JP2010284895A - Laminated body, tube, insulated wire, and method for manufacturing them - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a laminated body, a tube and an insulated wire which are excellent in mechanical strength, heat resistance, oil resistance, and flexibility and in which favorable adhesion is established between layers, and a method for manufacturing them. <P>SOLUTION: Each of the laminated body, the tube, and the insulated wire is composed of a first layer 1 formed of a composition mainly containing an ethylene-polar monomer copolymer and a second layer 2 formed of a radiation cross-linkable fluorocarbon resin. The first layer and the second layer are adhered to each other without being subjected to adhesion treatment, and both the first and second layers are cross-linked. The content of a polar monomer of the ethylene-polar monomer copolymer is 1-60%. An inorganic filler is compounded in the composition, and the inorganic filler contains silicon, aluminum, or magnesium as a component, or contains silicate. In the method for manufacturing them, the molten second layer is formed on the first layer, and the composition of the first layer and the fluorocarbon resin of the second layer are cross-linked in a lump. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a laminate, a tube, an insulated wire, and a method for producing the same, which are excellent in mechanical strength, heat resistance, oil resistance, and flexibility, and have good adhesion between layers.

  Fluoropolymers are particularly excellent in mechanical strength, heat resistance, oil resistance, chemical resistance, and flame resistance, so various materials used under harsh conditions such as high-temperature parts and oil-immersed parts of automobiles, For example, it is widely used as a coating material for electric wires and cables. However, since the fluororesin is hard and inferior in flexibility, it is conceivable that, for example, a composite material such as an elastomer or another flexible resin material is combined to give flexibility as a whole.

  For example, Patent Documents 1 and 2 disclose an electric wire in which a fluoro rubber is coated on the circumference of a conductor to form an inner layer, and a fluororesin is coated on the outer circumference to form an outer layer. Moreover, patent document 3 is mentioned as invention by the said applicant. Moreover, as a technique relevant to the present invention, for example, Patent Document 4 is cited.

JP-A-9-288914: Hitachi Cable Utility Model No. 2561072: Nissei Electric JP 2009-9744 A: Krabe JP-T 8-506780 Publication: Elf Atchem

  Here, the electric wires according to Patent Documents 1 and 2 are ones in which fluororubber and fluororesin are not bonded. This causes another problem as shown below. When processing and wiring an electric wire, the end of the electric wire is stripped by a machine, and the electric wire is passed through a rubber bush to perform wiring. At this time, in addition to the flexibility described above, it is also necessary for the strip processability and the ease of insertion into the rubber bush. In the case of coating with a fluororesin as described above, the fluororubber coating and the fluororesin coating easily deviate from each other. Therefore, the strip dimensions are not stable at the time of strip processing, the workability is inferior, and insertion into the rubber bush is difficult. It becomes extremely poor and workability is poor.

  Furthermore, if the inner layer and the outer layer are not bonded as in Patent Documents 1 and 2, after the wire is subjected to terminal crimping, the outer layer may come off from the insulation barrel, and the terminal crimping strength may be greatly reduced, leading to disconnection. There is. It is also conceivable that oil or the like enters the gap between the inner layer and the outer layer from one end of the electric wire by capillarity and reaches the opposite end, adversely affecting peripheral devices. Furthermore, when bending with a small bending radius or when bending is repeated, wrinkles are generated in the outer layer, and cracks or the like may be generated based on the wrinkles. For this reason, restrictions are imposed on the processing and wiring of the electric wires, and the workability and workability are reduced. In order to suppress the generation of wrinkles, it is conceivable to reduce the difference in hardness between the inner layer and the outer layer, but in that case, the mechanical strength of the outer layer is lowered, and the protective function of the inner layer is lowered. Even so, the generation of wrinkles is not completely suppressed and cannot be a drastic measure.

  In addition, it is easy to bond the inner layer and the outer layer with an adhesive. However, if the inner layer and the outer layer are arranged in the vicinity of the AT device, the adhesive swells or dissolves due to the influence of the AT fluid. If the adhesive swells, the outer shape of the wire will be deformed. If the adhesive dissolves, the inner and outer layers will peel off, and the dissolved adhesive will adversely affect the surrounding equipment. It is not preferable.

  The above Patent Document 3 was invented for such a problem, but the fluoro rubber used as the inner layer of Patent Document 3 is expensive, so a change to another material is required rather than a cost reduction request. Has been. Fluorocarbon resin is a material that is difficult to bond. In the case of Patent Document 3, it is adhesion with fluororubber, which is a similar material, but if it is changed to another material, it becomes more difficult to adhere, so further knowledge is required.

