JP2009026666A - Multilayer insulation electric wire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multilayer insulation electric wire which includes flame resistance, abrasion resistance, and surface smoothness in addition to mechanical characteristics, and which is superior in appearance. <P>SOLUTION: The multilayer insulation electric wire is constituted of a resin composition with high-density polyethylene with melt flow rate of 0.5 g/10 minutes or more as a main component as an outermost layer, of which at least one layer of the insulation layers except the outermost layer is constituted of resin composition containing metal hydrate by 30 to 300 pts. by mass against 100 pts. by mass of synthetic resin kinds with direct-chain low-density polyethylene as a main component. By such constitution, the insulation electric wire is endowed with the mechanical characteristics necessary for the insulation electric wire, in which the outermost layer improves mainly smoothness and abrasion resistance of the surface, in which the insulation layer except the outermost layer improves mainly the flame resistance, which is equipped with flame resistance, abrasion resistance, surface smoothness and mechanical characteristics, which is superior in appearance, and which is superior in adaptability to environments. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a multilayer insulated wire. More specifically, the present invention relates to a multilayer insulated wire that has flame retardancy, surface smoothness, and wear resistance and is used in automobiles, railway vehicles, electrical / electronic devices, and the like.

  Insulation coating materials for components such as automobiles, railway vehicles, electrical / electronic devices, and insulated wires placed in them, in addition to heat resistance, cold resistance, moisture resistance, flame resistance, wear resistance, etc. Various characteristics are required. Polyvinyl chloride (PVC) resins and polyolefin resins containing halogen-based flame retardants containing bromine (Br) atoms or chlorine (Cl) atoms in the molecule are widely used as resin materials constituting them. It had been. When products using such materials are disposed of without proper treatment, various problems have occurred. For example, when these products are disposed of in landfills, they are included in the materials. In the case of incineration and disposal, corrosive halogen gas or dioxin is generated. It was.

  For this reason, in recent years, non-halogen flame retardant resin compositions that do not generate harmful heavy metals or corrosive halogen-based gases have been studied, and some have been put into practical use. Non-halogen flame retardant resin compositions that have been studied and put into practical use use polyolefin resins as the base polymer, and mixed with metal hydrates such as magnesium hydroxide and aluminum hydroxide to improve flame retardancy. In addition, an ethylene copolymer that easily disperses a large amount of metal hydrate has been used as the base polymer of the resin composition.

  The resin composition obtained by pace polymerizing such polyolefin resin or ethylene copolymer is improved in flame retardancy by mixing a large amount of metal hydrate such as magnesium hydroxide, but also has wear and tensile properties. There was a problem that the mechanical properties such as the above deteriorated. On the other hand, in order to suppress a decrease in wearability, it may be possible to increase the amount of polypropylene or high-density polyethylene, which is relatively hard and wearable, to the base polymer. This is not preferable because the properties are impaired and the processability of the resin composition is also deteriorated. Further, in order to improve the wear resistance of the insulated wire, the wire coating has a multilayer structure of an outer layer and an inner layer, and a metal hydrate is added to the polyolefin resin as the inner layer, and the Shore D hardness of ASTM D2240 is 40 to 55. A multilayer insulated wire employing a resin composition and high-density polyethylene having a Shore D hardness of ASTM D2240 of 60 or more as an outer layer is provided (see, for example, Patent Document 1).

JP 11-219626 A ([Claim 1], [0013])

  However, the above-described conventional multilayer insulated wires having a specific range of Shore D hardness of the outer layer and the inner layer have a problem that the mechanical characteristics are poor and sufficient wear resistance cannot be maintained. On the other hand, a high-strength insulated wire in which an inorganic flame retardant such as magnesium hydroxide or aluminum hydroxide is added to linear low density polyethylene (LLDPE) is also known. Addition of a flame retardant has a problem that the surface becomes rough and the appearance is deteriorated, the surface smoothness as an insulated wire is lowered, and the wear resistance is also deteriorated.

  The present invention has been made in view of the above problems, and provides a multilayer insulated wire having mechanical properties, flame retardancy, wear resistance and surface smoothness, and having a good appearance. It is in.

