Resin film for conductive wire, method of manufacturing same, and insulated wire

Abstract

To provide a resin film for a conductive core wire which can prevent delamination and can improve heat resistance and electric characteristics, a method for manufacturing the same, and an insulated wire.SOLUTION: There is provided a resin film for a conductive core wire of an insulated wire 1 in which conductive core wires 2 having substantially rectangular or substantially circular cross sections are coated with insulation resin members 4, wherein a relative crystallization degree of the insulation resin member 4 as a polyarylene sulfide resin film 5 fused to the conductive core wires 2 is less than 80%. Accompanying softening of the polyarylene sulfide resin film 5, the pair of conductive core wires 2, an insulation layer 3, and the polyarylene sulfide resin film 5 are fused and integrated with each other, which can surely omit an adhesive layer for bonding the conductive core wires 2 and the polyarylene sulfide resin film 5. The resin film can prevent delamination among the plurality of conductive core wires 2, the insulation layer 3 and the polyarylene sulfide resin film 5, and can improve heat resistance and electric characteristics.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a resin film for conductive wires used in electric and electronic devices, a method for producing the same, and an insulated wire. [Background technology]

[0002] High-frequency insulated wires have traditionally been used in AC motors, high-frequency electrical equipment, transformer coils, motors for hybrid vehicles (HVs), electric vehicles (EVs), motors for high-speed rail vehicles, etc. This type of insulated wire is formed into a rectangular wire by laminating rectangular metal bodies with a square cross-section and an insulating enamel or oxide film formed on the outer periphery. Also known as an insulated wire without an enamel coating is a type that laminates rectangular metal bodies with a rectangular cross-section and an adhesive thermosetting resin or oxide film formed on the outer periphery.

[0003] For example, a rectangular electric wire with an assembled conductor having an adhesive layer of insulating thermosetting resin between conductor wires is known (see Patent Document 1). Also known is a rectangular electric wire in which rectangular metal bodies with oxide films formed on the outer periphery are laminated, and the laminated conductor portion is covered with an insulating layer (see Patent Document 2).

[0004] However, these rectangular electric wires cannot be expected to produce strong welds because the enamel coating remains as soot during the welding process when assembling the motor. Furthermore, in the case of wires that do not use enamel coating, although good welding can be expected, there are problems with adhesion between rectangular metal bodies during bending.

[0005] In view of this, conventionally, rectangular electric wires have been developed and proposed, which include an assembly conductor in which a plurality of conductive wires with rectangular cross sections are stacked with interlayer insulating layers sandwiched therebetween, an outer insulating layer that covers the assembly conductor including the interlayer insulating layer, and an adhesive layer made of a thermoplastic resin with a thickness of 3 μm to 10 μm between the assembly conductor and the outer insulating layer (see Patent Documents 3 and 4).An insulated electric wire that is insulated with a highly crystalline polyphenylene sulfide resin for film manufacturing has also been proposed (see Patent Document 5).

[0006] However, insulated wires coated with polyphenylene sulfide resin have the problem that the polyphenylene sulfide resin cannot be coated with a uniform thickness, resulting in pinholes and reduced insulation at the pinhole portions. Furthermore, when a highly crystalline polyphenylene sulfide resin film is used, an adhesive layer is required on at least one side, and if an adhesive layer is present, degradation of the adhesive layer can lead to delamination between the assembly conductor, the outer insulating layer, and the adhesive layer. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-186724 [Patent Document 2] Japanese Patent Application Laid-Open No. 2009-245666 [Patent Document 3] WO2015 / 033821 publication [Patent Document 4] Japanese Patent Application Laid-Open No. 2017-098030 [Patent Document 5] Japanese Utility Model Application Publication No. 2-61022 Summary of the Invention [Problem to be solved by the invention]

[0008] Conventional insulated wires are constructed as described above, and may have an adhesive layer made of a thermoplastic resin interposed between the assembly conductor and the outer insulating layer. However, if an adhesive layer is simply interposed, the adhesive layer will deteriorate and delamination will occur between the assembly conductor, the outer insulating layer, and the adhesive layer, resulting in major new problems with heat resistance, electrical properties (electrical insulation), etc.

[0009] The present invention has been made in view of the above, and aims to provide a resin film for conductive wires that can prevent delamination and improve heat resistance, electrical properties, etc., a method for producing the same, and an insulated wire. [Means for solving the problem]

[0010] In order to solve the above problems, the present invention provides a conductive wire having a substantially rectangular or circular cross section covered with an insulating resin member, Insulating resin material is attached to the conductive wire Fusion without an adhesive layer The relative crystallinity of the polyarylene sulfide resin film is 5% or more but less than 80% The storage modulus (E') of polyarylene sulfide resin film is 1.0 x 10 in the temperature range of [glass transition point (Tg) - 10°C] or more [glass transition point (Tg) + 60°C] or less. 8 Resin film with a portion where the strength drops to 0.01 Pa or less, and the tensile elongation at break in the MD direction is 200% or more and 500% or less when measured in accordance with JIS K 6781 It is characterized by:

[0011] In addition, a plurality of conductive wires may be provided with insulating layers interposed therebetween, and a polyarylene sulfide resin film may be fusion-bonded to the plurality of conductive wires sandwiching the insulating layers at a temperature below the melting point. The insulating resin member may be a polyarylene sulfide resin film spirally wound around the conductive wire and fused thereto.

[0012] The polyarylene sulfide resin film is preferably at least one of a resin film made of a polyphenyl sulfide resin, a polyphenylene sulfide ketone resin, a polyphenylene sulfide sulfone resin, a polyphenylene sulfide ketone sulfone resin, a random copolymer thereof, a block copolymer thereof, and a mixture thereof. The thickness of the polyarylene sulfide resin film can be set to 1 μm or more and 50 μm or less.

[0013] Furthermore, when the tensile modulus of the polyarylene sulfide resin film is measured in accordance with JIS K 6781, it can be set to 2000 MPa or more and 3100 MPa or less. In addition, the dielectric breakdown voltage of the polyarylene sulfide resin film can be 0.5 kV or more when measured in accordance with JIS C 2110-1994, and the relative dielectric constant of the polyarylene sulfide resin film at 1 GHz can be 3.5 or less when measured by the cavity resonator perturbation method.

[0014] In order to solve the above problems, the present invention provides a method for producing a resin film for conductive wire according to any one of claims 1 to 5, A molding material containing at least a polyarylene sulfide resin is melt-kneaded, and the molding material is extruded into a polyarylene sulfide resin film using a die of a molding machine. The polyarylene sulfide resin film is then brought into contact with a cooling roll. By cooling, the relative crystallinity of the polyarylene sulfide resin film is adjusted to 5% or more and less than 80%. It is characterized by the following.

[0015] In order to solve the above problems, the present invention is characterized by an insulated wire having a resin film for conductive wires as set forth in any one of claims 1 to 5.

[0016] Here, the term "approximately rectangular cross section" in the claims includes both a rectangular cross section and a shape that is roughly recognized as a rectangular cross section. The term "circular cross section" also includes both a circular cross section and a shape that is roughly recognized as a circular cross section. Furthermore, the conductive wire may be singular, but in the case of multiple wires, there is no particular restriction on the number of wires, and the conductive wires may be two, three, four, five, six, seven, etc. In the case of multiple conductive wires, the conductive wires may be of the same size, shape, and thickness, or may be of different sizes, shapes, and thicknesses, as long as they have a roughly rectangular or circular cross section. The insulating resin member and insulating layer may be singular or plural.

[0017] The insulating resin member may be a polyarylene sulfide resin film, and may be a plurality of resin films of the same type or a plurality of resin films of different types. The polyarylene sulfide resin film has a storage modulus (E') of 1.0 x 10 in the temperature range of (glass transition point (Tg) - 10°C) or more (glass transition point (Tg) + 60°C) of the polyarylene sulfide resin film. 8 It is preferable that the resin film has a portion where the resistance drops to below Pa. Furthermore, fusion bonding is softening by heating and bonding together, and includes thermocompression bonding (bonding together by heat and pressure).

