JP5052775B2 - Electrically insulated cable, cable connection structure, and molded part having the same - Google Patents

Description

  The present invention relates to an electrically insulated cable used for automobiles, robots, electronic devices, and the like, and more specifically, necessary for hermetically sealing the connecting portion when connecting to various sensors, electrode terminals, and the like with a housing. An electrically insulated cable that has excellent heat fusion properties with the housing and does not elute heavy metal compounds, generate a large amount of smoke or harmful gas when disposed of in landfills, combustion, etc. The present invention relates to a connection structure for cables and a molded part having them.

  As cables used in automobiles, robots, electronic devices, and the like, cables in which the outer periphery of an insulated wire made of a conductor and an insulator of polyvinyl chloride or flame retardant polyethylene is covered with a sheath are used. For the sheath of this cable, a crosslinked body of a resin composition mainly composed of a thermoplastic polyurethane elastomer (TPU) is mainly used from the viewpoints of flexibility, wear resistance, bending resistance and the like.

  When connecting equipment parts such as sensors and electrode terminals to such cables, the connection and the surrounding area are protected by covering them with a housing in an airtight or watertight manner without taking any special measures. For example, it is formed by injection molding. Therefore, polybutylene terephthalate (PBT) resin and polyamide (PA) resin are often used as materials constituting the housing from the viewpoint of dimensional system, mechanical strength, molding processability, and the like.

In order to ensure airtightness or watertightness between the housing and the cable, it is extremely important that the outermost layer of the housing and the cable is fused by heat and pressure during injection molding. For this reason, there is a method for selecting a cable outermost layer that is easily fused with each molding resin. For example, for PBT, thermoplastic polyester elastomer (TPEE) having PBT in the hard segment, and for PA, thermoplastic polyamide elastomer (TPAE) having PA in the hard segment can be mentioned. There is a method of using a resin composition mainly composed of a mixture for the outermost layer of the cable (see Patent Document 1).
However, when the resin composition is used as a cross-linked body in the outermost cable layer, TPEE and TPAE have high cross-linking efficiency, the cross-linking degree is excessively increased, and the heat-sealing property with the housing is lowered. In particular, in the case of TPAE, the decrease is remarkable, and it is difficult to firmly heat-bond the cross-linked product of the mixed resin composition of TPU and TPAE with the PA resin. Also, TPAE is not practical because it is very expensive compared to TPU.

  On the other hand, one of the items required for cables used for automobiles, robots, electronic devices and the like is flame retardancy. On the other hand, thermoplastic elastomer compositions containing halogen-based flame retardants and antimony compounds containing bromine atoms and chlorine atoms in the molecule have been mainly used as the above-mentioned cable coating (cable sheath) materials ( (See Patent Documents 2 and 3).

  However, when these are disposed of without appropriate treatment and landfilled, heavy metals contained in the material are eluted or burnt, which is not preferable from the halogen compounds contained in the flame retardant. Gases may be generated, and improvements have been discussed in recent years.

For this reason, the examination of the sheath material using the non-halogen flame-retardant material which does not have the possibility of elution of heavy metals affecting the environment and generation of halogen gas has been conducted, and metal hydrates are mainly used.
However, when a housing in which a sheath material obtained by adding a metal hydrate to a thermoplastic elastomer such as TPU is coated with a resin such as PBT, the injection molding temperature becomes high, for example, 260 ° C. or higher. The metal hydrate in the sheath material is decomposed by this heat to form bubbles. If air bubbles are generated in the insulating coating material, the predetermined fusion (adhesion) property with the injection molding resin cannot be obtained, and the interface between the injection molding material and the insulating coating material is easily peeled off, resulting in the predetermined airtightness and watertightness. Cannot be obtained. Furthermore, in the insulating coating material in which a metal hydrate is added to the above-mentioned thermoplastic elastomer such as TPU, it is difficult to fuse (adhere) when a resin such as PBT is injection-molded even when the generation of bubbles is small. .