  In order to solve the above problems, a multilayer insulated wire according to claim 1 of the present invention is a multilayer insulated wire in which at least two or more insulating layers are formed on a metal conductor, and the outermost layer of the insulating layers. Is composed of a resin composition mainly composed of high-density polyethylene having a melt flow rate specified by JIS K7210 of 0.5 g / 10 min or more (190 ° C., 2.16 kgf load), and an insulating layer other than the outermost layer. At least one layer is composed of a resin composition containing 30 to 300 parts by mass of a metal hydrate with respect to 100 parts by mass of a synthetic resin mainly composed of linear low density polyethylene.

  In the multilayer insulated wire according to claim 2 of the present invention, in the above-described claim 1, the resin composition constituting the outermost layer contains a lubricant of 5.0 parts by mass or less with respect to 100 parts by mass of the resin composition. It is characterized by containing.

  The multilayer insulated wire according to claim 3 of the present invention has the melt flow rate defined in JIS K7210 of linear low-density polyethylene constituting the insulating layer other than the outermost layer in the above-described claim 1 or claim 2. 5.0 g / 10 min or less (190 ° C., 2.16 kgf load).

  A multilayer insulated wire according to a fourth aspect of the present invention is the multilayer insulated wire according to any one of the first to third aspects, wherein the linear low density polyethylene constituting the insulating layer other than the outermost layer is polymerized by a metallocene catalyst. It is a linear low density polyethylene.

  The multilayer insulated wire according to claim 1 of the present invention is a resin composition mainly composed of high-density polyethylene having a multilayer insulation structure and an outermost layer having a melt flow rate of 0.5 g / 10 min or more. At least one insulating layer other than the outer layer is composed of a resin composition containing 30 to 300 parts by mass of a metal hydrate with respect to 100 parts by mass of a synthetic resin mainly composed of linear low density polyethylene. Therefore, it has the mechanical properties necessary for an insulated wire, and the outermost layer mainly improves the smoothness and wear resistance of the surface, and the insulating layer other than the outermost layer mainly improves the flame retardancy, and as the insulating layer other than the outermost layer. Multi-layer insulated wire with flame retardancy, wear resistance, surface smoothness and mechanical properties, good appearance and excellent adaptability to the environment despite the use of linear low density polyethylene It becomes.

  In the multilayer insulated wire according to claim 2 of the present invention, the resin composition constituting the outermost layer of the multilayer insulated wire can reduce friction by adding a specific amount of lubricant, and the outermost layer or the multilayer insulated wire. The wear resistance of can be further improved. Moreover, the strength fall by lubricant addition can be prevented by making content of the said lubricant into 5.0 mass parts or less.

  The multilayer insulated wire according to claim 3 of the present invention has a specific range of the melt flow rate defined in JIS K7210 of linear low density polyethylene constituting the insulating layer other than the outermost layer, and therefore contains a flame retardant. In addition, the strength of the insulating layer can be maintained in a high state.

  In the multilayer insulated wire according to claim 4 of the present invention, the linear low density polyethylene polymerized by the metallocene catalyst is selected as the linear low density polyethylene constituting the insulating layer other than the outermost layer. It is possible to suppress the deterioration of the mechanical properties of the insulating layer due to the filling of the Japanese product and to improve the wearability.

  Hereinafter, the multilayer insulated wire of the present invention will be described. The multilayer insulated wire of the present invention is a multilayer insulated wire in which at least two or more insulating layers are formed on a metal conductor, and the outermost layer of the insulating layers has a melt flow rate defined by JIS K7210 of 0.5 g / 10. Min. (190 ° C., 2.16 kgf load) (about 21.2 N load, the same applies to the present specification), and a resin composition mainly composed of high-density polyethylene, and at least one insulating layer other than the outermost layer A layer is comprised with the resin composition which consists of 30-300 mass parts of metal hydrates with respect to 100 mass parts of synthetic resins which have a linear low density polyethylene as a main component.

