JPH10233120A - Cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cable for use in an automobile, robot, electronic equipment, and the like, that is excellent in airtightness at its connection with a terminal and in mechanical strength and flexibility. SOLUTION: In a cable having cover layers provided on the outside of a multiconductor stranded wire comprising a plurality of insulating conductors twisted together, at least the outermost cover layer comprises a resin composition obtained by adding 2.5-60 pts.wt. of an epoxy resin to 100 pts.wt. of a base resin in which 25-100wt.% ethyleneglycidyl methacrylate copolymer, glycidyl, and 75-0wt.% thermoplastic polyurethane are blended. Therefore, the cable has excellent mechanical characteristics and flexibility and is particularly excellent in terminal processability.

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 devices, and the like, and more particularly, to a cable having excellent mechanical properties and flexibility. The present invention relates to a cable suitable for being subjected to molding processing with polyethylene terephthalate or polybutylene terephthalate in order to maintain air-tightness or water-tightness after connecting to a terminal or the like.

[0002]

2. Description of the Related Art Cables coated with a thermoplastic polyurethane resin composition have been used as cables used for automobiles, robots, electronic equipment, etc. because of their particularly good mechanical properties and flexibility. . The conductors of such a cable are connected to equipment parts such as sensors, or electrode terminals are connected, and the connection and its surroundings are to be airtightly or watertightly protected by a resin mold (molded body). In this case, polyethylene terephthalate or polybutylene terephthalate is frequently used as a molding material because of its excellent moldability and mechanical strength.

[0003]

However, depending on the selection of the covering material of the cable and the molding material, the difference in the heat shrinkage between the materials causes the formation of the cable in the heating and cooling process during the terminal processing or use. There is a gap at the body interface,
There is a problem that moisture infiltrates from a gap generated at the interface. If moisture enters through the gaps formed at the interface, the conductors of the cable will corrode or the performance of the connected equipment parts will deteriorate, causing problems such as various types of seals to maintain airtightness and watertightness. Measures are needed. For this reason, the workability at the time of terminal processing becomes extremely complicated, and the work required a high degree of skill.

In order to solve such a problem, it is conceivable that the covering material of the cable is made of the same or similar material as the mold material. However, these resin materials have high moldability as a covering material of the cable. Poor, there is a problem with the flexibility as an electric wire, and it is not practical because the material is expensive. An object of the present invention is to maintain the air-tightness and water-tightness of the interface between a cable and a molded body without taking any special sealing measures to maintain the air-tightness and water-tightness, and to corrode the conductor of the cable. It is an object of the present invention to provide a cable which is capable of preventing deterioration of performance of connected equipment components and has excellent heat resistance and low temperature characteristics.

[0005]

In order to achieve the above object, the present invention provides a cable having at least two coating layers provided on the outside of a multi-core stranded wire in which a plurality of insulated conductors are twisted. The outermost layer of the coating layer is made of ethylene
Extrusion molding of a composition obtained by adding 2.5 to 60 parts by weight of an epoxy resin to 100 parts by weight of a base resin blended in a proportion of 25 to 100% by weight of a glycidyl methacrylate copolymer and 75 to 0% by weight of a thermoplastic polyurethane. The present invention provides a cable characterized in that the cable is constituted by layers.

[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. In this case, at least the outermost layer of the coating layer is: Ethylene / glycidyl methacrylate copolymer 2
5 to 100% by weight C. Based on 100 parts by weight of the base resin blended at a rate of 75 to 0% by weight of the thermoplastic polyurethane. A resin composition to which 2.5 to 60 parts by weight of an epoxy resin is added is extruded to form a suitably crosslinked layer.

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 formed of a layer obtained by appropriately cross-linking a resin composition containing A and B as base resins and C added. FIG. 2 shows another embodiment of the present invention, in which a multi-layer (two layers in FIG. 2) coating layer 2 covering the multifilamentary stranded wire 1 is used, and an inner layer 2a is a resin having thermoplastic polyurethane as a base resin. The composition or the density is 0.86-0.90 g / cm ³
At least one selected from the group consisting of ethylene / α-olefin copolymer and ethylene / vinyl acetate copolymer
It is composed of a layer obtained by appropriately crosslinking a resin composition having a seed as a base resin. The outer layer 2b is composed of a layer obtained by appropriately cross-linking a resin composition containing A and B as base resins and C added.