JP 2004-281577 A Japanese Patent Laid-Open No. 10-269859 JP-A-10-233124

In the present invention, first, even if no special sealing measures are taken, the airtightness and watertightness of the interface between the cable and the housing can be maintained, and the corrosion of the cable conductor and the performance deterioration of the continuous equipment parts can be prevented. In addition, an object is to provide an electrically insulated cable in which the outermost layer of the cable is not easily damaged even in a high temperature atmosphere.
Furthermore, the present invention, secondly, achieves the above-mentioned first object and is excellent in flame retardancy, and suppresses elution of heavy metal compounds and generation of a large amount of smoke at the time of disposal such as landfill and combustion, The purpose is to provide a flame-retardant cable that can cope with recent environmental problems.

As a result of repeated studies by the present inventors, an expensive material such as TPEE or TPAE can be obtained by controlling the degree of crosslinking using a resin composition based on TPU in the outermost layer of the cable covering layer. The present inventors have found that it is possible to impart heat-fusibility with PBT resin and PA resin, in particular, good heat-fusibility with PA resin without using it, and have reached the present invention based on this finding. .
That is, the present invention
(1) An electrical insulation cable is connected to a main body device, and the main body device side terminal portion of the electric insulation cable and the main body device are collectively sealed by a housing provided by injection molding with polyamide resin, and the cable terminal portion An electrically insulating cable used in a cable connection structure for hermetically sealing the cable and the housing by fusing the outermost layer of the cover and the housing,
The electrically insulating cable is provided with a coating layer on the outside of a multi-core stranded wire in which a plurality of insulated wires are twisted together, and the coating layer is composed of at least two coating layers,
(I) The outermost layer is formed by extrusion molding a resin composition containing 3 to 80 parts by mass of the triazine compound (B) with respect to 100 parts by mass of the resin component consisting of only the thermoplastic polyurethane elastomer (A). It is formed with an irradiated crosslinked body, and the crosslinking degree of the crosslinked body is 5 to 40% by mass,
(Ii) The coating layer other than the outermost layer of the coating layer is formed by adding 30 to 30 parts of the metal hydrate (D) with respect to 100 parts by mass of the resin component (C) having a polyolefin resin or an ethylene copolymer as a main component. halogen-free flame retardant electrical insulating cable characterized in that to 250 parts by mass including Yes,
(2) The non-halogen flame-retardant electrically insulated cable according to (1), wherein an average thickness of the outermost layer of the coating layer is 0.2 mm to 0.5 mm,
(3) The non-halogen flame-retardant electrically insulated cable described in (1) or (2) is connected to the main body device, and the main body device side terminal portion of the electrically insulated cable and the main body device are injection-molded with a polyamide resin. A cable connection structure, wherein the cable and the housing are hermetically sealed by fusing the outermost layer of the cable end portion and the housing together,
(4) A molded part comprising the cable connection structure according to (3).

The electrically insulated cable of the present invention has a heat fusion property with a polyamide resin or a polybutylene terephthalate resin by adjusting the degree of crosslinking without using an expensive material such as polyamide elastomer or polyester elastomer for the sheath. As a result, it becomes possible to integrally manufacture a sealing part made of polyamide resin or polybutylene terephthalate resin, thereby improving the reliability of the airtightness of the connecting portion, reducing the assembly process, and thereby reducing the cost. . For example, when the cable is integrally molded at the same time as the formation of the housing of the wheel speed sensor, a high airtight performance of the cable connection portion can be obtained simply by injection molding a housing material of polyamide resin or polybutylene terephthalate resin in the molding process. It can be used as a wide and high value in the automobile field.
In addition, the cable of the present invention can be composed of a non-halogen flame retardant material, which not only has excellent mechanical properties, flame resistance, heat resistance, and low temperature properties, but also harmful heavy metal compounds at the time of disposal such as landfill and combustion. Elution, a large amount of smoke, and generation of gas that affects the environment can be suppressed.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic cross-sectional view schematically showing one embodiment of an electrically insulated cable of the present invention. In the figure, the cable 10 has a structure described below. The multi-core stranded wire has a structure in which a plurality of insulated electric wires 11 provided with an insulating layer 11b made of a polyethylene resin composition on a conductor 11a are twisted together. The covering layer 12 covering the multi-core stranded wire is composed of a plurality of layers, and the inner layer 12a is a layer in contact with the outermost layer 12b in the covering layer. At least the outermost layer 12b is formed of a crosslinked body of the resin composition.

