JPS59139508A - Method of producing wire and cable - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention The present invention relates to a method for manufacturing electric wires and cables with excellent heat resistance and oil resistance, and in particular to electric wires and cables using a specific fluorine-containing elastic copolymer as a protective coating layer around the outer periphery of an insulated wire core. The present invention relates to a manufacturing method.

De1~Raful A Fluorine-containing elastic copolymer mainly composed of Roedylene and α-olefin having 2 to 4 carbon atoms has excellent heat resistance, oil resistance, chemical resistance, etc.
It has been used in a variety of applications, including packing, diaphragm, and hoses, and has high expectations as a coating material for electric wires and cables.

However, known soft-containing elastic copolymers have poor extrusion moldability and cannot be applied to protective coating layers that require uniform thickness over a long length.

The present invention has been made based on the above, and aims to provide a manufacturing method that can easily obtain electric wires and cables that have various properties such as heat resistance and oil resistance that are comparable to those of fluorine-containing elastic copolymers. That is.

The present inventors have conducted intensive research to apply a fluorine-containing elastic copolymer to the protective coating of electric wires and cables, and as a result, they have discovered a fluorine-containing elastic copolymer having a specific molecule (a) and composition. We have come to the knowledge that the main composition has excellent extrusion moldability, and that its crosslinked product satisfies the required properties as a protective coating layer for electric wires and couples, such as heat resistance, oil resistance, and mechanical properties. Ta.

Thus, the production method of the present invention has a number average molecular weight of 20,000 to 1
A composition mainly composed of a fluorine-containing elastic copolymer containing units based on tetrafluoroethylene and units based on an α-olefin having 2 to 4 carbon atoms was applied onto an insulated wire core. It is characterized in that it is extrusion coated with a protective coating layer and then crosslinked.

In the present invention, it is important to use a fluorine-containing elastic copolymer having a number average molecular weight of 20,000 to 100,000. If the number average molecular weight is too large, cracks will occur in the coating layer during extrusion coating, while if the number average molecular weight is too small, the mechanical strength of the crosslinked product will be insufficient, so both are not preferred.

In the present invention, the number average molecular weight is within the above-mentioned preferred range.
The method for producing the fluorine-containing elastic copolymer is not particularly limited, and copolymerization reaction conditions such as monomer concentration, polymerization initiator concentration, monomer to polymerization initiator suspension, polymerization temperature, use of chain transfer agent, etc. Although it is possible to directly adjust the molecular weight of the produced polymer by the operation of
b) A method of forming a copolymer and heating it in the presence of oxygen to lower the molecular weight can also be smoothly adopted.

The number average molecular weight of a fluorine-containing elastic copolymer can be measured by an osmotic pressure method, but a value converted from a measured value of intrinsic viscosity can be used for relative comparison between copolymers having the same structure. For example, the method that can be suitably adopted in the present invention is as follows.
Lafluoroethylene-propylene copolymer (tetrafluoro[1 ethylene-based unit content δ154-57-[
%) in tetrahydrofuran according to the following formula.
The number average molecule ωMn can be calculated from the intrinsic viscosity [η) (dffl/9) measured at 0°C.

Mn = (η), 18x2. Ox105 In the present invention, it is also important to use a fluorine-containing elastic copolymer containing as main components a unit based on tetrafluoroethylene and a unit based on an α-olefin having 2 to 4 carbon atoms. .

Even if it is a fluoroelastic copolymer, one containing units based on vinylidene fluoride as a main component has poor dielectric properties,
It is undesirable because it impairs the electrical characteristics of wires and cables in terms of electrical insulation.

The α-olefin having 2 to 4 carbon atoms that is copolymerized with tetrafluoroethylene to give an elastic copolymer includes propylene and butyne-1 alone, and a combination of two or more selected from ethylene, propylene, butene-1, and isobutene. is exemplified, but propylene can be preferably used to achieve the purpose of the present invention.

