JP2012109061A - Coil wire and induction heating coil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coil wire for induction heating and an induction heating coil, which can be steadily held in a coil holding member and is capable of remaining in a coil shape in high temperature environment at around 200°C.SOLUTION: A coil wire for induction heating is composed of an insulation layer formed on a conductor wire by extrusion coating and a fusion layer formed on the insulation layer by extrusion coating. The insulation layer is formed of fluorine resin and the fusion layer is formed of a composition of polyphenylene sulfide resin and an elastomer component. The melting point of the fluorine resin forming the insulation layer is higher than that of the composition forming the fusion layer. The coil wire is given adhesion treatment on the outer surface of the insulation layer by discharge treatment. The coil wire, in a state of being wound spirally or cylindrically, has the fusion layer melt-solidified and the coil wire is fusion-integrated reciprocally.

Description

The present invention relates to a coil wire for induction heating and a coil for induction heating that can be suitably used as, for example, a coil for a heating cooker or the like using an electromagnetic induction heating method.

  In recent years, heating cookers using an electromagnetic induction heating method have become widespread in ordinary households. As such a coil wire for an induction heating cooker, for example, a plurality of conductor wires on which an insulating film is formed are bundled to form an assembly wire, and the assembly wire is twisted to form a conductor wire, and an insulating layer is formed on the conductor wire. It is known that various fusion layers are formed on this insulating layer. As the insulating layer, it is necessary to have excellent heat resistance that can withstand a high temperature environment such as a cooking device, and therefore, a fluororesin is mainly used. Moreover, in recent induction heating cookers for home use, a high frequency of 40 to 100 kHz is passed through the coil wire in order to cope with copper pans and aluminum pans with low permeability, and thus corona resistance is required. From this point, a fluororesin having a low dielectric constant is preferably used. Such a coil wire is wound in a spiral shape to form a high-power coil. At this time, in order to stabilize the shape of the coil, the fused layer is melted and solidified to be integrated with each other. (See, for example, Patent Documents 1 to 4).

Japanese Patent No. 3601533: Matsushita Electric Industrial Co., Ltd. Japanese Patent No. 4096712: Matsushita Electric Industrial Co., Ltd. JP 2000-58251 A: Crabe JP 2010-135157 A: Hitachi AP

  Due to the recent demand for higher output, it is necessary to improve the heating efficiency of the coil, and as the amount of heat generation increases, it is also necessary to improve the heat resistance of the coil. Here, the coil wires according to Patent Documents 1 and 2 are made of a fluororesin whose fusion layer has a low melting point. The coil is installed in a heating cooker or the like after being held by the coil holding member. However, since the fluororesin is a material that is difficult to adhere, in the case of the coil wire according to Patent Documents 1 and 2, the coil is held by an adhesive. It cannot be held on the member. Therefore, although it hold | maintains at a coil holding member by a fixing member and screwing etc., work efficiency will deteriorate while the number of parts increases. In addition, if the coil and the coil holding member are not completely fixed due to variations in work when the coil is held by the coil holding member, the coil will be misaligned, resulting in deterioration of heating efficiency and noise due to vibration. It will be. In the coil wire according to Patent Document 3, the fusion layer is made of any of a polyester elastomer, a polyamide resin, and a polyurethane resin. As described above, the amount of heat generation has increased due to the recent increase in output, and the coil wire is also exposed to a high temperature of about 200 ° C. Since all of the above materials have a melting point of 200 ° C. or lower, when applied to a heating cooker with high output, the fused layer is melted during heating. Thereby, while the shape of the coil wound by the spiral shape will collapse | crumble, the melted heat-fusion layer will flow and will contaminate the inside or periphery of a heating cooker. Further, the coil wire according to Patent Document 4 is configured by winding a tape of a polyphenylene sulfide resin (hereinafter sometimes referred to as a PPS resin) as a fusion layer. In the case of such tape winding, a step or a gap (interval where no tape is present) is inevitably generated, so that a portion that cannot be fused is generated, and the fusion cannot be firmly integrated. Thereby, the shape of the coil wound in a spiral shape collapses, and the heating efficiency may deteriorate. It is also empirically clear that in the case of tape winding, peeling due to thermal deterioration and peeling during assembly processing are likely to occur. In addition, although it is suggested by the cited reference 4 to carry out extrusion coating of PPS resin, there is no description at all about details, and the PPS resin extrusion coating was not actually made.