  FIG. 2 schematically shows an example of a cable connection structure using the electrically insulated cable of the present invention. Here, the insulated wire 26 of the cable 21 is connected to the output terminal 24a of the main body device (for example, device sensor portion) 24, and then PA resin or PBT resin is injection molded to form the housing 25 for sealing the sensor portion. At the same time, the outer periphery of the main device side terminal portion 21a of the electrically insulated cable is wrapped with a housing, and the housing and the sheath of the cable are heat-sealed at the interface.

  In the electrically insulated cable of the present invention, the coating layer provided on the multi-core stranded wire in which a plurality of insulated wires are twisted together may be composed of two or more layers as long as it is at least two layers or more. Those are preferred. In the case of forming a coating layer composed of a plurality of layers, it can be subjected to coextrusion coating, or the next outer layer may be sequentially coated after the inner layer is coated. In this case, each coating layer is formed of a resin composition to be described later in order to have adhesion with the housing and predetermined flame retardancy.

Next, a preferred embodiment of the present invention will be described with reference to an example in which the coating layer is composed of two layers.
In the electrically insulated cable of the present invention, the average thickness of the outermost layer is preferably 0.2 mm to 0.5 mm in consideration of the balance between productivity and cost.

1. Outer Layer Material (A) Thermoplastic Polyurethane Elastomer Thermoplastic polyurethane elastomer (TPU) is a resin excellent in flexibility at low temperatures, mechanical strength, and oil and chemical resistance. Examples of TPU include polyester-based urethane resins (adipate-based, caprolactone-based, polycarbonate-based), and polyether-based urethane resins, and polyether-based urethane resins are preferable from the viewpoint of water resistance and mold resistance. The TPU hardness (JIS K 253, type A durometer, 1 kgf (9.80665 N)) is preferably 98 or less.

(B) Triazine compound In the electrically insulated cable of the present invention, the outermost layer of the coating layer is blended with a predetermined amount of triazine compound (B) in the thermoplastic polyurethane resin for the purpose of imparting flame resistance to the cable. To do. The main flame retardant effect of the triazine compound is dilution of combustible cracked gas by generating N ₂ gas during decomposition.
In addition, the cable of the present invention contains a triazine compound in the outermost layer of the coating layer, so that bubbles are not generated at the interface between the cable and the injection molding resin due to thermal decomposition of the injection molding resin, and high adhesive strength and It becomes possible to maintain confidentiality.
Further, the fusibility will be explained. First, both TPU and PBT resin or PA resin have polar groups, and it is considered that strong fusing (adhesion) is performed by the intermolecular force of these polar groups. On the other hand, metal hydrate has a strong polar group. Therefore, when a metal hydrate is added, the polar group in the thermoplastic elastomer such as TPU is oriented to the polar group side of the metal hydrate, and it is difficult to contribute to fusion (adhesion) with a resin such as PBT. It is considered to be. In other words, when magnesium hydroxide or the like is used as a flame retardant, polar groups of TPU and the flame retardant attract each other and inhibit fusibility. In the electrical insulating cable of the present invention, since there is no such interaction, it is considered that extremely good heat-sealability with the injection molding resin can be obtained.

Although it does not specifically limit as a triazine compound which can be used as an outer layer material of the electrical insulation cable of this invention, Cyanuric acid, a melamine derivative, a melamine cyanurate compound, etc. are mentioned.
The particle size of the triazine compound that can be used as the outer layer material of the electrically insulated cable of the present invention is preferably as small as possible. The average particle size is preferably 10 μm or less, more preferably 5 μm or less.
For example, examples of the melamine cyanurate compound include MCA-0 and MCA-1 (both trade names, manufactured by Mitsubishi Chemical Corporation), MC860 (trade name, manufactured by Nissan Chemical Industries, Ltd.), and the like.

Examples of the melamine cyanurate compound surface-treated with a fatty acid and the melamine cyanurate compound treated with a silane surface include MC610, MC440, MC640 (all trade names, manufactured by Nissan Chemical Co., Ltd.) and the like. It is preferable to use a melamine cyanurate compound that has been surface-treated from the viewpoint of dispersibility in the resin.
Furthermore, as a triazine compound, STI-300 (trade name, manufactured by Shikoku Kasei Kogyo Co., Ltd.) and the like are marketed.
In addition, the structure of a melamine cyanurate compound is represented by the following structures, for example.

