JPH08298022A - Wire and cable covered with fluorine-containing elastomer - Google Patents

Abstract

PURPOSE: To improve elastic fatigue resistance by crosslinking a wire covered with a composition obtained by adding a specified oxidizing agent to a resin component containing a tetrafluoroethylene-propylene copolymer and an ethylene copolymer in a specified weight ratio. CONSTITUTION: To 100 parts by weight of a resin component having a contained weight ratio of tetrafluoroethylene-propylene copolymer to ethylene copolymer of 90/10 to 60/40, 0.5-10 parts by weight each of a hindered phenol antioxidant and a thioether antioxidant are added to form a mixed polymer. An organic peroxide and a crosslinking assistant, and a metal oxide are blended thereto followed by kneading to form a composition. This is extruded onto the outer circumference of a copper stranded wire conductor 1 to form a coating layer 2, and crosslinked in pressurized steam to form an insulated wire 3. The above composition is arranged on the outer circumference of the two stranded wires 3 together with an inclusion 5 followed by crosslinking to manufacture a cable.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluorine-containing elastomer-coated electric wire / cable having a coating layer mainly composed of a tetrafluoroethylene-propylene copolymer.

[0002]

2. Description of the Related Art Generally, there are chloropropylene rubber, chlorosulfonated polyethylene rubber and the like as a covering material for electric wires / cables. In addition to these, there is a tetrafluoroethylene-propylene copolymer.

This tetrafluoroethylene-propylene copolymer is a crosslinkable fluorine-containing elastomer copolymer having a high degree of thermal stability, electrical insulation, heat resistance, oil resistance, chemical resistance and flame retardancy. By coating this copolymer on the conductor or on the outer periphery of the electric wire core and crosslinking it by high-pressure steam or lead canning crosslinking using peroxide, an electric wire / cable having extremely excellent characteristics can be obtained.

[0004]

However, electric wires and cables using the coating material made of the tetrafluoroethylene-propylene copolymer are widely used such as chloropropylene rubber and chlorosulfonated polyethylene rubber. Since the bending fatigue resistance is extremely inferior to that of electric wires and cables made of coating materials, the coating layer will crack in a relatively short time when used in an environment where repeated bending is applied. There was a point.

Therefore, an object of the present invention was devised in order to effectively solve the above problems, and an object thereof is to provide a novel fluorine-containing elastomer-coated electric wire / cable excellent in flex fatigue resistance. It is provided.

[0006]

In order to achieve the above object, the invention of claim 1 is a fluoroelastomer-coated electric wire / cable in which a coating layer is formed on a conductor or on the outer periphery of an electric wire core. The hindered phenol-based antioxidant and the thioether-based antioxidant are each added in an amount of 0.5 to 10 parts by weight with respect to 100 parts by weight of the resin component having a content weight ratio of the ethylene-based copolymer and the ethylene-based copolymer of 90/10 to 60/40. A fluorine-containing elastomer-coated electric wire / cable having a coating layer composed of a composition added by parts by weight, the coating layer being crosslinked.

The invention according to claim 2 is characterized in that the coating layer is crosslinked in the presence of an organic peroxide having a one-hour half-life of 130 ° C. or more, and the fluorine-containing elastomer coating according to claim 1 is characterized. It is an electric wire / cable.

The invention of claim 3 is characterized in that the coating layer is crosslinked in the presence of an organic peroxide and a crosslinking aid, and the fluorine-containing elastomer-coated electric wire according to claim 1 or 2. -It is a cable.

[0009]

The tetrafluoroethylene-propylene copolymer, which is the main component of this composition, includes, in addition to the main components tetrafluoroethylene and propylene, components copolymerizable with them, such as ethylene, butene-1, and isobutene. , Acrylic acid and its alkyl ester, methacrylic acid and its alkyl ester, vinyl fluoride, vinylidene fluoride, hexafluoropropene, chloroethyl vinyl ether, glycidyl vinyl ether, chlorotrifluoroethylene, perfluoroalkyl vinyl ether, etc. Good.