(I) Outermost layer:
The outermost layer constituting the multilayer insulated wire of the present invention is a high density polyethylene (hereinafter referred to as “specific high density”) having a melt flow rate specified by JIS K7210 of 0.5 g / 10 min or more (190 ° C., 2.16 kgf load). It may be referred to as “polyethylene”.). By adopting a specific high density polyethylene having an MFR in the range as the resin constituting the outermost layer, the moldability is also good, and the smoothness and wear resistance of the surface as an insulated wire can be improved. As the high density polyethylene constituting the outermost layer of the multilayer insulated wire, those having a density of approximately 940 kg / m ³ or more can be used. The MFR of the high density polyethylene is preferably 0.5 g / 10 g or more (190 ° C., 2.16 kgf load).

  The specific high-density polyethylene is a main component of the resin composition constituting the outermost layer, and is preferably contained in an amount of 50% by mass or more, more preferably 80 to 100% by mass with respect to the entire resin composition. Particularly preferably, the high density polyethylene is 100% by mass. Examples of constituent materials other than high-density polyethylene include synthetic resins such as polypropylene, modified polypropylene, modified polyethylene, ultrahigh-density polyethylene, and general-purpose polyolefin resins such as ETFE (ethylene / tetrafluoroethylene copolymer). Is mentioned.

  Moreover, it is preferable to add a lubricant to the resin composition mainly composed of a specific high-density polyethylene constituting the outermost layer. By adding a lubricant, the abrasion resistance of the outermost layer or the multilayer insulated wire can be further improved. As the lubricant, for example, a silicon-based lubricant, a fluorine-based lubricant, a wax, a fatty acid amide (fatty acid amide), etc. can be used. Can be improved efficiently. One type of these lubricants may be used alone, or two or more types may be used in combination.

  Examples of the silicone-based lubricant include a dimethylsiloxane having a hydrophobic main chain as a main chain, a polyalkylene oxide pendant type having a hydrophilic side chain, a dimethylsiloxane having a hydrophobic group at the end of a molecule, and a polyalkylene oxide having a hydrophilic group as the other end. Terminal modified type, surfactant such as block copolymer type in which dimethylsiloxane unit of hydrophobic group and polyalkylene oxide unit of hydrophilic group are alternately repeated, or silanol modified silicone oil, alkoxy modified silicone oil, epoxy modified silicone oil, amino Examples thereof include emulsions of reactive silicone oils such as modified silicone oil and alcohol-modified silicone oil.

  Examples of the fluorine-based lubricant include a potassium salt of perfluoroalkyl carboxylic acid, a fluorine-based surfactant such as perfluoroalkyl polyoxyethylene ethanol, and a perfluoroalkyl acrylic modified resin.

  Examples of the wax include polyethylene wax, oxidized polyethylene wax, paraffin wax, microcrystalline wax, carnauba wax, beeswax, rice wax, candelilla wax, polytetrafluoroethylene wax, lanolin, montan wax, ceresin wax and the like. Examples thereof include waxes dispersed in the emulsion, self-emulsified types by introducing salt groups or water-soluble segments in the molecule, and emulsion type waxes emulsified with emulsifiers.

  Examples of the fatty acid amide (fatty acid amide) lubricant include higher fatty acid amides such as stearic acid amide, erucic acid amide, and palmitic acid amide, and (alkyl) bis fatty acid amides such as methylene bis stearic acid amide and ethylene bis stearic acid amide. Etc.

  As the content of the lubricant with respect to the resin composition mainly composed of the specific high density polyethylene constituting the outermost layer, it is preferably 5.0 parts by mass or less with respect to 100 parts by mass of the resin composition, 0.05 More preferably, it is -5.0 mass parts. By containing the lubricant in such a range with respect to 100 parts by mass of the specific high density polyethylene, it is possible to efficiently improve the wearability of the multilayer insulated wire. On the other hand, if the content is less than 0.05 parts by mass, the effect of improving the wear resistance by adding a lubricant may not be exhibited. If the content exceeds 5.0 parts by mass, the resin In some cases, a decrease in the strength of the lubricant itself and a bleeding phenomenon in which the lubricant aggregates on the surface may occur. It is particularly preferable that the content of the lubricant with respect to the resin composition containing a specific high-density polyethylene as a main component is 0.1 to 1.0 part by mass with respect to 100 parts by mass of the resin composition.

