JPH0687372B2 - Fluorine-containing elastomer coated wire - Google Patents

Description

TECHNICAL FIELD The present invention relates to an electric wire coated with a resin composition containing a tetrafluoroethylene-propylene-based copolymer as a main component, and particularly to an electric wire excellent in heat distortion resistance. Is.

[Prior Art] Tetrafluoroethylene-propylene copolymer is known as a crosslinkable fluorine-containing elastomer copolymer having high thermal stability, oil resistance, insulation, chemical resistance and flame retardancy. However, it is possible to obtain an electric wire / cable having the above-mentioned features by coating the outer periphery of a conductor or an electric wire core with such a copolymer, and it is currently being studied in various fields.

Tetrafluoroethylene-propylene-based copolymer has a problem in heat distortion resistance, and in order to solve this, thermal carbon, which is conventionally known as a filler for fluororubber, talc, white filler such as clay is used. A coating layer is formed with the resin composition used.

[Problems to be Solved by the Invention] However, it is inferior in heat deformation resistance as compared with general fluororesin which represents tetrafluoroethylene-hexafluoropropylene, and has high heat resistance such as electric wires for automobiles and lead wires for motors. Deformability is required and there is a problem in application to the field.

It is an object of the present invention to provide a fluorine-containing elastomer covered electric wire having a high degree of thermal deformation resistance.

[Means for Solving Problems] The electric wire of the present invention is a resin containing 5 to 40 parts by weight of silicon dioxide surface-treated with dialkyldichlorosilane, based on 100 parts by weight of a tetrafluoroethylene-propylene copolymer. A coating layer of the composition is provided and the coating layer is cross-linked.

In the present invention, the tetrafluoroethylene-propylene-based copolymer includes, in addition to the main components tetrafluoroethylene and propylene, a component copolymerizable therewith, such as ethylene, butene-1, isobutene, acrylic acid and alkyls thereof. Ester, methacrylic acid and its alkyl ester, vinyl fluoride, vinylidene fluoride, hexafluoropropene, chloroethyl vinyl ether,
Glycidyl vinyl ether, chlorotrifluoroethylene, perfluoroalkyl vinyl ether and the like may be appropriately contained.

In such a copolymer, the content molar ratio of tetrafluoroethylene / propylene is 95/5 to 30/70, particularly 90/10.
From the viewpoint of heat resistance, moldability, etc., it is preferable to select from the range of ~ 45/55, and the content of components other than the appropriately added main component is usually 50 mol% or less, particularly 30 mol% or less. It is preferable to select from

The surface treatment of dialkyldichlorosilane on silicon dioxide is performed, for example, with an inert gas atmosphere at about 400 with steam.
It is carried out by heating to ℃. The admixture amount of silicon dioxide surface-treated with this dialkyldichlorosilane must be in the range of 5 to 40 parts by weight with respect to 100 parts by weight of the tetrafluoroethylene-propylene-based copolymer. The effect of improving the deformability is small, and if it exceeds 40 parts by weight, the viscosity increases greatly and the extrusion process becomes difficult.

Specific examples of the dialkyldichlorosilane include dimethyldichlorosilane, diethyldichlorosilane, diphenyldichlorosilane and the like, and dimethyldichlorosilane is preferable.

Although silicon dioxide which is not surface-treated with dialkyldichlorosilane is also effective in improving the heat distortion resistance, it has a problem that extrusion processing becomes difficult because the viscosity of the composition remarkably increases.

The resin composition containing the above-mentioned tetrafluoroethylene-propylene-based copolymer and dimethyldichlorosilane as a surface-treated silicon dioxide as essential components is extrusion-coated on the outer circumference of the conductor or the electric wire core and then crosslinked.

The cross-linking method may be chemical cross-linking by addition of induced peroxides, amines or the like, or irradiation cross-linking by irradiation of ionizing radiation such as γ-rays or electron beams, and is not particularly limited.

Specific examples of the organic peroxide include di-t-butyl peroxide, t-butyl cumyl peroxide, dicumyl peroxide, and 2,5-dimethyl-2,5-di (t-butylperoxy) -hexyne. -3,1,3-bis- (t-butylperoxy-isopropyl) benzene and the like.

Specific examples of amines include hexamethylenediamine,
Examples thereof include so-called alkyl polyamines such as tetraethylene pentamine and triethylene tetramine, salts thereof such as carbamic acid and cinnamylidene acid, aromatic polyamines such as piperazine, piperidine, pyridine, aniline and phenanthroline and salts thereof.

Further, it is possible to employ a crosslinking aid such as an allyl compound, sulfur, organic amines, maleimides, methacrylates, divinyl compounds, etc., preferably diallyl phthalate, triallyl phosphoric acid, triallyl isocyanurate, triallyl cyanurate, etc. Allyl compounds of can be used.

In the present invention, in addition to the above components, a filler (silicic acid-based,
Carbon black, calcium carbonate, aluminum hydroxide, magnesium hydroxide, etc.), pigments, lubricants, extrusion aids,
You may mix | blend various additives, such as an antioxidant and a stabilizer.

Further, a fluororesin such as polyvinylidene fluoride or an ethylene-tetrafluoroethylene copolymer, or a resin such as fluororubber such as vinylidene fluoride-hexafluoropropylene may be mixed.

[Example] The composition as shown in each example in Table 1 was kneaded with an 8-inch roll heated to 60 ° C.

Next, head: 100 ℃, cylinder 1: 100 ℃, cylinder 2: 80
Using a 40 m / m extruder (L / D = 22) set to ℃, the outer shape is 1.6 m
The outer circumference of the mφ tin-plated copper stranded wire was extrusion-coated to a thickness of 0.5 mm, and then held in steam at 13 atm for 3 minutes to crosslink.

The heating deformation rate of the electric wire produced in this manner was measured based on JIS standards. The extrusion processability was also evaluated. The results are shown in the lower column of Table 1.

As is clear from Table 1, Example 1 within the scope of the present invention
In Nos. 5 to 5, the heat distortion resistance is extremely good and the extrusion processability is also excellent.

On the other hand, in Comparative Example 1 in which the content of silicon dioxide surface-treated with dimethyldichlorosilane is less than the specified value of the present invention, and Comparative Examples 2 to 4 in which the non-specified filler of the present invention is used, heat deformation is caused. The rate is high. Further, in Comparative Example 5 using silicon dioxide that was not surface-treated, the composition had a high viscosity, so that the heat generated in the extruder was large, and as a result, premature cross-linking occurred in the extruder and extrusion processing could not be performed.

[Effects of the Invention] As described above, according to the present invention, the thermal deformation resistance can be significantly improved while maintaining the excellent extrusion processability, and as a result, the usage range of the fluorine-containing elastomer-coated electric wire can be further expanded. It will be possible.

Claims (1)

[Claims] 1. A coating layer of a resin composition containing 5 to 40 parts by weight of silicon dioxide surface-treated with dialkyldichlorosilane, based on 100 parts by weight of a tetrafluoroethylene-propylene copolymer. A fluorine-containing elastomer-coated electric wire, wherein the coating layer is crosslinked.