JP2011132393A - Insulating film coating and insulated wire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin insulating coating having a high thermal conductivity in order to improve the resistance to the partial discharge deterioration of an insulating film; and to provide an insulated wire using the same. <P>SOLUTION: The insulating film coating is obtained by mixing a resin coating and a precursor of an inorganic insulating particle. The precursor of an inorganic insulating particle is a siloxane compound obtained by a hydrolytic polycondensation reaction of a silane compound represented by chemical formula 1: and pure water. In the formula, each symbol has a specified definition. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an insulated wire having an insulating coating formed on a metal conductor surface with an insulating coating, and more particularly to an insulating coating suitable for a coil of an electric device such as a motor or a transformer, and an insulated wire manufactured using the same. .

  Insulated wires (enamel-insulated insulated wires) are widely used as coil wires for electrical equipment such as motors and transformers, and are formed into a cross-sectional shape (for example, round or flat) that matches the application and shape of the coil. In addition, a single-layer or multiple-layer insulating film is formed on the outer layer of the metal conductor. The insulating coating is generally prepared by applying and baking an insulating coating (in some cases simply referred to as insulating coating) obtained by dissolving a resin such as polyimide, polyamideimide, or polyesterimide in an organic solvent. The

  In recent years, inverter control and higher voltage of electric devices are progressing due to demands for miniaturization, higher output, and higher efficiency of electric devices such as motors and transformers. As a result, higher voltages such as inverter surge voltage are applied to coils in electrical equipment. In addition, the operating temperature of electrical equipment (particularly coils) tends to rise more than before.

  On the other hand, if a minute gap remains between the insulated wires constituting the coil, electric field concentration occurs in that portion, and the portion between adjacent insulated wires (between the coating and the coating) or between the ground (between the coating and the core) Discharge is likely to occur. When partial discharge occurs, collision of charged particles induces degradation of the insulating film (partial discharge deterioration) by inducing the resin material molecular chain of the insulating film to be cut, sputtered, thermal decomposition due to local temperature rise, and the like. The partial discharge deterioration is promoted by the above-described high voltage and increase in operating temperature, and as a result, there is a risk of coil breakdown.

  In order to suppress deterioration and thermal decomposition of the insulating coating due to temperature rise, it is desirable that the insulating coating has high thermal conductivity. Conventionally, as an insulating coating (insulating coating) having high thermal conductivity, a resin composition in which inorganic insulating fine particles for improving thermal conductivity are dispersed in a resin dissolved in an organic solvent has been proposed.

  For example, Patent Document 1 discloses a resin composition obtained by mixing a sintered powder of aluminum nitride (AlN) whose surface is previously oxidized in an organic polymer resin such as an epoxy resin. According to Patent Document 1, a resin composition in which aluminum nitride having an oxidized surface is mixed has high thermal conductivity and hydration resistance, and has high reliability.

In Patent Document 2, an insulating layer obtained by mixing a metal oxide powder such as silica, alumina, or magnesia with an organometallic polymer compound such as a silicone resin is coated on the surface of the conductor with a thickness of 10 to 50 μm, and a polyimide varnish is further formed thereon. A resin composition having a two-layer structure in which an insulating reinforcing layer such as a heat-resistant insulating varnish is coated with a thickness of 5 to 20 μm is disclosed. An insulated wire using the resin composition described in Patent Document 2 is said to have a high thermal conductivity of 10 × 10 ⁻⁴ cal / (s · cm · ° C.) or more.

  In Patent Document 3, at least one selected from metal oxide fine particle sol and silicon oxide fine particle sol is dispersed, and at least one fine particle selected from metal oxide fine particles and silicon oxide fine particles is enameled wire. A resin composition containing 3 to 100 parts by weight with respect to 100 parts by weight of the resin content of the coating material is disclosed. The resin composition described in Patent Document 3 is uniformly dispersed by adding metal oxide fine particles and silicon oxide fine particles in the form of a sol in an organic dispersion medium excellent in compatibility with enamel wire paints. You can do that. It is said that when this resin composition is used, an insulated wire excellent in flexibility, flexibility, winding property, and extensibility can be obtained.