(II) Insulating layers other than the outermost layer:
At least one of the insulating layers other than the outermost layer constituting the insulating layer of the multilayer insulated wire of the present invention has a specific amount with respect to 100 parts by mass of the synthetic resin mainly composed of linear low density polyethylene (LLDPE). It is comprised with the resin composition which adds a metal hydrate. By using a linear low-density polyethylene as the main component of the base polymer of the insulating layer other than the outermost layer, an insulated wire excellent in flame retardancy and mechanical strength can be provided. On the other hand, when a metal oxide is added to linear low-density polyethylene, the surface becomes rough and the appearance deteriorates, but the surface smoothness also decreases and the wear resistance also deteriorates. By covering with the above-mentioned specific high density polyethylene excellent in surface smoothness and wear resistance, problems such as rough surfaces are eliminated, and wear resistance, surface smoothness, flame retardancy and mechanical properties are improved. It becomes a multilayer insulated wire that combines. The insulating layer other than the outermost layer constituting the multilayer insulated wire of the present invention may be a single layer, or may be formed by combining two or more layers having different resin composition configurations.

As these linear low density polyethylene constituting the insulating layer other than the outermost layer, those having a density of approximately 900 to 940 kg / m ³ can be used. In addition, from the viewpoint of improving the flame retardancy of the resin composition constituting the insulating layer other than the outermost layer and the kneadability at the time of molding, JISK
The melt flow rate (MFR) specified in 7210 is preferably 5.0 g / 10 min (190 ° C., 2.16 kgf load) or less.

  Further, in the present invention, as the linear low density polyethylene, C4 linear linear low density polyethylene, C5 linear linear low density polyethylene, C6 linear linear low density polyethylene (hereinafter referred to as “C4 linear linear”). It is preferable to use “chain low density polyethylene”. Surface smoothness and wear resistance can be improved by using such a C4 linear low density polyethylene as the linear low density polyethylene. C4 linear low density polyethylene, C5 linear low density polyethylene, and C6 linear low density polyethylene as linear low density polyethylene may be used alone or in two types. You may use it in combination.

  Further, as the linear low density polyethylene, it is preferable to use a linear low density polyethylene polymerized by a metallocene catalyst. The metallocene catalyst is also called a single site catalyst or a Kaminsky catalyst, and has a single polymerization active point and has a high polymerization activity. Linear low density polyethylene polymerized using such a metallocene catalyst is characterized by a narrow molecular weight distribution and composition distribution. Since linear low density polyethylene polymerized by such a metallocene catalyst has high tensile strength, tear strength, impact strength, etc., when used for an insulating material that needs to be highly filled with metal hydrate, Mechanical properties due to the highly filled metal hydrate can be suppressed.

  The linear low density polyethylene constituting the insulating layer other than the outermost layer of the present invention is particularly preferably a C4 linear low density polyethylene that is polymerized with a metallocene catalyst. . By applying such linear low density polyethylene to an insulating layer other than the outermost layer, an insulated wire having both effects can be obtained.

  About the linear low density polyethylene which comprises insulating layers other than the outermost layer of the multilayer insulated wire of this invention, what modified | denatured by unsaturated carboxylic acid and / or its derivative (acid modified substance) can also be used. Examples of the unsaturated carboxylic acid include maleic acid, itaconic acid, and fumaric acid, and examples of the unsaturated carboxylic acid derivative include maleic acid monoester, maleic acid diester, maleic anhydride, itaconic acid monoester, itaconic acid diester, Examples include itaconic anhydride, fumaric acid monoester, and fumaric acid diester. One of these acid-modified products may be used alone, or two or more of these acid-modified products may be used in combination.