  The present invention has been made to solve such problems of the prior art, and its object is to provide excellent mechanical strength, heat resistance, oil resistance, flexibility, and good adhesion between layers. It is in obtaining the laminated body, tube, insulated wire, and these manufacturing methods.

In order to achieve the above object, a laminate according to claim 1 of the present invention comprises a first layer composed of a composition mainly composed of an ethylene-polar monomer copolymer and a second layer composed of a radiation-crosslinkable fluororesin. The first layer and the second layer are bonded without being subjected to an adhesion treatment, and both the first layer and the second layer are cross-linked. is there.
The laminate according to claim 2 is characterized in that the content of the polar monomer in the ethylene-polar monomer copolymer is 1 to 60%.
The laminate according to claim 3 is characterized in that an inorganic filler is blended in the composition, and the inorganic filler contains at least one selected from silicon, aluminum and magnesium as a component. It is what.
The laminate according to claim 4 is characterized in that the inorganic filler contains silicate.
According to a fifth aspect of the present invention, in the tube according to the fifth aspect, the laminate is molded into a cylindrical shape so that the first layer is formed on the outer periphery of the second layer.
The insulated wire according to claim 6, wherein a first layer made of a composition mainly composed of an ethylene-polar monomer copolymer is coated on the circumference of the conductor, and a radiation-crosslinkable fluororesin is formed on the outer circumference of the first layer. The first layer and the second layer are bonded together without being subjected to an adhesion treatment, and the first layer and the second layer are both crosslinked. It is characterized by this.
Moreover, the manufacturing method of the laminated body of Claim 7 forms the 2nd layer which consists of a radiation crosslinkable fluororesin in a molten state on the 1st layer which consists of a composition which has ethylene-polar monomer copolymer as a main component. The composition of the first layer and the radiation crosslinkable fluororesin of the second layer are cross-linked together.
Further, in the method for producing an insulated wire according to claim 8, a first layer made of a composition mainly composed of an ethylene-polar monomer copolymer is extrusion coated on the circumference of the conductor, and the first layer is extrusion coated. After or simultaneously with the extrusion coating of the first layer, the outer periphery of the first layer is extrusion coated with a second layer made of a radiation-crosslinkable fluororesin, and the composition of the first layer and the radiation crosslinking property of the second layer. The fluororesin is cross-linked at once.

In the laminate, tube and insulated wire according to the present invention, a flexible composition can be selected for the first layer, and the second layer is made of a fluororesin excellent in mechanical strength, heat resistance and oil resistance. Also, the laminate, tube and insulated wire can be excellent in mechanical strength, heat resistance and oil resistance and have sufficient flexibility. Furthermore, since the first and second layers are bonded, when used as an insulated wire, while maintaining the terminal crimp strength, workability during stripping and workability during insertion into the bush It will be excellent. In addition, when a flexible composition is selected for the first layer and the second layer is made of a hard fluororesin, the hardness of each layer differs greatly, for example, when the thickness of the second layer is reduced, etc. Tends to cause wrinkles in the second layer. However, this bonding does not cause wrinkles in the second layer even when bending or bending is repeated with a small bending radius. Therefore, there is no generation of cracks starting from wrinkles, and durability as a material can be improved. Further, since the adhesion is not via an adhesive, there is no influence by the swelling or dissolution of the adhesive.
In addition, the fluororesin is originally a material that is difficult to adhere. However, according to the production method of the present invention, the first layer composed of a composition mainly composed of an ethylene-polar monomer copolymer and the second layer composed of a fluororesin. The layers can be easily adhered.

1 is a partially cutaway perspective view showing a configuration of an electric wire according to an embodiment of the present invention. It is a partially notched perspective view which shows the structure of the electric wire by the other Example of this invention.

  In the present invention, an excellent adhesiveness can be obtained without using an adhesive by forming a fluororesin on an uncrosslinked composition composed mainly of an ethylene-polar monomer copolymer. . When the composition is crosslinked before forming the fluororesin, sufficient adhesion between the composition and the fluororesin cannot be obtained.

  Hereinafter, each structure at the time of applying this invention to an insulated wire is demonstrated.