  Patent Document 4 discloses an organosilica sol obtained by dispersing silica in a mixed solvent containing 5 to 80% by mass of phenols or benzyl alcohols and 1 to 40% by mass of monohydric alcohol having 3 to 7 carbon atoms. Discloses an insulating paint in which the organosilica sol is dispersed by mixing with a resin paint in which a heat-resistant insulating resin is dissolved. Since the insulating paint described in Patent Document 4 uses an organosilica sol dispersed with a dispersion medium containing a solvent having properties close to those of the resin paint, the compatibility is improved and the silica does not agglomerate. It is said that the organosilica sol is uniformly dispersed in the paint. Moreover, the insulated wire produced using this insulating paint is said to have high partial discharge resistance.

Japanese Patent Laid-Open No. 2-133450 JP-A-8-317583 JP 2001-307557 A JP 2004-204187 A

  In order to stably obtain an insulating coating (insulating coating paint) having high thermal conductivity, it is extremely important to uniformly disperse the inorganic insulating particles added and mixed in the resin coating. However, since the inorganic insulating particles (particularly particles having a small primary particle diameter) have the property of being easily aggregated, the inorganic insulating fine particles as described in Patent Document 1 and Patent Document 2 are simply dispersed in the resin solution. However, there is a problem that the inorganic insulating fine particles are easily aggregated in the resin solution and it is difficult to obtain a uniform dispersion state (that is, stable high thermal conductivity).

  On the other hand, the method of dispersing the silica sol in the resin solution as described in Patent Document 3 and Patent Document 4 is more uniformly dispersed than the method of simply dispersing the inorganic insulating fine particles in the resin solution. However, there is a possibility that the inorganic insulating fine particles are unevenly distributed due to aggregation in the resin solution, and further improvement has been desired.

  Accordingly, an object of the present invention is to solve the above-described problems, by dispersing the inorganic insulating fine particles more uniformly in the resin paint, thereby improving the thermal conductivity and having a high resistance against partial discharge deterioration and It is to provide an insulated wire using the same.

  In order to achieve the above object, the present invention provides an insulating coating paint obtained by mixing a resin paint and a precursor of inorganic insulating particles, wherein the precursor of the inorganic insulating particles is represented by the following chemical formula 1 Provided is an insulating coating composition characterized in that it is a siloxane compound obtained by hydrolytic polycondensation reaction of water and pure water.

Moreover, in order to achieve the said objective, this invention can add the following improvements and changes in the insulating-film coating material which concerns on said this invention.
(1) the silane compound is phenyltrimethoxysilane _{(C 6 H 5 Si (OCH} 3) 3), phenyltriethoxysilane _{(C 6 H 5 Si (OC} 2 H 5) 3), methyltrimethoxysilane (CH ₃ Si (OCH ₃ ) ₃ ), methyltriethoxysilane (CH ₃ Si (OC ₂ H ₅ ) ₃ ), ethyltrimethoxysilane (C ₂ H ₅ Si (OCH ₃ ) ₃ ), ethyltriethoxysilane (C ₂ Any one selected from H ₅ Si (OC ₂ H ₅ ) ₃ ).
(2) The resin paint is made of polyimide resin.
(3) The resin paint is made of polyamideimide resin.

  In order to achieve the above object, the present invention provides an insulated wire characterized in that an insulating coating is formed by applying and baking the insulating coating paint on a metal conductor.

Moreover, in order to achieve the said objective, this invention can add the following improvements and changes in the insulated wire which concerns on said invention.
(4) A lubricating insulating coating is further formed on the outer periphery of the insulating coating.
(5) An adhesive insulating film is formed between the metal conductor and the insulating film.

  According to the present invention, it is possible to provide an insulating coating having a high resistance to partial discharge deterioration by improving the thermal conductivity by dispersing the inorganic insulating fine particles more uniformly in the resin coating. Further, by using the insulating coating material, it is possible to provide an insulated wire suitable for a coil of an electric device such as a motor or a transformer.

It is the schematic diagram which showed the evaluation method of the heat conductivity of an insulating film.

  Hereinafter, embodiments according to the present invention will be described in detail. However, the present invention is not limited to the embodiment taken up here, and can be appropriately combined and improved without departing from the scope of the invention.

  The insulating coating material according to the present invention is an insulating coating material obtained by mixing a resin paint and a precursor of inorganic insulating particles, wherein the precursor of the inorganic insulating particles is pure with a silane compound represented by the following chemical formula 1. It is a siloxane compound obtained by hydrolytic polycondensation reaction with water.

