JPH10294023A - Cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cable which is used for an automobile, a robot and an electric apparatus, has excellent airtight and watertight functions in a connection part with a terminal to be connected, can prevent corrosion of a conductor of the cable and degradation in performance of apparatus parts connected and has excellent heat resistance, waterproof, extrusion characteristics. SOLUTION: This cable 3 is provided with a coating layer 2 positioned of multicore strunded wire 1 composed of standard insulation conductors. At least the outer most layer 2b of the coating layer 2, comprises a composition composed of 30-70 wt.% thermoplastic polyurethane resin; 5-50 wt.% thermoplastic polyester elastomer; and 3-30 wt.% of at least any one of ternary copolymers used as a base resin, i.e., ethylene-ester acrylate-diode copolymer and ethylene- polyvinyl acetate copolymer. In the composition, a cross-linking treatment is made to make the gas separation ratio 5-40%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cable used for automobiles, robots, electronic equipment, and the like, and more particularly, to a cable having excellent mechanical characteristics and flexibility, and having a terminal portion of the cable connected to various sensors and terminals. The present invention relates to a cable suitable for being molded with a polybutylene terephthalate (hereinafter also referred to as PBT) resin or a polyamide resin in order to keep the connection portion airtight or watertight after being connected thereto.

[0002]

2. Description of the Related Art Thermoplastic polyurethane-based compositions having good mechanical properties and flexibility are used as insulating coating materials for cables used in automobiles, robots, electronic equipment and the like. Then, after molding, the thermoplastic polyurethane composition has heat resistance by crosslinking treatment by irradiation with ionizing radiation,
In some cases, the chemical resistance and the water resistance are improved, but a polyfunctional monomer is usually added to promote the crosslinking reaction. When connecting a component such as a sensor or an electrode terminal to such a cable, the connection portion and the periphery thereof are molded airtight or watertight with a resin mold (molded body) and protected. In order to secure airtightness and watertightness with a resin mold as described above, PBT resin or polyamide resin is often used as a mold material because of ease of molding and excellent mechanical strength.

[0003]

However, depending on the selection of the covering material and the molding material of the cable, the difference in the thermal shrinkage between the materials may cause the cable and the molded body to be heated and cooled during the terminal processing and the use. A gap is created at the interface,
There is a problem that moisture infiltrates from a gap generated at the interface. If moisture enters through the gaps created at the interface, the conductors of the cable will corrode and the performance of the connected equipment parts will deteriorate, and other problems will occur.Therefore, various sealing measures must be taken to maintain airtightness and watertightness. Required. For this reason, the workability at the time of terminal processing becomes extremely complicated, and the work required a high degree of skill.

[0004] In order to solve such a problem, it is conceivable that the covering material of the cable is the same as or similar to the molding material, but these resin materials have poor moldability as a covering material of the cable. There is also a problem with the flexibility required for the electric wire, and it is not practical because the material is expensive. An object of the present invention is to maintain air-tightness and water-tightness at an interface between a cable and a molded body without taking special sealing measures for maintaining air-tightness and water-tightness, and to prevent corrosion and connection of a cable conductor. It is an object of the present invention to provide a cable which can prevent the performance deterioration of the equipment component and which is excellent in heat resistance, water resistance and extrusion characteristics.

[0005]