[0018] According to the present invention, the conductive wires and the polyarylene sulfide resin film adhere to each other as the thermoplastic polyarylene sulfide resin film softens, so that an adhesive layer for adhering the conductive wires and the polyarylene sulfide resin film can be omitted. [Effects of the Invention]

[0019] According to the present invention, the insulating resin member is a polyarylene sulfide resin film fused to the conductive wire, which has the effect of preventing delamination and improving heat resistance, electrical properties, etc. In addition, since the adhesive layer that bonds the conductive wire and the polyarylene sulfide resin film can be omitted, volatile organic compounds generated during the manufacturing of the insulated wire can be reduced, which is expected to reduce manufacturing costs while being environmentally friendly. Furthermore, by omitting the adhesive layer, thermal conductivity can be improved and the insulated wire can be made thinner, thereby improving motor performance. In addition, since the relative crystallinity of the polyarylene sulfide resin film is set to 5% or more and less than 80%, the polyarylene sulfide resin film can be softened and its thermoformability can be improved. In addition, the polyarylene sulfide resin film has a storage modulus (E') of 1.0 x 10 in the temperature range of [glass transition point (Tg) - 10°C] to [glass transition point (Tg) + 60°C] of the polyarylene sulfide resin film. 8 Since the resin film has a portion where the strength drops below Pa, fusion of the polyarylene sulfide resin film can be expected. Furthermore, since the tensile elongation at break in the MD direction is 200% or more and 500% or less, it is possible to impart sufficient toughness to the polyarylene sulfide resin film, thereby eliminating the risk of problems such as breakage or cracking during the winding process of the polyarylene sulfide resin film around a rectangular electric wire.

[0020] According to the invention of claim 2, since there are multiple conductive wires instead of a single one, it is possible to reduce the amount of loss at high frequencies when the device is incorporated into, for example, a motor. Furthermore, the insulating layer prevents contact between multiple conductive wires with a potential difference, thereby eliminating the risk of partial discharge occurring between the multiple conductive wires.

[0021] According to the invention of claim 3, the insulating resin member is a polyarylene sulfide resin film that is spirally wound around the conductive wire and fused thereto, and the spiral winding can improve the breakdown voltage and mechanical strength.

[0022] According to the invention of claim 4, the polyarylene sulfide resin is at least one of a resin film made of a polyphenyl sulfide resin, a polyphenylene sulfide ketone resin, a polyphenylene sulfide sulfone resin, a polyphenylene sulfide ketone sulfone resin, a random copolymer thereof, a block copolymer thereof, and a mixture thereof, so that it is possible to obtain excellent mechanical properties, heat resistance, cold resistance, electrical properties, chemical resistance, radiation resistance, hydrolysis resistance, low water absorption, flame retardancy, recyclability, etc.

[0023] According to the invention of claim 5, the tensile modulus of the polyarylene sulfide resin film is set to 2000 MPa or more and 3100 MPa or less when measured in accordance with JIS K 6781. This makes it possible to prevent a decrease in rigidity of the polyarylene sulfide resin film, which would otherwise cause a decrease in handleability during winding of the polyarylene sulfide resin film or an increase in deviation in the laminated state of the polyarylene sulfide resin film when bending a conductive wire. It also makes it possible to prevent the polyarylene sulfide resin film from peeling off from the conductive wire.

[0024] According to the sixth aspect of the present invention, the polyarylene sulfide resin film is formed by melt extrusion molding, which makes it possible to improve the handling properties of the polyarylene sulfide resin film and simplify the manufacturing equipment. According to the seventh aspect of the present invention, it is possible to prevent delamination of the insulated wire and improve the heat resistance, electrical properties, and the like. [Brief explanation of the drawings]

[0025] [Figure 1] 1 is a perspective view illustrating an embodiment of a resin film for a conductive wire and an insulated wire according to the present invention; [Figure 2] 1 is a cross-sectional view illustrating a resin film for a conductive wire and an insulated wire according to an embodiment of the present invention; [Figure 3] 1 is an overall explanatory view schematically illustrating an embodiment of a resin film for conductive wires and a method for producing the same according to the present invention. [Figure 4] 1 is a graph showing the storage modulus when the relative crystallinity of a polyarylene sulfide resin film is 33% in an embodiment of a resin film for conductive wire and a method for producing the same according to the present invention. [Figure 5] 1 is a graph showing the storage modulus when the relative crystallinity of a polyarylene sulfide resin film is 100% in an embodiment of a resin film for conductive wire and a method for producing the same according to the present invention. [Figure 6]FIG. 2 is a cross-sectional explanatory view schematically showing a second embodiment of the resin film for a conductive wire and the insulated wire according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0026] A preferred embodiment of the present invention will now be described with reference to the drawings. As shown in FIGS. 1 and 2 , an insulated wire 1 in this embodiment comprises a plurality of opposing conductive wires 2, an insulating layer 3 interposed between the plurality of conductive wires 2, and an insulating resin member 4 that covers and protects the plurality of conductive wires 2 and the insulating layer 3. The insulated wire 1 is a rectangular electric wire for high current use as a component of a transformer, hybrid vehicle (HV), electric vehicle (EV), etc. The insulating resin member 4 is fused to the plurality of conductive wires 2 and the insulating layer 3 as a thermoplastic polyarylene sulfide resin film 5, eliminating the need for an adhesive layer or the like, thereby contributing to the achievement of Goal 9 of the SDGs (the United Nations' international goals for sustainable development, consisting of 17 global goals and 169 targets (criteria for achievement)) adopted at the United Nations Summit.

[0027] The multiple conductive wires 2 are each formed in a roughly band-like shape of the same size in plan view, stacked in pairs in the vertical direction of Fig. 2 and adjacent to each other, and each conductive wire 2 is formed in a rectangular cross section with a large cross section, which improves the skin effect and contributes to reducing resistance. The multiple conductive wires 2 are formed in pairs because, when the insulated wire 1 is incorporated into a motor or transformer, a sufficient reduction in loss at high frequencies can be expected if the number of layers is one pair (two layers).

[0028] The material of the conductive wires 2 is not particularly limited, but a flexible conductor made of low-oxygen copper or oxygen-free copper with an oxygen content of 30 ppm or less is preferable. This is because a low oxygen content in the conductive wires 2 can prevent voids from occurring in the welded portion due to the contained oxygen when the conductive wires 2 are melted with heat to weld them. This also prevents the electrical resistance of the welded portion from deteriorating, and is expected to maintain the strength of the welded portion.

[0029] The insulating layer 3 is sandwiched between the opposing surfaces of a pair of conductive wires 2, and prevents the pair of conductive wires 2 having a potential difference from contacting each other, effectively preventing partial discharge from occurring between the pair of conductive wires 2 and resulting in insulation breakdown. Examples of materials for this insulating layer 3 include thermoplastic resins having a melting point of 250°C or higher and 350°C or lower, specifically polyester resins such as polyethylene terephthalate (PET) resin, polyethylene naphthalate (PEN) resin, and polybutylene terephthalate (PBT) resin; polyamide resins such as polyamide 66 (PA66) resin, polyamide 6T (PA6T) resin, and polyamide 9T (PA9T) resin; polyarylene sulfide resins such as polyphenyl sulfide (PPS) resin, polyphenylene sulfide ketone resin, polyphenylene sulfide sulfone resin, and polyphenylene sulfide ketone sulfone resin; polyarylene ether ketone resins such as polyether ketone (PEK) resin, polyether ether ketone (PEEK) resin, and polyether ketone ketone (PEKK) resin; and polyimide resins such as polyamide imide (PAI) resin, polyimide (PI) resin, and polyether imide (PEI) resin.

[0030] The melting point of the thermoplastic resin is set to 250°C or higher and 350°C or lower because temperatures outside this range result in a deterioration in the electrical properties of the insulating layer 3. Such an insulating layer 3 is formed by applying a resin varnish containing a thermoplastic resin onto the conductive wires 2 and baking it.

[0031] The polyarylene sulfide resin film 5, which is the insulating resin member 4, is made of at least one resin film selected from polyphenyl sulfide (PPS) resin, polyphenylene sulfide ketone resin, polyphenylene sulfide sulfone resin, polyphenylene sulfide ketone sulfone resin, random copolymers thereof, block copolymers thereof, and mixtures thereof, and is directly fused and wound around the pair of conductive wires 2 and the insulating layer 3 as a resin film for conductive wires. The polyarylene sulfide resin film 5 is selected because the selection of the polyarylene sulfide resin film 5 can improve heat resistance, electrical properties (electrical insulation), cold resistance, mechanical properties, chemical resistance, solvent resistance, flame retardancy, etc.