[0008] The resin component in the resin composition constituting the outermost layer 2 of the cable of the present invention is mainly composed of the base resin composed of A and B and the C compounded therewith. The blending amount of the ethylene / glycidyl methacrylate copolymer in the base resin may be 25% by weight or more, preferably 55% or more and 85% or less. If the content is less than 25% by weight, the adhesive strength between the outermost layer of the cable and the polyethylene terephthalate or polybutylene terephthalate resin molding material is weak, and a large amount of epoxy resin must be added to improve the adhesive strength. Because there is. However, adding a large amount of epoxy resin is not preferable because the flexibility and cold resistance of the cable are reduced. The blending ratio of the thermoplastic polyurethane is 75% by weight or less, preferably in the range of 15 to 45% by weight. The reason for blending the thermoplastic polyurethane is to improve the mechanical properties such as abrasion resistance and tensile properties of the outermost layer of the cable. However, if it exceeds 75% by weight, the adhesiveness to the resin molding material is reduced. This is because other characteristics are not improved.

An epoxy resin is used in an amount of 2.5 to 60 parts by weight based on 100 parts by weight of a base resin obtained by mixing an ethylene / glycidyl methacrylate copolymer alone or a urethane resin.
The addition by weight is for improving the adhesiveness with the resin mold material, and the preferred mixing ratio of the epoxy resin is 1%.
0 to 45 parts by weight. 2.5 parts of epoxy resin
If the amount is less than the weight part, there is no effect in improving the adhesiveness between the cable and the resin molding material, and if the amount is more than 60 parts by weight, the flexibility and the cold resistance of the cable decrease as described above.

[0010] The coating layer provided on the outside of the multi-core stranded wire is preferably a multilayer to increase the roundness of the cable cross section. The coating material for the inner layer of the multilayer coating layer is preferably a resin composition whose main component is thermoplastic polyurethane. By using this as a coating material, the coating layers of the inner layer and the outer layer are completely adhered to each other, and it is possible to maintain good airtightness and repeated bending resistance therebetween. Further, as the resin composition of the inner layer in the coating layer, ethylene · α having a density of 0.86 to 0.90 g / cm ³
It is preferable to use a resin composition containing at least one selected from the group consisting of an olefin copolymer and an ethylene / vinyl acetate copolymer 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.

Examples of the ethylene / glycidyl methacrylate copolymer used in the present invention include ethylene / glycidyl methacrylate / ethylene glycidyl methacrylate / vinyl acetate terpolymer, ethylene / glycidyl methacrylate / vinyl acetate terpolymer, and ethylene / glycidyl methacrylate / vinyl acetate terpolymer. Examples include glycidyl methacrylate / methyl acrylate terpolymer, and two or more of these may be used in combination. The melt flow rate (MFR) of the ethylene / glycidyl methacrylate copolymer is 2 to 10 g / 10 min. (Load 216kgf, temperature 1
(90 ° C.). As such a material, for example, “Bonfast” (trade name, manufactured by Sumitomo Chemical Co., Ltd.) is commercially available, and the characteristics required for a cable such as mechanical characteristics and flexibility are sufficiently considered. And various grades of commercial products can be appropriately selected and used.

The thermoplastic polyurethane used in the present invention includes polyester-based urethane resins (adipate-based, caprolactone-based, and polycarbonate-based) and polyether-based urethane resins. Polyether-based urethane resins are preferred in terms of properties and the like.
The hardness (type A durometer, 1 kgf) of the thermoplastic polyurethane is preferably 90 or less.

The epoxy resin used in the present invention includes bisphenol A type, bisphenol F type, bisphenol AD type, phenol novolak type, cresol novolak type and the like. Among them, bisphenol-type epoxy resin has particularly good compatibility with the resin molding material and, therefore, good adhesiveness with the resin molding material, and therefore has a great effect on improving the adhesion between the cable and the molded product. . Bisphenol-type epoxy resins are superior in terms of reactivity, high-temperature characteristics, and the like. In order to improve the flame retardancy of the cable of the present invention, an appropriate amount of the epoxy resin is used as a brominated epoxy resin. Examples of the brominated epoxy resin include a reaction product of tetrabromobisphenol A and epichlorohydrin, a reaction product of tetrabromobisphenol A type and bisphenol A type epoxy resin, and a reaction product of brominated phenol novolak and epichlorohydrin. And a reaction product of brominated methylphenol and epichlorohydrin. Among these brominated epoxy resins, those having a tetrabromobisphenol A type in the structure thereof have good compatibility with polyethylene terephthalate and polybutylene terephthalate, and therefore, the end processing property of the cable of the present invention is further improved. Show the effect.

The ethylene / α-olefin copolymer used in the present invention includes ethylene and propylene, 1-butene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene and 1-dodecene. It is a copolymer with at least one kind of α-olefin, and preferably has a density of 0.86 to 0.90 g / cm ³ from the viewpoint of crosslinkability and elasticity.

