JP2014237748A - Coating material for forming insulating film, gas insulated switch, and rotary electric machine - Google Patents

Abstract

The present invention provides a coating material for forming an insulating film capable of forming a uniform and thick insulating film. The present invention also provides a gas insulated switchgear and rotating electric machine having a uniform and thick insulating film. A coating material for forming an insulating film according to the present invention is characterized by containing microcapsules enclosing a powdery thermosetting resin composition. The powdery thermosetting resin composition can include at least one resin selected from the group consisting of an epoxy resin, a polyester resin, an epoxy polyester resin, and an acrylic resin, a curing agent, and a filler. . The gas insulated switchgear and the rotating electrical machine of the present invention are characterized by having an insulating film formed from this insulating film forming paint. [Selection figure] None

Description

  The present invention relates to an insulating film forming paint, a gas insulated switchgear, and a rotating electrical machine.

In devices such as rotating electrical machines (small, medium, and large) and gas-insulated switchgear, insulating films are formed on the surfaces of various members in order to insulate the various members.
For example, in a rotating electric machine, in order to insulate a stator coil disposed in a slot, an insulating film is formed on the surface of the stator coil using a powder paint or a liquid thermosetting resin. Further, in a gas insulated switchgear, a stator coil (conductor) is disposed inside a sealed metal container, and sulfur hexafluoride gas (SF6) is generally used as an insulating medium, so that the dielectric strength is improved. Therefore, an insulating film is formed on the surface of the stator coil. This insulating film is generally formed by applying a powder coating containing an epoxy resin by a powder coating method such as a fluid immersion method or an electrostatic coating method.

  However, although the powder coating method is generally suitable for forming a thin insulating film, it is not suitable for forming a thick insulating film. For example, in the powder coating method, as the insulating coating becomes thicker, the powder coating becomes difficult to melt, and as a result, the powder coating falls off before the powder coating melts and adheres to the object to be coated. Is difficult. Even if the powder coating does not fall off, the powder coating does not melt sufficiently, and defects such as voids are likely to occur in the insulating film.

As a method of forming a thick coating film, Patent Document 1 surrounds the surface of an object to be coated with a frame having a height required for the thickness of the film, and fills the object to be coated with plastic powder in the frame. And proposed a method of melting.
Patent Document 2 proposes a method of forming a coating film in which a fluororesin and a polyester resin are separated from each other by using a powder coating material containing a fluororesin, a polyester resin, and a filler (pigment). doing.

Japanese Patent Laid-Open No. 2-160082 JP 2011-12119 A

  However, although Patent Documents 1 and 2 both propose a method for forming a thick coating film, they do not propose any paint for forming a uniform and thick insulating film. Moreover, since it is necessary to provide the frame corresponding to the surface of a to-be-coated object, the method proposed by Patent Document 1 is limited to a planar object. For example, when the object to be coated has a shape other than a flat surface (for example, a cylindrical shape), dripping of the molten paint occurs when heated, and a uniform coating film cannot be formed. Therefore, even if the method is applied to a coating material that gives an insulating film, it is difficult to form a uniform insulating film on the surfaces of various members having various shapes.

The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an insulating film-forming coating material capable of forming a uniform and thick insulating film.
Another object of the present invention is to provide a gas insulated switchgear and a rotating electrical machine having a uniform and thick insulating film.

As a result of diligent research to solve the above problems, the inventors of the present invention microencapsulate the components of the coating material that gives the insulating film, thereby preventing the coating from sagging and making the insulating film uniform and thick. It has been found that both film formation can be achieved.
That is, the present invention is an insulating film-forming coating material containing a microcapsule enclosing a powdery thermosetting resin composition.
The present invention also provides a gas-insulated switchgear and a rotating electrical machine having an insulating film formed from the above-described insulating film forming paint.

ADVANTAGE OF THE INVENTION According to this invention, the coating material for insulating film formation which can form a uniform and thick insulating film can be provided.
In addition, according to the present invention, it is possible to provide a gas insulated switchgear and a rotating electrical machine having a uniform and thick insulating film.

Embodiment 1 FIG.
The coating material for forming an insulating film of the present invention (hereinafter abbreviated as “paint”) contains microcapsules enclosing a powdery thermosetting resin composition.
The powdery thermosetting resin composition is not particularly limited as long as it is suitable for forming an insulating film, and those known in the art can be used.

The powdery thermosetting resin composition suitable for the coating material of the present invention generally contains a thermosetting resin.
The thermosetting resin is not particularly limited as long as it is in a solid state at room temperature (25 ° C.) and can be used for forming an insulating film, and a resin known in the technical field can be used. Examples of thermosetting resins include epoxy resins, polyester resins, epoxy polyester resins, and acrylic resins. These can be used alone or in combination of two or more. Among these, an epoxy resin excellent in properties such as mechanical strength, heat resistance, chemical resistance, and adhesiveness is preferable.

  Examples of epoxy resins include bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol AD type epoxy resins, brominated bisphenol A type epoxy resins, brominated bisphenol F type epoxy resins, brominated bisphenol AD type epoxy resins, etc. Bisphenol type epoxy resin; cycloaliphatic epoxy resin such as brominated alicyclic epoxy resin; novolak such as phenol novolak type epoxy resin, cresol novolak type epoxy resin, brominated phenol novolak type epoxy resin, brominated cresol novolak type epoxy resin Type epoxy resin and the like. These epoxy resins can be used individually or in mixture of 2 or more types.

