JPS6260425B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention can be used even at temperatures up to about 700°C.
The present invention relates to a heat-resistant electrically insulating coating composition that maintains film properties and electrically insulating properties. In recent years, there has been a trend toward smaller and lighter rotating electrical equipment and other electrical equipment, and rotating electrical equipment is increasingly subject to high loads and generates high heat.
There is a strong desire to develop electrically insulating paints that can maintain film properties and electrically insulating properties even at high temperatures. Conventionally, epoxy resin powder coatings, molded films such as polyimide, etc. have been used for heat-resistant insulation treatment of rotating electric machines, but since these are organic materials, they have limited heat resistance. Paints that can maintain film properties and electrical insulation properties even at high temperatures of about 500℃ to 700℃ include glass frits or glass frits and inorganic substances suspended in organic solvents, colloidal silica, aluminum phosphate, etc. There are products suspended in water glass, but these require firing at high heat to form a coating film, and the coating film formed is brittle, which poses a practical problem. Heat-resistant paints made of silicone resins or silicone resins and high-melting point inorganic powders are known to improve these drawbacks, as described in, for example, JP-A-56-167305.
The coating film formed by this heat-resistant paint has a temperature range of 300 to 350 degrees Celsius or below, where the silicone resin begins to decompose, and the high melting point inorganic powder melts and becomes enameled.
In the temperature range of 600°C or higher, it exists as a strong insulating coating layer, but in the intermediate temperature range of 350°C to 600°C, silicone resin decomposes, while high melting point inorganic powder does not melt, so its mechanical strength decreases. There are almost no
As a heat-resistant paint, it was extremely incomplete. In addition, all of these heat-resistant paints that have been known so far are of the solution type, and no powder paints that can withstand practical use have been provided. By overcoming these drawbacks of conventional technology,
As a heat-resistant electrical insulating coating composition that maintains film properties and electrical insulation properties under a wide range of temperatures up to about ℃,
The present inventors have already proposed a thermosetting resin composition formed by mixing a silicone-modified epoxy resin and an inorganic filler containing a low-melting glass powder. This heat-resistant electrical insulating coating composition can also be used in the form of a powder coating, which is applied to the surface of an element such as metal by a powder coating method such as a fluidized dipping method or an electrostatic dynamic dipping method, and then heated. However, the insulating coating layer obtained by melting and curing has very good basic properties required for paints such as smoothness, gloss, impact resistance, and adhesion to the base body, and is also stable at room temperature. It has extremely excellent heat resistance, being able to maintain its film properties and electrical insulation properties over a wide temperature range from 700°C to 700°C. However, since the silicone-modified epoxy resin has flexibility, the insulation coating layer obtained by heating, melting, and curing this heat-resistant electrical insulation coating composition cannot be used as an epoxy resin-based paint using a heat-resistant epoxy resin. In comparison, the adhesive strength was slightly inferior at 100°C to 500°C, especially at 100°C to 300°C, where the resin begins to soften due to heat. The present inventors have developed a thermosetting resin composition obtained by mixing a silicone-modified epoxy resin and an inorganic powder containing low melting point glass at temperatures of 100°C to 500°C, particularly 100°C to 300°C.
As a result of intensive research on improving adhesive strength in It was discovered that not only the hardness and adhesion of the coating film were greatly improved, but also the hardness and adhesion of the coating from room temperature to 700°C, especially at high temperatures around 500°C to 700°C, were further improved, and this led to the completion of the present invention. It is. In other words, the present invention provides an epoxy resin modified with an organic silicone intermediate having a functional group capable of reacting with an epoxy resin containing a hydroxyl group in a range of 10 to 50% by weight, with a melting point of 40°C or higher and an epoxy equivalent of 400.
-2000 silicone-modified epoxy resin (A), one or more heat-resistant resins (B) with a thermal decomposition onset temperature of 200°C or higher, and a low-melting glass powder with a melting point of 400°C to 500°C. The main component is an inorganic filler (C) containing 10% by weight or more, and the mixing ratio is (A): (B) by weight.