The compounding amount of the triazine compound (B) is preferably 3 to 80 parts by mass, more preferably 7 to 40 parts by mass with respect to 100 parts by mass of TPU (A).
In addition, when the compounding quantity of this triazine compound (B) is less than 3 mass parts with respect to 100 mass parts of TPU (A), predetermined | prescribed flame retardance is not obtained and it is 100 mass parts of TPU (A). On the other hand, when it exceeds 80 parts by mass, the adhesion between the coating layer and the molding material is remarkably lowered, and the mechanical properties such as wear resistance and elongation of the coating material are remarkably lowered. Although not particularly limited, the amount of the triazine compound is preferably 40 parts by mass or less in order to maintain extremely good adhesiveness.

  Moreover, the cable of this invention WHEREIN: 5-40 mass% is preferable, and, as for the crosslinking degree of the outermost layer of the said coating layer, 10-30 mass% is more preferable. If the degree of cross-linking cannot be controlled and becomes too high, the heat resistance is improved but it is difficult to melt. The electrically insulated cable of the present invention can achieve both the heat resistance of the cable and the heat fusion property with a housing material such as PA resin by controlling the degree of crosslinking within the above-mentioned range.

In the electrically insulated cable of the present invention, other resins can be added as long as the effects of the present invention are not hindered, and examples thereof include ethylene copolymers and styrene elastomers.
The amount of resin other than TPU that can be added is 15% by mass or less, more preferably 10% by mass or less, and particularly preferably 8% by mass or less, in 100% by mass of the resin component of the outer layer material.

2. Inner layer material (C) Base resin The inner layer of the inner layer material refers to a layer in contact with the outermost coating layer. Therefore, even when the coating layer is composed of a plurality of layers, all the layers on the inner side from the layer in contact with the outermost layer of the coating layer are the inner layers.
The resin composition used for the inner layer in contact with the outermost layer in the coating layer in the electrically insulated cable of the present invention is not particularly limited, but for the purpose of the present invention, halogen compounds containing bromine atoms or chlorine atoms in the molecule, etc. It is preferable not to contain heavy metals such as antimony compounds. In view of availability, moldability and the like, a resin component mainly composed of a polyolefin resin or an ethylene copolymer is preferable.

  Examples of the polyolefin resin include low density polyethylene, high density polyethylene, metallocene polyethylene, and styrene elastomer. Examples of the ethylene copolymer include ethylene-α olefin copolymer, ethylene-propylene rubber, ethylene butadiene rubber. , Ethylene-vinyl acetate copolymer (EVA), ethylene-ethyl acrylate copolymer (EEA), and the like. These polyolefin resins and ethylene copolymers may be used alone or in combination of two or more.

(D) Metal hydrate In the electrically insulated cable of the present invention, a predetermined amount of metal hydrate (D) is blended with the base resin (C) for the purpose of improving the flame retardancy of the cable. Can do.
The metal hydrate used in the electrically insulated cable of the present invention is not particularly limited. For example, aluminum hydroxide, magnesium hydroxide, hydrated aluminum silicate, hydrated magnesium silicate, basic magnesium carbonate, hydrotalcite A compound having a hydroxyl group or water of crystallization such as these can be used alone or in combination of two or more. As the surface treatment agent, a silane compound (silane coupling agent), a fatty acid, a phosphate ester, or the like can be used. Other untreated ones can be used.
In these metal hydrates, magnesium hydroxide is preferable, and examples of such metal hydrates include “Kisuma 5”, “Kisuma 5A”, “Kisuma 5B”, “Kisuma 5J”, “Kisuma 5P” (product) (Commercial name, manufactured by Kyowa Chemical Co., Ltd.) is preferred.

The compounding quantity of a metal hydrate (D) is 250 mass parts or less with respect to 100 mass parts of base resin (C), and does not need to contain it. Preferably it is 30-250 mass parts, More preferably, it is 30-150 mass parts.
Although not particularly limited, in order to maintain stable flame retardancy, the amount of the metal hydrate is preferably 30 parts by mass or more. Moreover, when the compounding quantity of a metal hydrate (D) exceeds 250 mass parts with respect to 100 mass parts of base resin (C), low temperature property and a mechanical characteristic will fall remarkably. In order to maintain low temperature property, 150 mass parts or less are preferable.