  Examples of polyester resins include ethylene glycol, diethylene glycol, propylene glycol, propylene glycol, dipropylene glycol, butanediol, neopentyl glycol, trimethylol ethane, trimethylol propane, glycerin, pentaerythritol and other polyhydric alcohols and phthalic acid And polycondensates with polybasic acid compounds such as terephthalic acid, metaphthalic acid, trimellitic acid, adipic acid and hexahydroterephthalic acid.

  Examples of the epoxy polyester resin include a reaction product of the above epoxy resin and the above polybasic acid compound in excess of carboxyl group.

  Examples of acrylic resins include acrylic monomers such as glycidyl (meth) acrylate, β-methylglycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, styrene, styrene derivatives, acrylamide, acrylonitrile, vinylpyrrolidone , Vinyl acetate, polycaprolactone, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meta ) And other radical polymerizable monomers such as benzyl (meth) acrylate.

  Since the weight average molecular weight of each thermosetting resin described above varies depending on the type of thermosetting resin used, it is difficult to uniquely define it. The weight average molecular weight of each thermosetting resin should just be a range which will be in a solid state at normal temperature (25 degreeC). Here, “weight average molecular weight” in the present specification means a value determined by gel permeation chromatography (GPC).

Moreover, generally the powdery thermosetting resin composition suitable for the coating material of this invention further contains a hardening | curing agent and a filler in addition to said thermosetting resin.
It does not specifically limit as a hardening | curing agent, What is necessary is just to select suitably according to resin to be used. Examples of the curing agent include carboxylic acid anhydrides, amide compounds, phenol compounds, imidazole compounds and the like. These curing agents can be used alone or in admixture of two or more.

Examples of carboxylic anhydrides include aromatics such as phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenone tetracarboxylic anhydride, ethylene glycol trimellitic anhydride, biphenyltetracarboxylic anhydride Carboxylic anhydrides; anhydrides of aliphatic carboxylic acids such as azelaic acid, sebacic acid, dodecanedioic acid; tetrahydrophthalic anhydride, hexahydrophthalic anhydride, nadic acid anhydride, chlorendic anhydride, highmic acid anhydride And alicyclic carboxylic acid anhydrides. These can be used individually or in mixture of 2 or more types.
The compounding amount of the carboxylic acid anhydride is such that the equivalent ratio of the carboxyl group to a specific functional group of the thermosetting resin (for example, epoxy group of the epoxy resin) is generally 0.3 or more and 1.5 or less, preferably 0.5. The amount is 1.2 or less. When the equivalent ratio is less than 0.3, the heat resistance is lowered, and when the equivalent ratio is more than 1.5, the pot life tends to be shortened.

Examples of the amide compound include dicyandiamide.
The compounding amount of the amide compound is such that the equivalent ratio of the amide group to a specific functional group of the thermosetting resin (for example, epoxy group of epoxy resin) is generally 0.2 or more and 2.0 or less, preferably 0.3 or more and 1 The amount is 5 or less. When the equivalent ratio is less than 0.2, the heat resistance is lowered, and when the equivalent ratio is greater than 2.0, the pot life tends to be shortened.

Examples of phenolic compounds include bisphenol A, bisphenol F, bisphenol S, 4,4′-biphenylphenol, 2,2′-methylene-bis (4-methyl-6-tert-butylphenol), 2,2′-methylene. -Bis (4-ethyl-6-tert-butylphenol), 4,4'-butylene-bis (3-methyl-6-tert-butylphenol), 1,1,3-tris (2-methyl-4-hydroxy-) 5-tert-butylphenol), trishydroxyphenylmethane, pyrogallol, phenols having a diisopropylidene skeleton, phenols having a fluorene skeleton such as 1,1-di-4-hydroxyphenylfluorene, and polyphenol compounds such as phenolized polybutadiene , Various novolak resins and these Examples thereof include halides of phenol compounds. These can be used individually or in mixture of 2 or more types. Here, examples of various novolak resins include novolak resins and xylylene skeletons made from various phenols such as phenol, cresols, ethylphenols, butylphenols, octylphenols, bisphenol A, bisphenol F, bisphenol S, and naphthols. Examples thereof include a phenol novolac resin containing phenol, a phenol novolak resin containing dicyclopentadiene skeleton, and a phenol novolac resin containing fluorene skeleton.
The compounding amount of the phenol compound is such that the equivalent ratio of the hydroxyl group to a specific functional group of the thermosetting resin (for example, epoxy group of epoxy resin) is generally 0.2 or more and 2.0 or less, preferably 0.3 or more and 1. The amount is 5 or less. When the equivalent ratio is less than 0.2, the heat resistance is lowered, and when the equivalent ratio is greater than 2.0, the pot life tends to be shortened.

Examples of imidazole compounds include 2-methylimidazole, 2-phenylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-phenylimidazole, 1-benzyl. 2-methylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole, 2,4-diamino-6 (2′-methylimidazole (1 ′ )) Ethyl-s-triazine, 2,4-diamino-6 (2′-undecylimidazole (1 ′)) ethyl-s-triazine, 2,4-diamino-6 (2′-ethyl-4-methylimidazole) (1 ′)) Ethyl-s-triazine, 2,4-diamino-6 (2′-methyl) Ruimidazole (1 ')) ethyl-s-triazine isocyanuric acid adduct, 2-methylimidazole isocyanuric acid 2: 3 adduct, 2-phenylimidazole isocyanuric acid adduct, 2-phenyl-3,5-dihydroxy Examples include methylimidazole, 2-phenyl-4-hydroxymethyl-5-methylimidazole, and 1-cyanoethyl-2-phenyl-3,5-dicyanoethoxymethylimidazole. These can be used individually or in mixture of 2 or more types.
The amount of the imidazole compound is generally 0.01 to 10 parts by mass, preferably 0.05 to 5 parts by mass with respect to 100 parts by mass of the thermosetting resin. When the blending amount is less than 0.01 parts by mass, curing becomes insufficient, and when the blending amount is more than 10 parts by mass, the pot life tends to be shortened.

