JP2016035836A - Self-fusion insulated wire and wire for coil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a self-fusion insulated wire that facilitates fastening between wires and prevents dust emission.SOLUTION: A self-fusion insulated wire comprises a linear metal conductor, an insulating layer put on the peripheral surface side of the metal conductor, an expansion layer that is put on the peripheral surface side of the insulating layer and expands by heating, and a thermal fusion layer put on the peripheral surface side of the expansion layer. The expansion layer preferably comprises a matrix predominantly composed of synthetic resin, and chemical foaming agents or thermally expandable microcapsules dispersed in the matrix. It is preferable that an average thickness expansion rate of the expansion layer after heating is 1.1 times or more and 5 times or less. It is preferable that a porosity of the expansion layer after heating is 10% or more and 80% or less. It is preferable that an average thickness of the expansion layer is 5 μm or more and 200 μm or less.SELECTED DRAWING: Figure 1

Description

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

  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 the 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

  The self-bonding insulated wire disclosed in the above publication can be expanded by foaming of the heat-sealing layer to increase the contact pressure between the heat-sealing layers. Since the contact area between the heat-sealing layers is reduced, the fusing property may not be sufficiently improved. In the self-bonding insulated wire disclosed in the above publication, the foaming agent may be detached from the heat-sealing layer, or a part of the heat-sealing layer may become brittle due to foaming.

  The present invention has been made on the basis of the circumstances as described above. The self-bonding insulated wire and the bonding reliability between the wires are easy to bond between the wires and the fusion layer has sufficient strength. It is an object of the present invention to provide a coil electric wire that is highly resistant to dust generation.

  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. An expansion layer that is laminated on the outer peripheral surface side and expands by heating, and a heat fusion layer that is laminated on the outer peripheral surface side of the expansion layer are provided.

  The self-bonding insulated wire and the coil wire according to one embodiment of the present invention are easy to fix between the wires, and the fusion layer has sufficient strength.

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. An expansion layer that expands, and a thermal fusion layer that is laminated on the outer peripheral surface side of the expansion layer.

  The self-bonding insulated electric wire has a heat-sealing layer laminated on the outer peripheral surface side of the expansion layer, so that it does not contain a component that contributes to expansion of a foaming agent or the like but can inhibit fusion. By fusing each other, high fusion properties are exhibited and the electric wires are easily fixed, and the heat fusion layer seals the expansion layer to prevent dust generation.

  The expansion layer may have a matrix mainly composed of a synthetic resin and a chemical foaming agent or thermally expandable microcapsules dispersed in the matrix. In this way, the expansion rate can be increased by the chemical expansion agent or the thermally expandable microcapsules dispersed in the matrix. As a result, the heat-sealing layers can be more strongly bonded to each other, and adhesion between the wires and between the wires and the core can be more reliably performed.

  The average thickness expansion coefficient after heating of the expansion layer is preferably 1.1 to 5 times. As described above, when the expansion coefficient of the expansion layer is within the above range, the adjacent heat-sealing layers can be more securely pressed and fused together, and tearing of the heat-sealing layer can be prevented.

  The porosity of the expanded layer after heating is preferably 10% or more and 80% or less. As described above, by setting the porosity after heating the expansion layer within the above range, the expansion layer can be expanded more uniformly while ensuring the constant expansion rate and ensuring the continuity of the matrix of the expansion layer. The heat fusion layer can be surely fused.

  The average thickness of the heat sealing layer is preferably 5 μm or more and 200 μm or less. As described above, by setting the average thickness of the heat-sealing layer within the above range, it is possible to ensure the fusion property and prevent an unnecessary increase in thickness (increase in diameter).

  The coil wire according to one embodiment of the present invention is formed by expanding the expansion layer after the self-bonding insulated wire is coiled by coiling.

  Since the heat-sealing layer of the self-bonding insulated wire is fused with each other by expanding the expansion layer after the coiled wire is coiled and coiled in this way, the wire for the coil is between the wires and between the wire and the core. High reliability of fixing.