In order to achieve the above object, the present invention provides (1) a cable in which a coating layer is provided outside a multi-core stranded wire obtained by twisting a plurality of insulated conductors. At least the outermost layer of the layer comprises (a) 30 to 70% by weight of a thermoplastic polyurethane resin, (b) 5 to 50% by weight of a thermoplastic polyester elastomer, and (c)
Resin having at least one terpolymer selected from the group consisting of ethylene-acrylic acid ester-carbon monoxide copolymer and ethylene-vinyl acetate-carbon monoxide copolymer in an amount of 3 to 30% by weight as a base resin. A cable formed of the composition and being cross-linked to have a gel fraction of 5 to 40% by weight; (2) the outermost layer having a gel fraction of 5 to 30% by weight; (3) The cable according to (1), wherein (3) the polyfunctional monomer contained as a crosslinking aid in the resin composition of the outermost layer is 1 part by weight or less based on 100 parts by weight of the base resin ( (1) to (3), wherein the cable according to (1) or (2), (4) the coating layer is composed of two layers, and a resin composition containing thermoplastic polyurethane as a base resin is used for the inner layer.ケBull, (5) the covering layer is composed of two layers, the density on the inner layer 0.86~0.90g / cm ³
(1) to (3), wherein a resin composition containing at least one selected from the group consisting of an ethylene / α-olefin copolymer and an ethylene / vinyl acetate copolymer as a base resin is used. The described cable is provided.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION In the cable of the present invention, one or more coating layers may be provided on a multifilamentary stranded wire obtained by twisting insulated conductors. When a plurality of layers are formed, the next outer layer may be sequentially coated after the coextrusion coating or the inner layer is coated. At this time, at least the outermost layer of the coating layer comprises (a) 30 to 70% by weight of a thermoplastic polyurethane resin, (b) 5 to 50% by weight of a thermoplastic polyester elastomer, and (c) an ethylene-acrylate-carbon monoxide copolymer. And a resin composition containing 3 to 30% by weight of at least one terpolymer selected from ethylene-vinyl acetate-carbon monoxide copolymer as a base resin.

An embodiment of the present invention will be described below. FIG. 1 is a schematic sectional view showing an embodiment of a cable according to the present invention, wherein 1 is a multi-core stranded wire, and the multi-core stranded wire 1 is a conductor (for example, 20 tinned soft copper wires having an outer diameter of 0.18 mmφ are stranded). A plurality of (two in FIG. 1) insulated conductors having an insulating layer 1b made of polyethylene, polyvinyl chloride, or the like are provided on a stranded wire conductor 1a having a conductor diameter of 1 mmφ. ing. 2 is a coating layer covering the multi-core stranded wire 1,
The coating layer 2 is a layer obtained by appropriately cross-linking a resin composition using the above (a), (b) and (c) as a base resin.

The coating layer provided on the outer side of the multi-core stranded wire is preferably a multilayer of two or more layers in order to increase the roundness of the cable cross section. FIG. A plurality of coating layers 2 (two layers in FIG. 2) for covering the wire 1 are provided, and the inner layer 2a is a resin composition containing a thermoplastic polyurethane as a base resin, or a density of 0.86 to 0.90 g /
It can be formed of a resin composition having a base resin of at least one selected from the group consisting of an ethylene / α-olefin copolymer and an ethylene / vinyl acetate copolymer having a cm ³ . This inner layer may be an appropriately crosslinked layer.
The outer layer 2b is composed of a layer obtained by appropriately cross-linking a resin composition using the above (a), (b) and (c) as a base resin. In the cable of the present invention, since the outermost layer of the coating layer provided on the multi-core stranded wire is formed by a crosslinked body of a specific resin composition, by receiving high temperature and high pressure during resin molding of the terminal portion of the cable. In addition, the problem of poor airtightness and poor watertightness at the interface between the cable and the molding material (molded body), which is the result of repeated heating and cooling during use, is solved.

The base resin in the resin composition constituting at least the outermost layer of the coating layer of the cable of the present invention is mainly composed of the base resin composed of the above (a), (b) and (c). Examples of the thermoplastic polyurethane (a) used in the present invention include polyester-based urethane resins (adipate-based, caprolactone-based, and polycarbonate-based) and polyether-based urethane resins. Polyurethane resins are preferred in terms of water resistance and mold resistance. Ether urethane resins are preferred. The hardness (type A durometer, 1 kgf) of the thermoplastic polyurethane is preferably 90 or less.

