JP6059701B2 - Self-bonding insulated wire, coil wire and winding bundle - Google Patents

Description

  The present invention relates to a self-bonding insulated wire, a coil wire, and a winding bundle.

  For example, when manufacturing a coil for a motor using an insulated wire, after winding the wire on the core, the gap between the wires and the gap between the wires and the core are impregnated with varnish to fix the wires and between the wires and the core. It is common. However, it is difficult to ensure complete impregnation of the varnish, and there is a possibility that the fixing of the electric wire is partially insufficient. Moreover, man-hours increase by impregnation of the varnish, and the coil may be expensive.

  On the other hand, in order to simplify the motor manufacturing process, a self-bonding insulated wire provided with a heat-sealing layer that is fused to the outer periphery of a metal conductor may be used. When such a self-bonding insulated wire is used, if the winding density of the wire is small, there is a possibility that the fusion between the wires or between the wire and the core may be insufficient, and heat is used to improve the fusion property. If the fusion layer is thickened, the density of the windings is lowered, and the volumetric efficiency of the coil may be lowered. Moreover, there exists a possibility that the workability | operativity at the time of inserting an electric wire in a motor may deteriorate because the film thickness of an electric wire becomes thick.

  Therefore, a technique has been proposed in which a foaming agent is added to the heat-sealing layer, and the heat-sealing layer is foamed after the winding process to improve the fusion property between the wires (see Japanese Patent Laid-Open No. 4-87214).

JP-A-4-87214

  In the self-bonding insulated wire disclosed in the above publication, the heat-sealable layer expands by foaming to increase the contact pressure between each other and expands and melts so as to fill the gap between each other. However, in order to expand the use of the self-bonding insulated wire, it is desired to improve the reliability of fusion between the wires.

  Moreover, the self-bonding insulated electric wire disclosed in the above publication can obtain an effect of facilitating adhesion between the electric wires by fluidizing the heat-sealing layer during expansion. However, since the heat fusion layer flows too much, the distribution of the fusion resin becomes partially non-uniform. As a result, the distance between the wires varies, and the insulation voltage originally expected by the self-fusion layer, that is, the partial discharge start voltage In some cases, the improvement effect of (Partial Discharge Acceptance Voltage) could not be exhibited sufficiently.

  The present invention has been made based on the above-mentioned circumstances, and has high reliability of fusion between wires and high insulation property after fusion, a self-fusing insulated wire, a coil wire, and a winding bundle. It is an issue to provide.

  A self-bonding insulated electric wire according to an aspect of the present invention made to solve the above-described problems includes a linear metal conductor, an insulating layer laminated on the outer peripheral surface side of the metal conductor, and the insulating layer. A self-bonding insulated wire that is laminated on the outer peripheral surface side and expands by heating, wherein the heat-sealing layer is dispersed in a matrix mainly composed of synthetic resin. The thermal expansion layer has a chemical foaming agent or a thermally expandable microcapsule, and an average thickness expansion coefficient after heating of the heat-fusible layer is 1.1 to 5 times.

  The self-bonding insulated wire and coil wire according to one embodiment of the present invention have high reliability of fusion between wires and high insulation after fusion.

FIG. 1 is a schematic cross-sectional view showing a self-bonding insulated wire according to an embodiment of the present invention.

[Description of Embodiment of the Present Invention]
The self-bonding insulated wire according to one aspect of the present invention includes a linear metal conductor, an insulating layer laminated on the outer peripheral surface side of the metal conductor, and an outer peripheral surface side of the insulating layer, and is heated. A self-fusible insulated wire comprising a thermally fusible layer that expands, wherein the heat fusible layer comprises a matrix mainly composed of a synthetic resin, and a chemical foaming agent or a thermally expansible micro material dispersed in the matrix. The average thickness expansion coefficient after heating of the heat-fusible layer is 1.1 times or more and 5 times or less.

  In the self-bonding insulated wire, the heat-fusible layer is formed by dispersing a chemical foaming agent or a heat-expandable microcapsule in a matrix mainly composed of a synthetic resin, and has an average thickness expansion coefficient of 1 after heating. When it is 1 time or more and 5 times or less, the insulation after fusion can be improved while ensuring the reliability of fusion between the heat-sealing layers particularly when a coil is formed.

  The elastic modulus of the matrix of the heat fusion layer at the foaming start temperature of the chemical foaming agent or the thermally expandable microcapsule is preferably 1 kPa or more. As described above, by setting the elastic modulus of the matrix of the heat fusion layer within the above range, it is possible to promote substantially uniform expansion of the heat fusion layer and reliable fusion of the heat fusion layers.

  The content of the chemical foaming agent or the thermally expandable microcapsule in the heat fusion layer is preferably 1% by mass or more and 15% by mass or less. As described above, by setting the content of the chemical foaming agent or the heat-expandable microcapsule within the above range, the heat-fusion layer can be more uniformly expanded.

  The average diameter of the pores formed in the thermal fusion layer by foaming of the chemical foaming agent or the thermally expandable microcapsule is preferably 300 μm or less. Thus, by making the average diameter of the pores of the heat-fusible layer after expansion formed by foaming of the chemical foaming agent or the heat-expandable microcapsule below the above upper limit, the heat-expandable microcapsule is thermally fused. The heat fusion layer can be expanded more uniformly without hindering the fusion of the layers.