  In the present invention, at least one of the insulating layers other than the outermost layer is composed of synthetic resins mainly composed of the above-described linear low-density polyethylene. Examples of other synthetic resins that can be used include synthetic resins substantially free of halogen components, unsaturated carboxylic acids and / or derivatives thereof, such as polyethylene other than linear low-density polyethylene, ethylene α -Olefin copolymer, polypropylene, propylene / α-olefin copolymer, ethylene / vinyl acetate copolymer, ethylene / acrylic acid ester copolymer, ethylene / methacrylic acid ester copolymer, ethylene / acrylic acid copolymer , Polyolefin resin such as ethylene / methacrylic acid copolymer, ionomer, polyamide, polyurethane, polymer Re-ester, polystyrene and other thermoplastic resins, thermoplastic resin elastomers, styrene butadiene rubber, butadiene rubber, isoprene rubber, acrylonitrile butadiene rubber, ethylene propylene rubber, ethylene propylene terpolymer, butyl rubber, acrylic rubber, silicone rubber, etc. Can be mentioned. Moreover, resin materials such as acid-modified products obtained by modifying the above-described thermoplastic resins with unsaturated carboxylic acids and / or derivatives thereof can be used. One of these synthetic resins may be used alone, or two or more of these may be used in combination. The content of the linear low density polyethylene with respect to the entire synthetic resins is preferably 70 mass% or more, more preferably 70 to 100 mass%, and more preferably 70 to 80 mass% with respect to the entire synthetic resins. % Is particularly preferable.

  In the insulating layers other than the outermost layer, the metal hydrate added to the linear low density polyethylene serving as the base resin is added for the purpose of improving the flame retardancy of the multilayer insulated wire. Examples of the metal hydrate that can be used in the present invention include magnesium hydroxide, aluminum hydroxide, basic magnesium carbonate, and the like. One of these may be used alone, or two or more of these may be used. Can be used in combination. In the present invention, from the viewpoint of efficiently improving the flame retardancy, among these metal hydrates, magnesium hydroxide or aluminum hydroxide may be used, or a combination of these may be used. preferable. Specific examples of the metal hydrate include Kisuma (manufactured by Kyowa Chemical Co., Ltd.) and magnifin (manufactured by Albemarle) as magnesium hydroxide.

  The average particle size of the metal hydrate is preferably about 0.3 to 5.0 μm, for example, about 0.5 to 1.0 μm in order to improve dispersibility with respect to the linear low density polyethylene. It is particularly preferable to do this.

  In addition, it is preferable to use a metal hydrate that has been treated with a surface treatment agent in consideration of dispersibility in linear low-density polyethylene. Examples of such surface treatment agents include alkali metal salts of higher fatty acids such as sodium caprate, sodium laurate, sodium myristate, sodium palmitate, sodium stearate, potassium stearate, sodium oleate, potassium oleate. Sodium linoleate, etc. are higher fatty acids such as capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, fatty acid amide, fatty acid ester, higher aliphatic alcohol, etc. Examples of the ring agent include isopropyl triisostearoyl titanate, isopropyl tris (dioctyl bisphosphate) titanate, tetraisopropyl bis (dioctyl phosphite) titanate, The grayed agents, for example, vinyl triethoxy silane, .gamma.-methacryloxypropyltrimethoxysilane, .gamma.-glycidoxypropyltrimethoxysilane, amino coupling agent, silicone oil, various phosphoric acid esters and the like.

  As content of the metal hydrate with respect to linear low density polyethylene, it is 30-300 mass parts with respect to 100 mass parts of linear low density polyethylene. By containing the metal hydrate in such a range with respect to 100 parts by mass of the linear low density polyethylene, the flame resistance of the multilayer insulated wire can be improved efficiently. On the other hand, if the content is less than 30 parts by mass, flame resistance that can withstand practical use cannot be obtained, and if the content exceeds 300 parts by mass, the tensile properties deteriorate, and the multilayer insulated wire has the inherent flexibility. In addition to losing, there may be a problem that molding processability at the time of molding deteriorates. It is preferable that content of the metal hydrate with respect to a linear low density polyethylene is 50-150 mass parts.

  In addition, in the multilayer insulated wire of the present invention, the resin composition containing 30 to 300 parts by mass of metal hydrate with respect to 100 parts by mass of the above-described synthetic resins mainly composed of linear low density polyethylene. However, in order to exert the effect of the present invention, the insulating layer other than the outermost layer may be an insulating layer composed of the resin composition. The thickness of the layer is preferably 50 to 100% of the entire insulating layer other than the outermost layer, more preferably 80 to 100%, and particularly preferably 100%.