[0032] Any resin film made of a polyphenyl sulfide resin, a polyphenylene sulfide ketone resin, a polyphenylene sulfide sulfone resin, a polyphenylene sulfide ketone sulfone resin, a random copolymer thereof, a block copolymer thereof, or a mixture thereof can be used. However, from the viewpoints of easy availability, ease of molding, production costs, etc., a polyphenylene sulfide resin film is most suitable.

[0033] The polyarylene sulfide resin used in the polyarylene sulfide resin film 5 is, for example, a resin described in Japanese Patent No. 3823802. The polyarylene sulfide resin is a resin containing a repeating unit represented by the following structural formula (1):

[0034] [ka]

[0035] The polyarylene sulfide resin is a polymer containing 70 mol % or more, preferably 90 mol % or more of the repeating units. This is because if the repeating units are less than 70 mol %, not only will heat resistance and mechanical properties be reduced, but dimensional stability will also be adversely affected. Furthermore, the polyarylene sulfide resin has 30 mol % or less of its repeating units selected from one or more of the repeating units (2), (3), (4), (5), (6), (7), and (8) having the following structural formula:

[0036] [ka]

[0037] [ka]

[0038] [ka]

[0039] [ka]

[0040] [ka]

[0041] [ka]

[0042] [ka]

[0043] Representative examples of these polyarylene sulfide resins include polyphenylene sulfide resins, polyphenylene sulfide sulfone resins, polyphenylene sulfide ketone resins, polyphenylene sulfide ketone sulfone resins, random copolymers thereof, block copolymers thereof, and mixtures thereof, and among these, polyphenylene sulfide resins are particularly preferred.

[0044] In the present invention, the polyarylene sulfide resin obtained as described above can of course be used after being subjected to various treatments such as crosslinking / polymerization by heating in air, heat treatment in an inert gas atmosphere such as nitrogen or under reduced pressure, washing with an organic solvent, hot water, an acid aqueous solution, or the like, or activation with a functional group-containing compound such as an acid anhydride, an amine, an isocyanate, or a functional group-containing disulfide compound.

[0045] The apparent shear viscosity of polyphenylene sulfide resin measured at 310°C with a flow tester using a die with a diameter of 1.0 mm and a length of 10 mm under the conditions of a temperature of 310°C and a load of 50 kgf is 1 x 10 1 Pa·s or more 1×10 4 Pa·s or less, preferably 5×10 1 Pa·s or more 5×10 3 Pa·s or less, preferably 1×10 2 Pa·s or more 1×10 3 It is better if it is in the range of Pa·s or less.

[0046] This is 1 x 10 1 If the viscosity is less than Pa·s, the apparent shear viscosity will be low, which will result in a decrease in melt tension and make it difficult to mold the polyphenylene sulfide resin, so care must be taken. 4 If the viscosity exceeds Pa·s, the melt viscosity will increase and the melt elongation will decrease, making it difficult to mold the polyphenylene sulfide resin, so care must be taken.

[0047] Examples of polyphenylene sulfide resin products include the Torelina series manufactured by Toray Industries, the Gelafide (formerly Fortron) PPS series manufactured by Polyplastics, the Fortron KPS series manufactured by Kureha Corporation, the DIC.PPS series manufactured by DIC, the Ryton PPS series manufactured by Solvay Specialty Polymers, and the ECOTRAN series manufactured by Teijin Limited. Such polyarylene sulfide resin film 5 has the characteristics of being soluble in almost no solvents, being excellent in chemical resistance, hydrolysis resistance, acid resistance, alkali resistance, and solvent resistance, being laser weldable and printable, and also being flame retardant.

[0048] The polyarylene sulfide resin film 5 may be made of, in addition to polyarylene sulfide resin, polyimide resins such as polyimide (PI) resin, polyamideimide (PAI) resin, polyetherimide (PEI) resin, etc., polyamide 4T (PA4T) resin, polyamide 6T (PA6T) resin, modified polyamide 6T (modified PA6T) resin, polyamide 9T (PA9T) resin, polyamide 10T (PA10T) resin, polyamide 11T (PA11T) resin, polyamide 6 (PA6) resin, polyamide 66 (PA66) resin, polyamide 46 (PA46) resin, etc., polysulfone resins such as polysulfone (PSU) resin, polyethersulfone (PES) resin, polyphenylene sulfone (PPSU) resin, polyester resins such as polyethylene terephthalate (PET) resin, polybutylene terephthalate (PBT) resin, polyethylene naphthalate (PEN) resin, polyetherketone (PET), etc., within the range not impairing the characteristics of the present invention. Polyarylene ether ketone resins such as polyether ether ketone (PEK) resin, polyether ether ketone (PEEK) resin, polyether ether ketone ketone (PEKK) resin, polyether ether ketone ketone (PEEKK) resin, and polyether ketone ether ketone ketone (PEKEKK) resin; polytetrafluoroethylene (PTFE) resin, polytetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) resin, tetrafluoroethylene-hexafluoropropyl copolymer (FEP) resin, tetrafluoroethylene-ethylene copolymer (ETFE) resin, polychlorotrifluoroethylene (PCTFE) resin, polyvinylidene fluoride (PVdF) resin, vinylidene fluoride-tetrafluoroethylene-hexafluoropropylene copolymer resin, and fluororesins such as acid-modified fluororesins; polycarbonate (PC) resin, polyarylate (PAR) resin, and liquid crystal polymer (LCP) are added as needed.

[0049] In addition to the above resins, the polyarylene sulfide resin film 5 may selectively contain antioxidants, light stabilizers, ultraviolet absorbers, plasticizers, lubricants, flame retardants, antistatic agents, heat resistance improvers, inorganic compounds, organic compounds, glass fibers, carbon fibers, etc., within the range that does not impair the characteristics of the present invention.

[0050] The polyarylene sulfide resin film 5 may be simply wound flat around the pair of conductive wires 2 and the insulating layer 3 in the longitudinal direction of the circumference, but is preferably spirally wound diagonally (traversely wound) without any gaps. This is because spiral winding without gaps is expected to improve the breakdown voltage compared to when polyarylene sulfide resin is extruded into a cylindrical shape to encapsulate the multiple conductive wires 2 and the insulating layer 3. This is because it is expected to improve the breakdown voltage particularly at the corners of the conductive wires 2 where the electric field is concentrated. In addition, when the insulated wire 1 is used as a rectangular wire in a transformer, spiral winding is expected to improve voltage conversion.

[0051] The polyarylene sulfide resin film 5 can be produced by known production methods such as melt extrusion, calendaring, or casting, but from the viewpoints of ease of handling and simplification of equipment, continuous extrusion by melt extrusion is optimal. Here, the melt extrusion method refers to a production method in which a melt extruder 10 consisting of a single-screw extruder, a twin-screw extruder, or the like is used, and a molding material 6 containing at least a polyarylene sulfide resin is continuously extruded through a T-die 13 at the tip of the melt extruder 10 to form a strip-shaped polyarylene sulfide resin film 5.

[0052] 3, the melt extruder 10 is, for example, a single-screw extruder or a twin-screw extruder, and functions to melt and knead the introduced molding material 6. A raw material inlet 11 for the molding material 6 is provided at the upper rear of the melt extruder 10, and an inert gas supply pipe 12 is connected to this raw material inlet 11, which supplies an inert gas such as helium gas, neon gas, argon gas, krypton gas, nitrogen gas, or carbon dioxide gas as needed. The inflow of the inert gas through this inert gas supply pipe 12 effectively prevents oxidative degradation and oxygen crosslinking of the molding material 6.