  The porosity after heating of the heat sealing layer is preferably 10% or more and 80% or less. Thus, by setting the porosity after heating of the heat-sealing layer within the above range, the matrix of the heat-sealing layer is ensured during expansion while achieving the expansion coefficient, and the heat-sealing layer The reliability of fusion between each other can be further improved.

  The coil electric wire according to one embodiment of the present invention is formed by subjecting the self-bonding insulated wire to a winding process and expanding a heat-sealing layer.

  In this way, the coil wire can be easily fixed between the wires because the heat fusion layer of the self-bonding insulated wire is fused to each other by conducting the wire processing and expanding the heat fusion layer. High reliability of fixing.

  The winding bundle which concerns on 1 aspect of this invention is a winding bundle formed by carrying out the winding process of the said several self-bonding insulated wire and bundling.

  As described above, the winding bundle has high reliability of heat-sealing of the self-bonding insulated wire and high insulation after heat-sealing, so that a highly reliable motor or the like can be formed.

  Here, the “average thickness expansion coefficient” means the ratio of the average pressure of the heat-fusion layer after expansion by heating to the average thickness of the heat-fusion layer before heating. The “average pore diameter” is a value obtained by measuring a cross section with a pore diameter distribution measuring device (for example, “Porous Materials Automatic Pore Diameter Distribution Measuring System” manufactured by Porus Materials). The “porosity” of the heat-sealing layer is a percentage of the volume of the gas in the heat-sealing layer with respect to the volume of the heat-sealing layer, and the matrix of the heat-sealing layer and the outer shell of the thermally expandable microcapsule. This is an amount calculated by (V1−V0) / V1 × 100, where V0 is an actual volume calculated from the contained mass and density of V, and V1 is an apparent volume including voids in the heat-sealing layer. The “matrix elastic modulus” means a shear elastic modulus measured in accordance with JIS-K-6868-2 (1999). The “foaming start temperature” is the temperature at which gas generation is confirmed from the chemical foaming agent, or the volume of the thermally expandable microcapsule is 1.05 times that before expansion (normal temperature, specifically 25 ° C.). Temperature.

[Details of the embodiment of the present invention]
Hereinafter, one embodiment of a self-bonding insulated wire according to the present invention will be described in detail with reference to the drawings.

  The self-bonding insulated electric wire shown in FIG. 1 includes a linear metal conductor 1, an insulating layer 2 laminated on the outer peripheral surface side of the metal conductor 1, and an outer peripheral surface side of the insulating layer 2. And a thermal fusion layer 3 that expands.

<Metal conductor>
The metal conductor 1 is, for example, a round wire having a circular cross section, but may be a square wire having a circular cross section or a rectangular flat wire having a cross section, or a stranded wire obtained by twisting a plurality of strands.

  The material of the metal conductor 1 is preferably a metal having high conductivity and high mechanical strength. Examples of such metals include copper, copper alloys, aluminum, nickel, silver, iron, steel, and stainless steel. The metal conductor 1 is a material in which these metals are formed in a linear shape, or a multilayer structure in which such a linear material is further coated with another metal, such as a nickel-coated copper wire, a silver-coated copper wire, a copper-coated wire. Aluminum wires, copper-coated steel wires, etc. can be used.

The lower limit of the average cross-sectional area of the metal conductor 1 is preferably 0.01 mm ^2, 0.1 mm ² is more preferable. On the other hand, the upper limit of the average cross-sectional area of the metal conductor 1 is preferably 100 mm ^2, 50 mm ² is more preferable. When the average cross-sectional area of the metal conductor 1 is less than the lower limit, the volume of the heat-sealing layer 3 with respect to the metal conductor 1 is increased, and the volume efficiency of a coil or the like formed using the self-bonding insulated wire is low. There is a risk. Conversely, when the average cross-sectional area of the metal conductor 1 exceeds the above upper limit, the coil can be formed relatively easily and inexpensively by the method of impregnating the conventional insulated wire with varnish, which is advantageous over the conventional insulated wire. May not be obtained.

<Insulating layer>
The insulating layer 2 is formed of an insulating resin composition. Although it does not specifically limit as a resin composition which forms the insulating layer 2, For example, polyvinyl formal, thermosetting polyurethane, thermosetting acrylic, epoxy, thermosetting polyester, thermosetting polyester imide, thermosetting polyester amide imide, aromatic polyamide, Main components are thermosetting resins such as thermosetting polyamideimide and thermosetting polyimide, and thermoplastic resins such as thermoplastic polyimide, polyphenylsulfone, polyphenylene sulfide, polyetherimide, polyetheretherketone and polyethersulfone. Can be used. The insulating layer 2 may be a composite or laminate of two or more kinds of resins, or may be a composite or laminate of a thermosetting resin and a thermoplastic resin.

  The glass transition temperature of the resin composition constituting the insulating layer 2 is higher than the glass transition temperature of the matrix 4 of the heat-fusible layer described later and the foaming start temperature of the foaming agent 5.

  As a minimum of average thickness of insulating layer 2, 5 micrometers is preferred and 10 micrometers is more preferred. On the other hand, the upper limit of the average thickness of the insulating layer 2 is preferably 200 μm, and more preferably 150 μm. If the average thickness of the insulating layer 2 is less than the lower limit, the insulating layer 2 may be broken and the metal conductor 1 may be insufficiently insulated. On the other hand, when the average thickness of the insulating layer 2 exceeds the upper limit, the volume efficiency of a coil or the like formed using the self-bonding insulated wire may be lowered.

