JPH0551128B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a fluorine-containing elastomer-covered electric wire having a coating layer with excellent toughness. [Prior art] Tetrafluoroethylene-propylene copolymers have properties such as heat resistance, oil resistance, chemical resistance, electrical insulation,
Due to its excellent flexibility, it is ideal as an insulating material for electric wires and as a sheet material. However, when compared with general fluororesins such as tetrafluoroethylene-hexafluoropropylene copolymer, mechanical properties such as tensile strength and tear strength are low, and there are problems with toughness. In order to improve the toughness of tetrafluoroethylene-propylene copolymers, it has been proposed to blend them with fluororesins such as ethylene-tetrafluoroethylene copolymers and polyvinylidene fluoride. [Problems to be solved by the invention] However, since the ethylene-tetrafluoroethylene copolymer has a high melting point of 260°C, it is necessary to raise the compounding and extrusion processing temperatures to nearly 300°C, and as a result, the This method has the problem of foaming and crushing during extrusion processing. Polyvinylidene fluoride has a relatively low melting point, so
Although it can be processed at about 200°C, it has poor compatibility with the tetrafluoroethylene-propylene copolymer, causing surface roughness and a problem in that a good extruded appearance cannot be obtained. The present invention has been made based on the above, and aims to provide a fluorine-containing elastic material-coated electric wire that has a strong coating, does not foam or collapse during extrusion processing, and has a good appearance. This is the purpose. [Means for Solving the Problems] The fluorine-containing elastomer-coated electric wire of the present invention is made of a tetrafluoroethylene-propylene copolymer, an ethylene-ethyl acrylate copolymer having an ethyl acrylate content of 5 to 50% by weight. A coating layer is formed from a composition in which 0.5 parts by weight or more of a crosslinking agent is added to 100 parts by weight of a resin containing a polymer and polyvinylidene fluoride, and this coating layer is crosslinked by irradiation with ionizing radiation. It is composed of In the present invention, the tetrafluoroethylene-propylene copolymer includes, in addition to the main components tetrafluoroethylene and propylene, components copolymerizable with these, such as ethylene, butene-
1. Contains isobutene, acrylic acid and its alkyl esters, methacrylic acid and its alkyl esters, vinyl fluoride, vinylidene fluoride, hexafluoropropene, chloroethyl vinyl ether, glycidyl vinyl ether, chlorotrifluoroethylene, perfluoroalkyl vinyl ether, etc. as appropriate. It may be something that has been forced upon you. The tetrafluoroethylene-propylene copolymer has a molar ratio of tetrafluoroethylene/propylene of 95/5 to 30/3 from the viewpoint of heat resistance, moldability, etc.
It is desirable to select from the range of 70, particularly preferably from 90/10 to 45/55. In addition, the content of components other than the main component that may be added as appropriate is 50 mol%.
Below, it is particularly desirable to select from a range of 30 mol% or less. It is necessary to use an ethylene-ethyl acrylate copolymer with an ethyl acrylate content of 5 to 50% by weight, and if it is less than 5% by weight, other 2
It is difficult to obtain a good appearance due to poor compatibility with the seed resin, and if it exceeds 50% by weight, the electrical insulation properties of the coating will deteriorate. Polyvinylidene fluoride may contain trifluoroethylene or chlorotrifluoroethylene as a third component. The content ratio of tetrafluoroethylene-propylene copolymer/ethylene-ethyl acrylate copolymer/polyvinylidene fluoride is 85~
It is preferable to select from the range of 20/10 to 50/5 to 30. If the amount of ethylene-ethyl acrylate copolymer is too large, the toughness will not be improved, and if it is too small, a good appearance will not be obtained. Furthermore, if the amount of polyvinylidene fluoride is too large, a good appearance cannot be obtained, and if it is too small, the toughness cannot be improved. As crosslinking aids, allyl type compounds, sulfur,
Examples include organic amines, maleimides, methacrylates, divinyl compounds, polybutadiene, etc., and allyl type compounds represented by triallyl isocyanurate and triallyl cyanurate are particularly preferred. The amount of crosslinking aid added must be 0.5 parts by weight or more per 100 parts by weight of the resin, and 0.5
If the amount is less than parts by weight, a sufficient degree of crosslinking cannot be achieved. Particularly preferably 1 to 20 parts by weight,
At 20 parts by weight, the effect of adding the crosslinking aid is saturated. In the present invention, in addition to the above-mentioned components, stabilizers, fillers, colorants, antioxidants, lubricants, etc. may be added as appropriate. Stabilizers include lead oxide, calcium oxide, magnesium oxide, aluminum oxide, titanium oxide, antimony oxide, phosphorus pentoxide, etc., and fillers include carbon black, aluminum silicate, silicic anhydride, etc. [Example of the invention] As shown in Table 1, each component was blended in a predetermined amount, and 80
The mixture was kneaded for 15 minutes with 8-inch rolls set at ~100°C. Next, head: 200℃, cylinder 1: 120℃, cylinder 2: 180℃
Using m/m extruder (L/D=22), outer diameter 1.6mm
Insulation thickness 0.7mm for the conductor (Tin plated copper stranded wire)
After coating, cross-linking was carried out by irradiation with a 5 Mrad electron beam. The results of evaluating the extrusion appearance and tensile properties of the insulated wires obtained as described above are shown in the lower column of Table 1.

[Table] Examples 1 to 5 within the scope of the present invention all have good appearance and sufficient properties in terms of tensile strength and elongation. Comparative Example 1 does not contain both ethylene-ethyl acrylate copolymer and polyvinylidene fluoride, and has low tensile strength. Comparative Example 2 does not contain ethylene-ethyl acrylate copolymer and has poor appearance when extruded, and Comparative Example 3 does not contain polyvinylidene fluoride and has low tensile strength. [Effects of the Invention] As explained above, the present invention provides a tetrafluoroethylene-propylene copolymer with an ethylene-ethyl acrylate copolymer having an ethyl acrylate content of 5 to 50% by weight and a polyvinylidene fluoride copolymer. The coating layer is made of a resin containing
It becomes possible to realize a fluorine-containing elastomer-coated electric wire that has excellent toughness, does not cause foaming or crushing during extrusion processing, and has a good appearance.

Claims (1)

[Claims] 1 Crosslinking aid per 100 parts by weight of the resin containing a tetrafluoroethylene-propylene copolymer, an ethylene-ethyl acrylate copolymer with an ethyl acrylate content of 5 to 50% by weight, and polyvinylidene fluoride. 1. A wire coated with a fluorine-containing elastomer, characterized in that a coating layer is formed of a composition containing 0.5 parts by weight or more of fluorine-containing elastomer, and the coating layer is crosslinked by irradiation with ionizing radiation.