  The present invention has been made to solve the above-described drawbacks of the prior art. The object of the present invention is to ensure the holding to the coil holding member and even in an environment of about 200 ° C. An object of the present invention is to provide a coil wire for induction heating and a coil for induction heating that can maintain the coil shape.

In order to achieve the above object, the coil wire for induction heating according to the present invention is a coil wire in which an insulating layer is formed by extrusion coating on a conductor wire, and a fusion layer is formed by extrusion coating on the insulating layer. The insulating layer is made of a fluororesin, the fusion layer is made of a composition comprising a polyphenylene sulfide resin and an elastomer component, and the melting point of the fluororesin constituting the insulation layer is a composition constituting the fusion layer. It is characterized by being higher than the melting point of the product.
Moreover, it is possible that the outer peripheral surface of the said insulating layer is given the adhesion | attachment process by electric discharge treatment.
In addition, the induction heating coil according to the present invention is a state in which the coil wire is wound in a spiral shape or a cylindrical shape, and the fused layer of the coil wire is melted and solidified so that the coil wires are fused together. It is characterized by having been made into.

  According to the present invention, since a composition composed of a PPS resin having a high melting point and an elastomer component (hereinafter sometimes referred to as a PPS composition) is used as the fusion layer, it can be melted even in an environment of about 200 ° C. The deposited layer does not melt and the coil shape can be maintained. Further, since the PPS composition has high adhesiveness, it can be fixed to the coil holding member with an adhesive and can be reliably and easily held. In addition, since the PPS composition is a sufficiently hard material, the position of the coil wire can be prevented from moving after the fusion integration.

  Further, conventionally known PPS resins have excellent properties such as heat resistance, but have low toughness and poor flowability at the time of melting. For this reason, molding is mainly performed by injection molding. When coating is performed by extrusion molding, not only cracking and peeling occur, but also extrusion molding itself cannot be performed due to the large resistance of the tube wall in the extrusion molding machine. It was. On the other hand, in the present invention, since the PPS composition having not only the PPS resin but also the elastomer component is used, the toughness is improved, the fluidity at the time of melting is improved, and extrusion molding is possible. Is. In addition, since the toughness is improved and the flexibility is improved from that of a single PPS resin, the fused layer is not cracked at the time of bending, and the coil shape can be easily processed.

It is the figure which showed the Example of this invention, and is a partially notched perspective view which shows the structure of the coil wire for induction heating. It is the figure which showed the Example of this invention, and is a perspective view which shows the structure of the coil for induction heating.

  Hereinafter, with reference to FIG. 1, the coil wire 10 which concerns on embodiment of this invention is demonstrated. Polyester amide-polyimide amide insulation coating is formed on an annealed copper wire with an outer diameter of 0.05 mm to form a conductor strand, 30 conductor strands are S-twisted to form an assembly wire, and then 40 assembly wires are Z-twisted. Thus, a conductor wire 1 having a diameter of 2.5 mmφ was obtained. The outer periphery of the conductor wire 1 was coated with a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) by extrusion molding to form an insulating layer 2 having a thickness of 0.25 mm. The melting point of this PFA is 310 ° C. A PPS composition comprising a polyphenylene sulfide resin and an elastomer component was coated on the outer periphery of the insulating layer 2 by extrusion molding to form a fusion layer 3 having a thickness of 0.20 mm. The melting point of this PPS composition is 280 ° C.