  The filler is not particularly limited, and those known in the technical field can be used. Examples of the filler include inorganic fillers such as alumina, calcium carbonate, and silica; organic fillers such as polyamide resin. In particular, when an inorganic filler is blended, the linear expansion coefficient of the insulating film becomes close to the linear expansion coefficient of the object to be coated, and the adhesion between the insulating film and the object to be coated can be improved. If an organic filler is blended, the stress relaxation of the insulating film can be increased, and the adhesion between the insulating film and the object to be coated can be improved.

  In addition to the above components, the powdery thermosetting resin composition can contain additional components such as a colorant, a coupling agent, a leveling agent, a lubricant, and a stress relaxation agent as necessary. These components are not particularly limited, and those known in the art can be used. Moreover, the compounding quantity of these components will not be specifically limited if it is a range which does not inhibit the effect of this invention.

  A powdery thermosetting resin composition can be manufactured by a well-known method using said component. For example, first, the above components are dry-mixed using a mixing device such as a mixer or a blender, and then melt-kneaded and cooled using a kneader or the like. Thereafter, the kneaded product is pulverized using a mechanical or airflow pulverizer and then classified using a classifier to obtain a powdery thermosetting resin composition having a specific size. it can.

In the coating material of the present invention, the powdery thermosetting resin composition is used after being microencapsulated.
The microcapsules encapsulating the powdered thermosetting resin composition are particularly those that can release the encapsulated powdered thermosetting resin composition to the outside when the coating is cured. It is not limited, A thing well-known in the said technical field can be used. Examples of microcapsules having such a function generally include sustained-release microcapsules and thermoresponsive microcapsules. The thermoresponsive microcapsule has a sufficient isolating function at room temperature and a function of disintegrating and releasing the encapsulated material when heated.

The microcapsule has a core-shell structure, and the core (core) portion is blocked from the outside by the shell (shell) portion. The shape of the microcapsule is not particularly limited, and for example, a spherical shape or an elliptical shape can be used. Moreover, the average particle diameter of the microcapsules is not particularly limited, and may be appropriately adjusted according to the type of the thermosetting resin composition to be used.
Examples of the material of the shell part of the microcapsule include polyurethane, polyurea, gelatin, cross-linked gelatin, alginate, cellulose, vinylidene chloride resin, melamine resin, nylon resin, melamine-formaldehyde resin, urea-formaldehyde resin, and the like. Among these, vinylidene chloride resin, polyurea and polyurethane, polyvinyl acetal, styrene butadiene elastomer, phenoxy resin, and polyvinyl alcohol are preferable from the viewpoint of separability and heat responsiveness.

  The microencapsulation method is not particularly limited, and methods known in the technical field can be used. As an example of the microencapsulation method, an in situ polymerization method, an interfacial polymerization method, a coacervation method, a spray drying method, a dry mixing method, an orifice method, or the like can be used. Among these, the spray drying method is preferable as a method for obtaining the thermoresponsive microcapsules. In the spray drying method, generally, a mixture of a core material such as powder (powdered thermosetting resin composition) and a shell material dissolved in a diluent, or a phase containing a core material and a phase containing a shell material. Is produced, and the mixture or emulsion is spray-dried using a spray-drying apparatus to be microencapsulated.

The coating material of the present invention may further contain an adhesive in addition to the microcapsules enclosing the powdery thermosetting resin composition from the viewpoint of preventing defects such as voids generated in the insulating film to be formed. it can.
It does not specifically limit as an adhesive agent, A well-known thing can be used in the said technical field. Examples of adhesives include epoxy adhesives, acrylic adhesives, and silicone adhesives. These can be used alone or in combination of two or more. Moreover, since these adhesives are generally marketed, it is also possible to use a commercial item.

Epoxy adhesives generally contain a compound having an epoxy group and a curing agent. It does not specifically limit as a compound and hardening | curing agent which have an epoxy group, A well-known thing can be used in the said technical field.
Examples of compounds having an epoxy group used for epoxy adhesives include glycidyl (meth) acrylate, itaconic acid monoglycidyl ester, butenetricarboxylic acid monoglycidyl ester, butenetricarboxylic acid diglycidyl ester, butenetricarboxylic acid glycidyl ester, butene Tricarboxylic acid triglycidyl ester, 2-methylallyl glycidyl ether, styrene-p-glycidyl ether, 3,4-epoxybutene, 3,4-epoxy-3-methyl-1-butene, 3,4-epoxy-1-pentene 3,4-epoxy-3-methylpentene, 5,6-epoxy-1-hexene, vinylcyclohexene monoxide, p-glycidylstyrene and the like. These can be used alone or in combination of two or more. Among these, glycidyl (meth) acrylate, which is easily available and inexpensive, is preferable. Moreover, the same thing as the epoxy resin used for a powdery thermosetting resin composition can also be used as a compound which has an epoxy group.

