JPH10106354A - Resin composition for insulation and coated electric wire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide sufficient heat resistance and plasticity and easiness to be peeled by using low density polyethylene and ethylenic copolymer as resin components in a resin composition containing silane-type crosslinking agent for insulation. SOLUTION: In a resin composition, which contains resin components and a silane cross-linking agent, for insulation for coated electric wires, not more then 90 pts.wt. of low density polyethylene and the balance ethylenic copolymer or ultra low density polyethylene are used as the resin components in the case the pts.wt. of resin components is set to be 100 pts.wt. In this case, the low density polyethylene has 0.910-0.930 specific gravity and the ultra low density polyethylene has lower than 0.910 specific gravity. In the case the content of low density polyethylene in the resin components is not higher than 75 pts.wt., the resin composition is provided with excellent plasticity and easiness to be peeled. The resin composition for insulation can be obtained by mixing resin components, alkoxysilane, peroxides, a tin type stabilizer, etc., while keeping at room temperature or heating at approximately 100 deg.C or lower.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low-voltage power cable which can be used as a domestic or residential assembled electric wire, and an insulating resin composition which can be used for its insulating layer and the like.

[0002]

2. Description of the Related Art A 600 V vinyl insulated vinyl sheath cable flat type widely used for household and residential assembled electric wires is a typical low-voltage power cable, which is mainly composed of polyvinyl chloride. The insulator is excellent in flexibility and peelability, and is easy to construct.

However, recently, with the increase in power consumption, it has been desired to improve the performance, that is, to cope with a large current. However, as described above, the heat resistance temperature of the conventional coating layer mainly composed of polyvinyl chloride is about 60 ° C., and therefore, it cannot cope with the heat generated when a large current is applied, and cannot meet this requirement. Here, by using a cross-linked polyethylene composition having a heat-resistant temperature of about 90 ° C. for the coating layer, the current can be increased to about 1.6 times that of a conventional power cable having a coating layer made of polyvinyl chloride. It is now possible to respond.
It should be noted that, when a current of the same level flows, the cable can be handled with a thinner cable than a conventional cable, so that it is possible to reduce the weight, space, and cost. However, the coating layer using such cross-linked polyethylene is disadvantageous in construction and the like because it is inferior in flexibility and peelability as compared with the conventional coating layer made of polyvinyl chloride, and improvement is required. Was.

[0004]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned drawbacks of the prior art, that is, a coated electric wire having a coating layer having sufficient heat resistance and excellent flexibility and peelability. It is another object of the present invention to provide an insulating resin composition for use in forming a coating layer of such a coated electric wire.

[0005]

The insulating resin composition of the present invention is an insulating resin composition containing a resin component and a silane crosslinking agent as described in claim 1, wherein the resin component is When the resin component is 100 parts by weight, the resin component has a composition comprising 90 parts by weight or less of low-density polyethylene, and the balance of an ethylene copolymer or / and ultra-low-density polyethylene. Further, the insulating resin composition of the present invention is an insulating resin composition containing a resin component and a silane crosslinking agent as described in claim 5, wherein the resin component is 100 parts by weight. 70 to 90 parts by weight of a mixture of a low-density polyethylene of 50 to 100% by weight and a low-density polyethylene of 0 to 50% by weight, and the remaining ethylene-based copolymer It has a configuration consisting of coalescing.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The insulating resin composition according to the present invention comprises an appropriate amount of the above-mentioned resin component and an alkoxysilane as a silane crosslinking agent, as well as a crosslinking aid, a tin-based stabilizer, an antioxidant, and an ultraviolet absorber. It is constituted by additives. Here, the ethylene-based copolymer is an ethylene-propylene copolymer,
One or a mixture of two or more selected from ethylene-ethyl acrylate copolymer, ethylene-vinyl acetate copolymer, ethylene-propylene-diene terpolymer, and the like.