The thermoplastic polyester elastomer (b) used in the present invention is a thermoplastic elastomer having flexibility, and comprises a hard segment composed of a crystalline polyester such as polybutylene terephthalate and a polytetramethylene ether glycol. It is a block copolymer with a soft segment composed of polyester glycol such as polyoxymethylene glycol or polycaprolactone glycol. Examples of such a thermoplastic polyester elastomer include “Hytrel” (trade name, manufactured by Toray Dupont) and “Perprene”
(Trade name, manufactured by Toyobo Co., Ltd.), "Arnitel" (trade name, Ak
zo) is commercially available, and can be appropriately selected and used from various grades of commercially available products. Furthermore, if the melting point of the polyester elastomer is close to the softening temperature of the thermoplastic polyurethane to be described later, the mixing state of both resins becomes uniform at the time of kneading, and a cable having a good extrusion appearance can be obtained.

The ethylene-acrylic acid ester-carbon monoxide copolymer and ethylene-vinyl acetate-carbon monoxide copolymer, which are the terpolymers (c) used in the present invention, have a low fluidity during melting. It is a resin that is excellent in flexibility at room temperature. As such a material, for example, "ELVALOY" (trade name, manufactured by Du Pont-Mitsui Polychemicals) is commercially available, and can be appropriately selected from various grades of commercially available products.

The amount of component (a) in the base resin of the resin composition used in the present invention is in the range of 30 to 70% by weight, preferably 37 to 45% by weight. When the amount of the component (a) is within this range, the adhesiveness between the outermost layer of the cable and the molding material is good, and watertightness and airtightness can be ensured. The blending amount of the component (b) in the base resin is in the range of 5 to 50% by weight, preferably 37 to 45% by weight. If the amount is less than 5% by weight, the adhesive strength between the outermost layer of the cable and the molding material such as PBT resin or polyamide resin is weak, and
When the amount exceeds 10% by weight, not only the adhesive strength between the outermost layer of the cable and the molding material is weak, but also the water resistance is lowered because the polyester portion of the hard segment is easily hydrolyzed. And the cable and the watertightness are impaired.

The amount of component (c) in the base resin is in the range of 3 to 30% by weight, preferably 10 to 25% by weight. If the amount is less than 3% by weight, not only does the adhesion to PBT or polyamide significantly decrease, but also the heat cycle given after molding reduces the adhesion. If the content is more than 30% by weight, the abrasion resistance of the resin composition is remarkably reduced, and the function as the insulating wire protective layer is lost. Since the terpolymer of (c) is a resin which is easily crosslinked, when the coating layer using the base resin composed of (a), (b) and (c) is subjected to a crosslinking treatment, (c) The components crosslink to form a network structure, and the thermoplastic polyurethane (a) and the polyester elastomer (b), which are less crosslinkable than (c), are incorporated into the network. At high temperatures, (a) and (b) provide a plasticizing effect on the entire coating layer. Therefore, a state in which the mold material and the coating layer are more easily adhered to each other at the time of molding is formed while securing heat resistance. For this reason, in the resin composition for the outermost layer coating material of the cable of the present invention, it is unnecessary to add a polyfunctional monomer as a cross-linking aid usually used for improving cross-linkability, or even if it is added, the base resin 100 It is preferable that the content be 1% by weight or less based on the weight part.

The resin composition used for the outermost layer of the cable coating layer of the present invention selectively uses a base resin in which (a), (b) and (c) are blended in a specific blending ratio with the base resin. In addition, the plasticizing effect of the outermost layer of the coating becomes extremely large due to the heat generated when the PBT resin or the polyamide resin is molded on the cable end, so that the resin has a fluid effect on the molding resin and exhibits higher adhesiveness. In addition, the outermost layer of the coating layer exhibits a low shrinkage even after cooling after molding of the molding material, prevents peeling of the cable and the molding material, and exhibits high adhesiveness over a long period of time. Further, the coating layer of the cable of the present invention has high water resistance and heat and moisture resistance, and has improved heat resistance as compared with the case where the thermoplastic polyurethane alone base resin is used. Further, since fluidity is added when the resin composition is melted, the appearance is good at the time of extrusion molding, and the extrusion characteristics such as a reduction in extrusion load are significantly improved.

