JPH04329212A - Fluorine-containing elastic-material coated electric wire - Google Patents

Abstract

PURPOSE:To provide a fluorine-containing elastic-material coated electric wire of which a coating material is improved and which is therefore subjected to no foaming or no production of any grain when extrusion-worked, thus exhibiting a good surface appearance and a superior toughness. CONSTITUTION:A coating layer is formed by a composition wherein 5 to 100 weight part of ethylene-vinylacetate based copolymer, etc., and 0.5 weight part or more of crosslinking agent are added to 100 weight part of a mixture of a graft polymer, prepared by grafting a tetrafluoroethylene-propylene based copolymer, and polyvinylidene fluoride in the weight ratio of 90/10 to 10/90. Radiation rays are irradiated onto this coating layer. The above-identified electric wire which is subjected to no foaming in being machined and is superior in toughness is obtained. Use of this electric wire provides an advantage that the operating efficiency and economy are enhanced.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improvements in elastic-coated electric wires, and more particularly to fluorine-containing elastic-covered electric wires having a coating layer with excellent toughness.

0002

BACKGROUND OF THE INVENTION Graft polymers have excellent heat resistance, oil resistance, chemical resistance, electrical insulation, flexibility, etc., and are therefore ideal as insulating materials and sheath materials for electric wires.

However, compared to general fluororesins such as tetrafluoroethylene-hexafluoropropylene copolymer, mechanical strength such as tensile strength and tear strength is low, and there are problems in terms of toughness. .

In order to improve the toughness of tetrafluoroethylene-hexafluoropropylene copolymers, it has been proposed to blend ethylene-tetrafluoroethylene copolymers.

[0005]

[Problems to be Solved by the Invention] However, since the ethylene-tetrafluoroethylene copolymer has a high melting point of 260°C, it is difficult to reduce the compounding and extrusion processing temperature to 300°C.
As a result, the conventional method has the problem of foaming and crushing during extrusion processing. The present invention has been made based on the above, and an object of the present invention is to provide a fluorine-containing elastic material-coated electric wire that has a tough coating and is free from foaming and crushing during extrusion processing.

[0006]

[Means for Solving the Problems] In order to solve the above problems, the fluorine-containing elastomer-covered electric wire of the present invention has a structure in which styrene and acrylic ester are added in an amount of 5 to 50% by weight in a tetrafluoroethylene-propylene copolymer. % and the weight ratio of the grafted polymer to polyvinylidene fluoride was 90/10 to 10/90. Ethylene-vinyl acetate copolymer or ethylene-acrylic acid ester copolymer Ionizing radiation is irradiated onto a coating layer made of a composition containing 5 to 100 parts by weight of at least one selected from the group consisting of 5 to 100 parts by weight of at least one selected from the group consisting of 5 to 100 parts by weight of a crosslinking aid and 0.5 parts by weight or more of a crosslinking aid.

[0007]

[Action] In addition to the main components of tetrafluoroethylene and propylene, the tetrafluoroethylene-propylene copolymer contains components that can be copolymerized with these, such as
Ethylene, butene-1, isobutene, acrylic acid and its alkyl esters, methacrylic acid and its alkyl esters, vinyl fluoride, vinylidene fluoride, hexafluoropropene, chloroethyl vinyl ether, glylene, perfluoroalkyl vinyl ether, etc. are added as appropriate. But that's fine.

[0008] The tetrafluoroethylene-propylene copolymer has a molar ratio of tetrafluoroethylene/propylene of 95/5 to 30/70 in terms of heat resistance, moldability, etc.
It is desirable to select from the range of 9, particularly preferably 9.
It is in the range of 0/10 to 45/55. Further, the content of components other than the main component, which may be added as appropriate, is desirably selected from a range of 50 moles or less, particularly 30 moles or less.

Examples of the acrylic ester grafted onto the tetrafluoroethylene-propylene copolymer include methyl acrylate, ethyl acrylate, n-butyl acrylate, and 2-ethyl-hexyl acrylate.

[0010] The amount of grafting of styrene and acrylic acid ester must be in the range of 5 to 50% by weight, and 5% by weight
If it is less than 50% by weight, the compatibility with the ethylene copolymer will be poor, and if it exceeds 50% by weight, the heat resistance, which is one of the characteristics of the tetrafluoroethylene-propylene copolymer, will be impaired.

The content ratio of styrene/acrylic acid ester is preferably in the range of 20 to 50% by weight from the viewpoint of electrical insulation and heat resistance.

The content of vinyl acetate and acrylic ester in the ethylene-vinyl acetate copolymer and ethylene-acrylic ester copolymer is preferably 5 to 50% by weight, respectively.

The polyvinylidene fluoride may contain trifluoroethylene or chlorotrifluoroethylene as a third component.

[0014] The content ratio of graft polymer/polyvinylidene fluoride must be selected from the range of 90/10 to 10/90 in terms of weight ratio. If the amount of polyvinylidene fluoride is more than 90 parts by weight, the elongation will be small, and if it is less than 10 parts by weight, the abrasion resistance will not be improved.