In the present invention, low density polyethylene is
Specific gravity refers to polyethylene having a specific gravity of 0.910 or more and 0.930 or less, and ultra-low density polyethylene refers to polyethylene having a specific gravity of less than 0.910. The linear low-density polyethylene is a copolymer of ethylene and an α-olefin.
When the content of the low-density polyethylene in 100 parts by weight of the resin component is 75 parts by weight or less, better flexibility and peelability can be obtained. When the content of the low-density polyethylene in 100 parts by weight of the resin component is 50 parts by weight or more, the cost of the raw material can be reduced without impairing the effects of the present invention.

In the present invention, generally known alkoxysilanes such as vinyltrimethoxysilane, vinyltriethoxysilane, vinylmethyldiethoxysilane and vinylphenyldimethoxysilane can be used as the alkoxysilane as a silane crosslinking agent. is there. These silane crosslinking agents are desirably compounded in an amount of 1 part by weight or more and 3 parts by weight or less when the above resin component is 100 parts by weight.
If the amount is less than 1 part by weight, the crosslinking is incomplete and is not practical. On the other hand, the addition of more than 3 parts by weight is not preferable because the effect is saturated and the economy becomes uneconomical.

As a crosslinking aid, dicumyl peroxide, 2,5-dimethyl-2,5- (tert-butylperoxy) hexyne-3, 1,3-bis (tert-butylperoxyisopropyl) benzene or the like is used. be able to.
These peroxides are desirably compounded in an amount of 0.05 to 0.15 parts by weight based on 100 parts by weight of the resin component. If the amount is less than 0.05 part by weight, the crosslinking is incomplete and is not practical. On the other hand, the addition of more than 0.15 parts by weight is not preferred because the effect is saturated and the economy becomes inefficient.

Examples of the tin-based stabilizer include dibutyltin dilaurate (hereinafter referred to as "DBTDL"), dibutyltin dimaleate, dibutyltin methylcaptide and the like. In addition, the compounding amount of DBTDL is 100 parts of the above resin component.
In terms of parts by weight, the amount is desirably 0.05 to 0.2 parts by weight. If the amount is less than 0.05 parts by weight, the crosslinking is incomplete, and the product is not practical. On the other hand, the addition of more than 0.2 parts by weight is not preferable because the effect is saturated and the economy becomes inefficient.

As anti-aging agents, hindered phenols (tetrakis- [methylene-3- (3 ′, 5′-
Di-tert-butyl-4'-hydroxyphenyl) propionate] methane), thiobisphenol-based (4,4 '
Commonly known antioxidants such as -thiobis- (6-tert-butyl-3-methylphenol) can be used.
These antioxidants are desirably added in an amount of 0.01 part by weight or more and 0.2 part by weight or more based on 100 parts by weight of the resin component. If the amount is less than 0.01 part by weight, heat resistance cannot be maintained, and thus it cannot be put to practical use. On the other hand, the addition of more than 0.2 parts by weight is not preferable because the effect is saturated and the economy becomes inefficient.

The insulating resin composition according to the present invention is prepared by heating a resin component, an alkoxysilane, a peroxide, a tin-based stabilizer and the like to a room temperature to about 100 ° C. or lower using a mixing means such as a Henschel mixer. While mixing. Further, as another method, a resin component, an alkoxysilane,
It is also obtained by mixing the peroxide while heating it to about 100 ° C. or lower, and then adding a tin-based stabilizer or the like. The former method is economical because it can be obtained by one mixing.

The insulating resin composition thus obtained can be formed into an electric wire coating layer by extrusion molding in the same manner as a usual insulating composition. The cross-linking reaction is performed in a state where the electric wire is covered. That is, the electric wire is immersed in warm water or hot water, or is placed in an environment containing water vapor to perform silane crosslinking, thereby forming an insulating layer. In addition, in the insulating resin composition after the crosslinking, the elasticity at the time of a 5% load of the elongation in the tensile test after the crosslinking (hereinafter referred to as “5.
% Elasticity) is 5.7 MPa or less, good flexibility and peelability can be obtained. This elasticity is related to the ease of scissors when peeling and the ease of applying force when peeling. If it is 5.7 MPa or less, conductors may be accidentally scratched when peeling. Along with drastic reduction, peelability is remarkably improved.