The coating layer provided on the outside of the multi-core stranded wire is preferably a multilayer of two or more layers in order to increase the roundness of the cable cross section. Of the multilayer coating layer, the coating material of the inner layer is:
It is selected in consideration of the adhesion to the outermost coating layer, etc.
In particular, a thermoplastic polyurethane composition having a density of 0.86
A resin composition containing, as a base resin, any one of an ethylene / α-olefin copolymer and an ethylene / vinyl acetate copolymer having a weight of up to 0.90 g / cm 3 or a mixture thereof is preferred. When a thermoplastic polyurethane-based resin composition is used as the inner layer coating material, the inner layer and the outer layer are completely adhered to each other, and it is possible to maintain good airtightness and repetitive bending resistance therebetween. The coating material for the inner layer is at least one selected from the group consisting of ethylene / α-olefin copolymer and ethylene / vinyl acetate copolymer having a density of 0.86 to 0.90 g / cm 3.
It is preferable to use a resin composition having a seed as a base resin. When these resins are used, it is possible to form a cable at low cost while maintaining the airtightness and the repeated bending characteristics between the inner layer and the outer layer.

In the present invention, as the thermoplastic polyurethane used for the inner layer when the number of the coating layers is two or more, those exemplified as the component (a) in the resin composition for forming the outermost layer can be used. The ethylene / α-olefin copolymer that can be used for the inner layer of the coating layer includes ethylene and propylene, 1-butene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene, A copolymer with at least one kind of α-olefin such as dodecene,
From the viewpoint of crosslinkability and elasticity, the density is 0.86 to 0.90 g /
cm ³ is preferred. Furthermore, ethylene-vinyl acetate copolymer that can be used for the inner layer of the coating layer is:
From the viewpoint of crosslinkability and elasticity, the vinyl acetate content is 10 to 3
0% by weight is preferred. Ethylene / α-olefin copolymer and ethylene / vinyl acetate copolymer alone,
Alternatively, both can be used in combination. The heat resistance of the resin composition constituting the inner layer can be improved by crosslinking, and when molding with a resin having a high melting point such as polybutylene terephthalate or polyamide, the resin composition is preferably crosslinked. The heat resistance and rubber elasticity can be improved by crosslinking the coating layer, and as a result, the elastic repulsive force of the cable insulating layer, that is, the air-tightness and water-tightness of the interface with the molded body molded into the terminal in order to improve the restoring force. Is improved.

As a method for crosslinking the coating layer, a conventionally known crosslinking method using ionizing radiation or a chemical crosslinking method can be adopted, but from the viewpoint of productivity, a crosslinking method using irradiation with ionizing radiation such as an electron beam is preferable. . The dose of the electron beam is 1 to 30
Mrad is appropriate. When cross-linking the coating layer,
It is preferable to blend a polyfunctional monomer (trimethylolpropane trimethacrylate, triallyl cyanurate, etc.) as a crosslinking aid in the resin composition. The compounding amount varies depending on the type of the crosslinking assistant, but the appropriate amount is 0.2 to 15 parts by weight based on 100 parts by weight of the resin composition constituting the coating layer. The degree of crosslinking is controlled by the irradiation dose, the type of crosslinking aid,
It can be carried out appropriately depending on the amount of the crosslinking assistant. Also,
In the case of the chemical crosslinking method, a resin composition containing an organic peroxide as a crosslinking agent is used, and the crosslinking is completed by heat treatment after extrusion molding.