Further, the tetrafluoroethylene-propylene copolymer has a tetrafluoroethylene-propylene content molar ratio of 95/5 to 3 from the viewpoints of heat resistance and moldability.
It is desirable to select from the range of 0/70, and particularly preferably the range of 90/10 to 45/55.

The content of the components other than the main component that is appropriately added is preferably selected from the range of 50 mol% or less, particularly 30 mol% or less.

The number average molecular weight of the tetrafluoroethylene-propylene copolymer is 20,000 to 150,000, preferably 3-1.
It is preferable to select from the range of 0,000 from the viewpoint of extrudability and mechanical strength. If the number average molecular weight is too large, cracks are likely to occur in the molded body, while if it is too small, the mechanical strength becomes insufficient, In this case, adjustment of the number molecular weight is carried out by directly controlling the molecular weight of the polymer produced by the operation of the copolymerization reaction conditions such as the monomer concentration, the polymerization initiator concentration, the monomer polymerization initiator amount ratio, the polymerization temperature and the use of the chain transfer agent. It can be carried out by a method of adjusting or a method of reducing the molecular weight by producing a high molecular weight copolymer during the copolymerization reaction and subjecting this to a heat treatment in the presence of oxygen.

The ethylene copolymers to be mixed with the tetrafluoroethylene-propylene copolymer include ethylene ethyl acrylate, ethylene methyl acrylate, ethylene methyl methacrylate, ethylene propylene copolymer, ultra low density polyethylene and ethylene. Examples thereof include vinyl acetate copolymers and ethylene-propylene copolymers.

The content weight ratio of the tetrafluoroethylene-propylene copolymer to the ethylene copolymer was limited to 90/10 to 60/40 because the flexural fatigue resistance was high when the proportion of the tetrafluoroethylene-propylene copolymer was large. Is not improved, and if the proportion of ethylene-based copolymer is large, the heat resistance and oil resistance are significantly reduced.

The antioxidant has a very large synergistic effect due to the action of the semi-hindered or highly hindered phenol type and the thioether type.

As the hindered phenol type, 1,
1,3-tris- (2-methyl-4-hydroxy-5-
Tert-butylphenyl) butane, 4,4'-butylidene bis- (3-methyl-6-tert-butylphenol), 2,
2-thiobis (4-methyl-6-tert-butylphenol), n-octadecyl-3- (4'-hydroxy-3)
′, 5′-Di-tert-butylphenyl) propionate, tetrakis [methylene-3- (3 ′, 5′-di-tert-butyl-4′-hydroxyphenyl) propionate] methane, 6- (4-hydroxy) -3,5-di-third
Bryl anilino) -2,4-bis octyl-thio-
1,3,5-triazine, tris- (3,5-di-third
Butyl-4-hydroxybenzyl) -isocyanate, A: bis (3,5-di-tert-butyl-4-hydroquin benzylethylphosphonate ethyl) calcium, B: polyethylene wax, 3,5-di-third Butyl-4-hydroxybenzyl phosphonate-diethyl ester, hindered phenol, hindered bisphenol and the like can be mentioned.

As the thioether type, dilauryl thiodipropionate, distearyl-thiodipropionate, dimyristyl-3,3'thiodibropionate, ditridecyl-3,3'-thiodipropionate, pentaerythritol-tetrakis -(Β-lauryl-thiopropionate), dilauryl thiodipropionate, β-
Alkyl thioester / propionate, sulfur-containing ester compounds, 1,1′-thiobis (2-naphthol) and the like.

The amount of addition of both of these is limited to 0.5 to 10 parts by weight, respectively. When the amount is less than 0.5 parts by weight, the antioxidant effect is low, and when the amount is more than 10 parts by weight, a higher effect is obtained. In addition, there is no crosslinking and bleeding occurs.