  A conventionally well-known thing can be used as a conductor. As the material, for example, copper, copper alloy, stainless steel, aluminum, aluminum alloy and the like, and those whose surfaces are coated with nickel, tin, copper, silver or the like can be considered. Also, the structure may be made of a single wire, or a plurality of wires that are aligned or twisted may be used.

  The composition used as the first layer in the present invention is mainly composed of an ethylene-polar monomer copolymer. Here, “mainly” means that the resin and rubber components of the composition occupy 2/3 or more by weight.

  The ethylene-polar monomer copolymer is a polymer obtained by copolymerizing ethylene and a monomer having polarity. Examples of the polar monomer include an unsaturated carboxylic acid, a salt thereof, an ester thereof, an amide thereof, a vinyl ester, and carbon monoxide. More specifically, unsaturated carboxylic acids such as acrylic acid, methacrylic acid, fumaric acid, itaconic acid, monomethyl maleate, monoethyl maleate, maleic anhydride, itaconic anhydride, lithium of these unsaturated carboxylic acids, sodium, Monovalent metal salts such as potassium, polyvalent metal salts such as magnesium, calcium and zinc, methyl acrylate, ethyl acrylate, isopropyl acrylate, isobutyl acrylate, nbutyl acrylate, isooctyl acrylate, methyl methacrylate And unsaturated carboxylic acid esters such as ethyl methacrylate, isobutyl methacrylate and dimethyl maleate, vinyl esters such as vinyl acetate and vinyl propionate, carbon monoxide, sulfur dioxide and the like. More specific examples of the ethylene-polar monomer copolymer include ethylene-acrylic acid copolymers, ethylene-unsaturated carboxylic acid copolymers such as ethylene-methacrylic acid copolymers, and ethylene-unsaturated carboxylic acid copolymers. Ionomer, ethylene-methyl acrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-methyl methacrylate copolymer, ethylene-acrylic acid, wherein some or all of the carboxyl groups of the coalesced are neutralized with the above metals Isobutyl copolymer, ethylene-unsaturated carboxylic acid ester copolymer such as ethylene-n-butyl acrylate copolymer, ethylene-isobutyl acrylate-methacrylic acid copolymer, ethylene-n-butyl acrylate-methacrylic acid copolymer Ethylene-unsaturated carboxylic acid ester-unsaturated carboxylic acid copolymer such as polymer Ionomer in which part or all of the Bisono carboxyl group is neutralized with the metal, ethylene - vinyl ester copolymer, and the like - ethylene such as vinyl acetate copolymer. Among these, an ethylene-vinyl acetate copolymer, an ethylene-ethyl acrylate copolymer, an ethylene-methyl methacrylate copolymer, an ethylene-methacrylic acid copolymer, and an ethylene-methyl acrylate copolymer are particularly preferable. These can be used alone or in combination of two or more.

  The ethylene-polar monomer copolymer varies depending on the type of polar monomer, but the polar monomer content is preferably 1 to 60% by weight, particularly preferably 5 to 45% by weight. Further, such an ethylene-polar monomer copolymer has a melt flow rate of 0.05 to 500 g / 10 min at 190 ° C. under a load of 2160 g, particularly 0.1, in consideration of molding processability and mechanical strength. It is preferable to use the one of ˜100 g / 10 minutes.

  You may mix | blend another resin or rubber material with the said composition. For example, high density polyethylene, low density polyethylene, linear low density polyethylene, ethylene-α-olefin copolymer, polypropylene, polyolefin such as ethylene-propylene thermoplastic elastomer, polyester, polyamide, polystyrene, polyurethane and the like can be mentioned. . However, these other resins or rubber materials are blended in the resin and rubber components of the composition so that the weight ratio is less than 1/3.

  You may mix | blend an inorganic filler with the said composition. Examples of the inorganic filler include metal oxide powder, metal hydroxide powder, metal carbonate powder, and silicate (including hydrated silicate) powder. Examples of the metal oxide powder include aluminum oxide, magnesium oxide, and zinc oxide. Examples of the metal hydroxide powder include magnesium hydroxide and aluminum hydroxide. Examples of the silicate powder include magnesium carbonate, calcium carbonate, and barium carbonate. Examples of the silicate powder include magnesium silicate, calcium silicate, barium silicate, aluminum silicate, and silica. By blending these, the moldability at the time of extrusion molding can be improved, but the most expected effect is to improve the adhesion with the second layer. Among the inorganic fillers described above, those containing at least one selected from silicon, aluminum, and magnesium as a component are preferable because of the high effect of improving adhesiveness. Silicate powder is particularly preferred, and most preferably contains both hydrous magnesium silicate and hydrous aluminum silicate. The total addition amount of the inorganic filler is preferably 1 to 150 parts by weight with respect to 100 parts by weight of the resin component and the rubber component in the composition. If it is 1 part by weight or less, sufficient adhesion and extrusion moldability cannot be obtained, and if it is more than 150 parts by weight, properties such as mechanical strength and heat resistance are deteriorated.