The resin composition used in the outermost layer of the coating layer can maintain heat resistance, mechanical strength, etc. and exhibit a plasticizing effect at high temperatures by being appropriately crosslinked, but its gel fraction Is 5 to 40% by weight, preferably 5 to 30% by weight
In the range, the improvement in adhesiveness and heat resistance is most recognized. If the gel fraction is less than 5% by weight, the coating layer of the cable may melt in a high-temperature atmosphere, which is the environment in which the cable is used, and may not function as a protective layer for the insulated wire. If the gel fraction is more than 40% by weight, the network structure becomes very strong, so that the plasticizing effect of the outermost layer of the coating layer is greatly reduced when molding the cable end with PBT resin or polyamide resin. However, this is because the adhesiveness with the mold resin is not sufficient.

In the resin composition of the inner layer and the outer layer of the coating layer of the cable according to the present invention, various additives generally used in insulated wires and cables, for example, antioxidants, metal deactivators, Flame retardants, dispersants, coloring agents, fillers, lubricants and the like can be appropriately compounded within a range that does not impair the purpose of the present invention.

Examples of the antioxidant include amines such as 4,4'-dioctyl diphenylamine, N, N'-diphenyl-p-phenylenediamine, and a polymer of 2,2,4-trimethyl-1,2-dihydroquinoline. -Based antioxidant, pentaerythrityl-tetrakis (3- (3,5-di-t-
Butyl-4-hydroxyphenyl) propionate),
Octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4)
Phenolic antioxidants such as -hydroxybenzyl) benzene, bis (2-methyl-4- (3-n-alkylthiopropionyloxy) -5-t-butylphenyl) sulfide, 2-mercaptobenzimidazole and zinc salts thereof And sulfur-based antioxidants such as pentaerythritol-tetrakis (3-lauryl-thiopropionate).

Examples of the metal deactivator include N, N'-bis (3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyl) hydrazine, 3- (N-salicyloyl) amino-1, 2,4-triazole, 2,2′-oxamidobis- (ethyl 3-((3,5-di-t-butyl-
4-hydroxyphenyl) propionate) and the like.

As the flame retardant, tetrabromobisphenol A (TBA), decabromodiphenyl oxide (DBDPO), octabromodiphenyl ether (O
BDPE), hexabromocyclododecane (HBC
D), bistribromophenoxyethane (BTBP)
E), halogen-based flame retardants such as tribromophenol (TBP), ethylenebistetrabromophthalimide, TBA / polycarbonate oligomer, brominated polystyrene, brominated epoxy, ethylenebispentabromodiphenyl, chlorinated paraffin, dodecachlorocyclooctane, etc. And inorganic flame retardants such as aluminum hydroxide and magnesium hydroxide, and phosphorus-based flame retardants such as phosphoric acid compounds, polyphosphoric acid compounds and red phosphorus compounds. Examples of the flame retardant aid and filler include carbon, clay, zinc oxide, tin oxide, magnesium oxide, molybdenum oxide, antimony trioxide, silica, talc, calcium carbonate, magnesium carbonate, zinc borate and the like.

[0023]

【Example】

(Examples 1 to 20, Comparative Examples 1 to 10) Conductor (conductor diameter 1 m)
mφ tinned annealed copper stranded wire Composition: 20 / 0.18mm
On top of φ), low-density polyethylene was extrusion-coated so as to have an outer diameter of 1.7 mm, and irradiated with an electron beam having an acceleration voltage of 500 keV and a dose of 20 Mrad to obtain an insulated conductor having a crosslinked polyethylene insulating layer. A multi-core stranded wire was prepared by twisting two of these insulated conductors. Then, using a 40 mmφ extruder (L / D = 25) on the multi-core stranded wire, a die temperature of 180 ° C., and then to a feeder side C3 = 170 ° C.
Under the conditions of C2 = 160 ° C. and C1 = 150 ° C., (A) thermoplastic polyurethane (material of (01) described later) and (B) ethylene-vinyl acetate copolymer ((10) of Material) or (C) an ethylene-α-olefin copolymer (material of (11) described later) by extrusion coating so that the outer diameter becomes 4.2 mmφ to form an inner coating layer. Then, the outer layer resin composition shown in Table 2 was extrusion-coated thereon under the same conditions as the inner layer so that the outer diameter became 5.0 mmφ. Next, after extrusion coating, the coating layer was cross-linked by irradiating an electron beam with an acceleration voltage of 750 keV and the irradiation dose shown in the table, to obtain a cable having two coating layers as shown in FIG. In Example 20, the inner coating layer was formed of the same material as the outer coating material.