=90:10~50:50, (A)+(B):(C)=20:80~60:40
The present invention relates to a heat-resistant electrically insulating coating composition comprising: The silicone-modified epoxy resin (A) used in the present invention has a melting point of 40% by modifying the epoxy resin in a range of 10 to 50% by weight with an organic silicone intermediate having a functional group that can react with an epoxy resin containing a hydroxyl group. ℃ or higher, the epoxy equivalent is 400 to 2000, preferably the melting point is 40℃ to 90℃, more preferably 60℃ to 75℃, and the number average molecular weight is 700 to 70℃.
3,000, and those having an epoxy equivalent of 700 to 1,200 are preferably used. If the amount of modification by the organosilicone intermediate is less than 10% by weight, the heat resistance of the paint will be insufficient;
If it exceeds , the wettability with the painted body will be insufficient.
If the melting point of the silicone-modified epoxy resin is below 40°C, it will flow too much when the coating composition is heated, melted, and cured, resulting in extremely poor edge coverage of the formed insulating layer, which may easily cause insulation defects. Become. Furthermore, when the coating composition is made into powder, blocking occurs within several hours even if it is left at room temperature. On the other hand, if the melting point exceeds 90°C, the fluidity during heating, melting, and curing of the coating composition will be insufficient, and the smoothness of the formed insulating layer will deteriorate, making it difficult to obtain a coated product with a good appearance. It tends to become more difficult. Moreover, if the blending ratio of resin is increased in order to improve the appearance, the heat resistance becomes insufficient. When the epoxy equivalent of the silicone-modified epoxy resin is less than 400, the crosslinking density of the insulating layer formed by heating, melting, and curing the coating composition becomes too high, resulting in a decrease in impact resistance and making it easy to break. Also, the epoxy equivalent is
If it exceeds 2000, the crosslinking density of the insulating layer becomes too low, resulting in a decrease in the hardness of the insulating layer, which poses a practical problem. The organic silicone intermediate used to obtain the silicone-modified epoxy resin (A) of the present invention includes:
Those that have a functional group that can react with an epoxy resin containing a hydroxyl group, that is, those that have a hydroxyl group directly bonded to a silicon atom, a halogen group such as chlorine or bromine, an alkoxy group such as a methoxy group or an ethoxy group, an acetoxy group, etc. Among these, those having an alkoxy group are most preferred because they can easily react with the epoxy resin. For other substituents directly bonded to silicon,
For example, those having two or more types of groups having different decomposition temperatures, such as methyl group and phenyl group, are preferable because decomposition occurs in stages at high temperatures. Furthermore, the epoxy resin used to obtain the silicone-modified epoxy resin (A) of the present invention has two or more epoxy groups in the molecule, such as bisphenol type epoxy resin, halogenated bisphenol type epoxy resin, etc. , novolac type epoxy resin, resorcinol type epoxy resin, tetrahydroxydiphenylethane type epoxy resin, polyalcohol type epoxy resin, polyglycol type epoxy resin, glycerin triether type epoxy resin,
Polyolefin type epoxy resins, alicyclic type epoxy resins, etc. are not particularly limited, and these epoxy resins can be used alone or in combination. The thermal decomposition initiation temperature used in the present invention is
The resin (B) having a temperature of 200°C or higher is selected from the group of novolac type epoxy resins, phenolic resins, oxazolidone ring- and/or isocyanurate ring-containing resins, imide group-containing resins, triazine ring-containing resins, and hydantoin ring-containing resins. One or more resins, such as aromatic polyamide, polybenzimidazole, polyphenylene sulfide, polyphenylene oxide, and aromatic polyester, which cannot be used alone because they have a high melting point and reduce the flowability of the coating composition. If the amount is within 20%, it can be used in combination with the above heat-resistant resin. The novolak-type epoxy resin used in the present invention is a resin obtained from the reaction of the phenolic hydroxyl group of the novolak resin with epichlorohydrin, and preferably has a melting point of 50°C to 150°C, more preferably 60°C to 100°C, The epoxy equivalent is preferably 130 to 400, more preferably 180 to 250, such as phenol novolac type epoxy resin, cresol novolac type epoxy resin, resorcinol novolac type epoxy resin, co-condensation of phenol and bisphenol A. A novolak type epoxy resin or the like is preferably used. The phenolic resin used in the present invention is a novolac type or resol type resin obtained from the reaction of phenol or a phenol derivative with formaldehyde, or a resin cocondensed with the novolac type or resol type resin and a xylene resin, mesitylene resin, etc. , the melting point is preferably 50°C to 150°C,
More preferably, the melting point is 60°C to 100°C, and the hydroxyl equivalent is preferably 100 to 400, even more preferably 110 to 200.