Further, as the organic peroxide mixed with the tetrafluoroethylene-propylene copolymer,
Examples of the one-hour half-life of 130 ° C. or higher include diacyl peroxides such as dibenzoyl peroxide,
Monoperoxy compounds such as peroxyesters such as dicumyl peroxide, di-t-butylperoxide, t-butylperoxyacetate, t-butylperoxyisopropyl carbonate, t-butylperoxybenzoate and 2,5- Dimethyl-2,5-di- (t-butylperoxy) -hexyne 3,2,5-dimethyl-2,5-di- (t-butylperoxy) -hexane, 1,4-bis- (t- Butylperoxyisopropyl) benzene, 1,3-bis- (t-butylperoxyisopropyl) benzene, 2,5-dimethyl-2,5
Examples thereof include peroxy compounds such as -di- (benzoylperoxy) -hexane.

The blending amount of these is preferably 0.5 to 5 parts by weight with respect to 100 parts by weight of the resin component,
If it is less than 0.5 parts by weight, the crosslinking will be insufficient and good mechanical properties will not be obtained, and if it exceeds 5 parts by weight, there will be no further effect and rather heat resistance and flex fatigue resistance will be reduced. Because.

Similarly, examples of the crosslinking aid include allyl compounds, sulfur, organic amines, maleimides, methacrylates, divinyl compounds and the like. Preferably polyallyl compounds such as diallyl phthalate, triallyl phosphate, triallyl dianurate, triallyl isocyanurate, diallyl melamine, ethylene glycol dimethacrylate, trimethylolpropane trimethacrylate,
Oxime compounds such as polyhydric alcohol methacrylate and para-benzoquinone dioxime and P, P'-dibenzoquinone dioxime are used, and polyallyl compounds are particularly desirable.

Similarly, the amount of the cross-linking auxiliary compounded is also preferably 0.1 to 5 parts by weight. If the amount is less than this range, the cross-linking is insufficient, and if it is more than the range, bleeding occurs and the screw bites the material. This is because it causes defects.
In the present invention, the compounding amount of the crosslinking aid is limited to 0.1 to 5 parts by weight, but a remarkable effect can be obtained in the range of 1 to 4 parts by weight.

In addition to these compounding agents, metal oxides, lubricants, fillers, reinforcing agents, stabilizers, colorants, carbon black and the like may be added in appropriate amounts.

[0024]

An embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

First, an electric wire / cable according to the present invention will be described with reference to FIG.

In FIG. 1, 1 is a conductor, 2 is a coating layer, and 3
Is an insulated wire, 4 is a sheath, and 5 is an interposition.

Next, the materials for the coating layer and the sheath were adjusted according to the formulation shown in Table 1, and the conductor was extrusion-coated to form insulated wires (Examples 6 and 7). Further, the wires were covered with the sheath. Cable (Examples 1 to 5, Comparative Examples 1 to 5).

[0028]

[Table 1]

As shown in Examples and Comparative Examples of Table 1, a mixed polymer of a tetrafluoroethylene-propylene copolymer and an ethylene-based copolymer was blended with an organic peroxide, a crosslinking aid and a metal oxide, After uniformly kneading this with a roll heated to 50 to 60 ° C. for 15 minutes to form a composition,
As shown in FIG. 1, these compositions were applied to a head: 80 ° C.,
Cylinder 1: 80 ° C., cylinder 2: 60 ° C. Set the 40 m / m extruder (L / D = 22) with a thickness of 1 to the outer periphery of the conductor 1 of copper twisted wire cross-sectional area 0.75 mm ^2. Extrusion coating to 1 mm to form coating layer 2, then
This coating layer 2 was cross-linked by immersing this in water vapor of 13 atm (about 190 ° C. for 3 minutes) to manufacture seven types (Examples 6 and 7) of insulated wires 3.

Next, among these 7 types of insulated wires, 5
As shown in FIG. 1, two types of insulated electric wires 3 of the same type are used, and the same composition as the above is used together with the intervening electric wires 3 in the steam of 18 atm (about 200
C.) for 3 minutes to crosslink and the outer circumference is 11.
Five types of 0 mm sample cables (Examples 1 to 5) were manufactured.