Various characteristics of the obtained cables were evaluated by the following test methods, and the results are shown in Tables 1 to 5. 1) Appearance of extruded cable: good condition with glossy surface, smooth surface and no protrusions, good condition with little luster and smooth surface without protrusions, good condition with no luster and rough surface Was given as x. 2) Motor load current at extrusion molding The motor load current at extrusion was shown. 3) Gel fraction of outer layer Extract only the outer layer from the cable,
Extract at 24 ° C for 24 hours and dry thoroughly. After that, the mixture was further extracted with dimethylformamide at 110 ° C. for 24 hours, and then dried.
Measure the weight. The weight remaining after melting was defined as a gel content and expressed as a percentage of the weight before solvent extraction.

4) Terminal Airtightness (PBT) As shown in FIG. 3, the covering layers 2 and 1b of the cable were removed to expose the conductor 1a, and the electrode terminal 5 was connected to the end. Next, the connection portion and the vicinity thereof were covered with a resin molded body 4 by molding (injection molding) using PBT resin. About this cable, 120 degreeC x 1 hour, -40
A heat cycle test of 100 cycles was performed with one cycle of ° C × 1 hour. Thereafter, compressed air of 2 atm was injected from the terminal opposite to the resin molded body side, and immersed in water to check for leakage from the resin molded body side, and airtightness was confirmed by the presence or absence of bubbles. The test was carried out on 5 samples, and when all passed, it was evaluated as ○, and when any of the samples failed, it was evaluated as x. 5) Airtightness of terminal (polyamide) A test under the same conditions as in 4) above was conducted using a polyamide resin (nylon 1).
This was performed on the mold sample according to 2).

6) Observation of Adhesive Surface (PBT) As an evaluation of the adhesiveness, the resin molded body was dismantled, and the presence or absence of adhesion of the coating layer resin composition on the surface of the PBT resin molded body in contact with the cable covering layer. investigated. The case where peeling of the PBT resin molded product and the cable is impossible due to the strong adhesive strength is indicated by ◎, and the case where an aggregate of the coating resin composition is present at the bonding interface between the PBT resin molded product and the coating layer is indicated by ○. And in other cases, x. 7) Observation of bonded surface (polyamide) Observation under the same conditions as in 6) above was performed using polyamide resin (nylon 1).
This was performed on the mold sample according to 2). 8) Heat resistance 6 on a metal rod of the same diameter (5.0 mmφ) as the cable sample
It was left at 200 ° C. for 30 minutes while being wound for more than one turn.
After being taken out and sufficiently cooled at room temperature, it was visually confirmed that there was no crack or melting on the cable surface. Perform a three-sample test, and if all samples have no melting or cracks,
When even one sample melted or cracked, it was evaluated as x.

9) Water resistance From the cable sample, only the outer skin was cut in half and collected.
I punched it with an 8-inch dumbbell. The punched sample was polished so that the surface became smooth and immersed in hot water at 90 ° C. for 240 hours. The immersed sample is subjected to a tensile test at a constant speed type tensile tester at a distance of 20 mm between the marked lines and at a pulling speed of 500 mm / min. Tensile strength at break (TS) and elongation at break (El)
Was measured. The TS and El before hot water immersion were set to 10
It was expressed as a percentage assuming 0%. 10) Heat aging resistance The same sample as in the above 9) was prepared, and TS (tensile strength) and El after leaving for 168 hours in an atmosphere of 136 ° C.
(Elongation) was expressed as a percentage when TS and El before standing were taken as 100%. 11) Abrasion resistance It was based on the belt-type abrasion test of JASO D608 of Japanese automobile standard. However, the load was 450 gf. The results are as follows: x when the minimum abrasion resistance value is less than 20 m;
0 m or more is indicated by ◎.