  Insulating layers other than the outermost layer, the insulating layer is composed of a resin composition containing 30 to 300 parts by mass of a metal hydrate with respect to 100 parts by mass of the synthetic resin mainly composed of linear low-density polyethylene. Examples of the synthetic resin that can constitute other than the layer include a synthetic resin substantially free of a halogen component, an unsaturated carboxylic acid and / or a derivative thereof, such as polyethylene, ethylene / α-olefin copolymer, and polypropylene. , Propylene / α-olefin copolymer, ethylene / vinyl acetate copolymer, ethylene / acrylic acid ester copolymer, ethylene / methacrylic acid ester copolymer, ethylene / acrylic acid copolymer, ethylene / methacrylic acid copolymer Polyolefin resin such as coalescence, ionomer, polyamide, polyurethane, polyester, polystyrene, etc. Examples include thermoplastic resins, thermoplastic resin elastomers, and synthetic rubbers such as styrene butadiene rubber, butadiene rubber, isoprene rubber, acrylonitrile butadiene rubber, ethylene propylene rubber, ethylene propylene terpolymer, butyl rubber, acrylic rubber, and silicone rubber. Moreover, resin materials such as acid-modified products obtained by modifying the above-described thermoplastic resins with unsaturated carboxylic acids and / or derivatives thereof can be used. One of these synthetic resins may be used alone, or two or more of these may be used in combination.

  The outermost layer and the insulating layer other than the outermost layer constituting the multilayer insulated wire of the present invention have various resin components and rubber components other than those described above, and various types within the range not hindering the object and effect of the present invention. Additives can be appropriately added as necessary. As additives, conventionally known ones can be used. For example, lubricants (for insulating layers other than the outermost layer), antioxidants, light stabilizers, process oils, silicon oils, ultraviolet absorbers, carbon Black, dispersants, pigments, dyes, antiblocking agents, crosslinking agents, crosslinking aids, etc., and depending on applications, conventionally used red phosphorus, polyphosphate compounds, hydroxy hydroxy stannate, stannic acid Flame retardant aids such as zinc, zinc borate, calcium carbonate, hydrotalcite, and antimony oxide may be added.

The multilayer insulated wire of the present invention comprises a resin or a resin composition constituting an outermost layer and an insulating layer other than the outermost layer by using a conventionally known tandem extrusion method or common extrusion method, a copper wire, a tin-plated copper wire, an aluminum It can be simply manufactured by extrusion coating on a metal conductor such as a wire. Thickness of the conductor is not particularly limited and may be the cross-sectional area and 0.05 mm ² or more, it is preferable that the cross-sectional area as the 0.05~5.0mm ^2.

  In addition, the thickness of the insulating layer is not particularly limited. For example, the thickness of the outermost layer is preferably 0.05 mm or more, and the total thickness of the insulating layers other than the outermost layer is 0.00. It is preferable to be 1 mm or more. The thickness of the outermost layer is particularly preferably 0.05 to 0.4 mm, and the thickness of the insulating layer other than the outermost layer is particularly preferably 0.05 to 1.0 mm.

  Moreover, when manufacturing the multilayer insulated wire of this invention, you may make it pelletize by previously melt-kneading resin etc. which comprise insulation layers other than an outermost layer and an outermost layer. For pelletization, the above-described components and additives added as necessary are simply manufactured by melt-kneading with a conventionally known kneading apparatus such as a twin-screw kneading extruder, a Banbury mixer, a kneader, or a roll. be able to. Moreover, when a biaxial kneading extruder is used, a process can be implemented continuously. In addition, it is preferable to set as kneading | mixing temperature of resin compositions other than an outermost layer below the decomposition temperature of a metal hydrate (for example, it is 340 degrees C or less in the case of magnesium hydroxide). About other manufacturing conditions, such as the extrusion amount in the case of pelletizing, it can determine suitably with kinds, such as a resin component to be used.

  Moreover, you may make it bridge | crosslink about the outermost layer which comprises the multilayer insulated wire of this invention, and insulating layers other than an outermost layer as needed. The heat resistance of the resin composition can be further improved by subjecting the resin composition to a crosslinking treatment. As a crosslinking method, a conventional electron beam irradiation crosslinking method or chemical crosslinking method can be employed. The irradiation dose of the electron beam is suitably 1 to 30 Mrad, and in order to perform crosslinking efficiently, a resin or resin composition constituting each layer may include many compounds such as methacrylate compounds, allyl compounds, maleimide compounds, and divinyl compounds. A functional compound may be added as a crosslinking aid.