As a hardening | curing agent used for an epoxy-type adhesive agent, the same thing as the hardening | curing agent used for a powdery thermosetting resin composition is mentioned. An amine compound can also be used as a curing agent.
It does not specifically limit as an amine compound, A well-known thing can be used in the said technical field. Examples of amine compounds include chain aliphatic amines, cycloaliphatic amines and aromatic amines. These can be used alone or in combination of two or more.
Examples of chain aliphatic amines include diethylenetriamine (DTA), triethylenetetramine (TTA), tetraethylenepentamine (TEPA), dipropylenediamine (DPDA), diethylaminopropylamine (DEAPA), AMINE 248, and the like. .

Examples of cycloaliphatic amines include N-aminoethylpiperazine (N-AEP), Temirone C-260, Araldit HY-964, Mensendiamine (MDA), Isophoronediamine (IPDA), S Cure 211, S Cure 212, Wandamine HM, 1.3 BAC and the like.
Examples of aromatic amines include m-xylenediamine (m-XDA), shoamine X, amine black, shoamine black, shoamine N, shoamine N1001, shoamine N1010, metaphenylenediamine (MPDA), diaminodiphenylmethane (DDM), diaminodiphenylsulfone (DDS) and the like.
Among the above various amine compounds, diethylaminopropylamine, isophoroneamine, and m-xyleneamine are preferable.
The compounding amount of the amine compound is such that the equivalent ratio of the amine group to the epoxy group of the epoxy resin is generally 0.2 or more and 2.0 or less, preferably 0.3 or more and 1.5 or less. When the equivalent ratio is less than 0.2, the heat resistance is lowered, and when the equivalent ratio is greater than 2.0, the pot life tends to be shortened.

  The acrylic adhesive generally contains an acrylic monomer. The acrylic monomer is not particularly limited, and (meth) acrylic acid ester (for example, methyl acrylate, ethyl acrylate, n- or tert-butyl acrylate, isooctyl acrylate, 2-ethylhexyl acrylate, phenyl acrylate, benzyl acrylate, 2 -Hydroxyethyl acrylate, 2-hydroxypropyl acrylate, methyl methacrylate, ethyl methacrylate, ethylene diacrylate, neopentyl diacrylate, trimethylolpropane tris acrylate, pentaerythritol tetraacrylate, pentaerythritol tris acrylate), acrylonitrile, methacrylonitrile, acrylamide , Methacrylamide, N-substituted (meth) -acrylamide, polyester acrylic Over DOO, polyether acrylate. These can be used alone or in combination of two or more.

  As the silicone-based adhesive, any of an addition type, a dealcohol type, a deoxime type, a deacetone type, a deacetic acid type, and the like can be used. Silicone adhesives generally contain an alkoxysilane compound having an unsaturated group such as an acryl group, a methacryl group, a vinyl group, or an allyl group. Examples of the alkoxysilane compound include vinyltris (βmethoxyethoxy) silane, vinyltriethoxysilane, vinyltrimethoxysilane, vinyltripropoxysilane, allyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, and the like. These can be used alone or in combination of two or more.

  The adhesive can contain a filler from the viewpoint of improving the adhesion between the insulating film and the object to be coated. The filler is not particularly limited, and those known in the technical field can be used. Examples of the filler include inorganic fillers such as alumina, calcium carbonate, and silica; organic fillers such as polyamide resin. In particular, when an inorganic filler is blended, the linear expansion coefficient of the insulating film becomes close to the linear expansion coefficient of the object to be coated, and the adhesion between the insulating film and the object to be coated can be improved. If an organic filler is blended, the stress relaxation of the insulating film can be increased, and the adhesion between the insulating film and the object to be coated can be improved.

The adhesive may be either powder or liquid, and may be a mixture of powder and liquid.
When a liquid adhesive is used, the adhesive can further include an organic solvent. Although it does not specifically limit as an organic solvent, A thing with high volatility is preferable. Examples of the organic solvent include methyl ethyl ketone, acetone, tetrahydrofuran, toluene, xylene, methyl isobutyl ketone and the like. These can be used alone or in combination of two or more.

  The adhesive can be blended in the paint of the present invention as it is, but may be microencapsulated and blended in the paint of the present invention. In addition, a microcapsulated adhesive and an adhesive not microencapsulated can be used in combination. The microencapsulation of the adhesive can be performed in the same manner as described in the microencapsulation of the powdery thermosetting resin composition.

  The blending amount of the adhesive in the paint of the present invention is not particularly limited as long as it is appropriately adjusted according to the type of the adhesive. The general blending amount of the adhesive is preferably 1 part by mass or more and 50 parts by mass or less, more preferably 2 parts by mass or more with respect to 100 parts by mass of the microcapsules enclosing the powdery thermosetting resin composition. 40 parts by mass or less, most preferably 3 parts by mass or more and 30 parts by mass or less. The effect by mix | blending an adhesive agent is fully acquired as the compounding quantity of an adhesive agent is less than 1 mass part. On the other hand, when the compounding amount of the adhesive exceeds 50 parts by mass, the characteristics as an insulating film may not be sufficiently obtained.

  The paint of the present invention containing the above components is microencapsulated with a paint component (powdered thermosetting resin composition) that provides an insulating film. Can be painted. In addition, the microcapsule collapses during heating, and the powdered thermosetting resin composition encapsulated in the microcapsule is liquefied and cured, so that both the insulation film formed can be made uniform and the film thickness can be increased. It becomes possible. Furthermore, if the paint of this invention mix | blends the adhesive agent, the adhesiveness of microcapsules can be improved at the time of coating, and generation | occurrence | production of defects, such as a void, in an insulating film can be prevented.