The following components were used as the components shown in Tables 1 to 5. (01) Ether-based polyurethane elastomer manufactured by Nippon Milactran Co., Ltd., trade name: E-385PNA
T (02) polyester elastomer Toray Dupont Co., Ltd., trade name: Hytrel 2300X
06 (03) Polyester Elastomer Toray Dupont Co., Ltd., trade name: Hytrel HTC25
51 (05) Ethylene-acrylic acid ester-carbon monoxide copolymer Mitsui Dupont Polychemical Co., Ltd., trade name: Elvaloy HP553 (06) Ethylene-vinyl acetate-carbon monoxide copolymer Mitsui Dupont Polychemical Co., Ltd. , Trade name: Elvaloy 742

(07) Pentaerythrityl-tetrakis (3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate) Ciba Geigy Co., Ltd., trade name: Irganox 101
0 (08) Trimethylolpropane trimethacrylate, manufactured by Shin-Nakamura Chemical Co., Ltd., trade name: Ogmont T200 (09) Ethylene bispentabromophenyl, manufactured by Albemarle Co., Ltd., trade name: Cytex 8010 (10) Ethylene / vinyl acetate Polymer: manufactured by DuPont-Mitsui Polychemicals Co., Ltd., trade name: Evaflex V527-4 (vinyl acetate content 17% by weight, MFR 0.8 g / 10 min., Density 0.
94 g / cm3 (11) Ethylene / α-olefin copolymer Dow Chemical Co., Ltd., trade name: Engage CL8
003 (α-olefin (octene) content 18% by weight,
MFR 1 g / 10 min. 0.89g density
/ Cm3

[0030]

[Table 1]

[0031]

[Table 2]

[0032]

[Table 3]

[0033]

[Table 4]

[0034]

[Table 5]

As can be seen from the results shown in Tables 1 to 3, the cables of the examples were composed of (a) 30 to 70% by weight of a thermoplastic polyurethane resin, (b) 5 to 50% by weight of a thermoplastic polyester elastomer, and (C) 3 to 30% by weight of at least one terpolymer selected from the group consisting of ethylene-acrylate-carbon monoxide copolymer and ethylene-vinyl acetate-carbon monoxide copolymer as a base resin And a gel fraction of 5 to 4
Since the outermost layer is formed with a coating layer which has been cross-linked so as to be 0% by weight, the adhesiveness between the cable coating material and the molded article is excellent, and the airtightness of the cable terminal is maintained. In addition, it can withstand heat resistance, water resistance, heat aging resistance and abrasion resistance sufficiently. In particular, (a) component 3
7 to 45% by weight, 37 to 45% by weight of the component (b), and 10 to 25% by weight of the terpolymer of the component (c). 3
When a coating layer crosslinked so as to be 0% by weight is formed on the outermost layer (Examples 9 to 11, 13 to 15, 18 to 2)
In 0), the above effect is more remarkable.