  The coil wire 10 thus obtained is wound in a spiral shape or a cylindrical shape as shown in FIG. 2, and then the fusion layer 3 is melted and solidified so that the coil wires 10 are fused together. By integrating, the induction heating coil 20 is obtained. Such an induction heating coil 20 is held on a coil holding member by an adhesive, and connection terminals are connected to both ends of the coil wire 10 by a method such as fusing connection, and is installed in an induction heating cooker or the like. Will be.

  The present invention is not limited to the above embodiment. The conductor wire 1 may be any conductor wire that is normally used as a coil, and the configuration of the conductor wire may be appropriately set according to the purpose. As for the insulating film formed on the conductor wire, a conventionally known material may be appropriately selected. In some cases, the insulating film may not be formed. When the conductor wire is twisted to form the conductor wire 1, the twist pitch and twist direction may be set as appropriate, and multi-stage twisting such as further twisting the twisted wire may be repeated. Moreover, the form of the wire assembly is not limited to the concentric circle form, but may be an ellipse, a sector, or a flat form.

  The material constituting the insulating layer 2 is a fluororesin. For example, tetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), ethylene-tetrafluoroethylene copolymer ( ETFE) and tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA). Any of these fluororesins may be used, but in consideration of heat resistance, it is preferable to use PTFE or PFA having a high melting point, and among these, PFA that can be extruded is used. It is preferable to do.

  Further, the outer peripheral surface of the insulating layer 2 may be subjected to an adhesion treatment for the purpose of strengthening the adhesion with the fusion layer 3. Examples of adhesion treatment methods include physical modification such as surface roughening, discharge treatment by corona discharge or plasma discharge, radiation treatment, UV treatment, laser treatment, flame radiation treatment, sand blast treatment, sodium treatment, primer, etc. And a method such as forming an affinity layer. Among these, the discharge treatment by corona discharge is preferable because there is no complexity in the equipment process and the effect of bonding strength is great.

  As a material constituting the fusion layer 3, a PPS composition made of a PPS resin and an elastomer component is used. Examples of the PPS resin include not only a general repeating benzene ring and sulfur, but also various polyarylene sulfide resins including an ether bond, a sulfone bond, a biphenyl bond, and the like.

  Examples of the elastomer component include butadiene copolymer, acrylic polymer, butyl rubber, aliphatic polyester elastomer, acrylonitrile-styrene graft copolymer, ethylene-vinyl acetate copolymer, olefin copolymer, fluorine rubber, and silicon rubber. Etc. Among these, an elastomer component having at least one functional group selected from the group consisting of epoxy groups, carboxyl groups, hydroxyl groups, amino groups, mercapto groups, isocyanate groups, vinyl groups, acid anhydride groups and ester groups. Among these, a functional group derived from a carboxylic acid such as an epoxy group or an acid anhydride, an acid, or an ester is particularly preferable because the affinity with the polyphenylene sulfide resin is increased. The elastomer component can be obtained, for example, by copolymerization of α-olefins and vinyl polymerizable compounds having the functional group. Examples of the α-olefins include α-olefins having 2 to 8 carbon atoms such as ethylene, propylene, and butene-1. Examples of the vinyl polymerizable compounds having the functional group include α, β-unsaturated carboxylic acids such as (meth) acrylic acid and (meth) acrylic acid esters and alkyl esters thereof, maleic acid, fumaric acid, and itacon. Examples include acids, other unsaturated dicarboxylic acids having 4 to 10 carbon atoms and mono- and diesters thereof, α, β-unsaturated dicarboxylic acids such as acid anhydrides and derivatives thereof, glycidyl (meth) acrylate, and the like. Among these, an ethylene-propylene copolymer or an ethylene-butene copolymer having a carboxyl group is preferably used.

  The mixing ratio of the PPS resin and the elastomer component is preferably 1 to 50 parts by weight of the elastomer component with respect to 99 to 50 parts by weight of the PPS resin.