The ethylene / vinyl acetate copolymer used in the present invention preferably has a vinyl acetate content of 10 to 30% by weight from the viewpoint of crosslinkability and elasticity. The ethylene / α-olefin copolymer and the ethylene / vinyl acetate copolymer can be used alone or as a mixture of both. The heat resistance of the resin composition constituting the inner layer can be improved by crosslinking, and when the resin composition is molded with a resin having a high melting point, such as polyethylene terephthalate or polybutylene terephthalate, crosslinking is performed. It is good to let. 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 crosslinking method by electron beam irradiation is preferable. The dose of electron beam is 1-3
0 Mrad is appropriate. When the coating layer is crosslinked, a polyfunctional monomer (trimethylolpropane trimethacrylate, triallyl cyanurate, etc.) is added to the resin composition.
It is preferable to add a crosslinking aid of 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.

The resin composition constituting the coating layer of the cable of the present invention contains various additives generally used in insulated conductors and cables, for example, antioxidants, metal deactivators, flame retardants, and dispersants. Agents, coloring agents, fillers, lubricants and the like can be appropriately compounded within a range that does not impair the purpose of the present invention. As antioxidants, 4.4′-dioctyl diphenylamine, N,. '-Diphenyl-p-phenylenediamine, 2,2,4-trimethyl-1,. Amine-based antioxidants such as a polymer of dihydroquinoline, pentaerythrityl-tetrakis (3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate), octadecyl-3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-)
Phenolic antioxidants such as hydroxybenzyl) benzene, bis (2-methyl-4- (3-n-alkylthiopropionyloxy) -5-t-butylphenyl) sulfide, 2-mercaptobenzimidazole and Examples thereof include a zinc salt thereof and a sulfur-based antioxidant 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. Examples of the flame retardant include tetrabromobisphenol A (TBA), decabromodiphenyl oxide (DBDPO), and octabromodiphenyl ether (O
BDPE), hexabromocyclododecane (HBC
D), bistribromophenoxyethane (BTBP)
E), tribromophenol (TBP), ethylenebistetrabromophthalimide, TBA / polycarbonate oligomer, brominated polystyrene, brominated epoxy, ethylenebispentabromodiphenyl, chlorinated paraffin, dodecachloro Examples include halogen-based flame retardants such as cyclooctane, 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. can give.

[0020]

【Example】

(Examples 1 to 7) A low-density polyethylene is extrusion-coated on a conductor (tin-plated annealed copper stranded wire having a conductor diameter of 1 mmφ, 20 wires / 0.18 mmφ) 1a to form an insulating layer 1b having an outer diameter of 1.7 mm. A multi-core stranded wire 1 was prepared by irradiating an electron beam having an acceleration voltage of 500 keV and an irradiation amount of 20 Mrad to cross-link the insulating layer 1b.
Next, a 40 mmφ extruder (L /
D = 25), and extrusion-coated with a resin composition having the composition shown in Table 1 so as to have an outer diameter of 5.0 mmφ. This coating layer 2
Was irradiated with an electron beam at an acceleration voltage of 750 Kev and an irradiation amount of 12 Mrad to crosslink, thereby completing the cable 3 shown in FIG.

(Comparative Examples 1 to 5) A 40 mmφ extruder (L / D =
25), the resin composition having the composition shown in Table 2 was used to obtain an outer diameter of 5.
Extrusion coating was carried out so as to have a diameter of 0 mmφ, and crosslinking was carried out at the same dose as in the above example to obtain a cable.

(Examples 8 and 9) A resin composition A or B having the following composition was extrusion-coated on a multifilamentary stranded wire 1 prepared under the same conditions as in the above example so as to have an outer diameter of 4.2 mmφ. Then, the inner layer 2a was appropriately crosslinked. Then inner layer 2
The outer layer coating material shown in Table 3 was extrusion-coated so as to have an outer diameter of 5.0 mmφ by using an extruder (L / D = 25) with a 40 mmφ extruder, and electron beam crosslinking was performed to form an outer layer 2b. 2 was completed.

[0023] (1) Ethylene-vinyl acetate copolymer Evaflex V527-4 (trade name) manufactured by Mitsui-Pont-Polychemicals Co., Ltd. Vinyl acetate content 17% by weight Melt flow rate 0.8 g / 10 min. (Density 0.94 g / cm ³ (2) Ethylene / α olefin copolymer Engage CL8003 (trade name) Dow Chemical Co., Ltd. α olefin (octene) content 18% by weight Melt flow rate 1 g / 10 min. 0.89 g / cm ³

Various characteristics of the obtained cables were evaluated by the following test methods. (1) Airtightness of the terminal As shown in FIG.
b was removed to expose the conductor 1a, and the electrode terminal 5 was connected to the end. Next, the connection portion and the periphery thereof were injection-molded with polybutylene terephthalate to form a resin molded body 4 and the connection portion was protected. About this cable, 12
0 ° C x 1 hour, -40 ° C x 1 hour as one cycle,
A heat cycle test of 10 cycles was performed. 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 air 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.