The coating method using the paint of the present invention is not particularly limited, and methods known in the technical field can be used. Examples of the coating method include an electrostatic coating method, a fluid immersion method, an electrostatic fluid immersion method, brush coating, spray coating, and immersion.
The coating may be performed only once to form a single layer, but may be performed multiple times to form a multilayer. The coating is preferably performed while heating the object to be coated from the viewpoint of stably attaching the paint to the object to be coated. By coating the object to be coated while heating, the microcapsules contained in the paint of the present invention exhibit viscosity, and the adhesion between the microcapsules is improved. Although the temperature of a to-be-coated object is not specifically limited, Generally it is 50 to 200 degreeC, Preferably it is 60 to 150 degreeC.

After painting, the painted object is heated. By heating the coated material, the microcapsules in the coated material are collapsed, and the powdery thermosetting resin composition contained in the microcapsules is liquefied and cured, so that a uniform and thick insulating film is formed. be able to.
The heating temperature of the coated material is not particularly limited, and may be set as appropriate according to the type of paint used. The general heating temperature of the coated product is preferably 50 ° C. or higher and 300 ° C. or lower, more preferably 60 ° C. or higher and 250 ° C. or lower. When the heating temperature is less than 50 ° C., the powdery thermosetting resin composition encapsulated in the microcapsule may not melt and the microcapsule may not collapse. And since a microcapsule maintains the shape, defects, such as a void, arise between microcapsules. On the other hand, when the heating temperature exceeds 300 ° C., the powdery thermosetting resin composition or the like encapsulated in the microcapsule may be decomposed and an insulating film may not be formed.

  The material to be coated with the paint of the present invention is not particularly limited, and examples thereof include metal materials such as steel materials and aluminum materials, glass, concrete, and special resins. Moreover, it does not specifically limit as a shape of to-be-coated object, It can be various shapes, such as a column shape and a rectangular parallelepiped. In particular, by using the paint of the present invention, it is possible to form a uniform and thick insulating film without causing the paint to sag even on an object having a complicated three-dimensional shape that tends to cause the paint to sag.

  Since the coating material of the present invention can form a uniform and thick insulating film, the dielectric breakdown voltage of the insulating film can be improved. Therefore, the coating material of the present invention can be used as an insulating film that insulates various members in devices such as gas insulated switchgears and rotating electrical machines (small, medium, and large). For example, in a gas insulated switchgear, an insulating film formed from the paint of the present invention can be formed on the surface of the stator coil. In the rotating electric machine, an insulating film formed from the paint of the present invention can be formed on the surface of the stator coil in the slot.

EXAMPLES Hereinafter, although an Example demonstrates the detail of this invention, this invention is not limited by these.
Example 1
100 parts by mass of bisphenol A type epoxy resin (weight average molecular weight 1150) solid at room temperature, 30 parts by mass of cresol novolac type epoxy resin (weight average molecular weight 1400) solid at room temperature, 7 parts by mass of dicyandiamide (curing agent), imidazole (cured) Agent) 3 parts by mass and alumina (filler) 15 parts by mass were dry-mixed using a mixer and then melt-kneaded using a biaxial kneader. Next, the obtained kneaded product is cooled and solidified, and then pulverized using a pulverizer and classified using a classifier, whereby a powdery thermosetting resin composition having an average particle size of 40 μm is obtained. Got.

Next, vinylidene chloride resin Elmajon (Asahi Kasei Kogyo L-502) is added to and mixed with the powdery thermosetting resin composition, and sprayed using a spray dryer GS310 manufactured by Yamato Scientific Co., Ltd. Drying was performed to encapsulate the powdery thermosetting resin composition. And this microcapsule was used as a coating material.
Next, electrostatic powder coating was performed on the surfaces of the stator slots of the motor and the stator coils (conductors) of the gas-insulated switchgear (GIS) with an applied voltage of 80 kV using the above paint. At this time, the coating was performed while heating the stator slot of the motor and the GIS conductor to 100 ° C. After coating, the coated product was heated at 100 ° C. for 10 minutes, and further heated at 180 ° C. for 30 minutes to obtain an insulating film. No sagging of paint was observed during painting and heating.

About the insulating film obtained above, the film thickness was measured one by one in a 10 cm square using a film thickness meter, and the average film thickness, the maximum film thickness, and the minimum film thickness were obtained. As a result, the difference between the average film thickness and the maximum or minimum film thickness was within 20%, confirming that the insulating film had high uniformity.
Next, the dielectric breakdown voltage of the insulating film formed in the stator slot of the motor was measured and found to be 25 kV / mm. Here, the dielectric breakdown voltage was measured by installing a planar electrode on an insulating film and applying a high voltage therebetween.
Next, the GIS conductor on which the insulating film was formed was placed in a grounded metal container, and the container was filled with SF6 gas. Thereafter, a high voltage was applied to the GIS conductor, and the dielectric breakdown electric field on the surface of the insulating film was measured. As a result, the dielectric breakdown electric field on the surface of the insulating film was 1.8 times the dielectric breakdown electric field of the GIS conductor in which the insulating film was not formed.