Those are preferably used. The resin containing an oxazolidone ring and/or isocyanurate ring used in the present invention is a resin obtained by reacting a polyisocyanate having two or more isocyanate groups with an epoxy resin having two or more epoxy groups, or isocyanuric acid. A resin obtained by reacting with epichlorohydrin and has a melting point of preferably 50℃~
Those having a melting point of 150°C, more preferably 60°C to 100°C, and an epoxy equivalent of preferably 100 to 1000, more preferably 100 to 400 are suitably used. Further, the oxazolidone ring and/or isocyanurate ring-containing resin also includes a precursor that forms an oxazolidone ring and/or isocyanurate ring upon curing. Examples of such materials include mixtures of polyisocyanates blocked with phenol or caprolactam, and epoxy resins. The resin containing an imide group used in the present invention is a monomer containing an imide group, such as a compound containing an imide group obtained by reacting an aromatic carboxylic acid anhydride with aminophenol or an aminocarboxylic acid, an aromatic A prepolymer of a polyimide resin obtained by reacting a diamine with an aromatic tetracarboxylic acid dianhydride, a prepolymer of a polyamideimide resin obtained by reacting an aromatic diamine with an aromatic tricarboxylic acid monoanhydride, Prepolymer of polyesterimide resin obtained by reacting aromatic diamine, aromatic diol and aromatic tricarboxylic acid monoanhydride, bismaleimide, polybismaleimide obtained by reacting bismaleimide with aromatic diamine A resin with a melting point of preferably 60°C to 200°C, more preferably 70°C.
C. to 120.degree. C. is preferably used. The imide group-containing resin also includes a precursor that forms an imide group upon curing. Such materials include amic acid and polyamic acid. The resin containing a triazine ring used in the present invention includes a monomer containing a triazine ring obtained by reacting and trimerizing an aromatic cyanic acid diester, a prepolymer obtained by further reacting the monomer, and a triazine ring A prepolymer obtained by reacting a monomer or prepolymer containing bismaleimide with bismaleimide, preferably having a melting point of 50°C to 180°C, more preferably 60°C to 90°C, is suitably used. . The triazine ring-containing resin also includes a precursor that forms a triazine ring upon curing. Examples of such compounds include aromatic cyanic acid diesters. The resin containing a hydantoin ring used in the present invention is a polyhydantoin resin (Resistfol,
manufactured by Bayer), or hydantoin ring-containing epoxy resins obtained by reacting hydantoin or hydantoin derivatives with epichlorohydrin, preferably having a melting point of 40°C to 130°C, more preferably 60°C to 90°C. used. The resins used in the present invention include a silicone-modified epoxy resin (A) and one or more heat-resistant resins having a thermal decomposition initiation temperature of 200°C or higher (B).
The weight ratio of (A):(B)=90:10 to 50:50
Those within the range of are used. If the blending ratio of the heat-resistant resin (B) is less than 10% by weight, there will be little improvement in heat resistance and shear adhesive strength under heat, and if it exceeds 50% by weight, the crosslinking density will increase too much, resulting in poor durability. Impact resistance tends to decrease. The inorganic filler (C) used in the present invention has an average particle size of 1 μm to 60 μm and contains 10% by weight or more of a low melting point glass powder having a melting point of 400° C. to 500° C. The inorganic powder used in combination with the low melting point glass powder is not particularly limited, and one or more of silica, clay, mica, calcium carbonate, alumina, aluminum hydroxide, high melting point glass, etc. can be used. Among these, silica,
Most preferably, alumina or mica is used.