<Heat-fusion layer>
The heat-sealing layer 3 has a matrix 4 mainly composed of a synthetic resin and a foaming agent 5 dispersed in the matrix 4.

  The heat-fusible layer 3 expands when the foaming agent 5 expands when heated, and expands as a whole.

  As a minimum of average thickness before heating of heat fusion layer 3, 10 micrometers is preferred and 20 micrometers is more preferred. On the other hand, the upper limit of the average thickness of the expanded layer 3 before heating is preferably 300 μm, and more preferably 200 μm. If the average thickness of the expansion layer 3 before heating is less than the lower limit, the self-bonding insulated wires may not be firmly fixed. Conversely, when the average thickness of the expansion layer 3 before heating exceeds the above upper limit, the volume efficiency of a coil or the like formed using the self-bonding insulated wire may be lowered.

  The lower limit of the average thickness expansion coefficient after heating of the heat-fusible layer 3 is 1.1 times, and preferably 2 times. On the other hand, the upper limit of the average thickness expansion coefficient after heating of the heat-fusible layer 3 is 5 times, and preferably 4 times. When the average thickness expansion coefficient after heating of the heat-fusible layer 3 is less than the above lower limit, when the self-fusing insulated electric wire is subjected to a winding process, the adjacent heat-fusible layers 3 are not fused. May be sufficient. On the contrary, when the average thickness expansion coefficient after heating of the heat-fusible layer 3 exceeds the upper limit, the density of the heat-fusible layer 3 becomes insufficient, and the strength of the self-fusing insulated wire is not good. May be sufficient. The expansion coefficient of the heat-fusible layer 3 can be controlled by selecting the type and amount of the foaming agent 5 and the elastic modulus of the matrix 4 at the foaming start temperature of the foaming agent.

  The lower limit of the average diameter of the pores formed in the heat-fusible layer 3 by foaming of the foaming agent 5 by heating is preferably 1 μm and more preferably 5 μm. On the other hand, the upper limit of the average diameter of the pores formed in the heat fusion layer 3 is preferably 300 μm, and more preferably 200 μm. When the average diameter of the pores formed in the heat fusion layer 3 is less than the lower limit, a sufficient expansion rate may not be obtained. On the contrary, when the average diameter of the voids formed in the heat-sealing layer 3 exceeds the upper limit, the heat-sealing layer 3 may be unnecessarily thickened or the heat-sealing layer 3 is not uniformly expanded. There is a risk.

  As a minimum of the porosity after heating of heat fusion layer 3, 10% is preferred and 50% is more preferred. On the other hand, the upper limit of the porosity after heating of the heat-fusible layer 3 is preferably 80%, and more preferably 70%. When the porosity after heating of the heat-fusible layer 3 is less than the above lower limit, the contact pressure between the adjacent heat-fusible layers 3 may be insufficient, resulting in insufficient fusion. On the contrary, when the porosity after heating of the heat sealing layer 3 exceeds the upper limit, the strength of the heat sealing layer 3 after expansion may be insufficient.

(matrix)
The lower limit of the elastic modulus of the matrix 4 at the foaming start temperature of the foaming agent 5 is preferably 1 kPa. When the elastic modulus of the matrix 4 at the foaming start temperature of the foaming agent 5 is less than the above lower limit, the thermal fusion layer 3 may flow more than necessary during expansion, and the formation of the fusion layer may be uneven.

  As a main component of the resin composition constituting the matrix 4, for example, a thermoplastic resin such as phenoxy resin, polyamide, butyral resin can be used, and among them, phenoxy resin is preferably used. Moreover, it is also possible to make it a part thermosetting type by making it crosslink by adding an epoxy resin, a melamine resin, a phenol resin, isocyanate, etc. to the said thermoplastic resin. Furthermore, in the case of a thermosetting resin, it can be used as a semi-cured state or a cured state by combining with a curing agent. Moreover, the resin composition which comprises the matrix 4 may also contain additives, such as an adhesion improving agent.

  When a thermosetting resin and a curing agent are combined as the resin composition constituting the matrix 4, the matrix 4 of the heat-fusible layer 3 becomes a semi-cured state or a cured state by the heat at the time of forming the heat-fusible layer 3. ing. Furthermore, it is completely cured by heating during the foaming process. The elastic modulus of the matrix decreases with an increase in temperature in an uncured state, but starts to increase as the temperature further increases and the curing reaction proceeds. It is preferable to perform the foaming reaction in a state where the elastic modulus of the matrix is increased to 1 kPa or more because the foaming ratio and the foaming diameter can be easily controlled.

  Examples of the phenoxy resin include resins mainly composed of bisphenol A, bisphenol S, and bisphenol F, and modified phenoxy resins. Since the phenoxy resin can be cured after the fusion treatment by adding a curing agent, sufficient strength of the expansion layer is ensured even when a thermally expandable microcapsule that forms relatively large pores is used. be able to.

  Examples of the polyamide include various copolymer polyamides, 6-nylon, 6,6-nylon, and 6,10-nylon.

  Examples of the butyral resin include polyvinyl butyral.

  Examples of other thermoplastic resins that can be used as the main component of the resin composition constituting the matrix 4 include copolymerized polyester, polybutylene terephthalate, polyethylene terephthalate, thermoplastic polyurethane, polycarbonate, polyphenylene oxide, polyphenylene sulfide, polysulfone, poly Examples include ether imide, polyether ether ketone, polyether ketone, polyether sulfone, polyphenyl sulfone, semi-aromatic polyamide, thermoplastic polyamide imide, and thermoplastic polyimide.