Here, R ₁ is any _one of a CH ₃ group or a CH ₃ CH ₂ group, and R ₂ is any one of a CH ₃ group, a CH ₃ CH ₂ group, or a C ₆ H ₅ group. More specifically, the silane compound includes phenyltrimethoxysilane (C ₆ H ₅ Si (OCH ₃ ) ₃ ), phenyltriethoxysilane (C ₆ H ₅ Si (OC ₂ H ₅ ) ₃ ), methyltrimethoxy. silane _{(CH 3 Si (OCH 3)} 3), methyl triethoxysilane _{(CH 3 Si (OC 2 H} 5) 3), ethyltrimethoxysilane _{(C 2 H 5 Si (OCH} 3) 3), ethyl triethoxysilane Any one selected from (C ₂ H ₅ Si (OC ₂ H ₅ ) ₃ ).

  The siloxane compound obtained by hydrolytic polycondensation reaction of the silane compound and pure water has a slow hydrolysis reaction rate, and the polycondensation rate of silanol produced by hydrolysis is also slow. And can be dispersed more uniformly than before. As a result, it is possible to obtain an insulating coating material having improved heat conductivity and high resistance to partial discharge deterioration.

  The siloxane compound as the precursor of the inorganic insulating particles is preferably contained in an amount of 3 to 100 parts by weight with respect to 100 parts by weight of the resin component of the resin coating. When the amount of the siloxane compound is less than 3 parts by weight, the absolute amount of the inorganic insulating particles contained is too small and the thermal conductivity of the insulating coating is not sufficiently improved. On the other hand, when the amount of the siloxane compound exceeds 100 parts by weight, the absolute amount of the inorganic insulating particles contained is too large, and the flexibility and stretch resistance of the insulating coating are deteriorated. More preferably, the siloxane compound is contained in an amount of 5 to 50 parts by weight with respect to 100 parts by weight of the resin content of the resin coating.

  The resin paint consists of a resin and a solvent. The resin may be polyamideimide or polyimide. Examples of the solvent include N-methyl-2-pyrrolidone (NMP), dimethylformamide, dimethylacetamide, sulfolane, anisole, dioxolane, butyl cellosolve acetate, lactone, etc., and these can be used alone, Two or more kinds may be mixed and used. Moreover, what is marketed for industrial use as a resin coating material may be used, for example, the coating material for polyamide imide enamel wires, the coating material for polyimide enamel wires, etc. can be used.

  The insulated wire according to the present invention is a metal conductor (for example, a copper wire, an aluminum wire, a silver wire, a nickel wire, etc.) shaped into a cross-sectional shape (for example, a round shape or a rectangular shape) that matches the application / shape of the coil. It can be obtained by applying and baking the above insulating coating paint on the surface to form an insulating coating. If necessary, a lubricating insulating coating such as varnish may be further provided on the outer periphery (outermost periphery) of the insulating coating. By providing a lubricating insulating film, slipping is improved and wear resistance can be improved.

  Further, in order to further improve the adhesion between the metal conductor and the insulating coating, an adhesive insulating coating can be provided between the metal conductor and the insulating coating as necessary. The adhesive insulating coating can be obtained by applying and baking a silane coupling agent directly on a metal conductor. Examples of silane coupling agents include 3-glycidoxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane. Ethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane and the like can be used.

  EXAMPLES Hereinafter, although this invention is demonstrated in more detail based on an Example, this invention is not limited to these.

(Production of Example 1)
Hydrolysis polycondensation reaction of 5.0 g of phenyltriethoxysilane and 1.1 g of pure water produces 3.0 g of siloxane compound, and this siloxane compound and 100 g of polyamideimide paint with a resin concentration of 20 mass% are mixed. The insulating coating paint of Example 1 was obtained by stirring. The insulating coating paint was applied around a copper conductor (wire diameter 0.8 mm) and then baked to produce an insulated wire of Example 1 having an insulating coating thickness of 45 μm.

(Production of Example 2)
Hydrolysis polycondensation reaction of 5.0 g of phenyltriethoxysilane and 1.1 g of pure water produces 3.0 g of a siloxane compound, and the siloxane compound and 100 g of polyimide paint having a resin concentration of 20 mass% are mixed and stirred. Thus, the insulating coating material of Example 2 was obtained. The insulating coating paint was applied around a copper conductor (wire diameter 0.8 mm) and then baked to produce an insulated wire of Example 2 having an insulating coating thickness of 44 μm.