[0053] The temperature during melt-kneading in the melt extruder 10 is not particularly limited as long as it is a temperature at which the polyarylene sulfide resin can be melted and does not decompose, but is preferably in the range of the melting point of the polyarylene sulfide resin to less than its thermal decomposition temperature. Specifically, it is adjusted to a temperature between the melting point +10°C and the melting point +100°C, preferably a temperature between the melting point +20°C and the melting point +70°C, and more preferably a temperature between the melting point +20°C and the melting point +50°C. This is because, if the temperature is below the melting point, the polyarylene sulfide resin cannot be melt-extruded, and conversely, if the temperature exceeds the thermal decomposition temperature, the polyarylene sulfide resin may be severely decomposed.

[0054] The polyarylene sulfide resin melt-kneaded in the melt extruder 10 is continuously extruded into a strip-shaped polyarylene sulfide resin film 5 by a T-die 13 at the tip of the melt extruder 10, as shown in Figure 3, and this continuous polyarylene sulfide resin film 5 is cooled by being sandwiched between a pair of pressure-bonding rolls 17 and multiple cooling rolls 18 below, and then taken up by a winder 19, thereby producing the film.

[0055] The T-die 13 is attached to the tip of the melt extruder 10 via a connecting pipe 14 and functions to continuously extrude a strip-shaped polyarylene sulfide resin film 5 downward. The temperature during extrusion of this T-die 13 is in the range of the melting point or higher and lower than the thermal decomposition temperature of the polyarylene sulfide resin. Specifically, the temperature is adjusted to between the melting point +10°C and the melting point +100°C, preferably between the melting point +20°C and the melting point +70°C, and more preferably between the melting point +20°C and the melting point +50°C. This is because, if the temperature is lower than the melting point, the polyarylene sulfide resin cannot be melt-extruded, and conversely, if the temperature exceeds the thermal decomposition temperature, the polyarylene sulfide resin may be severely decomposed.

[0056] A gear pump 15 and a filter 16 are preferably attached to the connecting pipe 14 upstream of the T-die 13. The gear pump 15 transfers the polyarylene sulfide resin melt-kneaded by the melt extruder 10 to the T-die 13 at a constant flow rate and with high precision via the filter 16. The filter 16 also separates gels and foreign matter from the molten polyarylene sulfide resin and transfers the molten molding material 6 to the T-die 13.

[0057] The filter 16 is made of, for example, a circle with many concentric holes, sintered metal with many holes, or a metal mesh, and has a plurality of small openings that are 0.5 to 6 times, preferably 0.5 to 4 times, and more preferably 0.5 to 3.8 times the average thickness of the polyarylene sulfide resin film 5. The reason why the thickness is 0.5 times or more the average thickness of the polyarylene sulfide resin film 5 is that if the thickness is less than 0.5 times, the extrusion pressure of the molding material 11 will be too high, which may cause damage to the filter 16 and significantly reduce productivity.

[0058] A pair of pressure rolls 17 are rotatably supported below the T-die 13 and sandwich a plurality of cooling rolls 18 so that they can slide against each other, and a winder 19 is installed downstream of the downstream pressure roll 17 to wind the polyarylene sulfide resin film 5 onto a rotatable take-up tube 20. A slit blade 21 that forms a slit on the side of the polyarylene sulfide resin film 5 is arranged between this winder 19 and the downstream pressure roll 17 so that it can be raised and lowered, and a required number of rotatable tension rolls 22 are supported between this slit blade 21 and the winder 19 to apply tension to the polyarylene sulfide resin film 5 to smoothly wind it up.

[0059] The peripheral surface of each pressure roller 17 is coated as needed with a rubber layer made of at least natural rubber, isoprene rubber, butadiene rubber, silicone rubber, fluororubber, or the like, to improve adhesion between the polyarylene sulfide resin film 5 and the cooling roller 18. This rubber layer may optionally contain an inorganic compound such as silica or alumina. Of the rubbers used in this rubber layer, silicone rubber or fluororubber, which have excellent heat resistance, are preferably used.

[0060] A metal elastic roll having a metal surface is used as the pressure-bonding roll 17 as needed, and when this metal elastic roll is used, it becomes possible to form a polyarylene sulfide resin film 5 having an excellent surface smoothness. Examples of metal elastic roll products include a metal sleeve roll, an air roll (manufactured by Dymco Corporation: product name), and a UF roll (manufactured by Hitachi Zosen Corporation: product name).

[0061] Such a pressure-bonding roll 17 is adjusted to a temperature of 20°C or more and 50°C or less than the glass transition point of the polyarylene sulfide resin, preferably 30°C or more and 20°C or less than the glass transition point of the polyarylene sulfide resin, more preferably 10°C or more and 50°C or more and even more preferably 10°C or more and less than the glass transition point of the polyarylene sulfide resin, and is brought into sliding contact with the polyarylene sulfide resin film 5 and presses it against the cooling roll 18.

[0062] The reason why the temperature of the pressure roller 17 is within this range is that if the temperature of the pressure roller 17 exceeds the glass transition point of the polyarylene sulfide resin + 50°C, the relative crystallinity of the polyarylene sulfide resin film 5 may become 80% or more. Conversely, if the temperature of the pressure roller 17 is less than 20°C, condensation may occur on the pressure roller 17. Methods for adjusting the temperature or cooling the pressure roller 17 include methods using air, water, oil, etc., or an electric heater or dielectric heating.

[0063] The multiple cooling rolls 18 are, for example, metal rolls with a larger diameter than the pressure roll 17, and are adjacent to each other so that they can slide against each other.They are rotatably arranged below the T-die 13 and sandwich the extruded polyarylene sulfide resin film 5 between them and the pressure roll 17, and cool the polyarylene sulfide resin film 5 together with the pressure roll 17 while controlling its thickness within a predetermined range.

[0064] Like the pressure-bonding roll 17, each cooling roll 18 is adjusted to a temperature of 20°C or more and 50°C or less than the glass transition point of the polyarylene sulfide resin, preferably 30°C or more and 20°C or less than the glass transition point of the polyarylene sulfide resin, more preferably 50°C or more and 10°C or less than the glass transition point of the polyarylene sulfide resin, and even more preferably 30°C or more and less than the glass transition point of the polyarylene sulfide resin, and is brought into sliding contact with the polyarylene sulfide resin film 5.

[0065] The contact time between the cooling roll 18 and the polyarylene sulfide resin film 5 is not particularly limited, but from the viewpoint of instantaneously cooling the polyarylene sulfide resin film 5, it is optimal to set the time to 0.1 seconds or more and 120 seconds or less, preferably 0.5 seconds or more and 40 seconds or less, and more preferably 1 second or more and 30 seconds or less.

[0066] In the above configuration, when the polyarylene sulfide resin film 5 is actually produced more specifically, as shown in FIG. 3, first, the molding material 6 is fed into the raw material inlet 11 of the melt extruder 10 while supplying an inert gas as indicated by the arrow in the figure, and the polyarylene sulfide resin is melt-kneaded by the melt extruder 10, and the polyarylene sulfide resin film 5 is continuously extruded into a strip shape from the T-die 13.

[0067] The water content of the polyarylene sulfide resin before melt extrusion is adjusted to 2000 ppm or less, preferably 1000 ppm or less, and more preferably 100 ppm or more and 500 ppm or less, because if the water content exceeds 2000 ppm, the polyarylene sulfide resin may foam immediately after being extruded from the T-die 13.

[0068] After the polyarylene sulfide resin film 5 has been extrusion-molded, it is sequentially wound around a pair of pressure-bonding rolls 17, a plurality of cooling rolls 18, a tension roll 22, and a winder 19. After the polyarylene sulfide resin film 5 is cooled by the cooling roll 18, both side portions of the polyarylene sulfide resin film 5 are cut with slit blades 21, and the film is sequentially wound around a winding tube 20 of the winder 19, thereby producing the polyarylene sulfide resin film 5. During this production, fine irregularities can be formed on the surface of the polyarylene sulfide resin film 5 within a range that does not impair the effects of the present invention, thereby reducing the coefficient of friction of the surface of the polyarylene sulfide resin film 5.

[0069] From the viewpoint of preventing dielectric breakdown during operation of a motor or the like and contributing to thinning, the thickness of the polyarylene sulfide resin film 5 is preferably in the range of 1 μm to 50 μm, preferably 5 μm to 40 μm, more preferably 9 μm to 25 μm, and even more preferably 9 μm to 20 μm. This is because, if the thickness of the polyarylene sulfide resin film 5 is in the range of 1 μm to 50 μm, a decrease in the occupancy rate of the conductive wires 2 due to thinning can be prevented, and a decrease in the performance of the motor or transformer can be prevented.