(Foaming agent)
As the foaming agent 5, a chemical foaming agent or a thermally expandable microcapsule can be used.

  As a minimum of the content rate in the heat sealing | fusion layer 3 of the foaming agent 5, 1 mass% is preferable and 2 mass% is more preferable. On the other hand, the upper limit of the content of the foaming agent 5 in the heat-sealing layer 3 is preferably 15% by mass, and more preferably 10% by mass. If the content of the foaming agent 5 in the heat-sealing layer 3 is less than the above lower limit, the expansion rate of the heat-sealing layer 3 is small, and the self-bonding insulated wires may be insufficiently fixed. On the other hand, when the content of the foaming agent 5 in the heat-sealing layer 3 exceeds the upper limit, the matrix 4 may be relatively reduced, which may result in insufficient strength and fusibility of the heat-sealing layer 3. There is.

<Chemical foaming agent>
The chemical foaming agent used as the foaming agent 5 is decomposed by heating to generate, for example, nitrogen gas, carbon dioxide gas, carbon monoxide, ammonia gas, etc., and an organic foaming agent or an inorganic foaming agent can be used. .

  Examples of the organic blowing agent include azo blowing agents such as azodicarbonamide (A.D.C.A) and azobisisobutyronitrile (A.I.B.N), such as dinitrosopentamethylenetetramine (D P.T), N, N′dinitroso-N, N′-dimethyl terephthalamide (DNDMTA), and the like, for example, P-toluenesulfonyl hydrazide (T.S. H), P, P-oxybisbenzenesulfonyl hydrazide (OBSH), benzenesulfonyl hydrazide (BSH), and others, and trihydrazinotriazine (TH T), acetone-P-sulfonylhydrazone and the like are exemplified, and these can be used alone or in combination of two or more.

  Examples of the inorganic foaming agent include sodium bicarbonate, ammonium carbonate, ammonium bicarbonate, sodium borohydride, sodium boron hydride, silicon oxyhydride and the like. In general, an inorganic foaming agent has a slower gas generation rate than an organic foaming agent, and adjustment of gas generation is difficult. Therefore, an organic foaming agent is preferable as the chemical foaming agent.

  As a minimum of the decomposition temperature of a chemical foaming agent, 60 ° C is preferred and 70 ° C is more preferred. On the other hand, the upper limit of the decomposition temperature of the chemical foaming agent is preferably 250 ° C and more preferably 200 ° C. When the decomposition temperature of the chemical foaming agent is less than the above lower limit, the chemical foaming agent may unintentionally foam during production of the self-bonding insulated wire, during transportation, or during storage. Conversely, if the decomposition temperature of the chemical foaming agent exceeds the above upper limit, an excessive heat load is applied to the motor parts other than the coil in the expansion process, and the energy cost required for foaming the foaming agent is increased. May be excessive.

  The heat fusion layer 3 may be blended with a foaming aid together with the chemical foaming agent. The foaming aid is not particularly limited as long as it promotes thermal decomposition of the chemical foaming agent. For example, the vulcanization accelerator, filler, vulcanization acceleration aid, PVC stabilizer, anti-aging agent, vulcanization Agents, urea compounds and the like. Such a foaming aid accelerates the decomposition of the chemical foaming agent and lowers the foaming temperature.

  Examples of the vulcanization accelerator include guanidine, aldehyde-ammonia, sulfenamide, thiuram, xanthate, aldehyde-amine, thiazole, thiourea, and dithiocarbamate. Examples of the filler include silica, magnesium carbonate, calcium carbonate, magnesium silicate, aluminum carbonate, talc, barium sulfate, aluminum sulfate, and calcium sulfate. Examples of vulcanization accelerators include zinc white, activated zinc white, zinc carbonate, magnesium oxide, lead monoxide, basic lead carbonate, calcium hydroxide, stearic acid, oleic acid, lauric acid, diethylene glycol, di- Examples thereof include n-butylamine, dicyclohexylamine, diethanolamine, and organic amine. Examples of the stabilizer for PVC include tribasic lead sulfate, dibutyltin dilaurate, dibutyltin dimaleate, zinc stearate, cadmium stearate, barium stearate, calcium stearate and the like. Examples of the anti-aging agent include naphthylamine, diphenylamine, P-phenylene, quinoline, monophenol, polyphenol, thiobisphenol, and phosphite esters. Examples of the vulcanizing agent include Thaik and ammonium sulfur benzoate. Examples of other chemicals include phthalic anhydride, salicylic acid, benzoic acid, antimony trioxide, white petrolatum, titanium oxide, cadmium oxide, borax, glycerin, and dibutyltin dimaleate. Among these, zinc oxide, tribasic lead sulfate, and various vulcanization accelerators are preferable as the foaming aid.

  As a minimum of the compounding quantity with respect to 100 mass parts of chemical foaming agents of these foaming adjuvants, 5 mass parts are preferred and 50 mass parts are more preferred. On the other hand, the upper limit of the blending amount of the foaming aid is preferably 200 parts by weight, and more preferably 150 parts by weight. When the compounding quantity of the said foaming adjuvant is less than the said minimum, there exists a possibility that the effect which decomposes | disassembles a chemical foaming agent may become inadequate. On the contrary, when the blending amount of the foaming aid exceeds the upper limit, the heat-sealing layer 3 may expand unintentionally during the production or storage of the self-bonding insulated wire.