  Here, the “average thickness expansion coefficient” means the ratio of the average thickness of the expanded layer after expansion by heating to the average thickness of the expanded layer before heating. The “porosity” of the expansion layer is the percentage of the volume of the void (gas) in the expansion layer with respect to the apparent volume of the expansion layer, and the mass contained in the matrix of the expansion layer and the outer shell of the thermally expandable microcapsule This is an amount calculated by (V1−V0) / V1 × 100, where V0 is the actual volume calculated from the density and V1, and V1 is the volume including the voids of the expanded layer.

[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. The expansion layer 3 which expand | swells and the heat sealing | fusion layer 4 laminated | stacked on the outer peripheral surface side of this expansion layer 3 are provided.

<Metal conductor>
The metal conductor 1 is, for example, a round wire having a circular cross section, but may be a rectangular wire having a square or rectangular 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 expansion 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 may be reduced. There is. 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 Mainly thermosetting resins such as thermosetting polyamideimide and thermosetting polyimide, and thermoplastic resins such as thermoplastic polyimide, polyphenylsulfone, polyphenylene sulfide, polyetherimide, polyetheretherketone and polyethersulfone. What is used as a component can be used. The insulating resin layer 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 (in the case of a thermoplastic resin having a melting point, the melting point) is higher than the glass transition temperature of the matrix 5 of the expansion layer 3 and the thermal fusion layer 4 described later.

  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.

<Expanded layer>
The expansion layer 3 includes a matrix 5 mainly composed of a synthetic resin and a foaming agent 6 dispersed in the matrix 5.

  The expansion layer 3 expands as a whole when the foaming agent 6 expands by heating.

  As a minimum of average thickness before heating of expansion 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 expansion layer 3 is preferably 1.1 times and more preferably 2 times. On the other hand, the upper limit of the average thickness expansion coefficient after heating of the expansion layer 3 is 5 times, and preferably 4 times. When the average thickness expansion coefficient after heating of the expansion layer 3 is less than the lower limit, when the self-bonding insulated wire is subjected to a winding process, the adjacent heat-bonding layers 4 are not sufficiently bonded to each other. There is a risk. On the contrary, when the average thickness expansion coefficient after heating of the expansion layer 3 exceeds the above upper limit, the density of the expansion layer 3 may be insufficient, and the strength of the self-bonding insulated wire may be insufficient. There is. The expansion rate of the expansion layer 3 can be controlled by selecting the type and amount of the foaming agent 6 and the glass transition temperature (Tg) of the matrix 5.

  As a minimum of the porosity after heating of expansion layer 3, 10% is preferred and 50% is more preferred. On the other hand, the upper limit of the porosity after heating of the expansion layer 3 is preferably 80% and more preferably 70%. When the porosity of the expanded layer 3 after heating is less than the lower limit, the contact pressure between the adjacent heat-sealing layers 4 may be insufficient, resulting in insufficient fusion. On the contrary, when the porosity after heating of the expansion layer 3 exceeds the upper limit, the strength of the expansion layer 3 after expansion may be insufficient.

(matrix)
The matrix 5 of the expansion layer 3 is composed of a resin composition that exhibits fluidity at the decomposition temperature of the foaming agent 6. That is, the glass transition temperature of the resin composition constituting the matrix 5 is close to the decomposition temperature of the foaming agent 6 and is, for example, 50 ° C. or higher and 250 ° C. or lower. Thus, when the matrix 5 is a resin exhibiting fluidity in the foaming temperature region of the foaming agent 6, the expansion of the expansion layer 3 can be made uniform and the expansion coefficient can be easily controlled to a desired value. The “expansion start temperature of the expansion layer” refers to a temperature at which the apparent volume of the expansion layer is 1.05 times that before expansion (normal temperature: 25 ° C.). The “decomposition temperature” of the foaming agent 6 is a temperature at which generation of gas from the foaming agent 6 is confirmed or a temperature at which the volume of the foaming agent 6 is 1.05 times that before expansion (normal temperature: 25 ° C.). Say.

  As a main component of the resin composition constituting the matrix 5, 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, even if it is a thermosetting resin, it can be used as a main component of the resin composition which comprises the matrix 5 by adjusting hardening conditions and making it a semi-hardened state. Or even if it is a thermosetting resin, if it shows fluidity | liquidity in the foaming temperature area | region of the foaming agent 6 by controlling the hardening state of a thermosetting resin, it can be used. Moreover, the resin composition which comprises the matrix 5 may contain additives, such as an adhesion improving agent.