The thus obtained coated electric wire having an insulating layer has the same heat resistance as the conventional insulating layer made of crosslinked polyethylene, and has the same flexibility and peeling properties as the insulating layer made of polyvinyl chloride. It has excellent properties. Although the coated electric wire according to the present invention can be produced by the method described above, a cross-linking agent, an alkoxysilane, a tin-based stabilizer, and the like are mixed in advance to form a master batch, and this is mixed with a resin component. In addition, it can be obtained by insulating extrusion.

[0015]

EXAMPLES The resin component, dicumyl peroxide, vinyltrimethoxysilane, dibutyltin dilaurate, and an antioxidant (Irganox 1010 manufactured by Ciba-Geigy) were used in Examples 1 to 44 and Comparative Examples 1 to 4 in Tables 1 and 2, respectively. 7 and Comparative Examples 10 to 13 so as to have a weight ratio as shown in FIG.
The mixture was kneaded for minutes to obtain a composition. For comparison, a comparative example 8 in Table 2 was used assuming that a coating layer according to the prior art was formed.
And as shown in Comparative Example 9, a soft polyvinyl chloride resin composition and a resin composition for crosslinked polyethylene were prepared.

The abbreviation "LDP" in Tables 1 to 4 is used.
"E" is a low-density polyethylene, "EEA" is an ethylene-ethyl acrylate copolymer, "EVA" is an ethylene-vinyl acetate copolymer, "VLDPE" is an ultra-low-density polyethylene, and "EPDM" is ethylene-propylene-diene triene. Copolymer, "flexible PVC" is flexible polyvinyl chloride,
“XLPE” refers to cross-linked polyethylene and “L-LDPE”
Is linear low-density polyethylene, "EPM" is ethylene-
Each means a propylene copolymer. Also, "MF
"R" is a melt index value measured according to JIS K7210, "d" is specific gravity, "EA content" and "V
"A content" indicates the content of the ethyl acetate unit and the content of the vinyl alcohol unit in the polymer, respectively.

Examples 1 to 44 and Comparative Examples 1 to 13
A 600 V vinyl sheath cable flat type (size 2 × 1.6 mm) having an insulating layer made of the above resin composition was prepared using an extruder. Of these insulated wires,
Examples 1 to 40 and Comparative Examples 1 to 7 and Comparative Examples 10 to 13
With respect to the resin composition using the above resin composition, the crosslinking treatment was performed by immersing the resin composition in warm water at 90 ° C. for 4 hours. In addition,
The elasticity of the insulating resin composition after cross-linking under a load of 5% of the elongation at the time of a tensile test was determined using a resin layer obtained by extracting a conductor from the cable alone as a sample and a tensile speed of 200 mm /
It was determined from a load-strain curve when a tensile test was performed in min. At the same time, the elasticity under a 10% load (hereinafter referred to as “
% Elasticity).

The cable thus obtained was evaluated for its heat deformation rate, flexibility, and peelability. That is, as for the heating deformation ratio, the deformation ratio when a force of 10 N at 120 ° C. was applied was examined. If the heating deformation rate at this time is 40% or less, it is judged that the heating deformation is small and good. On the other hand, the flexibility is the feeling when the above cable is bent by hand, and the peeling is the peeling when the insulator of 30 mm is peeled from the cable end of the 600 V power cable (flat type) using scissors. Of the cable having the insulating layer made of the soft polyvinyl chloride resin composition of Comparative Example 8 and the cable having the crosslinked polyethylene insulating layer of Comparative Example 9 were evaluated as follows: ○, □, Δ, and The four-stage evaluation of x was performed. That is, は indicates that the feeling was as good as that of Comparative Example 8, □ indicates that the feeling was slightly inferior to that of ○, but almost the same, and Δ indicates that the feeling of Comparative Example 8 and that of Comparative Example 9 were intermediate. And x indicate those having an inferior feeling equal to the feeling in Comparative Example 9. These evaluation results are also shown in Tables 1 to 4.