(Example 2)
A powdery thermosetting resin composition having an average particle size of 40 μm was obtained in the same manner as in Example 1 except that 15 parts by mass of m-xyleneamine was used as a curing agent.
Next, 10 g of the above powdery thermosetting resin composition and a solution obtained by dissolving 1 g of a thermoplastic resin (phenoxy resin, YP-50 (manufactured by Tohto Kasei Co., Ltd.)) in 9 g of ethyl acetate as a solvent, Were mixed and spray-dried using a spray dryer GS310 manufactured by Yamato Scientific Co., Ltd. to microencapsulate the powdery thermosetting resin composition. And this microcapsule was used as a coating material.
Next, electrostatic powder coating was applied to the stator slot of the motor and the surface of the GIS conductor with an applied voltage of 80 kV using the above paint. At this time, the coating was performed while heating the stator slot of the motor and the GIS conductor to 100 ° C. After coating, the coated product was heated at 100 ° C. for 5 minutes and further heated at 180 ° C. for 30 minutes to obtain an insulating film. No sagging of paint was observed during painting and heating.

Next, as a result of measuring the film thickness of the insulating film in the same manner as in Example 1, the difference between the average film thickness and the maximum or minimum film thickness is within 20%, indicating that the insulating film has high uniformity. confirmed.
Further, the dielectric breakdown voltage of the insulating film formed in the stator slot of the motor was measured in the same manner as in Example 1, and the result was 24 kV / mm.
Further, the breakdown electric field on the surface of the insulating film of the GIS conductor was measured in the same manner as in Example 1. As a result, the breakdown electric field on the surface of the insulating film was 1.7 times that of the conductor not formed with the insulating film. Met.

Example 3
A powdery thermosetting resin composition having an average particle size of 40 μm was obtained in the same manner as in Example 1 except that 10 parts by mass of isophoronediamine was used as a curing agent.
Next, 10 g of the above powdery thermosetting resin composition is mixed with a solution in which 1 g of urethane resin (Desmocol 500 (manufactured by Bayer Holding Co., Ltd.)) is dissolved in 9 g of ethyl acetate as a solvent, Spray drying was performed using a spray dryer GS310 manufactured by Yamato Scientific Co., Ltd., and the powdery thermosetting resin composition was microencapsulated. And this microcapsule was used as a coating material.
Next, 10 parts by mass of an epoxy adhesive containing 60 parts by mass of an acid anhydride (Kayahard MCD) with respect to 100 parts by mass of the bisphenol A type epoxy resin is added to 100 parts by mass of the microcapsule produced above. The paint was obtained by mixing.
Next, electrostatic powder coating was applied to the stator slot of the motor and the surface of the GIS conductor with an applied voltage of 80 kV using the above paint. At this time, the coating was performed while heating the stator slot of the motor and the GIS conductor to 100 ° C. After coating, the coated product was heated at 100 ° C. for 8 minutes, and further heated at 180 ° C. for 30 minutes to obtain an insulating film. No sagging of paint was observed during painting and heating.

Next, as a result of measuring the film thickness of the insulating film in the same manner as in Example 1, the difference between the average film thickness and the maximum or minimum film thickness is within 20%, indicating that the insulating film has high uniformity. confirmed.
Further, the dielectric breakdown voltage of the insulating film formed in the stator slot of the motor was measured in the same manner as in Example 1, and the result was 25 kV / mm.
Further, the breakdown electric field on the surface of the insulating film of the GIS conductor was measured in the same manner as in Example 1. As a result, the breakdown electric field on the surface of the insulating film was 1.8 times the breakdown electric field of the conductor not formed with the insulating film. Met.

Example 4
A coating material was obtained by adding and mixing 5 parts by mass of a polyester acrylate adhesive to 100 parts by mass of the microcapsules enclosing the powdery thermosetting resin composition prepared in Example 1.
Next, electrostatic powder coating was applied to the stator slot of the motor and the surface of the GIS conductor with an applied voltage of 80 kV using the above paint. At this time, the coating was performed while heating the stator slot of the motor and the GIS conductor to 100 ° C. After coating, the coated product was heated at 100 ° C. for 10 minutes, and further heated at 180 ° C. for 30 minutes to obtain an insulating film. No sagging of paint was observed during painting and heating.

Next, as a result of measuring the film thickness of the insulating film in the same manner as in Example 1, the difference between the average film thickness and the maximum or minimum film thickness is within 20%, indicating that the insulating film has high uniformity. confirmed.
Further, the dielectric breakdown voltage of the insulating film formed in the stator slot of the motor was measured in the same manner as in Example 1, and the result was 22 kV / mm.
Further, the breakdown electric field on the surface of the insulating film of the GIS conductor was measured in the same manner as in Example 1. As a result, the breakdown electric field on the surface of the insulating film was 1.7 times that of the conductor not formed with the insulating film. Met.

(Example 5)
After 50 parts by mass of polycarboxylic acid (phthalic acid), 50 parts by mass of polyhydric alcohol (trimethylolpropane) and 50 parts by mass of filler (silica) are dry-mixed using a mixer, they are melted using a biaxial kneader. Kneaded. Next, the obtained kneaded product is cooled and solidified, and then pulverized using a pulverizer and classified using a classifier, whereby a powdery thermosetting resin composition having an average particle size of 50 μm is obtained. Got.
Next, 10 g of the above powdery thermosetting resin composition and a solution obtained by dissolving 1 g of a thermoplastic resin (phenoxy resin, YP-50 (manufactured by Tohto Kasei Co., Ltd.)) in 9 g of ethyl acetate as a solvent, Were mixed and spray-dried using a spray dryer GS310 manufactured by Yamato Scientific Co., Ltd. to microencapsulate the powdery thermosetting resin composition. And this microcapsule was used as a coating material.