  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 resin include various copolymerized polyamides, 6-nylon, 6,6-nylon, and 6,10-nylon.

  Examples of the butyral resin include polyvinyl butyral.

  Other thermoplastic resins that can be used as the main component of the resin composition constituting the matrix 5 include, for example, copolyester, 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 6, a chemical foaming agent or a physical foaming agent can be used.

<Chemical foaming agent>
The chemical foaming agent used as the foaming agent 6 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 content of a chemical foaming agent to content rate in expansion layer 3 of matrix 5, 0.1 mass% is preferred and 1 mass% is more preferred. On the other hand, as an upper limit of content of the said chemical foaming agent, 35 mass% is preferable and 20 mass% is more preferable. When content of the said chemical foaming agent is less than the said minimum, there exists a possibility that the expansion coefficient of the expansion layer 3 may become inadequate. On the contrary, when the content of the chemical foaming agent exceeds the upper limit, the mechanical strength of the expansion layer 3 may be insufficient.

  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 expansion layer 3 may contain 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. Other chemicals include phthalic anhydride, salicylic acid, benzoic acid, antimony trioxide, white petrolatum, titanium oxide, cadmium oxide, borax, glycerin, dibutyltin dimaleate and the like. 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 expansion layer 3 may expand unintentionally during the production or storage of the self-bonding insulated wire.

<Physical foaming agent>
Examples of the physical foaming agent used as the foaming agent 6 include thermally expandable microcapsules and microballoons. The thermally expandable microcapsule has a core material (inner package) made of an internal foaming agent and an outer shell that encloses the core material, and the outer shell expands due to the expansion of the core material. On the other hand, the microballoon seals pressurized gas in the outer shell, and the outer shell is thermally decomposed by heating to release the gas.

  Especially, as a physical foaming agent used as the foaming agent 6, the thermal expansion microcapsule which can promote the comparatively uniform expansion | swelling of the expansion layer 3 by forming a closed cell is preferable.

  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 decomposition temperature of the internal foaming agent of the thermally expandable microcapsule, that is, the boiling point of the low boiling liquid or the thermal decomposition temperature of the chemical foaming agent is 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 decomposition 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 decomposition temperature of the internal foaming agent of the thermally expandable microcapsule is preferably 250 ° C., more preferably 200 ° C. If the decomposition temperature of the internal foaming agent of the thermally expandable microcapsule is less than the above lower limit, the thermally expandable microcapsule may expand unintentionally during the production of the self-bonding insulated wire, during transportation or storage. is there. Conversely, when the decomposition 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, and the thermal expandable microcapsule is There is a possibility that the energy cost required for the expansion is 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 expands and can 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 50 μm, and more preferably 40 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. Conversely, when the average diameter of the thermally expandable microcapsules before heating exceeds the above upper limit, the expansion layer 3 may be unnecessarily thick or the expansion of the expansion layer 3 may be nonuniform. 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.

  As a minimum of the content rate in the expansion layer 3 of a thermally expansible microcapsule, 0.5 mass% is preferable with respect to the resin component of the matrix 5 of an expansion layer, and 1 mass% is more preferable. On the other hand, as an upper limit of the content rate in the expansion layer 3 of a thermally expansible microcapsule, 10 mass% is preferable and 6 mass% is more preferable. When the content rate in the expansion layer 3 of a thermally expansible microcapsule is less than the said minimum, the expansion rate of the expansion layer 3 is small, and there exists a possibility that the adhering between the said self-fusing insulated wires may become inadequate. On the other hand, when the content of the thermally expandable microcapsule in the expanded layer 3 exceeds the upper limit, the matrix 5 is relatively decreased, which may result in insufficient strength and fusibility of the expanded layer 3. .

  The lower limit of the ratio of the average diameter of the thermally expandable microcapsule to the average thickness of the expansion layer 3 is preferably 1/16 and more preferably 1/8. On the other hand, the upper limit of the ratio of the average diameter of the thermally expandable microcapsule to the average thickness of the expansion 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 5 and the expandable layer 3 may not be sufficiently expanded. There is a possibility that it cannot expand uniformly.