  In the said composition, you may mix | blend the various additive generally used within the range which does not inhibit the objective of this invention. Examples of such additives include antioxidants, extenders, flame retardants, anti-aging agents, cross-linking agents, cross-linking aids, lubricants, softeners, dispersants, colorants, and the like.

  The composition of the present invention is sufficiently kneaded using a known kneader such as a roll, a kneader, a banbury, a uniaxial kneader, a biaxial kneader, or the like by appropriately blending the above constituent materials. Obtainable.

  The fluororesin used as the second layer in the present invention is a radiation crosslinkable fluororesin. Here, the radiation-crosslinkable fluororesin is a fluororesin that is cross-linked by irradiation with ionizing radiation such as X-ray, γ-ray, electron beam, proton beam, deuteron beam, α-ray, and β-ray. Specific examples include an ethylene-tetrafluoroethylene copolymer, a tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride copolymer, and the like. With such a radiation-crosslinkable fluororesin, the adhesiveness can be improved by collectively crosslinking with the first layer, and the heat resistance of itself can be improved.

  The crosslinking method in crosslinking the composition or the fluororesin is not particularly limited. For example, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 1,3-bis (t- Chemistry using organic peroxides such as butylperoxyisopropyl) benzene, 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, dicumyl peroxide, polyols, amines, etc. as crosslinking agents Examples include a crosslinking method, an irradiation crosslinking method using ionizing radiation such as X-ray, γ-ray, electron beam, proton beam, deuteron beam, α-ray, and β-ray. In this invention, it is necessary to bridge | crosslink the 1st layer and 2nd layer which consist of a different material collectively. In the case of the above chemical cross-linking method, the cross-linking conditions such as heating temperature and pressure differ between the first layer and the second layer, so that it is difficult to cross-link at once. In contrast, irradiation cross-linking is preferable because it is very easy to cross-link the first layer and the second layer at once. Of course, the cross-linking conditions may be adjusted to cross-link by the chemical cross-linking method, or the chemical cross-linking method and the irradiation cross-linking method may be used in combination.

  When crosslinking, the above composition is extrusion coated on the conductor circumference by a known method to form the first layer, and the fluororesin is known on the circumference of the first layer in a state where this composition is uncrosslinked. From the viewpoint of productivity, it is preferable that the second layer is extrusion-coated by the above method, and the first layer and the second layer are collectively crosslinked. In the case of extrusion coating, the extrusion coating of the first layer and the extrusion coating of the second layer may be performed in separate steps, or the first layer and the second layer may be simultaneously performed by a technique such as so-called two-layer extrusion. It may be extrusion coated.

  In addition, in this invention, although expressed as a 1st layer or a 2nd layer, it is not necessarily limited to what a 1st layer or a 2nd layer is a single layer. For example, a composition in which a composition is laminated in a plurality of layers may be generally used as the first layer, and a composition in which a fluororesin is laminated in a plurality of layers may be generally used as the second layer. Moreover, you may coat | cover another 3rd layer on the outer periphery of a 2nd layer. Moreover, in the said embodiment, although the 1st layer which consists of a composition is made into an inner layer and the 2nd layer which consists of a radiation crosslinkable fluororesin is made into an outer layer, a 2nd layer can be made into an inner layer and a 1st layer can be made into an outer layer. Conceivable.