  In the case of the electron beam irradiation cross-linking method, the cross-linking can be performed by irradiating an electron beam by a conventional method after molding the resin composition of the present invention. On the other hand, in the case of the chemical crosslinking method, an organic peroxide or the like may be added to the resin composition as a conventionally known crosslinking agent, and after the molding, heat treatment may be performed by a conventional method for crosslinking.

  The multilayer insulated wire of the present invention described above is a resin composition mainly composed of high-density polyethylene having a multilayer structure of the insulating layer and a melt flow rate of 0.5 g / 10 min or more as the outermost layer, except for the outermost layer. At least one of the insulating layers is composed of a resin composition containing 30 to 300 parts by mass of a metal hydrate with respect to 100 parts by mass of a synthetic resin mainly composed of linear low-density polyethylene. Therefore, it has the mechanical properties necessary for an insulated wire, and the outermost layer mainly improves the smoothness and wear resistance of the surface, and the insulating layer other than the outermost layer mainly improves the flame retardancy, and as the insulating layer other than the outermost layer. Despite the application of linear low-density polyethylene, it is possible to provide a multilayer insulated wire that combines flame retardancy, wear resistance, surface smoothness, and mechanical properties, and has a good appearance.

  In addition, the multilayer insulated wire of the present invention does not generate a toxic gas such as halogen gas or dioxin during combustion because the constituent material of the insulating layer does not contain a halogen component. Thus, an environment-friendly multilayer insulated wire that can be disposed of without inconvenience during disposal such as incineration or landfilling is obtained.

  Therefore, the multilayer insulated wire of the present invention can be used as an electric wire disposed in automobiles, railway vehicles, electric / electronic devices and the like that require wear resistance, flame retardancy, mechanical properties, and the like.

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

[Examples 1-6, Comparative Examples 1-5]
Table 1 shows the composition of the materials forming the multilayer insulated wires of Examples 1 to 6 and Comparative Examples 1 to 5. The details of the materials used are as follows. In addition, the melt flow rate (MFR) about the resin component was measured on the following temperature conditions and load conditions according to the prescription | regulation of JISK7210.

(Outermost layer)
(1) High density polyethylene 1 (HDPE-1)
MFR: 0.5 g / 10 min (190 ° C., 2.16 kgf load)

(2) High density polyethylene 2 (HDPE-2)
MFR: 0.1 g / 10 min (190 ° C., 2.16 kgf load)

(3) Ethylene-vinyl acetate copolymer (EVA)
MFR: 0.5 g / 10 min (190 ° C., 2.16 kgf load)

(4) Low density polyethylene (LDPE)
MFR: 0.5 g / 10 min (190 ° C., 2.16 kgf load)

(5) Lubricant (silicone lubricant)
Type: Silicon-based lubricant (Example 2 only, 1.0 parts per 100 parts by mass of outermost layer)
Part by mass was added. )

(Inner layer)
(6) C4 linear low density polyethylene (LLDPE (C-4))
MFR: 5.0 g / 10 min (190 ° C., 2.16 kgf load)

(7) C6 linear low density polyethylene (LLDPE (C-6))
MFR: 5.0 g / 10 min (190 ° C., 2.16 kgf load)

(8) C8 linear low density polyethylene (LLDPE (C-8))
MFR: 5.0 g / 10 min (190 ° C., 2.16 kgf load)

(9) C6 linear low density polyethylene polymerized by metallocene catalyst (Me-LLDPE (C-6))
MFR: 5.0 g / 10 min (190 ° C., 2.16 kgf load)

(10) C6 linear low density polyethylene 2 (Me-LLDPE (C-6) 2) polymerized by metallocene catalyst
MFR: 10.0 g / 10 min (190 ° C., 2.16 kgf load)

(11) Ethylene / ethyl acrylate copolymer (EEA)
MFR: 1.0 g / 10 min (190 ° C., 2.16 kgf load)

(12) Ethylene / vinyl acetate copolymer (EVA)
MFR: 1.0 g / 10 min (190 ° C., 2.16 kgf load)