  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 thermally expandable microcapsule is less than the lower limit, the expansion coefficient of the expansion layer 3 may be insufficient. On the contrary, when the expansion coefficient of the thermally expandable microcapsule exceeds the above upper limit, the matrix 5 of the expanded layer 3 cannot follow the thermally expandable microcapsule, and the expanded layer 3 may not be expanded as a whole. There is. 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.

<Heat-fusion layer>
The heat-sealing layer 4 is composed of a resin composition that exhibits fluidity and fusibility at the expandable temperature of the expansion layer 3. As the main component of the resin composition constituting the heat fusion layer 4, the same resin as the matrix 5 of the expansion layer 3 can be used.

  The lower limit of the average thickness of the heat fusion layer 4 is preferably 5 μm, and more preferably 10 μm. On the other hand, the upper limit of the average thickness of the heat fusion layer 4 is preferably 200 μm, and more preferably 150 μm. When the average thickness of the heat-fusible layer 4 is less than the above lower limit, there is a possibility that the adhesion between the self-bonding insulated wires is insufficient. On the contrary, when the average thickness of the heat-fusible layer 4 exceeds the above upper limit, the diameter of the self-bonding insulated wire becomes unnecessarily large, and a coil formed using the self-bonding insulated wire, etc. There is a risk that the volumetric efficiency of the resin becomes low.

[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. A step of curing the applied thermosetting resin composition for forming an insulating layer, and an expansion in which a foaming agent 6 is dispersed in a matrix 5 diluted with a solvent on the outer peripheral surface side of the thermosetting resin composition for forming an insulating layer. The step of applying the layer forming composition, the step of volatilizing the solvent and drying the composition for forming the expansion layer, and the formation of the heat-fusible layer diluted with the solvent on the outer peripheral surface side of the dried composition for forming the expansion layer Can be produced by a method comprising: a step of applying the composition for heating, and a step of evaporating the solvent and drying the composition for forming the 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, the liquid composition adheres to the outer peripheral surface of the conductor as the conductor passes through the liquid composition tank, and then passes through the coating die so that the liquid composition has a substantially uniform thickness. To be applied. 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 for example, a cylindrical baking furnace that is long in the running direction of the conductor 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 and the number of repetitions of the coating die are appropriately adjusted according to the conductor diameter and the target coating film thickness of the insulating layer.

<Expansion layer forming composition application step>
In the expansion layer forming composition application step, the expansion layer forming composition in which the foaming agent 6 is dispersed in a solution obtained by diluting the resin composition constituting the matrix 5 with a solvent is applied to the outer peripheral surface side of the insulating layer 2. . As a coating method, it can be made to be the same as that of the said thermosetting resin composition application | coating process for insulating layer formation.

<Drying step of the composition for forming the expansion layer>
In the step of drying the expansion layer forming composition, the expansion layer 3 is formed by drying the expansion layer forming composition by volatilizing the solvent at a temperature lower than the decomposition temperature of the foaming agent 6. 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.

<The process of applying a composition for forming a heat-fusible layer>
In the heat sealing layer forming composition application step, the heat sealing layer forming composition obtained by diluting the resin composition constituting the heat sealing layer 4 with a solvent is applied to the outer peripheral surface side of the expansion layer 3. As a coating method, the same method as the thermosetting resin composition application process for insulating layer formation and the composition application process for expansion layer formation can be used.

<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 to evaporate the solvent at a temperature lower than the decomposition temperature of the foaming agent 6 to form the heat-sealable layer 4. To do. 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 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 expansion layer 3.

  As a heating method for expanding the expansion layer 3, for example, a method using heat generated by energization of the metal conductor 1 can be applied in addition to a conventionally known method such as hot air heating, infrared heating, and high frequency heating. it can.

[advantage]
Since the self-bonding insulated electric wire includes the heat-sealing layer 4 laminated on the outer peripheral surface side of the expansion layer 3, the heat-bonding layers 4 or the heat-fusion layer 4 It can be fused by crimping between the cores. Since the heat-fusible layer 4 does not contain a foaming agent, it has sufficient strength and can easily and reliably adhere between the wires and between the wires and the core.