Further, regarding the metal hydrate used in the present invention, the presence or absence of surface treatment is not particularly limited. However, in consideration of dispersibility in the base resin (C), stearic acid, oleic acid treated with fatty acid, acid resistance, In view of water resistance, those using phosphate esters are preferred.
Furthermore, in order to improve the strength of the cable covering material, it is preferable to use a metal hydrate surface-treated with a reactive silane coupling agent. By surface treatment with a reactive silane coupling agent, not only can the tensile strength of the resulting resin material be improved, but also a sheath material that does not deteriorate in mechanical properties even when a large amount of magnesium hydroxide is added. Can do.

  In order to exert these effects remarkably, a silane coupling agent having a double bond such as a vinyl group at the end or a silane coupling agent having an epoxy group at the end is preferable. Further, although not particularly limited, surface treatment is performed with an aliphatic surface treatment agent such as stearic acid or a phosphate ester surface treatment agent in combination with a silane coupling agent having a vinyl group or an epoxy group at the terminal. As a result, it is possible to maintain both the acid resistance, water resistance, and mechanical strength while securing the extrusion characteristics.

The vinyl group, epoxy group, and amino group-terminated silane coupling agents include vinyl trimethoxysilane, vinyltriethoxysilane, glycidoxypropyltrimethoxysilane, glycidoxypropyltriethoxysilane, and glycidoxypropylmethyl. Examples include dimethoxysilane, methacryloxypropyltrimethoxysilane, methacryloxypropyltriethoxysilane, methacryloxypropylmethyldimethoxysilane, mercaptopropyltrimethoxysilane, and mercaptopropyltriethoxysilane.
Further, two or more kinds of the above-mentioned magnesium hydroxide may be used as a mixture, or may be used as a mixture with other metal hydrates.

  By using a metal hydrate treated with a reactive silane coupling agent, the reactive silane coupling agent reacts at the time of electron beam irradiation and crosslinks with the base resin (C). The entire composition having an interaction through the surface treatment agent becomes a crosslinked product having excellent mechanical strength. Even when a large amount of metal hydrate is added due to this interaction, a high mechanical strength of the resin composition is maintained, and a resin composition having excellent wear resistance and being hardly scratched is obtained.

  In the cable of the present invention, as a method for crosslinking the coating layer after coating provided on the multicore stranded wire, a conventionally known crosslinking method by irradiation with ionizing radiation such as electron beam is preferable from the viewpoint of productivity. As irradiation amount of an electron beam, 5-20 Mrad is preferable. In addition, after the outermost layer and the other layers are sequentially coated, electron beam crosslinking may be performed.

  In the resin composition constituting the coating layer of the cable in the present invention (the outermost layer and other layers), various additives commonly used in insulated wires and cables, for example, antioxidants, A polyfunctional monomer that is a metal deactivator, a non-halogen flame retardant, a dispersant, a colorant, a filler, a lubricant, or a crosslinking aid can be appropriately blended within a range that does not impair the object of the present invention. In particular, it is preferable to add a flame retardant for automobile applications.

Antioxidants include amine-based antioxidants such as 4,4′-dioctyl diphenylamine, N, N′-diphenyl-p-phenylenediamine, and 2,2,4-trimethyl-1,2-dihydroquinoline polymer. Agent, 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-hydroxybenzyl) benzene and the like, bis (2-methyl-4- ( 3-n-alkylthiopropionyloxy) -5-tert-butylphenyl) sulfide, 2-mercaptobenzimidazole and its zinc salt, pentaerythris Tall - tetrakis (3-lauryl - thiopropionate) and the like sulfur-based antioxidant such.
Examples of metal deactivators include N, N′-bis (3- (3,5-di-t-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.

Furthermore, examples of the flame retardant used in the electrically insulated cable of the present invention include phosphorus-based flame retardants such as non-halogen phosphate compounds and red phosphorus compounds.
Furthermore, examples of flame retardants (auxiliaries) and fillers include carbon, clay, zinc oxide, tin oxide, titanium oxide, magnesium oxide, silicone compounds, quartz, talc, calcium carbonate, magnesium carbonate, zinc borate, and white carbon. It is done.

  As the polyfunctional monomer, polyfunctional vinyl monomers such as divinylbenzene and triallyl cyanurate, or ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, trimethylolpropane trimethacrylate And polyfunctional methacrylate monomers such as allyl methacrylate.