On the other hand, as can be seen from the results shown in Tables 4 and 5, out of the three components, component (b) deviates from the specified range.
If the amount is small, the adhesion to the PBT resin is weak and sufficient airtightness cannot be obtained (Comparative Example 1). If the amount is too large, the adhesion to the polyamide resin is weak and sufficient airtightness cannot be obtained (Comparative Example 2). . If the component (a) is out of the specified range and the amount is small, the abrasion resistance is poor (Comparative Example 3). If the amount is too large, the adhesiveness to both the PBT resin and the polyamide resin is weak and sufficient. No airtightness is obtained (Comparative Example 4). If the component (c) is out of the specified range and small in the three components,
As in Comparative Example 4, sufficient adhesion to both resins was not obtained (Comparative Example 5), and if too much, wear resistance was impaired (Comparative Example 6). Furthermore, in the composition (b) using only the polyester elastomer as the base resin, not only sufficient adhesion to the polyamide resin is not obtained, but also the water resistance is extremely poor (Comparative Example 7). Further, in the case of the composition (a) using only the thermoplastic polyurethane as the base resin, sufficient adhesion to both resins cannot be obtained as in Comparative Example 4 (Comparative Example 8). On the other hand, when the gel fraction is out of the specified range and high, the network structure is so strong that the plasticity of the resin composition is lost and sufficient adhesion to both resins is obtained as in Comparative Example 4. When the gel fraction is too low (Comparative Example 9), good adhesiveness is obtained but heat resistance is impaired (Comparative Example 10).

[0037]

The cable of the present invention comprises (a) 30 to 70% by weight of a thermoplastic polyurethane resin, (b) 5 to 50% by weight of a thermoplastic polyester elastomer, and (c) ethylene-acrylate-carbon monoxide. 3 to 30% by weight of at least one terpolymer selected from the group consisting of a copolymer and an ethylene-vinyl acetate-carbon monoxide copolymer
When the terminal portion of the cable is molded with a PBT resin or a polyamide resin, a special seal is formed because the coating layer formed by the resin composition having the base resin and being subjected to the cross-linking treatment is formed on the outermost layer. Even if no countermeasures are taken, the air-tightness and water-tightness of the interface between the cable and the molded product can be maintained, not only preventing corrosion of the conductor of the insulated wire inside the cable and deterioration of the performance of connected equipment parts, but also water resistance. Excellent in heat resistance, heat resistance, and extrusion characteristics, and can be used as a wiring cable for automobiles, robots, electronic devices, etc., with stability over time.

[Brief description of the drawings]

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

FIG. 2 is a sectional view showing another embodiment of the cable of the present invention.

FIG. 3 is an explanatory view showing an embodiment of a terminal portion of the cable of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Multi-core stranded wire 1a Conductor 1b Insulating layer 2 Coating layer 2a Inner layer 2b Outer layer 3 Cable 4 Resin molding 5 Electrode terminal

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI H01B 3/30 H01B 3/30 B 3/44 3/44 M (72) Inventor Ryoji Ohno 2-6 Marunouchi, Chiyoda-ku, Tokyo No. 1 Inside Furukawa Electric Co., Ltd.

Claims (5)

[Claims] 1. A cable provided with a coating layer outside a multi-core stranded wire in which a plurality of insulated conductors are twisted, wherein at least the outermost layer of the coating layer comprises (a) a thermoplastic polyurethane resin
0 to 70% by weight, (b) 5 to 50% by weight of a thermoplastic polyester elastomer, and (c) a group consisting of ethylene-acrylate-carbon monoxide copolymer and ethylene-vinyl acetate-carbon monoxide copolymer. It is formed of a resin composition containing 3 to 30% by weight of at least one selected terpolymer as a base resin, and is crosslinked so that a gel fraction is 5 to 40%. Cable. 2. The cable according to claim 1, wherein the outermost layer has a gel fraction of 5 to 30% by weight. 3. The resin composition according to claim 1, wherein the polyfunctional monomer contained as a crosslinking aid in the resin composition of the outermost layer is 1 part by weight or less based on 100 parts by weight of the base resin. cable. 4. The cable according to claim 1, wherein said coating layer comprises two layers, and a resin composition containing thermoplastic polyurethane as a base resin is used for an inner layer thereof. 5. The method according to claim 1, wherein said coating layer comprises two layers, and the inner layer has ethylene.α having a density of 0.86 to 0.90 g / cm ^3.
The cable according to any one of claims 1 to 3, wherein a resin composition comprising at least one selected from the group consisting of an olefin copolymer and an ethylene / vinyl acetate copolymer is used as a base resin.