<Thermal expandable microcapsule>
The thermally expandable microcapsule used as the foaming agent 5 has a core material (inner package) made of an internal foaming agent and an outer shell that wraps the core material, and the outer shell expands due to the expansion of the core material.

  The internal foaming agent of the heat-expandable microcapsule may be anything that expands or generates gas when heated, and its principle is not limited. As the internal foaming agent of the thermally expandable microcapsule, for example, a low boiling point liquid, a chemical foaming agent and a mixture thereof can be used.

  As the low boiling point liquid, for example, alkanes such as butane, i-butane, n-pentane, i-pentane and neopentane, and freons such as trichlorofluoromethane are preferably used.

As the chemical foaming agent, a thermally decomposable substance such as azobisisobutyronitrile that generates N ₂ gas by heating is preferably used.

  The expansion start temperature of the internal foaming agent of the thermally expandable microcapsule, that is, the boiling point of the low boiling point liquid or the thermal decomposition temperature of the chemical foaming agent is set to be equal to or higher than the softening temperature of the outer shell of the thermally expandable microcapsule described later.

  More specifically, the lower limit of the foaming start temperature of the internal foaming agent of the thermally expandable microcapsule is preferably 60 ° C, more preferably 70 ° C. On the other hand, the upper limit of the foaming start temperature of the internal foaming agent of the thermally expandable microcapsule is preferably 250 ° C and more preferably 200 ° C. If the foaming start temperature of the internal foaming agent of the heat-expandable microcapsule is less than the above lower limit, the heat-expandable microcapsule may expand unintentionally during manufacture, transportation or storage of the self-bonding insulated wire. There is. On the other hand, if the foaming start temperature of the internal foaming agent of the thermally expandable microcapsule exceeds the above upper limit, an excessive heat load is applied to the motor parts other than the coil in the expansion process. There is a risk that the energy cost required to expand the will be excessive.

  On the other hand, the outer shell of the thermally expandable microcapsule is formed of a stretchable material that can expand without breaking when the internal foaming agent is foamed to form a microballoon containing the generated gas. As a material for forming the outer shell of the thermally expandable microcapsule, a resin composition mainly composed of a polymer such as a thermoplastic resin is usually used.

  The thermoplastic resin used as the main component of the outer shell of the thermally expandable microcapsule is formed from monomers such as vinyl chloride, vinylidene chloride, acrylonitrile, acrylic acid, methacrylic acid, acrylate, methacrylate, styrene, etc. Polymers formed from two or more types of monomers are preferably used. An example of a preferred thermoplastic resin is an acrylonitrile copolymer. In this case, the decomposition temperature of the internal foaming agent is 70 ° C. or higher and 250 ° C. or lower.

  The lower limit of the average diameter of the thermally expandable microcapsules before heating is preferably 1 μm and more preferably 5 μm. On the other hand, the upper limit of the average diameter of the thermally expandable microcapsules before heating is preferably 300 μm, and more preferably 200 μm. When the average diameter of the thermally expandable microcapsules before heating is less than the above lower limit, a sufficient expansion rate may not be obtained. On the other hand, when the average diameter of the thermally expandable microcapsules before heating exceeds the above upper limit, the heat fusion layer 3 may be unnecessarily thick or the heat fusion layer 3 may be unevenly expanded. . The “average diameter” of the thermally expandable microcapsule is an average value of the maximum diameter in a plan view when 10 or more samples of the thermally expandable microcapsule are observed with a microscope and the diameter in a direction perpendicular to the maximum diameter. It shall be said.

  The lower limit of the ratio of the average diameter of the thermally expandable microcapsule to the average thickness of the heat-fusible layer 3 is preferably 1/16 and more preferably 1/8. On the other hand, the lower limit of the ratio of the average diameter of the thermally expandable microcapsule to the average thickness of the heat-fusible layer 3 is preferably 9/10, and more preferably 8/10. When the average diameter of the thermally expandable microcapsule is less than the above lower limit, there is a possibility that the thickness of the outer shell is insufficient and it may be broken during expansion, or the internal volume becomes small and the foaming agent is insufficient so that it cannot expand sufficiently. On the contrary, when the average diameter of the thermally expandable microcapsule exceeds the above upper limit, the thermally expandable microcapsule may protrude from the matrix 4 and the heat fusion layer 3 may not be sufficiently expanded, There is a possibility that it may partially expand and cannot be uniformly expanded.

  The lower limit of the expansion coefficient of the thermally expandable microcapsule is preferably 3 times, and more preferably 5 times. On the other hand, the upper limit of the expansion coefficient of the thermally expandable microcapsule is preferably 20 times, and more preferably 10 times. When the expansion coefficient of the heat-expandable microcapsule is less than the lower limit, the expansion coefficient of the heat-fusible layer 3 may be insufficient. On the contrary, when the expansion coefficient of the heat-expandable microcapsule exceeds the above upper limit, the matrix 4 of the heat-fusible layer 3 cannot follow the heat-expandable microcapsule, and the heat-fusible layer 3 expands as a whole. There is a risk that it will not be allowed. The “expansion coefficient” of the thermally expandable microcapsule means a ratio of the maximum value of the average diameter during heating to the average diameter before heating of the thermally expandable microcapsule.