Next, electrostatic powder coating was applied to the stator slot of the motor and the surface of the GIS conductor with an applied voltage of 80 kV using the above paint. At this time, the coating was performed while heating the stator slot of the motor and the GIS conductor to 100 ° C. After coating, the coated product was heated at 100 ° C. for 10 minutes, and further heated at 180 ° C. for 30 minutes to obtain an insulating film. No sagging of paint was observed during painting and heating.
Next, as a result of measuring the film thickness of the insulating film in the same manner as in Example 1, the difference between the average film thickness and the maximum or minimum film thickness is within 20%, indicating that the insulating film has high uniformity. confirmed.
Further, the dielectric breakdown voltage of the insulating film formed in the stator slot of the motor was measured in the same manner as in Example 1, and the result was 25 kV / mm.
Further, the breakdown electric field on the surface of the insulating film of the GIS conductor was measured in the same manner as in Example 1. As a result, the breakdown electric field on the surface of the insulating film was 1.8 times the breakdown electric field of the conductor not formed with the insulating film. Met.

(Example 6)
The acrylic powder was microencapsulated in the same manner as in Example 1 except that an acrylic powder (V-PET # 1370QD manufactured by Dainippon Paint Co., Ltd.) was used instead of the powdery thermosetting resin composition. .
Next, 10 parts by mass of a polyether acrylate adhesive was added to and mixed with 100 parts by mass of the above microcapsules to obtain a paint.

Next, electrostatic powder coating was applied to the stator slot of the motor and the surface of the GIS conductor with an applied voltage of 80 kV using the above paint. At this time, the coating was performed while heating the stator slot of the motor and the GIS conductor to 100 ° C. After coating, the coated product was heated at 100 ° C. for 10 minutes, and further heated at 180 ° C. for 30 minutes to obtain an insulating film. No sagging of paint was observed during painting and heating.
Next, as a result of measuring the film thickness of the insulating film in the same manner as in Example 1, the difference between the average film thickness and the maximum or minimum film thickness is within 20%, indicating that the insulating film has high uniformity. confirmed.
Further, the dielectric breakdown voltage of the insulating film formed in the stator slot of the motor was measured in the same manner as in Example 1, and the result was 24 kV / mm.
Further, the breakdown electric field on the surface of the insulating film of the GIS conductor was measured in the same manner as in Example 1. As a result, the breakdown electric field on the surface of the insulating film was 1.8 times the breakdown electric field of the conductor not formed with the insulating film. Met.

(Example 7)
In the same manner as in Example 2, except that an epoxy polyester powder (V-PET # 5000 manufactured by Dainippon Paint Co., Ltd.) was used instead of the powdery thermosetting resin composition, the epoxy polyester powder was microcapsuled. Turned into.
Next, an epoxy adhesive containing 80 parts by mass of an acid anhydride (Kayahard MCD) with respect to 100 parts by mass of a bisphenol A type epoxy resin is used as an emulsion. After adding polyvinyl alcohol to the emulsion, spray drying is performed. Microencapsulated.
Next, 15 parts by mass of microcapsules encapsulating an epoxy adhesive were added to and mixed with 100 parts by mass of microcapsules encapsulating the powdered thermosetting resin composition, thereby obtaining a paint.

Next, using the above paint, the stator slots of the motor and the surfaces of the GIS conductors were coated by the fluidized dipping method. At this time, the coating was performed while heating the stator slot of the motor and the GIS conductor to 100 ° C. After coating, the coated product was heated at 100 ° C. for 15 minutes and further heated at 180 ° C. for 30 minutes to obtain an insulating film. No sagging of paint was observed during painting and heating.
Next, as a result of measuring the film thickness of the insulating film in the same manner as in Example 1, the difference between the average film thickness and the maximum or minimum film thickness is within 20%, indicating that the insulating film has high uniformity. confirmed.
Further, the dielectric breakdown voltage of the insulating film formed in the stator slot of the motor was measured in the same manner as in Example 1, and the result was 26 kV / mm.
Furthermore, as a result of measuring the dielectric breakdown electric field on the insulating film surface of the GIS conductor in the same manner as in Example 1, the dielectric breakdown electric field on the surface of the insulating film was 1.9 times the dielectric breakdown electric field of the conductor on which the insulating film was not formed. Met.

(Example 8)
A microcapsule in which an epoxy adhesive containing 40 parts by mass of 2-phenylimidazole with respect to 100 parts by mass of a bisphenol A type epoxy resin and gelatin is microencapsulated by an orifice method, and a shell material (film) is gelatin Obtained.
Next, 3 parts by mass of microcapsules containing an epoxy adhesive were added to and mixed with 100 parts by mass of the microcapsules of epoxy polyester powder used in Example 7 to obtain a paint.

Next, using the above paint, the stator slots of the motor and the surfaces of the GIS conductors were coated by the fluidized dipping method. At this time, the coating was performed while heating the stator slot of the motor and the GIS conductor to 100 ° C. After coating, the coated product was heated at 100 ° C. for 15 minutes and further heated at 180 ° C. for 30 minutes to obtain an insulating film. No sagging of paint was observed during painting and heating.
Next, as a result of measuring the film thickness of the insulating film in the same manner as in Example 1, the difference between the average film thickness and the maximum or minimum film thickness is within 20%, indicating that the insulating film has high uniformity. confirmed.
Further, the dielectric breakdown voltage of the insulating film formed in the stator slot of the motor was measured in the same manner as in Example 1, and the result was 22 kV / mm.
Further, the breakdown electric field on the surface of the insulating film of the GIS conductor was measured in the same manner as in Example 1. As a result, the breakdown electric field on the surface of the insulating film was 1.6 times that of the conductor not formed with the insulating film. Met.