(Production of Example 3)
Hydrolysis polycondensation reaction of 5.6 g of phenyltrimethoxysilane and 1.1 g of pure water produces 4.0 g of a siloxane compound, and the siloxane compound and 100 g of polyamideimide paint having a resin concentration of 20 mass% are mixed. The insulating coating material of Example 3 was obtained by stirring. The insulating coating paint was applied around a copper conductor (wire diameter 0.8 mm) and then baked to produce an insulated wire of Example 3 having an insulating coating thickness of 45 μm.

(Production of Example 4)
Hydrolysis polycondensation reaction of 5.6 g of phenyltrimethoxysilane and 1.1 g of pure water produces 4.0 g of a siloxane compound, and the siloxane compound and 100 g of polyimide paint having a resin concentration of 20 mass% are mixed and stirred. Thus, an insulating coating material of Example 4 was obtained. The insulating coating paint was applied around a copper conductor (wire diameter 0.8 mm) and then baked to produce an insulated wire of Example 4 having an insulating coating thickness of 46 μm.

(Production of Example 5)
Hydrochloric polycondensation reaction of 1.4 g of phenyltrimethoxysilane and 1.1 g of pure water produces 1.0 g of a siloxane compound, and the siloxane compound and 100 g of polyimide paint having a resin concentration of 20 mass% are mixed and stirred. Thus, an insulating coating material of Example 4 was obtained. The insulating coating paint was applied around a copper conductor (wire diameter 0.8 mm) and then baked to produce an insulated wire of Example 5 having an insulating coating thickness of 46 μm.

(Production of Example 6)
Hydrochloric polycondensation reaction of 14 g of phenyltrimethoxysilane and 1.1 g of pure water produces 10 g of a siloxane compound, and the siloxane compound and 100 g of polyimide paint having a resin concentration of 20 mass% are mixed and stirred. Thus, an insulating coating material of Example 4 was obtained. The insulating coating was applied around the copper conductor (wire diameter 0.8 mm) and then baked to produce an insulated wire of Example 6 having an insulating coating thickness of 46 μm.

(Production of Comparative Example 1)
Insulation of Comparative Example 1 by mixing 5.0 g of silica fine particles (Nippon Aerosil Co., Ltd., Silica Aerosil R972), 1.1 g of pure water, and 100 g of polyamideimide paint with a resin concentration of 20 mass%, mixing and stirring. A coating was obtained. The insulating coating paint was applied around a copper conductor (wire diameter 0.8 mm) and then baked to produce an insulated wire of Comparative Example 1 having an insulating coating thickness of 44 μm.

(Production of Comparative Example 2)
Insulating coating of Comparative Example 2 containing 5.0 g of silica fine particles (Silica Aerosil R972, manufactured by Nippon Aerosil Co., Ltd.), 1.1 g of pure water, and 100 g of polyimide paint having a resin concentration of 20 mass%, mixed and stirred. A paint was obtained. The insulating coating paint was applied around the copper conductor (wire diameter 0.8 mm) and then baked to produce an insulated wire of Comparative Example 2 having an insulating coating thickness of 45 μm.

(Production of Comparative Example 3)
A silica sol (5.0 g), pure water (1.1 g), and a polyamideimide coating material (100 g) having a resin concentration of 20 mass% were blended, mixed, and stirred to obtain an insulating coating material of Comparative Example 3. The insulating coating paint was applied around a copper conductor (wire diameter 0.8 mm) and then baked to produce an insulated wire of Comparative Example 3 having an insulating coating thickness of 44 μm.

(Production of Comparative Example 4)
A silica sol (5.0 g), pure water (1.1 g), and a resin paint concentration of 20 mass% polyimide paint (100 g) were blended, mixed and stirred to obtain an insulating coating paint of Comparative Example 4. The insulating coating paint was applied around a copper conductor (wire diameter 0.8 mm) and then baked to produce an insulated wire of Comparative Example 4 having an insulating coating thickness of 45 μm.

  The following measurement evaluations and tests were performed on Examples 1 to 6 and Comparative Examples 1 to 4 (insulation coating paint and insulated wire) produced as described above.