[Method of manufacturing self-bonding insulated wire]
When the main component of the insulating layer 2 is a thermosetting resin, the self-bonding insulated electric wire includes a step of applying a thermosetting resin composition for forming an insulating layer to the outer peripheral surface side of the metal conductor 1, and heating. The step of curing the applied thermosetting resin composition for forming an insulating layer, and the foaming agent 5 were dispersed in a matrix 4 diluted with a solvent on the outer peripheral side of the cured thermosetting resin composition for forming an insulating layer. It can be produced by a method comprising a step of applying a composition for forming a heat-fusible layer and a step of volatilizing a solvent and drying the composition for forming a heat-fusible layer.

<Thermosetting resin composition application process for insulating layer formation>
In the insulating layer forming thermosetting resin composition application step, the insulating layer forming thermosetting resin composition is applied to the outer peripheral surface side of the metal conductor 1. As a method of applying the thermosetting resin composition for forming an insulating layer to the outer peripheral surface side of the metal conductor 1, for example, a liquid composition tank storing a liquid thermosetting resin composition for forming an insulating layer and a coating die are used. Examples thereof include a method using a coating apparatus provided. According to this coating apparatus, when the metal conductor 1 is inserted through the liquid composition tank, the liquid composition adheres to the outer peripheral surface of the metal conductor, and then passes through the coating die so that the liquid composition is substantially uniform. It is applied to a proper thickness. Prior to the application of the insulating layer forming thermosetting resin composition, a primer treatment layer may be formed on the outer peripheral surface of the metal conductor 1 by a known method.

<Thermosetting resin composition curing process for insulating layer formation>
In the insulating layer forming thermosetting resin composition curing step, the insulating layer forming thermosetting resin composition is cured by heating to form the insulating layer 2. The apparatus used for this heating is not particularly limited, but a cylindrical baking furnace that is long in the traveling direction of the metal conductor 1 can be used. The heating method is not particularly limited, but can be performed by a conventionally known method such as hot air heating, infrared heating, high frequency heating, or the like. Moreover, as heating temperature, it is set as 300 to 600 degreeC, for example.

  The insulating layer forming thermosetting resin composition coating step and the insulating layer forming thermosetting resin composition curing step may be repeated a plurality of times. In this way, the thickness of the insulating layer can be increased sequentially. At this time, the hole diameter of the coating die and the number of repetitions are appropriately adjusted according to the diameter of the metal conductor and the target coating thickness of the insulating layer.

<The process of applying a composition for forming a heat-fusible layer>
In the heat sealing layer forming composition coating step, the heat sealing layer forming composition in which the foaming agent 5 is dispersed in a solution obtained by diluting the resin composition constituting the matrix 4 with a solvent is used as the outer peripheral surface of the insulating layer 2. Apply to the side. The method for applying the composition for forming a heat-fusible layer can be the same as the step for applying the thermosetting resin composition for forming an insulating layer.

<The process for drying the composition for forming the heat-fusible layer>
In the heat-sealable-layer-forming composition drying step, the heat-sealable layer-forming composition is dried by evaporating the solvent at a temperature lower than the expansion start temperature of the foaming agent 5. Form. As a drying method, it can be performed by a conventionally known method such as hot air heating, infrared heating, high-frequency heating, or the like.

[Coil wire]
A coil electric wire according to another embodiment of the present invention is formed by subjecting the above self-bonding insulated wire to a winding process and expanding the heat-sealing layer 3.

  As a heating method for expanding the heat-sealing layer 3, for example, it can be performed by a conventionally known method such as hot air heating, infrared heating, high-frequency heating, etc., or a method using heat generated by energization of the metal conductor 1 Is applicable.

[Winding bundle]
A winding bundle according to another embodiment of the present invention is formed by winding and bundling a plurality of self-bonding insulated wires.

[advantage]
In the self-bonding insulated wire, the heat-sealable layer 3 is formed by dispersing the foaming agent 5 in the matrix 4 mainly composed of a synthetic resin. It can expand relatively uniformly.

  In addition, the self-bonding insulated wire has an average thickness expansion coefficient of the heat fusion layer 3 of 1.1 times or more and 5 times or less, so that the heat fusion layers 3 particularly in the case of forming a coil. Adhesion between the self-bonding insulated wires by fusion is easy and reliable, the distance between the metal conductors 1 is not reduced at the time of fusion, and constant holes can be formed between the metal conductors 1. .

  Therefore, the coil electric wire formed by subjecting the self-bonding insulated wire to the wire-bonding process and expanding the heat-bonding layer 3 has a high reliability of heat-bonding between the heat-bonding layers 3 and a metal conductor. The insulation between 1 is high.

  In addition, the winding bundle formed by winding and bundling a plurality of the self-bonding insulated wires, for example, firmly fixes the winding bundles together, and connects the winding bundle and its support and surrounding components. It can be firmly fixed. As a result, the self-bonding insulated wires can be reliably fused and mechanical strength and electrical insulation can be improved.

[Other Embodiments]
The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is not limited to the configuration of the above-described embodiment, but is defined by the scope of the claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of the claims. The

  For example, in the self-bonding insulated wire, a further layer such as a primer treatment layer may be provided between the metal conductor and the insulating layer or between the insulating layer and the heat-sealing layer.

(Primer treatment layer)
A primer process layer is a layer provided in order to improve the adhesiveness between layers, for example, can be formed with a well-known resin composition.