  EXAMPLES Hereinafter, although this invention is demonstrated further in detail based on an Example, this invention is not limited to these.

(Examples and comparative examples)
On the conductor (copper alloy conductor, 16 wires / twisted three 0.08 mmφ strands), low-density polyethylene is extrusion-coated so as to have an outer diameter of 1.4 mm, and this has an acceleration voltage of 500 keV. Then, an insulated conductor having a crosslinked polyethylene insulating layer was obtained by irradiation with an electron beam with an irradiation amount of 5 Mrad. A multi-core stranded wire in which two insulated conductors were twisted together was prepared.
Next, on the above multi-core stranded wire, using a 40 mmφ extruder (L / D = 25), die temperature 180 ° C., and then to the feeder side, C3 = 170 ° C., C2 = 160 ° C., C1 = 140 ° C. The inner layer resin composition shown in the following table is extrusion coated so that the outer diameter is 3.4 mmφ to form an inner layer coating layer, and the outer layer resin composition shown in the following table is further formed on the outer layer resin composition. Extrusion coating was performed under the same conditions as the inner layer so that the diameter was 4.0 mmφ.

  Next, after extrusion coating, the coating layer was crosslinked by irradiating with an electron beam at an acceleration voltage of 750 keV and an arbitrary irradiation amount to obtain a cable having two coating layers as shown in FIG. In addition, in the following table | surface, the usage-amount of each component of the resin composition for inner layers and outer layers was shown by the mass part.

Various characteristics of the obtained cables were evaluated by the following test methods, and the results are shown in Table 1 or 2.
(1) Adhesive strength with molded body (vs. PBT resin)
As shown in FIG. 3, a test body 31 having half the cable is prepared. As shown in FIG. 3, the PBT plate 32 is preheated at a surface temperature of 230 ± 2 ° C. on the PBT plate 32 for 5 minutes. After applying a pressure of 2 ± 0.2 MPa × 30 ± 1 second to a width of 4 mm, the cable is the maximum necessary to peel off the pressed test body 41 from the PBT plate 42 as shown in FIG. The force (N) was measured.
This maximum strength was multiplied by 2.5, and the value converted per cm was taken as the adhesive strength (N / cm). In addition, the said peeling was performed at the speed | rate of 50 mm / min at room temperature. Adhesive strength is 30 N / cm or more, which is acceptable, but preferably 50 N / cm or more.

(2) Adhesive strength with molded body (to PA resin)
The plate molding resin was changed to PA, and the same test as 1) was performed at a press plate surface temperature of 260 ± 2 ° C. In addition, the standard value of adhesive strength is the same as that of PBT.

(3) Low temperature The cable was cooled at −40 ° C. for 3 hours, wound around a mandrel of 50 mmφ three times, then rewound and endured at 1000 V for 1 minute as a pass. Tables 1 and 2 show the number of times the three cables were tested and passed.

(4) Flame retardance In accordance with JASO D 608, after igniting and removing for 10 seconds so that the inner flame with an inner flame length of 35 mm was in contact with the cable, those having an after flame time of 30 seconds or less were considered acceptable. Tables 1 and 2 show the number of times that five cables were tested and passed.

(5) Crosslinking degree of the outer layer material Only the outer layer material was collected from the cable, extracted with xylene at 110 ° C. for 24 hours, sufficiently dried, and extracted with dimethylformamide at 110 ° C. for 24 hours. It was shown as a percentage of the mass before extraction and was taken as the degree of crosslinking.

The following compounds were used as each compound shown in the table.
(A-1)
Thermoplastic polyurethane elastomer (TPU)
Product name manufactured by Dainichi Seika Kogyo Co., Ltd .; Rezamin P-2288
(A-2)
Thermoplastic ester elastomer (TPEE)
Product name manufactured by Toray DuPont Co., Ltd .; Hytrel 4057
(B)
Silane-treated melamine cyanurate compound, trade name, manufactured by Nissan Chemical Industries, Ltd .; MC-640
(C-1)
Ethylene-vinyl acetate copolymer (EVA)
Product name manufactured by Mitsui DuPont Polychemical Co., Ltd .; Evaflex 360
Vinyl acetate content: 25%
(C-2)
Metallocene linear polyethylene Nippon Polychem Co., Ltd. trade name; Kernel KS340T
(D)
Product name made of vinylsilane treated magnesium hydroxide Kyowa Chemical Industry Co., Ltd .; Kisuma 5L
(E)
Trimethylolpropane trimethacrylate made by Shin-Nakamura Chemical Co., Ltd .; Ogmont T200
(F)
Pentaerythrityl-tetrakis (3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate)
Product name manufactured by Ciba-Geeky Corporation; Irganox 1010