In addition to the main components tetrafluoroethylene and propylene, the preferred tetrafluoroethylene-propylene copolymer J5 in the present invention includes components copolymerizable with these, such as ethylene, budene-1, isobutene, acrylic rl and its alkyl ester, methacrylic acid d-3
and its alkyl esters, vinyl fluoride, vinylidene fluoride, hexafluoropropene, chloroethyl vinyl ether, glycidyl vinyl ether, chlorotrifluoroethylene, perfluoroargyl vinyl ether, and the like.

In such a copolymer, the molar content of tetrafluoroethylene/butylene is 9515 to 30/7.
0, especially from the range of 90-10-45-55, from the viewpoint of heat resistance, moldability, etc.
The content m of components other than the main component, which may be added as appropriate, is usually selected from a range of 50 mol% or less, particularly 30 mol% or less.

In d3 of the present invention, a composition mainly composed of a fluorine-containing elastic copolymer as described above is extruded onto the outer periphery of an insulated wire core containing one or more insulated wires, and then crosslinked. be exposed.

The crosslinking method may be a conventionally known method and is not particularly limited, but it is preferable to incorporate specific amounts of an organic peroxide and a polyallylic compound into the fluorine-containing elastic copolymer, and heat crosslinking after extrusion molding.

Here, 4JR peroxide serves as a crosslinking agent and plays the role of 'C. Specifically, diacyl peroxide such as dibenzoyl peroxide, dicumyl peroxide,
Monoperoxy compounds such as peroxy esters such as di-tert-butyl peroxide, [-butylperoxyaretate, 1-butylperoxyisobrobyl carbonate, [-butylperoxybenzoate], and 2°5-dimethyl -2,5-di(t-butylperoxy)-hexane-3,2,5-dimethyl-2゜5-di(t-butylperoxy)-hexane, 1,4-bis-
(L-butylperoxy-isopropyl)ben1,1
,3-bis-(t-butylperoxy-isopropyl)
Examples include benzene, 2,5-dimethyl-2,5-di(benzoylperoxy)-hexynone, and other ciba-oxy compounds. These may be used alone or in combination of two or more. The amount of organic peroxide to be used is 0.1 to 5i [
parts, preferably from about 0.5 to 3 parts by weight.

Further, the polyallylic compound plays a role as a cross-linking agent, and specific examples thereof include diallyl phthalate, triallyl phosphate, triallyl cyanurate, triallyl isocylphate, diallylmelamine, and the like. The amount of the polyallylic compound added is 0.1 to 20 parts by weight, preferably 0.2 to 20 parts by weight, per 100 parts by weight of the fluorine-containing elastic copolymer.
Selected from 10 parts by weight box size.

By performing peroxide vulcanization using a combination of an organic peroxide and a polyallylic compound as described above, it is possible to prevent the residual ionic impurities in the crosslinked product and the resulting deterioration of electrical properties. .

Other than the above-mentioned crosslinking methods, there may be mentioned a method using an amine as a crosslinking agent and a crosslinking method using ionizing radiation such as an electron beam.

For crosslinking using amines, J3 uses so-called alkyl polyamines such as hexamethylene diamine, tetraethylene pentamine, and triethylene tetramine, or their salts such as carbamic acid and cinnamylidene acid, or piperazine, piperidine, pyridine, aniline, and phenane. Aromatic polyamines such as lolin and their salts, as well as sic bases, hydroquinone, bisphenol A
It is recommended to use reagents with nucleophilic properties such as 6-catechol, their alkali metal salts, ammonium salts, etc., in combination with linear polyethers such as polyethylene glycol, polypropylene glycol, and cyclic polyneedle as an auxiliary agent. It is possible.

In J3 of the present invention, a composition in which a fluorine-containing elastic copolymer contains a crosslinking agent and a crosslinking aid, fillers, reinforcing agents, pigments, lubricants, extrusion aids, antioxidants, stabilizers, etc. Various additives such as agents can be added. Such a composition preferably has a Mooney viscosity ML++a (100°) of about 15 to 100, particularly about 30 to 90, from the viewpoint of moldability of the composition, surface condition of the coating layer, and particularly insulation properties. It is desirable to adjust the formulation to provide such a Mooney viscosity. It is also desirable that each compounded component is uniformly dispersed in the composition. Uniform dispersion can be achieved by mixing for about 10 to 60 minutes at a temperature of about .degree.