  Moreover, since the said self-bonding insulated wire has covered the expansion layer 3 with the heat sealing | fusion layer 4, falling of the foaming agent etc. of the expansion layer 3 can be prevented and dust generation can be suppressed.

  Therefore, the coil electric wire formed by subjecting the self-bonding insulated wire to a winding process and expanding the expansion layer 3 can be easily fused between the thermal fusion layer 4 and between the thermal fusion layer 4 and the core. And it is reliable and the reliability of the adhesion between the wires and between the wires and the core is high.

[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, an additional layer such as a primer treatment layer is provided between the metal conductor and the insulating layer, between the insulating layer and the expansion layer, or between the expansion layer and the heat fusion layer. May be.

(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. Properties 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.

  In addition, when providing a primer treatment layer between the insulating layer and the expansion layer or between the expansion layer and the heat-sealing layer, a resin composition having high adhesion to each layer is selected based on a known technique. Is done. In addition, as a method for improving the adhesion between the expansion layer and the heat-sealing layer, the main resin of the heat-fusion layer and the main component of the matrix of the expansion layer are made of the same resin rather than providing a primer treatment layer. It is preferable.

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

  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. 1-18>
Self-fusing insulation is obtained by laminating an insulating layer with an average thickness of 40 μm, an expansion layer with an average thickness of 15 μm, and a thermal fusion layer with an average thickness of 12.5 μm in this order on a copper wire with a diameter of 1.0 mm. Electric wire No. 1 to 18 were prototyped. The insulating layer, the expansion layer, and the heat fusion layer were each coated with a resin composition having the composition shown in Tables 1 and 2 using a coating die, and dried (baked) using a horizontal furnace having a furnace length of 3 m. In addition, the drying temperature of the expansion layer and the heat-sealing layer was set to a temperature at which the foaming agent of the expansion layer can be maintained below the decomposition temperature.

(Insulating layer forming resin composition)
Any of the resins A1 to A7 was used as the insulating layer forming resin. Resin A1 is a varnish (manufactured by Dainichi Seika Kogyo Co., Ltd.) whose main component is polyesterimide, resin A2 is a varnish whose main component is polyamideimide, resin A3 is a varnish whose main component is polyimide, and resin A4 is a varnish whose main component is polyetherketone, resin A5 is a varnish whose main component is polyphenylene sulfide, resin A6 is a varnish whose main component is polyphenylenesulfone, and resin A7 is a polyetherimide. Is a varnish mainly composed of

(Expansion layer forming resin composition)
As the resin composition for forming an intumescent layer, any one of the resins B1 to B3, any one of the foaming agents 1 to 7, and a curing agent are blended, and the solid content is 25% by mass in the solvent “Hisolv DM” of Toho Chemical Industry Co., Ltd. What was melt | dissolved so that it might become was used. Resin B1 is Nippon Steel & Sumitomo Metal's phenoxy resin “YPS-007A30”, Resin B2 is a butyral resin “Denka Butyral # 3000” manufactured by Denki Kagaku Kogyo Co., Ltd. -251 ". Further, the foaming agent B1 is a chemical foaming agent “Neocerbon N # 1000M” (decomposition temperature: 160 ° C.) manufactured by Eiwa Kasei Kogyo Co., Ltd., and the foaming agent B2 is a chemical foaming agent “Vinihole AC # 3C-K2” manufactured by Eiwa Kasei Kogyo Co., Ltd. (Decomposition temperature: 200 ° C.), foaming agent B3 is Matsumoto Yushi Seiyaku's thermally expandable microcapsule “Matsumoto Microsphere FN-100SD” (decomposition temperature: 130 ° C.), and blowing agent B4 is Matsumoto Yushi Seiyaku. Thermally expandable microcapsule “Matsumoto Microsphere FN-180SD” (decomposition temperature: 150 ° C.), and foaming agent B5 is Matsumoto Yushi Seiyaku's thermally expandable microcapsule “Matsumoto Microsphere FN-260D” ( Decomposition temperature: 195 ° C.), and the foaming agent B6 is a thermally expandable microcapsule “Expancel 920DU” manufactured by Nippon Philite Co., Ltd. 0 "(decomposition temperature: 128 ° C.) a and, blowing agents B7 Sekisui Chemical Co. of the thermally expandable microcapsule" ADVANCELL EM501 "(decomposition temperature: 170 ° C.) is. The curing agent is polyisocyanate “MILLIONATE MS-50” manufactured by Nippon Polyurethane Industry.