(1) Thermal conductivity measurement (thermal conductivity evaluation)
A sheet-shaped evaluation insulating film of 40 μm (thickness) × 10 mm × 10 mm was prepared using each insulating film paint. FIG. 1 is a schematic diagram showing a method for evaluating the thermal conductivity of an insulating coating. As shown in FIG. 1, the insulating coating for evaluation was placed in contact so as to be sandwiched between a copper heating shaft and a cooling shaft. After the temperature (temperature gradient) of the heating shaft and the cooling shaft was stabilized, the thermal resistance R _th (° C./W) was measured from the temperature difference T _h −T _c between the front and back surfaces of the insulating coating for evaluation and the heat flow rate Q. The thermal conductivity (W / (m · ° C.)) was calculated from the following formula 1. The measurement is performed in an environment at a temperature of 25 ° C. and a relative humidity of 50%, and the heat conduction area is 10 mm × 10 mm.
Thermal conductivity = (thickness of insulating coating for evaluation) / (thermal resistance × thermal conduction area) (Equation 1)

(2) Measurement of storage elastic modulus Each insulating coating paint was used to produce a 25 μm (thickness) × 5 mm × 20 mm sheet-like insulating coating for evaluation. Using a dynamic viscoelasticity measuring device (ITG Measurement and Control Co., Ltd., DVA-200) while raising the temperature from room temperature to 400 ° C at a rate of temperature increase of 10 ° C / min, The storage modulus was measured.

(3) Measurement of glass transition temperature (Tg) In the storage elastic modulus measurement of (2) above, the temperature at the inflection point at which the storage elastic modulus decreases was defined as the glass transition temperature (Tg).

(4) Unidirectional wear test (wear resistance evaluation)
Each insulated wire was cut out to a length of 120 mm, and the insulation coating on one end was peeled off with an abisofix device. After mounting on a Taber type wear tester (manufactured by Toyo Seiki Co., Ltd.), when an electrode is attached to the terminal and the slope is slid while applying a load from the vertical direction to the surface of the insulation coating, electricity is conducted The load of was measured.

(5) Torsion test (adhesion evaluation)
Each insulated wire was fixed in a straight line to two clamps separated by 250 mm, and two pieces of insulating coating were removed over the entire length so as to be parallel to the longitudinal direction of the wire. Thereafter, in a room temperature environment, one clamp was rotated (the other was fixed), and the number of rotations at the time when the unremoved insulating coating floated from the metal conductor (when partial peeling occurred) was measured.

(6) Self-diameter winding (flexibility evaluation)
Each insulated wire was wound around a round bar (winding bar) having the same diameter as the conductor diameter, and the presence or absence of cracks in the insulating coating was examined using an optical microscope. In this specification, the insulated wire was wound as 5 coils / coil for 5 coils and observed using a 50 × optical microscope. The case where no crack was observed was defined as “pass”.

  Specifications and various measurement results of Examples 1 to 6 are shown in Table 1, and specifications and various measurement results of Comparative Examples 1 to 4 are shown in Table 1.

  As shown in Tables 1 and 2, Examples 1 to 6 (insulating coating paint and insulated wire) according to the present invention are comparative examples 1 to 4 (insulating coating paint and insulated wire) that deviate from the definition of the present invention. It was confirmed that it has a high thermal conductivity. On the other hand, there was almost no difference in characteristics other than thermal conductivity between Examples 1-6 and Comparative Examples 1-4. Therefore, the insulating coating paint and the insulated wire according to the present invention maintain the storage elastic modulus, glass transition temperature, abrasion resistance, adhesion, and flexibility characteristics while maintaining the heat resistance as compared with the prior art. It has been demonstrated that conductivity can be improved.

Claims (7)

An insulating coating paint obtained by mixing a resin paint and a precursor of inorganic insulating particles,
An insulating coating material, wherein the precursor of the inorganic insulating particles is a siloxane compound obtained by hydrolytic polycondensation reaction of a silane compound represented by the following chemical formula 1 and pure water.

  2. The silane compound according to claim 1, wherein the silane compound is any one selected from phenyltrimethoxysilane, phenyltriethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, and ethyltriethoxysilane. Insulating coating paint.   The insulating coating material according to claim 1 or 2, wherein a resin component of the resin coating material is made of a polyimide resin.   The insulating coating material according to claim 1 or 2, wherein a resin component of the resin coating material comprises a polyamideimide resin.   An insulated wire comprising an insulating coating formed by applying and baking the insulating coating paint according to any one of claims 1 to 4 on a metal conductor.   6. The insulated wire according to claim 5, further comprising a lubricating insulating film formed on an outer periphery of the insulating film.   The insulated wire according to claim 5 or 6, wherein an adhesive insulating coating is formed between the metal conductor and the insulating coating.

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