  When providing the primer treatment layer between the metal conductor and the insulating layer, the resin composition forming the primer treatment layer is, for example, one or more kinds of resins among polyimide, polyamideimide, polyesterimide, polyester and phenoxy resin. It is good to include. Moreover, the resin composition forming the primer treatment layer may contain an additive such as an adhesion improver. By forming a primer treatment layer between the metal conductor and the insulating layer with such a resin composition, it is possible to improve the adhesion between the metal conductor and the insulating layer. Characteristics such as flexibility, wear resistance, scratch resistance, and workability of the fusible insulated wire can be effectively enhanced.

  Moreover, the resin composition which forms a primer process layer may contain other resin, for example, an epoxy resin, a phenoxy resin, a melamine resin, etc. with the said resin.

  Moreover, you may use a commercially available liquid composition (insulation varnish) as each resin contained in the resin composition which forms a primer process layer.

  As a minimum of the average thickness of a primer processing layer, 1 micrometer is preferable and 2 micrometers is more preferable. On the other hand, the upper limit of the average thickness of the primer treatment layer is preferably 20 μm, and more preferably 10 μm. When the average thickness of the primer treatment layer is less than the lower limit, there is a possibility that sufficient adhesion with the metal conductor cannot be exhibited. Conversely, when the average thickness of the primer-treated layer exceeds the above upper limit, the self-bonding insulated wire may be unnecessarily enlarged.

  Moreover, also when providing a primer processing layer between an insulating layer and a heat sealing | fusion layer, based on a well-known technique, the resin composition which has high adhesiveness with respect to an insulating layer and a heat sealing | fusion layer is selected.

  Moreover, the manufacturing method of the self-bonding insulated wire is not limited to the above-described method. For example, when the main component of the insulating layer is a thermoplastic resin, a method of diluting with a solvent and drying as in the above-described method of laminating the heat-fusible layer, or applying a molten resin composition with an application die A method of cooling and curing can be applied. Moreover, you may laminate | stack an insulating layer and a heat sealing | fusion layer by other methods, such as spray coating.

  In addition to forming a coil, the self-bonding insulated wire can also be used for other applications in which a plurality of insulated wires are arranged in parallel.

  EXAMPLES Hereinafter, although this invention is explained in full detail based on an Example, this invention is not interpreted limitedly based on description of this Example.

<Self-fusing insulated wire No. 1-8>
By laminating an insulating layer having an average thickness of 40 μm and a heat-sealing layer having an average thickness of 40 μm in this order on a copper wire having a diameter of 1.0 mm, the self-bonding insulated wire No. 1 to 8 were prototyped. The insulating layer and the heat-sealing layer were each coated with a resin composition having the composition shown in Table 1 using a coating die, and a furnace temperature of 200 ° C. and a linear velocity of 4.8 m / min using a horizontal furnace with a furnace length of 3 m. The product was dried (baked) under the following conditions.

(Insulating layer forming resin composition)
As the resin composition for forming an insulating layer, a varnish mainly composed of polyesterimide, a varnish mainly composed of polyamideimide, a varnish mainly composed of polyimide or a varnish mainly composed of polyetheretherketone was used.

(Composition for forming a heat-fusible layer)
As a resin component of the matrix of the composition for forming a heat-fusible layer, a polyhydroxy polyether (phenoxy resin) having a glass transition temperature of 130 ° C. (“YPS-007A30” manufactured by Nippon Steel & Sumikin Co., Ltd.), polyamideimide, polyesterimide, or heat resistance Polyurethane was used. A novolac type epoxy resin (“YDCN-704” manufactured by Nippon Steel & Sumikin Co., Ltd.) or polyisocyanate (“MILLIONATE MS-50” manufactured by Nippon Polyurethane Industry Co., Ltd.) was used as a curing agent for the matrix of the composition for forming the heat-fusible layer. In addition, as a foaming agent for the composition for forming the heat-fusible layer, a chemical foaming agent having a foaming start temperature of 190 ° C. (“Vinhole AC # 3C-K2” from Eiwa Kasei Kogyo Co., Ltd.) An expandable microcapsule (“EM501” from Sekisui Chemical Co., Ltd.) was used.

(Temperature dependence of matrix modulus)
Self-bonding insulated wire No. Regarding the matrices 1 to 8, a dried and solidified matrix was prepared separately without containing a foaming agent, and the temperature at which the modulus of elasticity was 1 kPa was measured by gradually increasing the temperature. No. In the matrix of 1-4, it is 137 degreeC, self-fusing insulated wire No. In the case of the matrix 5, the self-bonding insulated wire No. In the matrix of No. 6, 181 ° C., self-bonding insulated wire No. 7 matrix, 143 ° C., self-bonding insulated wire No. In the matrix of 8, it was 241 ° C. The “temperature at which the elastic modulus becomes 1 kPa” was measured using a viscoelasticity measuring apparatus manufactured by UBM.

(Evaluation of flexibility and insulation)
Self-bonding insulated wire No. About 1-8, the flexibility and insulation before expanding a heat sealing | fusion layer by heating were confirmed, what was favorable was set to "A", and what was unsatisfactory was set to "B." The flexibility was determined to be good if there were no cracks or lifts by winding 30 turns of the winding with self-diameter winding after 20% elongation and checking for cracks and lifts. Insulation, the dielectric breakdown voltage is measured according to JIS-C3003-5 (2011), an alternating voltage is applied between the two twisted wires, the voltage is increased at 500 V / second, and the voltage when the dielectric breakdown occurs is measured. A material having a dielectric breakdown voltage exceeding the standard value was considered good. As a result, as shown in Table 1, the self-bonding insulated wire No. All of 1 to 8 were good in both flexibility and insulation.