  It is also effective to add an epoxy compound to the PPS composition of the present invention in order to further enhance the affinity and mechanical properties of each component. The epoxy compound has one or two epoxy groups in the molecule, and β, γ-epoxypropyl ether, 1,4-bis (β, γ-epoxypropoxy) butane, 1,6-bis ( Epoxyethyl) hexane, 2,2-bis [p- (β, γ-epoxypropoxy) phenyl] propane, 1-epoxyethyl-3,4-epoxycyclohexane, 1- (β, γ-epoxypropoxy) -2- Examples include benzyloxyethane, 1- (β, γ-epoxypropoxy) -2-ethoxyethane, 1,4-bis (β, γ-epoxypropoxy) benzene. Furthermore, bisphenol A, bisphenol S, resorcinol, hydroquinone, pyrocatechol, bisphenol F, saligenin, 1,3,5-trihydroxybenzene, trihydroxy-diphenyldimethylmethane, 4,4'-dihydroxybiphenyl, 1,5-dihydroxy Glycidyl ethers of bisphenol such as naphthalene, cashew phenol, 2,2,5,5-tetrakis (4-hydroxyphenyl) hexane, glycidyl ethers such as halogenated bisphenol instead of bisphenol, diglycidyl ether of butanediol, phthalic acid Glycidyl ester resins such as glycidyl ester, glycidyl amine resins such as N-glycidyl aniline, etc., epoxidized polyolefin, epoxidized soybean Linear system and vinylcyclohexene dioxide and the like, include non Gurishijirupokishi resin ring system such as dicyclopentadiene dioxide. A novolac type epoxy resin can also be used as the epoxy compound. The novolac type epoxy resin contains two or more epoxy groups and is usually obtained by reacting a novolac type phenol resin with epichlorohydrin. A novolac type phenol resin is obtained by a condensation reaction of phenols and formaldehyde. Although there is no restriction | limiting as phenols of this raw material, For example, phenol, o-cresol, m-cresol, p-cresol, bisphenol A, bisphenol F, bisphenol S, resorcinol, p-tert-butylphenol, and mixtures thereof are particularly preferable. Used for. Furthermore, an epoxidized product of poly-p-vinylphenol can also be used as the epoxy compound. The epoxy compound may have a halogen, a hydroxyl group, or the like, and may be used alone or as a mixture of two or more.

  In addition, various fillers may be added to the PPS composition according to the present invention for the purpose of improving mechanical properties and molding processability as long as the object of the present invention is not impaired. Examples of the filler that can be used in the present invention include calcium titanate, potassium titanate, silicon carbide, silicon nitride, barium sulfate, calcium sulfate, kaolin, clay, bentonite, sericite, zeolite, mica, mica, talc. , Wollastonite, ferrite, aluminum silicate, calcium silicate, calcium carbonate, dolomite, magnesium oxide, magnesium hydroxide, aluminum oxide, aluminum hydroxide, antimony trioxide, titanium oxide, iron oxide, milled glass, glass beads, glass balloon Glass fiber, carbon fiber, aramid fiber, ceramic fiber, metal fiber and the like. However, since these fillers may lower the adhesive strength as the fusion layer, it is preferable not to add them if possible.

  In addition, a heat stabilizer, an antioxidant, an ultraviolet absorber, a rust inhibitor, a lubricant, a mold release agent, a colorant, and the like should be added to the PPS composition according to the present invention as long as the object of the present invention is not impaired. Can do.

  Further, the PPS composition according to the present invention can be used by mixing the following polymers within a range not impairing the object of the present invention. Examples of the polymer include polyethylene, polypropylene, polystyrene, styrene-butadiene copolymer, polyethylene terephthalate, polybutylene terephthalate, polyamide, polycarbonate, polysulfone, polyethersulfone, polyarylate, polyacetal, polyetherketone, polyether. Examples include ether ketone, polyimide, polyamideimide, polyetherimide, silicone resin, and liquid crystal polymer.