(13) Acid-modified polyethylene (acid-modified PE)
Product name: Polybond 3009 (Clonpron)
MFR: 5.0 g / 10 min (190 ° C., 2.16 kgf load)

(14) Metal hydrate (magnesium hydroxide)
Product name: Kisuma 5A (Kyowa Chemical Industry Co., Ltd.)
Average particle size: 1.0 μm

  In addition, the multilayer insulated wire is made by using a Banbury mixer as a kneading machine, kneading each component constituting the outer layer and the inner layer, and using a tandem extruder, extrusion-coating the conductor at a predetermined thickness shown in Table 1. Manufactured.

[Test Example 1]
For the multilayer insulated wires obtained in Examples 1 to 6 and Comparative Examples 1 to 5, “surface smoothness” and “abrasion resistance” were compared and evaluated according to the following criteria. The results are shown in Table 1.

(Surface smoothness)
The surface smoothness was determined based on whether the surface was uneven by visual observation and the feeling touched with the fingertip. Evaluation was made in two stages, and a case where there was no unevenness was good as “「 ”, and a case where there was unevenness was determined as“ x ”.

(Abrasion resistance)
The wear resistance was determined by swinging the loaded piano wire in the longitudinal direction of the insulating layer of the electric wire. Evaluation was made in three stages, and the case where the insulating layer was not worn at all was judged as “◎”, the case where a slight flaw was formed was judged as “◯”, and the case where a flaw was formed was judged as “x”.

(Configuration of resin composition and evaluation results)

  As shown in Table 1, the multilayer insulated wires shown in the examples of the present invention exhibited excellent surface smoothness and wear resistance. On the other hand, Comparative Example 1 and Comparative Example 2 which do not employ linear low density polyethylene as a layer (inner layer) other than the outermost layer have poor wear resistance and employ high density polyethylene for the outermost layer. The melt flow rate was smaller than 0.5 g / 10 min (0.1 g / 10 min), and Comparative Example 3 had poor surface smoothness. In addition, Comparative Example 4 and Comparative Example 5 in which ethylene-vinyl acetate copolymer or low-density polyethylene was adopted as the outermost layer instead of high-density polyethylene also had poor wear resistance.

  In Example 5, a C6 linear low density polyethylene polymerized with a metallocene catalyst having a melt flow rate of 10.0 g / 10 min was used as the inner layer, and Example 6 was composed of a C8 linear low density polyethylene. Although the wear resistance is slightly inferior to Example 1 using C6 linear low density polyethylene polymerized with a metallocene catalyst having a melt flow rate of 5.0 g / 10 min as the inner layer, it was excellent. It was a multilayer insulated wire having both surface smoothness and wear resistance.

Since the present invention is a multilayer insulated wire having mechanical properties and excellent in flame retardancy, wear resistance and surface smoothness, it is disposed in, for example, automobiles, railway vehicles, electric / electronic devices, etc. It can be advantageously used as an insulated wire.

Claims (4)

A multilayer insulated wire in which at least two or more insulating layers are formed on a metal conductor,
Among the insulating layers, the outermost layer is composed of a resin composition mainly composed of high-density polyethylene having a melt flow rate specified by JIS K7210 of 0.5 g / 10 min or more (190 ° C., 2.16 kgf load),
At least one of the insulating layers other than the outermost layer was composed of a resin composition containing 30 to 300 parts by mass of a metal hydrate with respect to 100 parts by mass of a synthetic resin mainly composed of linear low density polyethylene. A multilayer insulated wire characterized by that.   The multilayer insulated wire according to claim 1, wherein the resin composition constituting the outermost layer contains 5.0 parts by mass or less of a lubricant with respect to 100 parts by mass of the resin composition.   The melt flow rate defined by JIS K7210 of linear low density polyethylene constituting the insulating layer other than the outermost layer is 5.0 g / 10 min or less (190 ° C., 2.16 kgf load). The multilayer insulated wire according to claim 1 or 2. The multilayer according to any one of claims 1 to 3, wherein the linear low density polyethylene constituting the insulating layer other than the outermost layer is a linear low density polyethylene polymerized by a metallocene catalyst. Insulated wire.