[0070] The crystallization of the polyarylene sulfide resin film 5 can be expressed by the relative crystallinity. The relative crystallinity of the polyarylene sulfide resin film 5 is calculated by the following formula based on the results of thermal analysis measured at a temperature rise rate of 10°C / min using a differential scanning calorimeter. Relative crystallinity (%) = {1-(ΔHc / ΔHm)} × 100 ΔHc: Heat of recrystallization peak (J / g) ΔHm: Heat of crystal melting peak (J / g)

[0071] The relative crystallinity of the polyarylene sulfide resin film 5 is preferably less than 80%, preferably 70% or less, more preferably 50% or less, and even more preferably around 30%. This is because, when the relative crystallinity of the polyarylene sulfide resin film 5 is 80% or more, the polyarylene sulfide resin film 5 does not soften and therefore does not fuse to the conductive wires 2 or to the polyphenylene sulfide resin film itself. The lower limit of the relative crystallinity of the polyarylene sulfide resin film 5 is not particularly limited, but is preferably 5% or more.

[0072] The mechanical properties of the polyarylene sulfide resin film 5 can be evaluated by the maximum tensile strength, tensile elongation at break, and tensile modulus at 23°C. The maximum tensile strength of the resin film for conductive wires, measured in accordance with JIS K 6781, is 50 MPa or more, preferably 60 MPa or more, and more preferably 70 MPa or more. The upper limit of this maximum tensile strength is not particularly limited, but is preferably 500 MPa or less. Furthermore, the tensile elongation at break, measured in accordance with JIS K 6781, is preferably 50% or more, preferably 100% or more, more preferably 200% or more, and even more preferably 300% or more. The upper limit of this tensile elongation at break is not particularly limited, but is preferably 500% or less.

[0073] These numerical limitations are set because, if the maximum tensile strength is less than 50 MPa and the tensile elongation at break is less than 50%, the polyarylene sulfide resin film 5 does not have sufficient toughness, and problems such as breakage or cracking may occur during winding of the polyarylene sulfide resin film 5 around the rectangular electric wire, making the winding process difficult.

[0074] The tensile modulus of the polyarylene sulfide resin film 5 at 23°C, as measured in accordance with JIS K 6781, is preferably 2000 MPa or more, preferably 2200 MPa or more and 3100 MPa or less, more preferably 2300 MPa or more and 3075 MPa or less, and even more preferably 2500 MPa or more and 3050 MPa or less.

[0075] This is because, if the tensile modulus of the polyarylene sulfide resin film 5 is less than 2000 MPa, the rigidity of the polyarylene sulfide resin film 5 is poor, which reduces the handling properties during the winding process of the polyarylene sulfide resin film 5 and increases the deviation of the laminated state of the polyarylene sulfide resin film 5 when the conductive wire 2 is bent. Conversely, if the tensile modulus exceeds 3100 MPa, the rigidity is too high during bending, which causes the polyarylene sulfide resin film 5 to peel off from the conductive wire 2.

[0076] The storage modulus (E') of the polyarylene sulfide resin film 5 is important, and the storage modulus (E') is 1.0 × 10 in the temperature range of [glass transition point (Tg) - 10 ° C] or more [glass transition point (Tg) + 60 ° C] or less of the polyarylene sulfide resin film 5. 8 The resin film must have a portion where the thermal conductivity drops to 1.0×10 Pa or less (see FIG. 4). 8 This is because, when there is no portion where the resistance drops below Pa (see FIG. 5), the polyarylene sulfide resin film 5 softens and does not fuse.

[0077] 4 and 5 show the storage modulus in the extrusion direction, but the storage modulus in the width direction (direction perpendicular to the extrusion direction) is approximately the same.

[0078] The breakdown voltage of the polyarylene sulfide resin film 5, measured in accordance with JIS C 2110-1994, is preferably 0.5 kV or more to ensure insulation. Specifically, it is preferably 0.5 kV to 15 kV, preferably 0.9 kV to 9.0 kV, and more preferably 1.0 kV to 8.0 kV. This is because a breakdown voltage of less than 0.5 kV would not prevent breakdown during operation of a motor or the like. Furthermore, a breakdown voltage of more than 15 kV would prevent a reduction in the occupancy rate of the conductive wires 2 due to thinning, which would degrade the performance of the motor or transformer.

[0079] The relative dielectric constant of the polyarylene sulfide resin film 5 at 1 GHz, as measured by a cavity resonator perturbation method, is optimally 3.5 or less, preferably 3.3 or less, more preferably 3.2 or less, and even more preferably 3.1 or less, in order to ensure insulation. The lower limit of this relative dielectric constant is not particularly limited, but in practice it is 1.1 or more. This is because if the relative dielectric constant at a frequency of 1 GHz exceeds 3.5, the partial discharge breakdown voltage, which is the initial phenomenon of dielectric breakdown, cannot be sufficiently increased, making it difficult to prevent dielectric breakdown due to surge voltage.

[0080] Next, when manufacturing an insulated electric wire 1, which is a rectangular electric wire, using a polyarylene sulfide resin film 5, first, a pair of conductive wires 2 is prepared, and a resin varnish containing a thermoplastic resin for the insulating layer 3 is applied to one of the pair of conductive wires 2 and baked to form the insulating layer 3, and then the pair of conductive wires 2 are stacked on top of each other to interpose the insulating layer 3 therebetween.

[0081] Once the insulating layer 3 is sandwiched between the pair of conductive wires 2 in this manner, the insulating resin member 4, a long and thin polyarylene sulfide resin film 5, is spirally wound along the longitudinal direction to encase them, and the completely spirally wound polyarylene sulfide resin film 5 is heated and heat-sealed within a temperature range of not less than the glass transition point of the polyarylene sulfide resin film 5 and not more than the melting point of the polyarylene sulfide resin film 5, preferably not less than the glass transition point of the polyarylene sulfide resin film 5 + 50°C and not more than the melting point of the polyarylene sulfide resin film 5 - 50°C, and more preferably not less than the glass transition point of the polyarylene sulfide resin film 5 + 70°C and not more than the melting point of the polyarylene sulfide resin film 5 - 70°C.

[0082] This causes the thermoplastic polyarylene sulfide resin film 5 to soften and adhere, making it possible to produce an insulated wire 1 in which the pair of conductive wires 2, the insulating layer 3, and the polyarylene sulfide resin film 5 are integrated together. Furthermore, crystallization of the polyarylene sulfide resin film 5 progresses, improving heat resistance.

[0083] During the heating process, care must be taken because if the polyarylene sulfide resin film 5 is heated at a temperature below its glass transition point, the polyarylene sulfide resin film 5 will not soften and will not be able to bond, resulting in the insulated wire 1 being unable to be manufactured, which integrates the pair of conductive wires 2, the insulating layer 3, and the polyarylene sulfide resin film 5. Also, if the polyarylene sulfide resin film 5 is heated at a temperature equal to or higher than its melting point, the polyarylene sulfide resin film 5 will melt and flow, causing unevenness in the film thickness and pinholes in the polyarylene sulfide resin film 5 spirally wound around and encapsulating the insulated wire 1, which will result in a decrease in the insulating properties of the insulated wire 1.

[0084] The method for heating the polyarylene sulfide resin film 5 is not particularly limited, but examples thereof include a method using a heat medium such as air, water, superheated steam, or oil, or a method using an electric heater or dielectric heating. The insulated electric wire 1 manufactured in this manner is used as a component for a motor, a transformer, a generator, a reactor, or the like for a hybrid vehicle, an electric vehicle, or a high-speed rail vehicle, and is used to pass a large current.

[0085] According to the above configuration, as the polyarylene sulfide resin film 5 softens, the pair of conductive wires 2, the insulating layer 3, and the polyarylene sulfide resin film 5 are fused and integrated, making it possible to reliably omit an adhesive layer that bonds the conductive wires 2 and the polyarylene sulfide resin film 5. Furthermore, it is possible to prevent interlayer delamination from occurring between the plurality of conductive wires 2, the insulating layer 3, and the polyarylene sulfide resin film 5, thereby improving heat resistance, electrical properties, and the like.