  As a method for mixing the PPS composition, for example, a PPS resin, an elastomer component, and, if necessary, an epoxy compound, a filler, an additive, and the like are mixed in advance using a Henschel mixer or a tumbler, etc. Examples thereof include a method obtained by feeding to a shaft extrusion kneader or the like and kneading at 200 to 360 ° C., followed by pelletization.

  The insulating layer 2 and the fusion layer 3 can be formed by known extrusion molding. The insulating layer 2 and the fusion layer 3 may be separately extruded and laminated, or two layers may be formed simultaneously by coextrusion.

  The melting point of the fluororesin constituting the insulating layer 2 needs to be higher than the melting point of the PPS composition constituting the fusion layer 3. This prevents the insulating layer 2 from being melted by the heat of extrusion molding when the fusion layer 3 is extrusion coated on the insulating layer 2, and provides insulation when the fusion layer 3 is melted and solidified. This is to prevent the layer 2 from melting.

  In the present invention, the coil wire 10 having the above configuration is wound in a spiral shape or a cylindrical shape, and then the coil wire 10 is fused and integrated to form the induction heating coil 20. Any means known in the art can be employed as means for fusing and integrating the coil wire 10 and is not particularly limited. For example, the coil wire 10 wound in a spiral shape or a cylindrical shape may be left in a bath maintained at a predetermined temperature for a predetermined time and integrated by heat fusion, or the conductor wire 1 of the coil wire 10 may be predetermined. For example, a method may be used in which the fusion layer 3 is heated and melted from the inside by resistance heat generated by flowing the current. In addition, about the shape which winds the coil wire 10, not only the shape based on the circle like a spiral shape or a cylindrical shape but another shape may be sufficient. For example, it may be a rectangular tube shape, a star shape, various planar shapes or three-dimensional shapes, and may be appropriately designed according to the shape of the heating object, the required magnetic field line intensity distribution, and the like.

  The dielectric heating coil 20 obtained as in the above embodiment was subjected to a heat resistance test. The dielectric heating coil 20 was energized to increase the temperature, and the temperature of the coil surface was maintained at 200 ° C. for 1 hour, and then the surface condition, positional deviation of the coil wire 10 and the like were confirmed. In the dielectric heating coil 20 according to the present embodiment, even after the heat resistance test, the surface state did not change, and the positional deviation of the coil wire 10 did not occur.

  Moreover, although the induction heating coil 20 was held on the coil holding member by a commercially available adhesive, it was confirmed that the induction heating coil 20 was held by a sufficient adhesive force.

  The coil wire and the induction heating coil according to the present invention can be reliably held on the coil holding member and can maintain the coil shape even in an environment of about 200 ° C. Therefore, for example, it can be suitably used for an induction heating cooker, an electric rice cooker, an electric kettle, etc., in which a pan is placed on the top plate and heated.

DESCRIPTION OF SYMBOLS 1 Conductor wire 2 Insulating layer 3 Fusion layer 10 Coil wire 20 Dielectric heating coil

Claims (3)

A coil wire in which an insulating layer is formed by extrusion coating on a conductor wire, and a fusion layer is formed by extrusion coating on the insulating layer,
The insulating layer is made of a fluororesin, the fusion layer is made of a composition comprising a polyphenylene sulfide resin and an elastomer component, and the melting point of the fluororesin constituting the insulation layer is the melting point of the composition constituting the fusion layer. A coil wire for induction heating characterized by being higher. The coil wire according to claim 1, wherein the outer peripheral surface of the insulating layer is subjected to an adhesion treatment by a discharge treatment. In a state where the coil wire according to claim 1 or 2 is wound in a spiral shape or a cylindrical shape, the fused layer of the coil wire is melted and solidified, and the coil wires are fused and integrated. An induction heating coil.

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