Example 9
A solution obtained by dissolving 1 g of a thermoplastic resin (phenoxy resin, YP-50 (manufactured by Tohto Kasei Co., Ltd.)) in 10 g of the powdery thermosetting resin composition used in Example 1 and 9 g of ethyl acetate as a solvent. Were mixed and spray-dried using a spray dryer GS310 manufactured by Yamato Scientific Co., Ltd. to microencapsulate the powdery thermosetting resin composition. And this microcapsule was used as a coating material.
Next, polyester acrylate and urethane were used to make microcapsules by an interfacial polymerization method, and microcapsules whose shell material (film) was urethane were obtained.
Next, 20 parts by mass of microcapsules encapsulating polyester acrylate were added to and mixed with 100 parts by mass of microcapsules encapsulating the powdered thermosetting resin composition, thereby obtaining a paint.

Next, using the above paint, the stator slots of the motor and the surfaces of the GIS conductors were coated by the fluidized dipping method. At this time, the coating was performed while heating the stator slot of the motor and the GIS conductor to 100 ° C. After coating, the coated product was heated at 100 ° C. for 5 minutes and further heated at 180 ° C. for 30 minutes to obtain an insulating film. No sagging of paint was observed during painting and heating.
Next, as a result of measuring the film thickness of the insulating film in the same manner as in Example 1, the difference between the average film thickness and the maximum or minimum film thickness is within 20%, indicating that the insulating film has high uniformity. confirmed.
Further, the dielectric breakdown voltage of the insulating film formed in the stator slot of the motor was measured in the same manner as in Example 1, and the result was 21 kV / mm.
Further, the breakdown electric field on the surface of the insulating film of the GIS conductor was measured in the same manner as in Example 1. As a result, the breakdown electric field on the surface of the insulating film was 1.8 times the breakdown electric field of the conductor not formed with the insulating film. Met.

(Comparative Example 1)
100 parts by mass of bisphenol A type epoxy resin (weight average molecular weight 1150) solid at room temperature, 30 parts by mass of cresol novolac type epoxy resin (weight average molecular weight 1400) solid at room temperature, 7 parts by mass of dicyandiamide (curing agent), imidazole (cured) Agent) 3 parts by mass and alumina (filler) 15 parts by mass were dry-mixed using a mixer and then melt-kneaded using a biaxial kneader. Next, the obtained kneaded product is cooled and solidified, and then pulverized using a pulverizer and classified using a classifier, whereby a powdery thermosetting resin composition having an average particle size of 40 μm is obtained. Got. And this powdery thermosetting resin composition was used as a coating material.
Next, electrostatic powder coating was performed on the surfaces of the stator slots of the motor and the stator coils (conductors) of the gas-insulated switchgear (GIS) with an applied voltage of 80 kV using the above paint. At this time, the coating was performed while heating the stator slot of the motor and the GIS conductor to 100 ° C. After coating, the coated product was heated at 100 ° C. for 5 minutes and further heated at 180 ° C. for 30 minutes to obtain an insulating film. During painting and heating, dripping of the paint was confirmed.

Next, as a result of measuring the film thickness of the insulating film in the same manner as in Example 1, the difference between the average film thickness and the maximum or minimum film thickness is 150% or more, and the insulating film has low uniformity. confirmed.
Further, the dielectric breakdown voltage of the insulating film formed in the stator slot of the motor was measured in the same manner as in Example 1, and the result was 5 kV / mm.
Furthermore, as a result of measuring the dielectric breakdown electric field on the insulating film surface of the GIS conductor in the same manner as in Example 1, the dielectric breakdown electric field on the surface of the insulating film was 1.1 times the dielectric breakdown electric field of the conductor not forming the insulating film. Met.

  As can be seen from the above results, according to the present invention, it is possible to provide a coating for forming an insulating film capable of forming a uniform and thick insulating film. In addition, according to the present invention, it is possible to provide a gas insulated switchgear and a rotating electrical machine having a uniform and thick insulating film.

Claims (8)

  A coating material for forming an insulating film comprising a microcapsule encapsulating a powdery thermosetting resin composition.   The powdery thermosetting resin composition includes at least one resin selected from the group consisting of an epoxy resin, a polyester resin, an epoxy polyester resin, and an acrylic resin. Insulating film forming paint.   The coating composition for forming an insulating film according to claim 1, further comprising an adhesive.   The said adhesive agent is at least 1 sort (s) selected from the group which consists of an epoxy-type adhesive agent, an acrylic adhesive agent, and a silicone type adhesive agent, The coating material for insulating film formation of Claim 3 characterized by the above-mentioned.   The insulating film-forming paint according to claim 3 or 4, wherein the adhesive is microencapsulated.   The said microcapsule is a sustained release microcapsule or a thermoresponsive microcapsule, The coating material for insulating film formation as described in any one of Claims 1-5 characterized by the above-mentioned.   A gas-insulated switchgear comprising an insulating film formed from the insulating film-forming paint according to any one of claims 1 to 6.   A rotating electrical machine comprising an insulating film formed from the coating material for forming an insulating film according to claim 1.