[0086] Furthermore, by omitting the adhesive layer, it is possible to significantly reduce the amount of volatile organic compounds generated during the production of the insulated wire 1, which is expected to reduce manufacturing costs while also being environmentally friendly. Furthermore, by omitting the adhesive layer, it is possible to improve thermal conductivity and reduce the thickness of the insulated wire 1, thereby improving motor performance. Furthermore, by using the polyarylene sulfide resin film 5, it is possible to achieve excellent heat resistance, cold resistance, electrical properties, chemical resistance, solvent resistance, radiation resistance, hydrolysis resistance, flame retardancy, low water absorption, recyclability, dimensional stability, mechanical strength, adhesion to metals, and other properties.

[0087] In particular, selecting a polyphenylene sulfide resin film as the polyarylene sulfide resin film 5 can provide extremely excellent heat resistance, cold resistance, electrical properties, chemical resistance, moisture resistance, low water absorption, flame retardancy, dimensional stability, mechanical strength, metal adhesion, and other properties. Furthermore, polyphenylene sulfide resin films have a melting point of 270°C or higher and 300°C or lower and a glass transition point of 70°C or higher and 100°C or lower, providing stable and excellent heat resistance. Furthermore, although concentrated sulfuric acid oxidizes the polyarylene sulfide resin film, there is no solvent that can dissolve it, making it highly solvent-resistant and enabling laser welding and printing. Furthermore, since the relative crystallinity of the polyarylene sulfide resin film 5 is set to less than 80%, the polyarylene sulfide resin film 5 is softened, which is expected to significantly improve thermoformability.

[0088] Next, Figure 6 shows a second embodiment of the present invention, in which a polyarylene sulfide resin film 5 is spirally wound in multiple layers, rather than in a single layer, around the longitudinal direction of the circumferential surface of a pair of conductive wires 2 and an insulating layer 3.

[0089] The polyarylene sulfide resin film 5 may be spirally wound in two or more layers (for example, two, three, four, five, etc.), but considering workability and practicality, it is optimal to spirally wind in three layers. The total thickness of the polyarylene sulfide resin film 5 spirally wound in multiple layers is optimally 2 μm to 200 μm, preferably 10 μm to 175 μm, more preferably 20 μm to 150 μm, and even more preferably 30 μm to 100 μm. The other parts are the same as those in the above embodiment, so description thereof will be omitted.

[0090] This embodiment is also expected to have the same effects as the above-described embodiment, and furthermore, since the polyarylene sulfide resin film 5 is wound in multiple layers to increase its total thickness, it is clear that the electrical characteristics, i.e., the breakdown voltage, of the insulating resin member 4 can be further improved. In particular, the breakdown voltage at the corners of the conductive wires 2, where high insulation is required due to the concentration of the electric field, can be significantly improved.

[0091] In the above embodiment, the polyarylene sulfide resin film 5 is fused to a pair of conductive wires 2 and the insulating layer 3, but this is not limiting. For example, a single conductive wire 2 may have a circular cross section, omitting the insulating layer 3, and spirally winding and fusing the polyarylene sulfide resin film 5 around the circumferential surface of the conductive wire 2, thereby omitting the adhesive layer or adhesive. Furthermore, a plurality of polyarylene sulfide resin films 5 may be spirally wound and fusing around the circumferential surface of the conductive wire 2.

[0092] In addition, when producing the polyarylene sulfide resin film 5 in the above embodiment, a single polyarylene sulfide resin may be used, or two or more polyarylene sulfide resins may be used. Furthermore, the polyarylene sulfide resin film 5 may be subjected to a surface treatment such as a corona treatment, a plasma treatment, an acid treatment, a flame treatment, an Itro treatment, or a coating treatment, as needed. [Example]

[0093] EXAMPLES Hereinafter, examples of a resin film for conductive wires and a method for producing the same according to the present invention will be described together with comparative examples. Example 1 First, a commercially available polyphenylene sulfide resin (manufactured by DIC Corporation, product name: PS-115-368) was prepared as the polyarylene sulfide resin, and this polyphenylene sulfide resin was dried for 12 hours in a dehumidified hot air dryer heated to 150°C. Polyphenylene sulfide resin will be abbreviated as "PPS resin" hereinafter.

[0094] The content of the dried polyarylene sulfide resin was confirmed to be 300 ppm or less, and the dried polyarylene sulfide resin was melt-kneaded in a φ40 mm single-screw melt extruder equipped with a 900 mm wide T-die. The melt-kneaded polyarylene sulfide resin was continuously extruded from the T-die of the single-screw melt extruder to form a polyarylene sulfide resin film with a relative crystallinity of 33%. The moisture content of the PPS resin used as the molding material was measured by Karl Fischer titration using a trace moisture analyzer (Mitsubishi Chemical Corporation, product name: CA-100).

[0095] The apparent shear viscosity of the polyarylene sulfide resin was measured using a flow tester (Shimadzu Corporation, product name: Shimadzu Flow Tester CFT-500D). Specifically, the polyarylene sulfide resin was dried in advance in a hot air dryer at 160°C for 12 hours, and 1.5 cm of this polyarylene sulfide resin was 3 The mixture was packed into a cylinder at 310°C equipped with a die (diameter: 1 mm, length: 10 mm), and a 1.0 cm2 area was placed on the top of the cylinder. 2 The plunger was attached, and when the temperature of the cylinder reached 310°C, it was preheated for 5 minutes, and immediately after this preheating, a load of 50 kgf was applied to melt and flow out the polyarylene sulfide resin, and its apparent shear viscosity was measured. The apparent shear viscosity was measured in the same manner as below.

[0096] The single-screw melt extruder had an L / D ratio of 32, a compression ratio of 2.5, and a full-flight screw type screw. The temperature of this single-screw melt extruder was adjusted to 250 to 310°C, the temperature of the T-die to 310°C, and the temperature of the connecting pipe connecting the single-screw melt extruder and the T-die to 310°C. The temperature of the molten polyarylene sulfide resin was measured by measuring the resin temperature at the inlet of the T-die, and was found to be 310°C. When the polyarylene sulfide resin was introduced into the single-screw extruder, nitrogen gas was supplied at 18 L / min through an inert gas supply pipe.

[0097] After the polyarylene sulfide resin film was extrusion-molded, this continuous polyarylene sulfide resin film was sequentially wound around a pair of pressure rolls made of silicone rubber, multiple cooling rolls consisting of metal rolls at 50°C, and a 6-inch take-up tube of a winder located downstream of these, and was sandwiched between the pressure rolls and the cooling roll. Both ends of the polyarylene sulfide resin film were cut with a slit blade and sequentially taken up around the take-up tube of the winder, producing a polyarylene sulfide resin film 100 m long, 620 mm wide, and 5 μm thick.

[0098] After the polyarylene sulfide resin film was produced, the film thickness, glass transition temperature, melting point, relative crystallinity, mechanical properties, storage modulus (E'), and electrical properties of the polyarylene sulfide resin film were measured, and the fusion to a copper rod was evaluated. The results are shown in Table 1. The mechanical properties were evaluated by the maximum tensile strength, tensile elongation at break, and tensile modulus. The electrical properties were evaluated by the breakdown voltage and the relative dielectric constant at 1 GHz.

[0099] · Thickness of polyarylene sulfide resin film The thickness of the polyarylene sulfide resin film was measured using a micrometer (Mitutoyo Corporation, product name: Coolant Proof Micrometer, model number MDC-25PJ) at 10 random locations in the width direction of the polyarylene sulfide resin film (the direction perpendicular to the extrusion direction (hereinafter abbreviated as "TD")), and the average value was used as the film thickness.

[0100] Glass transition temperature (Tg) of polyarylene sulfide resin film The glass transition temperature (Tg) of the polyarylene sulfide resin film was measured by weighing out approximately 8 mg of a measurement sample from the polyarylene sulfide resin film and using a differential scanning calorimeter (manufactured by SII Nanotechnologies, Inc., product name: High-sensitivity Differential Scanning Calorimeter X-DSC7000) in accordance with JIS K 7121, at a heating rate of 10°C / min over a measurement temperature range of 20°C to 320°C.

