples of the polyfunctional compound used in combination with tetraoxacyclononane include the following.

Acrylic acid ester (eg ethyl acrylate) Methacrylic acid ester (eg methyl methacrylate) triallyl cyanurate triallyl isocyanurate xylene-α, α'-diylbis [3,5-di- (2-propenyl) -1, 3,5-Triazine-2,4,6- (1H, 3H, 5H) -trione] These can be used alone or in combination of two or more.

The polyfunctional compound is contained in the insulator in an amount of 0.05 to 1
It is preferable to add 0 part by weight. If it is less than 0.05 parts by weight, it will not be effective as a crosslinking aid, and if it exceeds 10 parts by weight, precipitation (bloom) will occur on the surface after molding.

The thermoplastic resin constituting the insulating material of the present invention includes low density polyethylene, medium density polyethylene, high density polyethylene, linear low density or very low density polyethylene, and ethylene with a copolymerization ratio of 50%. Ethylene copolymers containing the above, for example vinyl acetate, alkyl acrylates or alkyl methacrylates (eg ethyl acrylate, methyl methacrylate, glycidyl methacrylate), copolymers of propylene and ethylene, maleic anhydride to polyethylene, phthalic acid, acrylic acid, Grafted modified polyethylene grafted with methacrylic acid, polypropylene (including isotactic, syndiotactic and atactic), polybutene, poly (4-
Methylpentene-1), other α-olefin polymers,
Chlorinated polyethylene, substituted polyolefin such as polystyrene, polyester resin such as polyethylene terephthalate and polybutylene terephthalate, polyamide resin such as nylon 6, nylon 66, nylon 11 and nylon 12, vinylidene fluoride, ethylene-tetrafluoroethylene copolymer, Fluorine resins such as propylene-tetrafluoroethylene copolymer, FEP (tetrafluoroethylene-hexafluoropropylene main polymer) and PFA (tetrafluoroethylene-alkoxy perfluoroethylene copolymer) are included, and these are used alone or Two or more kinds can be used in combination.

Antioxidants, lubricants, colorants and the like can be added to the insulating material of the present invention.

[0016]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a cross-sectional view of an electric wire / cable, in which 1 is an annealed copper stranded wire, on which an inner semiconductive layer 2 and an insulating layer 3 made of an electrically insulating composition and an external conductive layer are provided. 4 is extruded, and then cross-linked
It is called cable 5.

Table 1 shows examples 1 to 8 in which 3,4-dimethyl-3,4-diphenylhexane was used as an electrically insulating composition.
And Table 2 shows Comparative Examples 1-5 with respect to Examples 1-8.
Is shown.

[0019]

[Table 1]

[0020]

[Table 2]

The electrically insulating compositions having the compositions shown in Tables 1 and 2 were kneaded at a temperature of 170 ° C. with a 22 inch mixing roll,
It was made into a sheet and pelletized with a pelletizer. Then
The pellets were introduced into the extruder, and at 160 ° C, 60 mm
^It was extruded as an insulating layer having a thickness of 4 mm onto the annealed copper wire of No. ² together with an inner semiconductive layer having a thickness of 0.7 mm and an outer semiconductive layer. Immediately thereafter, the sample was completed by completing cross-linking in a dry cross-linking tube using nitrogen gas as a heat medium, and then pressure cooling to complete the wire / cable.

The evaluation was based on the following.

Extrudability: Cable extrusion (temperature 160
The appearance after ℃), that is, whether or not scorch is generated is observed.

AC breakdown voltage: test cable at room temperature 17
The voltage was increased at a rate of kV / 10 min and then 5 kV / 10 min to measure the dielectric breakdown voltage.

Gel fraction: Measured according to JIS C3005.

Precipitation of additives: The surface of the molded cable was observed and examined.

As shown in Table 1, in Examples 1 to 8,
All of them have good extrusion processability and have a large AC breakdown voltage. On the other hand, as shown in Table 2, Comparative Example 1
In Nos. 4 and 5, the extrudability was poor and it was impossible to measure the AC breakdown voltage. Further, Comparative Examples 2 and 3 have good extrudability, but have a low AC breakdown voltage, and 2 has precipitation of additives.

Next, Examples 9 to 16 using 3,3,6,6,9,9-hexamethyl-1,2,4,5-tetraoxacyclononane as a cross-linking agent are shown in Table 3, and their comparisons are made. Examples 6 to 10 are shown in Table 4.

[0029]

[Table 3]

[0030]

[Table 4]

All of Examples 9 to 16 have good extrusion processability and large AC breakdown voltage. On the other hand, in Comparative Examples 6, 9 and 10, the extrudability was poor and it was impossible to measure the AC breakdown voltage. Further, Comparative Examples 7 and 8 are good in extrusion processing, but have a low AC breakdown voltage,
In Comparative Example 7, precipitation of the additive also occurred.

[0032]

As described above, according to the present invention,
An electric wire / cable that prevents scorch when melt-molding an electric wire / cable and its accessories with a resin composition containing a cross-linking agent, and enables cross-linking when a thermoplastic resin having a high melting point is used, and its It is possible to provide accessories and its industrial value is extremely high.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of an electric wire / cable.

[Explanation of symbols]

 3 Insulator (electrical insulation composition) 5 Electric wire / cable

Claims (4)

[Claims] 1. An electrical insulating composition comprising a thermoplastic resin containing 3,4-dimethyl-3,4-diphenylhexane and a polyfunctional compound. 2. A thermoplastic resin containing 3,3,6,6,9,9-hexamethyl-1,2,4,5-tetraoxacyclononane and a polyfunctional compound. Electrical insulation composition. 3. 3,4-based on 100 parts by weight of the thermoplastic resin
A resin composition containing 0.5 to 5.0 parts by weight of dimethyl-3,4-diphenylhexane and 0.05 to 10 parts by weight of a polyfunctional compound is provided on a conductor or a conductor shielding layer and subjected to a crosslinking treatment. Electric wires and cables characterized by being configured. 4. 100 parts by weight of the thermoplastic resin, 3,3,
0.5 to 5.0 parts by weight of 6,6,9,9-hexamethyl-1,2,4,5-tetraoxacyclononane and 0.0 to 10 parts of a polyfunctional compound.
An electric wire / cable comprising a resin composition containing 5 to 10 parts by weight on a conductor or a conductor shielding layer, and crosslinking treatment.