The conditions for extrusion coating are not particularly limited, but usually 50 to 1
An extrusion temperature of about 50°C, preferably from 70 to 130°C is employed.

In the present invention, it is desirable to select the optimum operating conditions during thermal crosslinking depending on the raw materials and formulation used. The normal temperature is about 80 to 250°C, preferably 130°C.
~210℃ is adopted, and the time is 0.5~20℃.
Approximately 0 minutes, preferably approximately 1 to 100 minutes is employed. If the heating temperature is increased, the heating time can be shortened.

d3, for the purpose of improving the physical properties of the crosslinked product, reheating treatment at 150 to 250°C for about 12 to 25 hours can also be employed.

Next, the present invention will be explained in more detail with reference to Examples.

Examples 1 to 3 and Comparative Examples 1 to 3, a tetrafluoroethylene-propylene copolymer having a molar ratio of buto-lafluoroethylene/propylene of 55/45 and a number average molecular weight of 130,000 was used. Various fluorine-containing elastic copolymers with different molecular weight levels were obtained by heat treatment under various conditions in the air.

Thus 1! : Dicumyl peroxide (organic peroxide) for 100 parts of the fluorine-containing elastic copolymer
, sardine null 11 ~ realyl ((l!! allyl compound)
, MT carbon (filler) and sodium stearate (lubricant) were blended in proportions of 1 part by weight, 5 parts by weight, 40 parts by weight and 1 part by weight, respectively, and J :Kneaded for 15 minutes.

Each of the above-obtained formulations was heated at 100°C in head, 100°C in cylinder 1, and 80°C in cylinder 2.
Using 0 protection φ extrusion 1 (+-/D=22), insulated core wire (1 b coated with ethylene-propylene rubber to a thickness of 1 m on a tin-plated copper single wire with an outer diameter of 1.6 mm) The outer periphery of the insulated wire core, which was formed by interposing glass rovings between the two pieces of wood, was extruded and coated with a D of 2 tnm, and heated by contacting with water vapor at 13 atm (approximately 190°C) for 3 minutes. Crosslinking was performed.

The surface smoothness and strength of the obtained covered wire are summarized in Table 1 in comparison with the number average molecule 1 (Mn) of the fluorine-containing elastic mourning copolymer and the Mooney viscosity (ML1+4 (100°C)) of the blended composition. Shown.

Table 1 Reference Example 1 Using the insulated wire cores used in the above Examples and Comparative Examples, the outer periphery was coated with black 1" Brene rubber to a thickness of 2 mm to obtain a coated wire.

Reference Example 2 A covered electric wire was obtained using chlorosulfonated polyethylene instead of the chloroprene rubber in Reference Example 1.

Example 2 Table 2 shows the results of evaluating the heat resistance and oil resistance of the coated wires of J3 and Reference Examples 1 and 2.

Table 2 Heat resistance was evaluated by the presence or absence of cracks when bent after deterioration at a temperature of 180℃ for 7 days, and oil resistance was evaluated after immersion in AS-Cho M-No. 2 oil at 120℃ for 18 hours. The volume increase rate was measured and rated C.

As described above in d1 and C, according to the present invention, extrusion molding when applying a fluorine-containing elastic copolymer as a protective covering material for electric wires and cables is extremely easy, and this makes it possible to improve heat resistance, oil resistance, etc. This means that excellent core wires and wobbles can be realized.

Claims (1)

[Scope of Claims] 1. A fluorine-containing elastic copolymer having a number average molecular weight of 20,000 to 100,000 and consisting mainly of units based on tetrafluoroethylene and units based on α-olefin having 2 to 4 carbon atoms. 1. A method for producing electric wires and cables, which comprises extrusion coating a composition mainly consisting of coalescence onto an insulated wire core as a protective coating layer, and then crosslinking the composition. 2. The method for producing electric wires and cables according to claim 1, wherein the α-olefin is propylene. 3. The method for producing electric wires and cables according to claim 2, wherein the molar content of tetrafluoroethylene/propylene is 9515 to 30/70. 4 Mooney viscosity of composition ML++a <100°C)
The method for manufacturing electric wires and cables according to claim 1, 2, or 3, characterized in that .