[0101] Melting point of polyarylene sulfide resin film The melting point of the polyarylene sulfide resin film was measured by weighing out approximately 8 mg of a measurement sample from the polyarylene sulfide resin film and using a differential scanning calorimeter (manufactured by SII Nanotechnologies, Inc., product name: EXSTAR7000 series X-DSC 7000) at a heating rate of 10°C / min over a measurement temperature range of 20°C to 320°C. The maximum value of the endothermic peak from the calorimetric curve obtained at this time was taken as the melting point.

[0102] Relative crystallinity of polyarylene sulfide resin film The relative crystallinity of the polyarylene sulfide resin film was measured by weighing approximately 8 mg of the measurement sample from the polyarylene sulfide resin film and using a differential scanning calorimeter (manufactured by SII Nanotechnologies, Inc., product name: EXSTAR7000 series X-DSC7000) at a heating rate of 10°C / min over a measurement temperature range of 20°C to 320°C. The heat quantity (J / g) of the crystal melting peak and the heat quantity (J / g) of the recrystallization peak obtained at this time were used to calculate the crystallinity using the following formula.

[0103] Relative crystallinity (%) = {1-(ΔHc / ΔHm)} × 100 Here, ΔHc represents the heat quantity (J / g) of the recrystallization peak of the polyarylene sulfide resin film under the condition of a temperature increase of 10°C / min, and ΔHm represents the heat quantity (J / g) of the crystalline melting peak of the polyarylene sulfide resin film under the condition of a temperature increase of 10°C / min.

[0104] ·Mechanical properties of polyphenylene sulfide resin film The mechanical properties of the polyphenylene sulfide resin film were evaluated in terms of maximum tensile strength, tensile elongation at break, and tensile modulus at 23°C. The mechanical properties were measured in the extrusion direction (hereinafter abbreviated as "MD") and TD. The measurements were performed in accordance with JIS K 6781 under conditions of a tensile speed of 50 mm / min, a temperature of 23°C ± 2°C, and a relative humidity of 50 RH ± 5% RH.

[0105] Storage modulus (E') of polyarylene sulfide resin film The storage modulus of the polyarylene sulfide resin film was measured in tensile mode in both MD and TD. Specifically, the polyarylene sulfide resin film was cut into a size of MD: 60 mm × TD: 6 mm to measure the storage modulus in MD, and MD: 6 mm × TD: 60 mm to measure the storage modulus in TD. Measurements were performed in tensile mode using a viscoelasticity spectrometer (TS Instruments Japan, product name: RSA-G2) under the following conditions: frequency 1 Hz, strain 0.1%, heating rate 3°C / min, temperature range -50°C to 300°C, and tick gap 21 mm. Results were indicated as ○ or ×.

[0106] ○: 1.0×10 within the temperature range of the polyarylene sulfide resin film (glass transition temperature (Tg) - 10°C) to (glass transition temperature (Tg) + 60°C) 8 Pa or less If there is a part that decreases ×: 1.0×10 within the temperature range of [glass transition point (Tg) - 10°C] or more [glass transition point (Tg) + 60°C] of the polyarylene sulfide resin film 8 Pa or less If there is no part that decreases

[0107] ·Breakdown voltage of polyarylene sulfide resin film The dielectric breakdown voltage of polyarylene sulfide resin film was measured using a short-time air breakdown test in accordance with JIS C 2110-1994. Specifically, the dielectric breakdown voltage was measured from the cooling roll side in an environment of 23±2°C and 50%RH±5%RH. The dielectric breakdown tester used was a withstand voltage and insulation resistance tester (Kikusui Electronics Co., Ltd., product name: TOS9201) and an air test electrode device (Tama Densoku Co., Ltd., product name: TJ-20). Measurements were performed in air using the temperature-rise method (short-time method) at AC (50 Hz). The electrode shape was cylindrical (upper shape: diameter 25 mm, height 25 mm, lower shape: diameter 25 mm, height 15 mm).

[0108] When the breakdown voltage of the polyarylene sulfide resin film reached the upper limit of 6100 V, it was measured in accordance with IEC 60243-1. Specifically, the breakdown voltage was measured from the cooling roll side in an environment of 23±2°C and 50%±5%RH. The breakdown voltage was evaluated using a YST-243-109RHO breakdown tester (manufactured by Yamayo Test Instruments Co., Ltd., product name: YST-243-109RHO) using the air temperature rising method (short-term method), AC (50 Hz), temperature 23°C±2°C, and electrode shapes: upper electrode φ25 mm (cylindrical) and lower electrode φ75 mm (cylindrical).

[0109] ·Dielectric constant of polyphenylene sulfide resin film The dielectric constant of the polyphenylene sulfide resin film was evaluated at a frequency of 1 GHz. This dielectric constant at 1 GHz was measured using a vector network analyzer (Anritsu MS46122B+040+002) by the cavity resonator perturbation method. The dielectric property measurement at 1 GHz was performed in accordance with ASTM D2520, except that the cavity resonator was changed to a 1 GHz cavity resonator (Keycom model; for use around 1 GHz). The dielectric constant measurement was performed in an environment of temperature: 23°C ± 1°C, humidity: 50% ± 5%.

[0110] -Fusing polyarylene sulfide resin film to copper rod The polyarylene sulfide resin film was cut into 1 cm width pieces and wrapped around a round copper rod corresponding to a conductive wire, and the copper rod wrapped with this polyarylene sulfide resin film was left standing for 1 hour in a heating oven heated to 200°C, after which the copper rod was removed from the heating oven and left standing in an environment of 23°C and 50% RH ± 5% RH, and cooled to below 40°C. After cooling to below 40°C in this way, the polyarylene sulfide resin film was pinched and pulled with the fingers, and the presence or absence of fusion of the polyarylene sulfide resin film was confirmed and evaluated as ◯ or ×.

[0111] ◯: When the polyarylene sulfide resin film does not peel off even when pulled, and fusion is observed ×: When the polyarylene sulfide resin film was pulled, it peeled off and no fusion was observed.

[0112] Example 2 Polyarylene sulfide resin films (PPS resin films) for conductive wires of different thicknesses were extrusion-molded into a strip shape with a relative crystallinity of 33% in the same manner as in Example 1, and the temperature of the molten polyarylene sulfide resin was measured at the inlet of the T-die and found to be 311° C. After the polyarylene sulfide resin film was extruded, both ends of the continuous polyarylene sulfide resin film were cut with a slit blade and sequentially wound onto a winding tube of a winder, producing a polyarylene sulfide resin film 100 m long, 620 mm wide, and 15 μm thick.

[0113] After the polyarylene sulfide resin film was produced, the film thickness, glass transition point, melting point, relative crystallinity, mechanical properties, storage modulus (E'), and electrical properties of the polyarylene sulfide resin film were measured, and the fusion to a copper rod was evaluated. The results are shown in Table 1.

[0114] Example 3 Polyarylene sulfide resin films (PPS resin films) for conductive wires of different thicknesses were extrusion-molded into a strip shape with a relative crystallinity of 34% in the same manner as in Example 1, and the temperature of the molten polyarylene sulfide resin was measured at the inlet of the T-die and found to be 311° C. After the polyarylene sulfide resin film was extruded, both ends of the continuous polyarylene sulfide resin film were cut with a slit blade and sequentially wound onto a winding tube of a winder, producing a polyarylene sulfide resin film 100 m long, 620 mm wide, and 25 μm thick.

[0115] After the polyarylene sulfide resin film was produced, the film thickness, glass transition point, melting point, relative crystallinity, mechanical properties, storage modulus (E'), and electrical properties of the polyarylene sulfide resin film were measured, and the fusion to a copper rod was evaluated. The results are shown in Table 1.

[0116] [Table 1]

[0117] Example 4 The procedure was basically the same as in Example 1, except that the polyarylene sulfide resin was replaced with a different PPS resin (manufactured by Polyplastics Co., Ltd., product name: Fortron 0220C9). To confirm that the dried polyarylene sulfide resin had a water content of 300 ppm or less, the water content of the polyarylene sulfide resin was measured by Karl Fischer titration using a trace water content analyzer (manufactured by Mitsubishi Chemical Corporation, product name: CA-100). The temperature of the molten polyarylene sulfide resin was measured at the inlet of a T-die, and was found to be 310°C.

