JPH0435845B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a polyester elastomer coated electric wire. More specifically, the present invention relates to an electric wire coated with a polyester type block copolymer consisting of a crystalline aromatic polyester segment and a polylactone segment. The coated electric wire can be used in a straight or spiral shape for general wiring, telephone lines, household electrical equipment, such as radios, televisions, vacuum cleaners, electric washing machines, electric rice cookers, etc., as well as for office electrical equipment, For example, it is widely used as code for copiers, word processors, personal computers, etc. Conventionally, the main materials used for covering electric wires are natural rubber, synthetic rubber, polyvinyl chloride, polyethylene,
Polypropylene, nylon, etc. have been used, but these have many drawbacks. For example, rubbers such as natural rubber and synthetic rubber require curing treatment, and also have poor heat resistance and light resistance, and are susceptible to aging and cracking. Furthermore, with resins such as polyvinyl chloride, increasing the coating speed not only significantly limits productivity as the coating becomes difficult, but also pinholes are more likely to occur when the thickness is reduced, or the resin is hard and has insufficient elasticity. For this reason, it has the disadvantage of poor flexibility. In order to improve the shortcomings of these conventional materials, it has been proposed to use polyester ether elastomers as wire coating materials. Although this resin has the advantage of being melt coatable and having excellent elasticity, it is still unsatisfactory in terms of coatability, flexibility, heat resistance, fatigue properties, etc. In particular, flexible resins with a high content of polyether have the disadvantage of being insufficient in mechanical properties such as heat resistance, light resistance, strength, and elongation. The purpose of the present invention is to improve the drawbacks of the covered electric wire made of the above-mentioned polyester ether elastomer. is used as a wire covering material. The polyester type block copolymer has relatively low melt viscosity, so it has excellent melt coating properties, and even though it has a flexible composition, it has excellent elasticity, and also has heat resistance,
It has good mechanical properties such as light resistance, strength, and elongation, making it possible to obtain an ideal coated wire. The polyester type block copolymer used in the present invention consists of a crystalline aromatic polyester segment and a polylactone segment. It can be obtained by block copolymerizing a ring-opening addition polymer) with a crystalline aromatic polyester. In the present invention, the crystalline aromatic polyester is a polymer mainly composed of ester bonds or ester bonds and ether bonds, which has at least one aromatic group as a main repeating unit and has a hydroxyl group at the end of the molecule. . The crystalline aromatic polyester is preferably a polyester having a melting point of 150° C. or higher when formed into a high polymer. Further, its molecular weight is preferably 3000 or more. Preferred specific examples include polyethylene terephthalate, polytetramethylene terephthalate,
Homopolyesters such as poly-1,4-cyclohexylene dimethylene terephthalate, polyethylene-2,6-naphthalate, polyester ethers such as polyethyleneoxybenzoate, poly-p-phenylene bisoxyethoxy terephthalate, mainly tetramethylene terephthalate units or ethylene consisting of terephthalate units, in addition to tetramethylene or ethylene isophthalate units, tetramethylene or ethylene adipate units, tetramethylene or ethylene sebacate units, 1,4-cyclohexylene dimethylene terephthalate units, tetramethylene or ethylene-p
- Copolymerized polyesters or copolymerized polyester ethers having copolymerized components such as -oxybenzoate units. In addition, in the case of a copolymer, it is desirable to contain 60 mol% or more of tetramethylene terephthalate or ethylene terephthalate units. As the lactone, ε-caprolactone ((CH ₂ ) ₅ COO) is most preferred, but enane lactone, caprylolactone, etc. can also be used. Moreover, two or more types of lactones can also be used. Furthermore, polylactone (HO[(CH ₂ ) ₅ COO] _oo H) can be block copolymerized with crystalline aromatic polyester. The copolymerization ratio of the above-mentioned crystalline aromatic polyester and lactones is the weight ratio of aromatic polyester/
Lactones can be selected as appropriate within the range of 97/3 to 5/95, but in the case of large-sized applications such as cables that require strength, the above ratio may be 95/5 to 70/30.
It is preferable to select a range of 80/80 for applications that require flexibility, such as home or office telephone lines, electric light lines, power lines, etc.
Preferably, a range of 20 to 60/40 is selected. The above-mentioned polyester type block copolymer is mainly obtained by heating and melt-mixing the crystalline polyester and lactones and subjecting the lactones to ring-opening addition polymerization, but this may be done without a catalyst or with a catalyst. May be used. Furthermore, a polycarbodiimide compound or an epoxy compound may be added to improve the heat resistance, water resistance, etc. of the polyester type block copolymer. The polycarbodiimide compound to be used may be one having two or more carbodiimide groups in the molecule. The structure of the epoxy compound used is not particularly limited as long as it has one or more epoxy groups in the same molecule. Specific examples include methyl glycidyl ether, phenyl glycidyl ether, ethylene glycol diglycidyl ether, polyethylene glycol monophenyl monoglycidyl ether, glycerin triglycidyl ether, and pentaerythritol tetraglycidyl ether. Among the epoxy compounds, those having an epoxy value of 0.9 to 14 equivalents/Kg are preferable, and it is preferable to use an epoxy compound having two or more functionalities. The amount of the polycarbodiimide compound or epoxy compound used varies depending on the amount of end groups in the polyester block copolymer used, but is usually 0.1% to 20% by weight based on the polyester block copolymer. 0.3% to 10% by weight is preferred. In addition, for the purpose of increasing melt viscosity,