With respect to each of these sample cables and sample electric wires, gel fraction, tensile properties and flex fatigue resistance,
The heat aging resistance and oil resistance were evaluated, and the results are shown in the lower column of Table 1. The simple gel fraction was determined by cutting a sample cut from the cable in a predetermined amount in tetrahydrofuran at 70 ° C.
After soaking for 4 hours, it was calculated by the following equation.

Simple gel (%) = weight after dissolution / initial weight × 100 Further, in the case of the evaluation method of tensile properties, the coating layer 2 (tube) is worn for the sample electric wire, and the sheath 5 is worn for the sample cable, 1mm sample is prepared, JISK-6301
It was carried out according to.

The oil resistance is AS heated to 120 ° C.
After being immersed in TM2 oil for 18 hours, the above tensile test was performed.

Regarding the heat aging resistance, the sample was put in an aging tank kept at 180 ° C. and the time (day) at which 50% of elongation was reached was evaluated.

The flex fatigue resistance is JIS C-3004.
The cable was pressed against a mandrel having a diameter 10 times that of the cable in an atmosphere at a constant temperature of 50 ° C. by a method according to the above method to repeatedly bend, and the number of times of bending until the sheath cracked was evaluated.

Further, the bleeding was evaluated by wrapping a part of the sample cable in aluminum foil and observing the surface of the sample after putting it in a thermostat kept at 60 ° C. for one week. Also in the comparative example, a sample cable was manufactured by the same manufacturing method as that of the example.

As a result, as is clear from Table 1, the sample cables of Examples 1 to 5 and the sample wires of Examples 6 and 7 according to the present invention all have a gel fraction of 90% or more and tensile properties. It is also found that the heat aging resistance and the oil resistance are good, and the number of repetitive flexing until crack initiation is 200,000 or more, which shows excellent flex fatigue resistance.

On the other hand, in Comparative Examples, when the ethylene copolymer is small as in Comparative Example 1, the flex fatigue resistance is inferior, and when the standard is exceeded as in Comparative Example 2, the oil resistance is greatly reduced. . Further, Comparative Examples 3 and 4 are examples in which the antioxidant is out of regulation, but when the amount of the antioxidant is small, the heat resistance is low,
If too much, bleeding occurs. In Comparative Example 5 in which the amount of the cross-linking aid exceeded the specified value, the material did not bite into the screw during extrusion, and extrusion was impossible. It is considered that this is because the crosslinking auxiliary agent bleeds.

[0039]

In summary, according to the present invention, by using a predetermined composition, electric wire characteristics, especially bending fatigue resistance are greatly improved, and a highly reliable fluorine-containing elastomer-coated electric wire / cable is obtained. It has an excellent effect such as being cut.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

[Explanation of symbols]

 1 conductor 2 coating layer 3 insulated wire 4 sheath 5 intervening

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical display location H01B 3/44 H01B 3/44 D

Claims (3)

[Claims] 1. In a fluorine-containing elastomer-coated electric wire / cable in which a coating layer is formed on a conductor or on the outer periphery of an electric wire core, the content weight ratio of the tetrafluoroethylene-propylene-based copolymer and the ethylene-based copolymer is 90/10 to 60.
A coating layer comprising a composition obtained by adding 0.5 to 10 parts by weight of a hindered phenol-based antioxidant and a thioether-based antioxidant to 100 parts by weight of a resin content of / 40, respectively. Fluorine-containing elastomer-coated wires / cables, wherein the layers are cross-linked. 2. The fluorine-containing elastomer-coated electric wire / cable according to claim 1, wherein the coating layer is crosslinked in the presence of an organic peroxide having a one-hour half-life of 130 ° C. or more. 3. The coating layer is crosslinked in the presence of an organic peroxide and a crosslinking aid.
Alternatively, the fluorine-containing elastomer covered electric wire / cable according to claim 2.