[0118] A polyarylene sulfide resin film with a relative crystallinity of 25% was extrusion-molded, and both ends of this continuous polyarylene sulfide resin film were cut with a slit blade and sequentially wound onto a winding tube of a winder to produce a polyarylene ether ketone resin film 100 m long, 620 mm wide, and 9 μm thick. After producing the polyarylene sulfide resin film in this way, the film thickness, glass transition temperature, melting point, relative crystallinity, mechanical properties, storage modulus (E'), and electrical properties of this polyarylene sulfide resin film were measured, and its fusion to a copper rod was evaluated, and the results are shown in Table 2.

[0119] Example 5 Polyarylene sulfide resin films (PPS resin films) for conductive wires of different thicknesses were extrusion molded into a strip shape with a relative crystallinity of 26% basically in the same manner as in Example 4, but the temperature of the molten polyarylene sulfide resin was measured at the inlet of the T-die and found to be 312° C. After the polyarylene sulfide resin film was extruded, both ends of the continuous polyarylene sulfide resin film were cut with a slit blade and sequentially wound onto a winding tube of a winder to produce a polyarylene ether ketone resin film 100 m long, 620 mm wide, and 12 μm thick.

[0120] After the polyarylene sulfide resin film was produced, the film thickness, glass transition point, melting point, relative crystallinity, mechanical properties, storage modulus (E'), and electrical properties of the polyarylene sulfide resin film were measured, and the fusion to a copper rod was evaluated. The results are shown in Table 2.

[0121] Example 6 Polyarylene sulfide resin films (PPS resin films) for conductive wires of different thicknesses were extrusion-molded into a strip shape with a relative crystallinity of 30% basically in the same manner as in Example 4, but the temperature of the molten polyarylene sulfide resin was measured at the inlet of the T-die and found to be 311° C. After the polyarylene sulfide resin film was extruded, both ends of the continuous polyarylene sulfide resin film were cut with a slit blade and sequentially wound onto a winding tube of a winder, producing a polyarylene sulfide resin film 100 m long, 620 mm wide, and 40 μm thick.

[0122] After the polyarylene sulfide resin film was produced, the film thickness, glass transition point, melting point, relative crystallinity, mechanical properties, storage modulus (E'), and electrical properties of the polyarylene sulfide resin film were measured, and the fusion to a copper rod was evaluated. The results are shown in Table 2.

[0123] [Table 2]

[0124] Comparative Example 1 A polyarylene sulfide resin film for a conductor element was produced basically in the same manner as in Example 1, but the temperature of the molten polyarylene sulfide resin was measured at the entrance of the T-die and found to be 311°C.

[0125] In Example 1, a polyarylene sulfide resin film was extrusion-molded at a cooling roll temperature of 50°C, but in Comparative Example 1, the cooling roll temperature was changed to 150°C, and a polyarylene sulfide resin film having a relative crystallinity of 100% was extrusion-molded. After the polyarylene sulfide resin film was extrusion-molded, both ends of this continuous polyarylene sulfide resin film were cut with a slit blade and sequentially wound around a winding tube of a winder, producing a polyarylene sulfide resin film having a length of 100 m, a width of 620 mm, and a thickness of 15 µm.

[0126] After the polyarylene sulfide resin film was produced, the film thickness, glass transition point, melting point, relative crystallinity, mechanical properties, storage modulus (E'), and electrical properties of the polyarylene sulfide resin film were measured, and the fusion to a copper rod was evaluated. The results are shown in Table 3.

[0127] Comparative Example 2 A polyarylene sulfide resin film for a conductor element was produced basically in the same manner as in Example 4, but the temperature of the molten polyarylene sulfide resin was measured at the entrance of the T-die and found to be 312°C.

[0128] In Example 1, a polyarylene sulfide resin film was extrusion-molded at a cooling roll temperature of 50°C, but in Comparative Example 2, the cooling roll temperature was changed to 150°C, and a polyarylene sulfide resin film having a relative crystallinity of 100% was extrusion-molded. After the polyarylene sulfide resin film was extrusion-molded, both ends of this continuous polyarylene sulfide resin film were cut with a slit blade and sequentially wound around a winding tube of a winder, producing a polyarylene sulfide resin film having a length of 100 m, a width of 620 mm, and a thickness of 40 µm.

[0129] After the polyarylene sulfide resin film was produced, the film thickness, glass transition point, melting point, relative crystallinity, mechanical properties, storage modulus (E'), and electrical properties of the polyarylene sulfide resin film were measured, and the fusion to a copper rod was evaluated. The results are shown in Table 3.

[0130] [Table 3]

[0131] 〔evaluation〕 In each example, the resin film for the conductive wire was a polyarylene sulfide resin film with a relative crystallinity of less than 80%, so the polyarylene sulfide resin film did not peel off from the copper rod even when pulled, confirming good fusion of the polyarylene sulfide resin film. This confirmed that it was possible to omit the adhesive layer that bonds the conductive wire and the polyarylene sulfide resin film and prevent delamination between multiple conductive wires, insulating layers, and polyarylene sulfide resin films.

[0132] In contrast, in each of the comparative examples, although the resin film for conductive wires was a polyarylene sulfide resin film, the relative crystallinity was greater than 80% and reached 100%, so when the polyarylene sulfide resin film was pulled, it peeled off from the copper rod. This peeling is thought to cause delamination between the multiple conductive wires, the insulating layer, and the polyarylene sulfide resin film. [Industrial Applicability]

[0133] The resin film for conductive wire, its manufacturing method, and insulated wire according to the present invention are used in the manufacturing fields of electric, electronic, information equipment, automobiles, railways, transformers, etc. [Explanation of symbols]

[0134] 1. Insulated wire 2 Conductive wire 3. Insulation layer 4. Insulating resin material 5 Polyarylene sulfide resin film 6 Molding material 10 Melt extrusion molding machine (molding machine) 13 T Dice (Dice) 17 Crimping roll 18 Cooling roll 20 Winder

Claims

1. A resin film for conductive wires in which a conductive wire having a substantially rectangular or circular cross section is covered with an insulating resin member, the insulating resin member is a polyarylene sulfide resin film that is fused to the conductive wire without an adhesive layer and has a relative crystallinity of 5% or more and less than 80%; The polyarylene sulfide resin film is a resin film for conductive wires, characterized in that it has a portion in which the storage modulus (E') drops to 1.0 x 10 Pa or less in the temperature range of [glass transition point (Tg) - 10°C] or more and [glass transition point (Tg) + 60°C] or less, and that its tensile elongation at break in the MD direction is 200% or more and 500% or less when measured in accordance with JIS K 6781.

2. A resin film for conductive wires as described in claim 1, which has multiple conductive wires with insulating layers interposed between them, and a polyarylene sulfide resin film fused to the multiple conductive wires sandwiching the insulating layers at a temperature below the melting point.

3. 3. A resin film for conductive wires according to claim 1, wherein the insulating resin member is a polyarylene sulfide resin film spirally wound around the conductive wire and fused thereto.

4. 4. The resin film for conductive wire according to claim 1, 2, or 3, wherein the polyarylene sulfide resin film is at least one of a resin film made of a polyphenyl sulfide resin, a polyphenylene sulfide ketone resin, a polyphenylene sulfide sulfone resin, a polyphenylene sulfide ketone sulfone resin, a random copolymer thereof, a block copolymer thereof, and a mixture thereof.

5. 5. The resin film for conductive wire according to claim 1, wherein the polyarylene sulfide resin film has a tensile modulus of elasticity of 2000 MPa or more and 3100 MPa or less when measured in accordance with JIS K 6781.

6. A method for producing a resin film for conductive wire according to any one of claims 1 to 5, A method for producing a resin film for conductive wires, characterized in that a molding material containing at least a polyarylene sulfide resin is melt-kneaded, the molding material is extruded into a polyarylene sulfide resin film using a die of a molding machine, and the polyarylene sulfide resin film is cooled by contacting it with a cooling roll, thereby making the relative crystallinity of the polyarylene sulfide resin film 5% or more and less than 80%.

7. An insulated wire comprising the resin film for conductive wires according to any one of claims 1 to 5.

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