  As mentioned above, although the application to an insulated wire was demonstrated, also in another aspect, it can obtain by the method similar to the above. For example, when obtaining a sheet-shaped laminate composed of a first layer and a second layer, the first layer is formed into a sheet shape with the above-described material, and the above-described material is extruded on the upper surface of the first layer. It can be obtained by forming a second layer by melt coating or cross-linking the first layer and the second layer together. Of course, the first layer and the second layer may be extruded simultaneously. Moreover, it is good also as an aspect which pinched | interposed the 1st layer with two 2nd layers, and the aspect which pinched | interposed the 2nd layer with 2 1st layers, and another 3rd other than 1st layer and 2nd layer A layer may be formed. As long as the first layer and the second layer exist, the shape may be extruded into a tube shape or other shapes in addition to the sheet shape, or may be formed into a three-dimensional shape by injection molding or molding. Also good. When forming into a tube shape, the first layer may be the inner layer, and the second layer may be the inner layer. In this case, if the second layer made of a fluororesin having high chemical resistance is used as the inner layer, it can be used as a tube for transferring various liquids stably for a long time. Specifically, for example, it can be applied to a water supply / hot water supply hose used for transferring tap water by utilizing its excellent chemical resistance (chlorine resistance).

  Hereinafter, an embodiment of the present invention will be described together with a comparative example with reference to FIG. Details of each material used in this example are shown in Table 2.

  The compounding materials shown in Table 2 were sufficiently kneaded with a biaxial kneader according to the number of parts shown in Table 1, and the resulting composition was formed by twisting 19 tin-plated annealed copper wires having a strand diameter of 0.18 mm. The conductor 3 having a diameter of about 0.9 mm is covered with a thickness of about 0.3 mm to form the first layer 1, and the periphery is further coated with a fluororesin to form the second layer 2. A 9 mm wire sample was prepared. In addition, about bridge | crosslinking, about Examples 1-11 and Comparative Examples 1-3, the 1st layer 1 and the 2nd layer 2 are bridge | crosslinked collectively as irradiation bridge | crosslinking by ionizing radiation, About Comparative Example 3, Cross-linking was performed after coating one layer, and then further cross-linking after coating the second layer 2. In Example 1, the first layer 1 was formed on the outer periphery of the second layer 2 as Example 12.

  Here, for a total of 15 types of electric wire samples obtained in this way, mechanical strength, oil resistance, flexibility, heat resistance, and adhesion between the first layer 1 and the second layer 2 were evaluated. It was. The results are shown in Table 1 together with the number of blended parts of each blended material.

The evaluation method is as follows.
(Blade wearability)
Based on JASO D 608, blade wear is measured at a load of 510 g and R = 0.125, and this is evaluated as mechanical strength.
(Oil resistance)
After dipping in a commercially available AT fluid at 165 ° C. for 5 days, the tensile strength and elongation are measured in accordance with JIS3005.
(Flexibility)
A 500 mm long wire sample is marked on the center and a portion 100 mm from the center, and both ends are connected to form a circular arc so that the center is set on a 2φ mandrel. Next, a weight of 100 g is hung at the joint, and after 30 seconds, the distance of the part marked 100 mm from the center is measured.
(Heat-resistant)
The wire is wound around its own diameter and held at 280 ° C. for 1 hour. Thereafter, the case where no crack or melting occurred on the surface was evaluated as ○ (passed), and the case where crack or melting occurred was evaluated as x (failed).
(Adhesiveness)
In an electric wire sample having a length of 5 mm and a width of 25 mm, a peel test is performed on the bonded portion of the first layer 1 and the second layer 2 at a speed of 50 mm / min. As a criterion for acceptance, the case where the first layer 1 and the second layer 2 were not peeled cleanly and the material was broken was ○, but the material was peeled off at the interface between the first layer 1 and the second layer 2 △, and what did not adhere at all is ×.
Of the above evaluations, with respect to blade wear resistance, oil resistance, flexibility, and heat resistance, Reference Example 1 consisting of a layer of only a fluororesin (ethylene-tetrafluoroethylene copolymer, with crosslinking) is used as a reference. Were similarly tested.

  The sample by Examples 1-12 has shown the value which passes about heat resistance, oil resistance, and adhesiveness, and it was confirmed that it is excellent in mechanical strength, heat resistance, oil resistance, and adhesiveness.

  When Examples 1-12 are compared with Comparative Examples 1 and 2, Comparative Examples 1 and 2 that are not mainly composed of an ethylene-polar monomer copolymer as the composition of the first layer 1 are bonded as compared with Examples 1-9. Power is inferior. This is clear from the comparison between Example 1 and Comparative Example 1. Moreover, when Example 1 and Comparative Example 3 are compared, Comparative Example 3 in which the first layer 1 is crosslinked when the second layer 2 is coated is inferior in adhesiveness to Example 1. Therefore, there is a concern that the workability of the electric wire and the workability of the wiring are deteriorated. For verification, the strip processing and the insertion into the bush were actually performed for Example 1 and Comparative Examples 1 to 3. In Example 1, the strip size was constant and the insertion into the bush was very easy, but in Comparative Examples 1 to 3, the strip size was different from the initial setting, and the insertion into the bush was the first. It became very difficult because the two layers shifted. Further, it was confirmed that Comparative Examples 1 to 3 did not have sufficient terminal crimping strength.