(Resin composition for forming a heat-fusible layer)
As the resin composition for forming a heat-fusible layer, a resin C and a curing agent were blended and dissolved in a solvent “Hisolv DM” manufactured by Toho Chemical Industry Co., Ltd. so as to have a solid content of 25% by mass. Resin C is a phenoxy resin “YPS-007A30” manufactured by Nippon Steel & Sumikin Co., Ltd., and a curing agent is a polyisocyanate “MILLIONATE MS-50” manufactured by Nippon Polyurethane Industry.

<Evaluation>
The self-bonding insulated wire No. obtained as described above was obtained. About 1-18, the flexibility and insulation before expansion | swelling of an expansion layer, the expansion rate of an expansion layer, and the adhering force after expansion | swelling of an expansion layer were evaluated. The evaluation results are shown in Tables 1 and 2.

(Flexibility)
After pre-stretching the self-bonding insulated wire by 10%, it is attached to a rod-shaped body having a diameter three times that of copper wire (diameter 3 mm) to produce an air-core helical coil, and the film cracks in 30 turns (thermal fusion layer) The presence or absence of occurrence of cracks was visually confirmed, and “A” indicates that no crack was found, and “B” indicates that the crack was found.

(Insulation)
According to JIS-C3003, the dielectric breakdown voltage of the electric wire produced by the two-strand method was measured. Twist the length of the test piece 12cm more than the specified number of times, apply an AC voltage between the wires, increase the voltage at 500V / sec, determine the voltage when it breaks, “B” was less than the specified voltage.

(Expansion rate)
Similar to the evaluation of flexibility, a helical coil was prepared, cut at 20 ° C. for 20 minutes and cut at 20 ° C., and the self-fusing insulated wire cross section was observed with an optical microscope. Then, the thickness of the expanded layer was measured at a plurality of locations and averaged, and the expansion coefficient was calculated by the following formula.
Expansion rate = (average thickness of heat-treated expansion layer) / (average thickness of unheated expansion layer)

(Fixing force)
A self-bonding insulated wire is attached to a stainless steel rod having a diameter of 6.4 mm to produce an air-core helical coil, and the decomposition temperature of the foaming agent used while applying a compressive force of 400 gf in the axial direction to the air-core helical coil. Then, a three-point bending test based on JIS-K7171 (2008) was performed to measure the bending stress of the air-core coil.

  Self-bonding insulated wire No. 1-18 had sufficient insulation before expansion | swelling of an expansion layer, and had sufficient adhering force after expansion | swelling of an expansion layer. Among them, self-bonding insulated wire No. Nos. 1 to 18 had good flexibility before expansion of the expansion 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 Expansion layer 4 Heat-fusion layer 5 Matrix 6 Foaming agent

Claims (6)

  A linear metal conductor, an insulating layer stacked on the outer peripheral surface side of the metal conductor, an expanded layer stacked on the outer peripheral surface side of the insulating layer and expanded by heating, and stacked on the outer peripheral surface side of the expanded layer A self-bonding insulated wire comprising a heat-sealable layer.   The self-bonding insulated wire according to claim 1, wherein the expansion layer has a matrix mainly composed of a synthetic resin, and a chemical foaming agent or a thermally expandable microcapsule dispersed in the matrix.   The self-bonding insulated electric wire according to claim 1 or 2, wherein an average thickness expansion coefficient after heating of the expansion layer is 1.1 to 5 times.   The self-bonding insulated wire according to any one of claims 1 to 3, wherein a porosity of the expanded layer after heating is 10% or more and 80% or less.   The self-fusible insulated wire according to any one of claims 1 to 4, wherein an average thickness of the heat-sealing layer is 5 µm or more and 200 µm 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 an expansion layer.

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