(Average thickness expansion coefficient of heat-sealing layer)
Self-bonding insulated wire No. Before and after expanding the heat fusion layer by heating 1 to 8, the average thickness of the heat fusion layer was measured, and the average thickness expansion coefficient was calculated. Specifically, the thermal foam layer of the self-bonding insulated wire is expanded by heating in a 180 ° C hot air circulating thermostat for 2 hours, and the wire diameter before and after expansion is measured with a micrometer. As a result, the average thickness expansion coefficient of the heat-fusible layer was calculated. As shown in Table 1, self-bonding insulated wire No. Although the heat-sealable layers Nos. 1 to 7 expanded moderately, the self-fusing insulated wire No. 8 did not swell at all. This is because the self-bonding insulated electric wire No. It is considered that the temperature at which the elastic modulus of the matrix of the heat-sealing layer No. 8 rises to 1 kPa or higher is higher than the expansion start temperature of the foaming agent.

(Average hole diameter)
Self-bonding insulated wire No. after heating About 1-8, the average diameter of the void | hole formed in the heat sealing | fusion layer was measured. In addition, the measurement of the average diameter of this void | hole measured the cross section of the heat-fusion layer using the "porous material automatic pore diameter distribution measurement system" of Porus Materials. As shown in Table 1, self-bonding insulated wire No. The average diameter of the holes formed in the heat-sealing layers 1 to 7 was in the range of 100 μm to 130 μm. On the other hand, as described above, the self-bonding insulated wire No. 1 which could not be expanded by heating was used. In No. 8, since no holes were formed, the average diameter of the holes could not be measured.

(Porosity)
In addition, the self-bonding insulated wire No. About 1-8, the porosity of the heat sealing | fusion layer was computed based on the measured value of the average thickness before and behind the said expansion | swelling. As shown in Table 1, self-bonding insulated wire No. The porosity of the heat-sealed layer after expansion of 1 to 7 was in the range of 65% to 76%. On the other hand, as described above, the self-bonding insulated wire No. 1 which could not be expanded by heating was used. No. 8 has no voids, so the porosity is 0%.

(Fixing force)
Self-bonding insulated wire No. An air core helical coil is manufactured by attaching 1 to 8 to a stainless steel rod having a diameter of 6.4 mm, and the air core helical coil is subjected to a compressive force of 400 gf in the axial direction for 20 minutes at the decomposition temperature of the blowing agent used. After the heat treatment, a three-point bending test based on JIS-K7171 (2008) is performed at a temperature of 180 ° C., the bending stress of the air-core coil is measured, and this is used as an index of the adhesion strength between the self-bonding insulated wires. did. As shown in Table 1, self-bonding insulated wire No. 1 to 8 all had a sufficient fixing force.

  No. The matrix resin of the sample No. 8 has a high temperature of 241 ° C. at which the elastic modulus becomes 1 kPa or higher, and the elastic modulus near the foaming temperature (180 ° C.) is estimated to be lower than 1 kPa. Therefore, although the decomposition reaction of the foaming agent occurs, the matrix resin tends to flow, so that bubbles are removed from the surface of the resin, and it seems that voids cannot be formed in the fusion layer.

  The self-bonding insulated electric wire according to the present invention can be suitably used for forming a coil, a motor or the like.

DESCRIPTION OF SYMBOLS 1 Metal conductor 2 Insulating layer 3 Heat-fusion layer 4 Matrix 5 Foaming agent (thermal expansion microcapsule)

Claims (7)

A self-bonding insulated electric wire comprising a linear metal conductor, an insulating layer laminated on the outer peripheral surface side of the metal conductor, and a thermal fusion layer laminated on the outer peripheral surface side of the insulating layer and expanded by heating. Because
The thermal fusion layer has a matrix mainly composed of a synthetic resin, and a chemical foaming agent or a thermally expandable microcapsule dispersed in the matrix.
A self-bonding insulated electric wire having an average thickness expansion coefficient after heating of the heat-fusible layer of 1.1 to 5 times.   2. The self-bonding insulated wire according to claim 1, wherein an elastic modulus of a matrix of the heat-fusible layer at a foaming start temperature of the chemical foaming agent or the thermally expandable microcapsule is 1 kPa or more.   The self-fusible insulated wire according to claim 1 or 2, wherein the content of the chemical foaming agent or the thermally expandable microcapsule in the heat-fusible layer is 1% by mass or more and 15% by mass or less.   The self-bonding property according to claim 1, 2 or 3, wherein an average diameter of pores formed in the heat-bonding layer by foaming of the chemical foaming agent or the thermally expandable microcapsule is 300 µm or less. Insulated wire.   The self-bonding insulated wire according to claim 1, 2 or 3, wherein the porosity of the heat-sealing layer after heating is 10% or more and 80% or less.   A coil wire formed by subjecting the self-bonding insulated wire according to any one of claims 1 to 5 to a winding process and expanding a heat-sealing layer.   A winding bundle formed by winding and bundling the plurality of self-bonding insulated wires according to any one of claims 1 to 5.

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