It is preferable to blend an alkali metal salt of an aliphatic polycarboxylic acid or an alkylene-carboxylic acid copolymer. Alkali metal salts of aliphatic polycarboxylic acids contain 20 or more carbon atoms and have a molecular weight of
1500 or less, and specifically, alkali metal salts such as octadecylsuccinic acid, octadecenylsuccinic acid, docosandicarboxylic acid, dimer acid, and trimer acid are used. Note that dimer acid is a dicarboxylic acid obtained by dimerizing unsaturated fatty acids with 18 carbon atoms, and trimer acid is a dicarboxylic acid obtained by dimerizing unsaturated fatty acids with 18 carbon atoms. That's true. The blending amount is approximately 0.3 to 8% by weight based on the polyester type block copolymer, and may be increased or decreased as appropriate depending on the situation. Alkylene-carboxylic acid copolymers are mainly copolymers of ethylene and vinyl unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, and fumaric acid, but instead of ethylene or in addition to ethylene, propylene etc. It may also be possible to use In addition, the copolymerization ratio of alkylene and carboxylic acid in the above copolymer is about 25 to 25 alkylene units.
Preferably, 98% by weight is present. The alkylene-carboxylic acid copolymer may be neutralized with alkali metal ions, alkaline earth metal ions, zinc ions, etc., and polycarbodiimide may be added to further increase the melt viscosity. The appropriate amount of the alkylene-carboxylic acid copolymer is 0.2 to 10% by weight based on the polyester block copolymer. The coated wire of the present invention can be manufactured by any suitable method such as melt coating or mold coating. Depending on the use of the covered wire, heat stabilizers, ultraviolet stabilizers,
Pigments, optical brighteners, carbon black, etc. can be added. Since the insulated wire of the present invention has the above-mentioned structure, it can be coated quickly and accurately, improving productivity, and is not affected by heat treatment at 120°C or higher, and has excellent elasticity and A coated wire with excellent mechanical properties, heat resistance, water resistance, etc. can be obtained. Next, the present invention will be explained in more detail with reference to Examples. Example 1 Production example of polyester block copolymer Polybutylene terephthalate with reduced specific viscosity of 1.28
Take 85 kg and 15 kg of ε-caprolactone into a reactor,
After purging with nitrogen gas, the mixture was melted and reacted at 230° C. for 4 hours with stirring, and unreacted ε-caprolactone was removed under vacuum. The obtained polyester type block copolymer had a melting point of 225°C and a reduced specific viscosity of 1.95. Polyester type block copolymer A obtained in the above production example (ε-caprolactone component 15% by weight, polybutylene terephthalate component 85% by weight, melting point 225
°C, reduced specific viscosity 1.95), and as a comparative example, polyester-polyether type block copolymer B consisting of polybutylene terephthalate and polytetramethylene oxide glycol (average molecular weight 1100) (polytetramethylene oxide glycol component 15% by weight, polytetramethylene oxide glycol component 15% by weight, Butylene terephthalate component 85
(% by weight, melting point: 220°C, reduced specific viscosity: 1.96) and high-density polyethylene, an insulating coating was extruded around the TEINSEL conductor to produce an electric wire with a diameter of 1.0 mm and an insulating coating thickness of 0.2 mm. The insulation resistance of the obtained wire is as follows: Wire Insulation layer Insulation resistance a Polyester block copolymer A
7.0×10 ⁵ or more b Polyester-polyether type block copolymer B 4.5×10 ⁵ or more c High-density polyethylene Pinhole generation Products coated with high-density polyethylene have difficulty in coating thinly and have many pinholes. Only those with low insulation resistance could be obtained. Example 2 Using the electric wires a and b of Example 1, four core wires each were coated with plasticized polyvinyl chloride to obtain an electric wire with a width of 5 mm and a thickness of 2.5 mm. Wrap this wire around a 12mm cylinder and fix it at 140℃.
After heat treatment for 40 minutes, spiral wires a and b
And so. After stretching this spiral electric wire 5 times 10,000 times, the dead weight length of the spiral was measured, and the rate of change from the initial dead weight length was measured. The results were as follows. Change in dead weight length after repeated stretching Spiral wire a 20% B 32% Spiral wire a obtained using an insulated core wire using polyester block copolymer A has less fatigue due to repeated stretching, and the spiral wire a It had excellent retention properties. On the other hand, the spiral electric wire b is inferior in spiral retaining ability compared to the former. Example 3 The electric wire of Example 1 was subjected to a high temperature heat aging test, and after the test, the conductor was removed and the tensile strength and elongation of the insulating layer was measured.

[Table] It can be seen that the insulation coating using a polyester block copolymer has excellent resistance to heat aging at high temperatures.

Claims (1)

[Claims] 1. A polyester elastomer-coated electric wire coated with a polyester block copolymer consisting of a crystalline aromatic polyester segment and a polylactone segment. 2 The copolymerization ratio of aromatic polyester segment and polylactone segment is 97/3 by weight
The polyester elastomer-coated electric wire according to claim 1, characterized in that the polyester elastomer-covered electric wire is within the range of 5/95 to 5/95.