  As is clear from Tables 1 and 2, Comparative Example 1 has a problem in flame retardancy due to the lack of the outer layer flame retardant, while Comparative Example 2 has a low temperature property because there are too many outer layer flame retardants. There is also a problem, and adhesion is also a problem. In Comparative Example 3, the amount of the flame retardant in the inner layer is too large, so that there is a problem with low temperature properties. In Comparative Example 4, although 20 parts by mass of TPEE having good adhesion with PBT is blended with TPU, adhesion to PBT is improved, but there is a problem with adhesion to PA. Even when only TPU is used as the base resin, if the degree of cross-linking exceeds 40% as in Comparative Example 5, the adhesiveness is significantly reduced. It turned out that all are excellent in adhesiveness, a flame retardance, and low temperature property in Examples 1-6 with respect to a comparative example.

It is a schematic sectional drawing which shows typically the preferable embodiment of the electrically insulated cable of this invention. It is explanatory drawing which shows typically an example of the cable connection structure of this invention. It is a schematic front view for demonstrating the preparation method of a pressurization test body in the measurement test of the adhesive strength of the cable and resin molding which were performed in the Example and the comparative example. It is a schematic perspective view for demonstrating the method of a peeling test in the measurement test of the adhesive strength of the cable and resin molding which were performed in the Example and the comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Electrically insulated cable 11 Insulated electric wire, 11a Conductor, 11b Insulating layer 12 Covering layer, 12a Inner layer, 12b Outermost layer 20 Connection structure (cable connection structure) of a cable and a housing
DESCRIPTION OF SYMBOLS 21 Electrically insulated cable, 21a Main body side terminal part 22 of electrically insulated cable 22 Conductor 24 Main body apparatus (device sensor part), 24a Main body output terminal 25 Housing 26 Insulated wire 31 Specimen 32 in which electrically insulated cable is halved PBT Board (PA board)
33 Pressing direction 34 Press plate (top), 35 Press plate (bottom)
41 Specimen 42 in which electric insulation cable deformed by pressurization is halved 42 PBT plate (PA plate), 42a Fused portion 43 Direction to peel off

Claims (4)

An electrically insulated cable is connected to the main body device, and the main device side terminal portion of the electrically insulated cable and the main body device are collectively sealed with a housing provided by injection molding with polyamide resin, and the cable terminal portion is covered with the outermost covering. An electrically insulated cable used for a cable connection structure that hermetically seals the cable and the housing by fusing the outer layer and the housing,
The electrically insulating cable is provided with a coating layer on the outside of a multi-core stranded wire in which a plurality of insulated wires are twisted together, and the coating layer is composed of at least two coating layers,
(I) The outermost layer is formed by extrusion molding a resin composition containing 3 to 80 parts by mass of the triazine compound (B) with respect to 100 parts by mass of the resin component consisting of only the thermoplastic polyurethane elastomer (A). It is formed with an irradiated crosslinked body, and the crosslinking degree of the crosslinked body is 5 to 40% by mass,
(Ii) The coating layer other than the outermost layer of the coating layer is formed by adding 30 to 30 parts of the metal hydrate (D) with respect to 100 parts by mass of the resin component (C) having a polyolefin resin or an ethylene copolymer as a main component. flame-retardant electrically insulating cable halogen-free, characterized in that the formation of a resin composition obtained by 250 parts by weight containing Yes.   2. The non-halogen flame-retardant electrically insulated cable according to claim 1, wherein an average thickness of an outermost layer of the covering layer is 0.2 mm to 0.5 mm.   3. The non-halogen flame retardant electrically insulated cable according to claim 1 or 2 is connected to a main body device, and the main body device side terminal portion of the electrically insulated cable and the main body device are collectively formed by a housing provided by injection molding with a polyamide resin. A cable connection structure characterized in that the cable and the housing are hermetically sealed by fusing the outermost coating layer of the cable end portion and the housing. A molded part comprising the cable connection structure according to claim 3.

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