[0019]

[Table 1]

[0020]

[Table 2]

[0021]

[Table 3]

[0022]

[Table 4]

According to Tables 1 to 4, the coated electric wire having the insulating layer formed by the insulating resin composition (Examples 1 to 44) according to the present invention has flexibility and heat resistance while maintaining sufficient heat resistance. It is clear that it has excellent peelability. The same composition as in Examples 1 to 24 and Comparative Examples 1 to 7 was used, and the resin component, vinyltrimethoxysilane, and dicumyl peroxide were mixed and kneaded at a set temperature of 200 ° C. by a single screw extruder, followed by grafting. After forming a polymer compound, dibutyltin dilaurate, an antioxidant and the like are added to obtain a resin composition, which is extruded together with a conductor into a 600 V power cable (flat type),
Similar evaluations were made for these cables. The results were exactly the same as those shown in Tables 1 and 2.

In the same manner as in Examples 1 to 24, the mixing ratio of non-resin components such as vinyltrimethoxysilane, dicumyl peroxide, dibutyltin dilaurate, and an antioxidant is the same, except that the mixing ratio of the resin components is changed. Only 1/20
As a result, a master batch having a relatively high concentration of non-resin components was obtained. Immediately before use, a resin component was added to the master batch so that the final composition was the same as in Examples 1 to 24.
A 0 V power cable (flat type) was obtained. Similar evaluations were performed on these cables, and as a result, Tables 1 and 2
Were completely equivalent to the results shown in FIG. From this, the resin composition of the present invention can be used for wire coating after previously containing a base resin and a silane crosslinking agent, or can be directly coated without graft polymerization, or Even in the case of using a resin composition prepared through a masterbatch containing only a small amount of components, it was confirmed that a cable excellent in flexibility and peelability was obtained while having sufficient heat resistance in each case. .

[0025]

The coated electric wire having the insulating layer formed by the insulating resin composition according to the present invention has the disadvantage that the conventional cross-linked polyethylene insulated electric wire has the advantage of having a large capacity, but has the conventional disadvantage. It is excellent in improving the drawback of poor flexibility and peelability.

Claims (9)

[Claims] 1. An insulating resin composition containing a resin component and a silane crosslinking agent, wherein the resin component is 90 parts by weight or less when the resin component is 100 parts by weight; An insulating resin composition comprising an ethylene copolymer or / and ultra-low density polyethylene. 2. The method according to claim 1, wherein the ethylene copolymer is ethylene-
1 selected from an ethyl acrylate copolymer, an ethylene-vinyl acetate copolymer, an ethylene-propylene copolymer, and an ethylene-propylene-diene terpolymer.
The insulating resin composition according to claim 1, wherein the insulating resin composition is a seed or a mixture of two or more kinds. 3. The insulating resin composition according to claim 1, wherein the content of the low-density polyethylene in 100 parts by weight of the resin component is 80 parts by weight or less and 50 parts by weight or more. . 4. The resin composition for insulation has an elasticity at a load of 5% of an elongation in a tensile test after crosslinking of 5.7.
The insulating resin composition according to any one of claims 1 to 3, wherein the composition is not more than MPa. 5. An insulating resin composition comprising a resin component and a silane crosslinking agent, wherein the resin component is 50% by weight or more and 100% by weight or less when the resin component is 100 parts by weight. An insulating resin composition comprising: 70 to 90 parts by weight of a mixture of low-density polyethylene and 0 to 50% by weight of low-density polyethylene; and the remainder of an ethylene copolymer. 6. The method according to claim 1, wherein the ethylene copolymer is ethylene-
1 selected from an ethyl acrylate copolymer, an ethylene-vinyl acetate copolymer, an ethylene-propylene copolymer, and an ethylene-propylene-diene terpolymer.
The insulating resin composition according to claim 5, wherein the resin composition is a seed or a mixture of two or more kinds. 7. The insulating resin composition according to claim 5, wherein the content of the low-density polyethylene in 100 parts by weight of the resin component is 80 parts by weight or more and 50 parts by weight or more. . 8. In the insulating resin composition, the elasticity at a load of 5% of the elongation in a tensile test after crosslinking is 5.7.
The insulating resin composition according to any one of claims 5 to 7, wherein the composition is not more than MPa. 9. The resin component constituting the insulating layer is obtained by subjecting an ethylene-based copolymer or / and ultra-low-density polyethylene to low-density polyethylene or / and / or linear low-density polyethylene by silane crosslinking. And insulated wires.