(2) Observation of Adhesive Surface In order to evaluate the adhesiveness, the resin molded body was dismantled, and the
Polybutylene terephthalate in contact with the coating layer
The presence or absence of the coating layer resin composition on the surface was examined. A case where an aggregate of the coating resin composition was present at the bonding interface between the polybutylene terephthalate and the coating layer of the cable,
In all other cases, it was marked as x. (3) Cold resistance After leaving the cable in a low temperature bath at −60 ° C. for 1 hour, it is wound around a mandrel having a diameter of 25 mm in the low temperature bath for 6 turns.
The presence or absence of cracks generated in the coating layer was investigated.無 し indicates no crack and X indicates a crack. The above evaluation results are also shown in Tables 1 to 3.

[0026]

[Table 1]

[0027]

[Table 2]

[0028]

[Table 3]

The components shown in Tables 1 to 3 were as follows. Ethylene / glycidyl methacrylate copolymer Bond First E (trade name) Sumitomo Chemical Co., Ltd. ethylene / glycidyl methacrylate / vinyl acetate copolymer Bond First 2B (trade name) Sumitomo Chemical Co., Ltd. Melt Flow rate 3g / 10min. Density 0.945 g / cm ³ Polyether-based urethane resin PNAT (trade name) Bisphenol A-based epoxy resin Araldite CT200 (trade name) manufactured by Nippon Miractran Co., Ltd. Epoxy equivalent 365-420 G / eq manufactured by Ciba Geigy Co., Ltd.

Bisphenol A-based brominated epoxy resin EBR-700 (trade name) Manac Co., Ltd. Epoxy equivalent 1000-1200 G / eq pentaerythrityl-tetrakis (3- (3,5-
(Di-t-butyl-4-hydroxyphenyl) propionate) (Antioxidant) Irganox 1010 (trade name) Trimethylolpropane trimethacrylate (trade name) manufactured by Ciba Geigy Co., Ltd. Ogmont (trade name) Shinnakamura Chemical Co., Ltd.

Each of the embodiments is excellent in airtightness, adhesiveness and cold resistance of the terminal. On the other hand, in Comparative Example 1, the amount of the epoxy resin was small.
Since the amount of the glycidyl methacrylate copolymer was small, the airtightness and adhesion of the terminals were not satisfactory.
Nos. 5 to 5 are inferior in cold resistance due to a large amount of the epoxy resin.

[0032]

According to the cable of the present invention, at least the outermost layer of the coating layer provided on the outer side of the multifilamentary stranded wire in which a plurality of insulated conductors are stranded is composed of an ethylene / glycidyl methacrylate copolymer at 25 to 100% by weight, Plastic polyurethane 75
The composition was formed by extruding a composition obtained by adding 2.5 to 60 parts by weight of an epoxy resin to 100 parts by weight of a base resin blended at a ratio of about 0% by weight, so that polyethylene terephthalate or polybutylene terephthalate was used. High adhesiveness to resin mold material, air-tightness and water-tightness at the interface with the terminal molding are maintained, and it has excellent cold resistance, and it is used for automobiles, robots, and electronic equipment for years. be able to.

[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

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hitoshi Yamada 2-6-1 Marunouchi, Chiyoda-ku, Tokyo Inside Furukawa Electric Co., Ltd.

Claims (4)

[Claims] 1. A cable having a coating layer provided on the outer side of a multi-core stranded wire in which a plurality of insulated conductors are twisted, wherein at least the outermost layer of the coating layer is formed of an ethylene-glycidyl methacrylate copolymer 25 to Base resin 100 blended at a ratio of 100% by weight and 75 to 0% by weight of thermoplastic polyurethane
A cable comprising a resin composition in which 2.5 to 60 parts by weight of an epoxy resin is added to parts by weight. 2. The cable according to claim 1, wherein at least a part of the epoxy resin is a brominated epoxy resin. 3. The method according to claim 1, wherein the coating layer provided outside the multi-core stranded wire is at least two layers, and the inner layer of the coating layer is made of a resin composition containing thermoplastic polyurethane as a base resin.
Or the cable according to 2. 4. The coating layer provided outside the multifilamentary stranded wire has two or more layers, and the inner layer of the coating layer has a density of 0.86 to 0.90 g / cm.
^3. A resin composition comprising a base resin comprising at least one selected from the group consisting of ethylene / α-olefin copolymer and ethylene / vinyl acetate copolymer (3). Or the cable according to 2.