The amount of the ethylene-vinyl acetate copolymer or the ethylene-acrylic acid ester copolymer needs to be 5 to 100 parts by weight per 100 parts by weight of the graft polymer and polyvinylidene fluoride in total. In other words, if the amount is less than 5 parts by weight, a large amount of inorganic filler cannot be added, and if it exceeds 100 parts by weight, the heat resistance will decrease.

Examples of crosslinking aids include allyl type compounds, sulfur, organic amines, maleimides, methacrylates, divinyl compounds, polybutadiene, etc. Allyl type compounds represented by triallyl isocyanurate and triallyl cyanurate Compounds are particularly preferred. The amount of the crosslinking aid added must be 0.5 parts by weight or more per 100 parts by weight of the resin, and if it is less than 0.5 parts by weight, a sufficient degree of crosslinking cannot be achieved. Particularly preferably 1 to 20
At 20 parts by weight, the effect of adding the crosslinking auxiliary agent is saturated.

In the present invention, in addition to the above components, as appropriate,
Stabilizers, fillers, colorants, antioxidants, lubricants, etc. may be added. Stabilizers include lead oxide, calcium oxide, magnesium oxide, aluminum oxide, titanium oxide, antimony oxide, phosphorus pentoxide, etc. Fillers include carbon black, aluminum silicate, anhydrous magnesium silicate, and calcium carbonate. , calcium silicate, etc.

[0018]

[Examples] Examples of the present invention and comparative examples will be explained below using Table 1.

Table 1 shows the components and evaluation items of 6 Examples and 4 Comparative Examples.

[0020] The materials for each component as shown in Table 1 were kneaded (
Melt and knead using a kneader). Using a 40 mm extruder (L/D = 22) set at cylinder 1: 100°C, cylinder 2: 180°C, head: 190°C, die: 200°C, a conductor (tin-plated copper (concentric stranded wire) with a thickness of 0.5 mm, then 10M
It was crosslinked by irradiation with a rad electron beam to obtain a test material.

[0021]

[Table 1]

In Table 1, Examples 1 to 6 have a weight ratio of graft polymer/polyvinylidene fluoride of 90/10 to 90/10.
10/90 (60/40), and 5 to 100 parts by weight of either ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, or ethylene-ethyl acrylate copolymer (20) and 0 crosslinking aids
．． At least 5 parts by weight (5) and appropriate amounts of stabilizers and the like were added. On the other hand, in the comparative examples, the amounts of the ingredients, etc. exceeded the above range.

The test method and evaluation method will be explained below.

The insulated wires of each example produced as described above were judged to be good or bad by visually observing the occurrence of foaming and crushing during extrusion and the appearance of the surface.

[0025] The tensile strength and elongation were evaluated by a tensile test.

[0026] Heat resistance was determined by winding an electric wire around a 35 mmφ mandrel and leaving it at 200°C for 10 days, and passing the test if there were no cracks.

[0027] Wear resistance is based on the automobile standard JASOD611.
We conducted a wear resistance test on (thin-walled low-voltage electric wire for automobiles). In other words, put a load of 450g on the wire, and
An abrasion tape was inserted between cylindrical rods of mmφ, the tape was moved, and the distance traveled by the tape to penetrate the conductor was measured, and a distance of 457 mm or more was considered to be passed.

As can be seen from Table 1, in Examples 1 to 6 within the scope of the present invention, no foaming or crushing occurred during extrusion, the appearance of the extruded surface was good, and the tensile properties and heat resistance were good. , wear resistance were all passed.

Comparative Example 1 is a case in which the content of polyvinylidene fluoride is less than the specified value of the present invention, and the wear resistance is poor. Comparative Example 2 is a case where the content of polyvinylidene fluoride is higher than the specified value of the present invention, and the elongation value is low. Comparative Example 3 is a case where the content of ethylene-vinyl acetate copolymer is less than the specified value, and a large amount of inorganic filler (80
), tensile strength, elongation, heat resistance, and abrasion resistance all decrease. Comparative Example 4 is a case where the content of the ethylene-vinyl acetate copolymer exceeds the specified value, and the heat resistance and abrasion resistance decrease.

[0030]

[Effects of the Invention] According to the present invention, it is possible to easily produce a fluorine-containing elastomer-coated electric wire that has excellent toughness, does not cause foaming or crushing during extrusion processing, and has a good finished surface appearance. . Therefore, use of this electric wire can contribute to improving workability and economic efficiency.

Claims (1)

[Claims] Claim 1: A tetrafluoroethylene-propylene copolymer containing 5 to 5 styrene and acrylic acid ester.
The weight ratio of the graft polymer to polyvinylidene fluoride, which was added by 0% by weight and subjected to graft reaction, was 90/10 to 10/90.
5 to 100 parts by weight of at least one selected from ethylene-vinyl acetate copolymer or ethylene-acrylic acid ester copolymer, based on 100 parts by weight of the resin content;
1. A fluorine-containing elastomer-coated electric wire, characterized in that it is formed by irradiating ionizing radiation to a coating layer made of a composition to which 0.5 parts by weight or more of a crosslinking aid is added.