  Moreover, although Example 10 with little polar monomer content is a little inferior in adhesiveness compared with Example 1, it is a level which is satisfactory in practical use. Moreover, although Example 11 with much polar monomer content is a little inferior to blade abrasion compared with Example 7, it is a level which is satisfactory in practical use.

  Further, when Examples 1 to 12 and Reference Example 1 were compared, Examples 1 to 12 were superior in flexibility and wiring workability.

  Moreover, when Example 4 and Example 5, Example 6 and Example 7 are compared, Example 5 and Example 7 which mix | blended the inorganic filler are Example 4 and Example which do not mix | blend an inorganic filler. Compared to 6, it was confirmed that the adhesion was improved. In addition, when Examples 1 and 2 were compared with Example 3, it was confirmed that Example 3 containing hydrous aluminum silicate and hydrous magnesium silicate as inorganic fillers was particularly improved in adhesion.

  Thus, it is confirmed that the samples according to Examples 1 to 12 according to the present invention are excellent in mechanical strength, heat resistance, oil resistance and adhesiveness. Here, Patent Document 4 described above describes a multilayer article having an elastomer layer formed on a predetermined thermoplastic resin, and the elastomer is directly bonded to the thermoplastic resin without using an adhesive. Yes. However, since Patent Document 4 does not describe anything about cross-linking of the thermoplastic resin side, it cannot obtain excellent adhesion as in the present invention.

  As described above in detail, according to the present invention, it is possible to obtain a laminated body, a tube, and an insulated wire that are excellent in mechanical strength, heat resistance, oil resistance, and flexibility and in which layers are well bonded. . Therefore, this electric wire is suitable, for example, as an electric wire / cable such as a wiring in an electric device and a harness for an automobile. In particular, it is optimal as an electric wire to be placed in an AT device of a car. Moreover, it is not limited to these as a use application, For example, it can be used also as a use with the request | requirement of other heat resistance requirements, and oil resistance and chemical resistance. Moreover, it is also possible to apply to the tube (hose) which transfers various liquids stably for a long time using the chemical resistance (chlorine resistance) being excellent.

1 First layer 2 Second layer 3 Conductor

Claims (8)

It consists of a first layer composed of a composition mainly composed of an ethylene-polar monomer copolymer and a second layer composed of a radiation-crosslinkable fluororesin, and the first layer and the second layer are subjected to an adhesion treatment. A laminated body characterized in that the first layer and the second layer are both crosslinked without being bonded. The laminate according to claim 1, wherein the content of the polar monomer in the ethylene-polar monomer copolymer is 1 to 60%. The laminate according to claim 2, wherein an inorganic filler is blended in the composition, and the inorganic filler contains at least one selected from silicon, aluminum and magnesium as a component. The laminate according to claim 2, wherein the inorganic filler contains silicate. A tube in which the laminate according to any one of claims 1 to 4 is formed into a cylindrical shape so that the first layer is formed on the outer periphery of the second layer. A first layer made of a composition mainly composed of an ethylene-polar monomer copolymer is coated on the circumference of the conductor, and a second layer made of a radiation-crosslinkable fluororesin is coated on the outer periphery of the first layer. The insulated wire, wherein the first layer and the second layer are bonded without being subjected to an adhesion treatment, and the first layer and the second layer are both crosslinked. A second layer made of a radiation-crosslinkable fluororesin is formed in a molten state on a first layer made of a composition mainly composed of an ethylene-polar monomer copolymer, and the composition of the first layer and the second layer are formed. A method for producing a laminate, wherein the radiation-crosslinkable fluororesin is cross-linked together. On the conductor circumference, a first layer made of a composition mainly composed of an ethylene-polar monomer copolymer is extrusion-coated, and after the first layer is extrusion-coated or simultaneously with the extrusion coating of the first layer, the first layer is formed. Insulation characterized in that a second layer made of a radiation crosslinkable fluororesin is extrusion coated on the outer periphery of one layer, and the composition of the first layer and the radiation crosslinkable fluororesin of the second layer are cross-linked together. Electric wire manufacturing method.

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