Glass frit with a melting point lower than 400°C is advantageous for film formation at high temperatures, but it is not sanitary because it contains a large amount of lead in its composition, and it softens at temperatures between 400°C and 600°C. Because the temperature is so high, the coating film hardness at high temperatures becomes insufficient. Furthermore, if the glass frit has a melting point higher than 500°C, film formation at high temperatures will be insufficient. The inorganic filler (C) used in the present invention has an average particle size of 1 to 60 μ, preferably 20 to 40 μ. If the average particle size is larger than 60μ, a smooth coating film cannot be obtained, and if it is smaller than 1μ, oil absorption increases and sufficient flowability cannot be obtained. The mixture containing silicone-modified epoxy resin (A), heat-resistant resin (B), and low-melting point glass powder-containing inorganic filler (C) as main components used in the present invention has a weight ratio of (A). )+(B):(C)=20:80
A ratio of ~60:40 is used. If the blending ratio of the inorganic filler (C) containing low melting point glass powder exceeds 80% by weight, good flowability cannot be obtained, and if it falls below 40% by weight, heat resistance becomes insufficient. Silicone-modified epoxy resin (A) according to the present invention
As the curing agent for the heat-resistant resin (B), curing agents commonly used for epoxy resins can be used as they are. That is, a carboxylic acid anhydride group,
Amino group, carboxyl group, carboxylic acid hydrazide group, hydrosyl group, -SH group, CONH- group, -
Conventionally known curing agents such as organic compounds having NCO groups or -NCS groups, organic mineral acid esters, organometallic compounds Lewis acids, titanium, zinc, boron or aluminum compounds containing organic groups, and other acidic or basic compounds. is used. For example, aliphatic polyamines such as ethylenediamine and triethylenetetramine, aliphatic hydroxylamines such as monoethanolamine and propanolamine, aromatic amines such as metaphenylenediamine and 4,4'-diaminodiphenylmethane, piperazine, triethylenediamine, etc. Aliphatic amines having a cyclic structure, imidazoles such as 2-ethyl 4-methylimidazole and 2-phenylimidazole, and other nitrogen-containing curing agents include dicyandiamide, carboxylic acid dihydrazide, and the like. As acid curing agents, phthalic acid, maleic acid, tetrahydrophthalic acid, trimellitic acid,
Examples include polyhydric carboxylic acids such as azelaic acid, benzophenonetetracarboxylic acid, and adipic acid, and their anhydrides. Other examples include -NCO group-containing prepolymers of polyurethane resins, titanium and zinc compounds containing organic groups such as tetrabutyl titanate and zinc octoate. In addition, some of these curing agents can achieve rapid curing by using a small amount of curing accelerator such as tertiary amine, imidazole, organic acid metal salt, Lewis acid, or amine complex salt. It is blended as appropriate. Among these curing agents, imidazole,
Dicyandiamide and carboxylic acid dihydrazide are preferably used for reasons such as storage stability. The mixture containing the silicone-modified epoxy resin (A), the heat-resistant resin (B), and the inorganic filler containing low melting point glass powder (C) as main components used in the present invention includes the above-mentioned resin, inorganic filler, hardened In addition to the curing agent and curing accelerator, various additives can be added as necessary. Examples of such additives include inorganic pigments, organic pigments, flame retardants, flame retardant aids, silane coupling agents, antifoaming agents, mold release agents, thixotropy improvers, surface smoothness improvers, and fluidity improvers. Agents, etc. are mentioned. The heat-resistant electrical insulating coating composition obtained in the present invention can be dissolved in an organic solvent and applied in the form of a varnish for insulation coating by dipping, coating, or spray coating. For hygiene and safety reasons, it is preferable to apply insulation coating in the form of paint using powder coating methods such as fluidized dipping, hot spraying, electrostatic dynamic dipping, and electrostatic spraying. Since there is almost no volatile content, deterioration such as foaming does not easily occur even at high temperatures.
This is preferable because an insulating coating layer having better heat resistance can be obtained. Obtained by heating, melting, and curing a mixture containing the silicone-modified epoxy resin (A) obtained by the present invention, a heat-resistant resin (B), and an inorganic filler containing low melting point glass powder (C) as main components. The insulating coating layer has smoothness and adhesion that are equal to or higher than the insulating coating layer that does not contain the heat-resistant resin (B) that the present inventors have already proposed, and
Adhesive strength at 100°C to 300°C and coating hardness and adhesion at around 500 to 700°C were significantly improved. That is, the mixture used in the present invention, whose main components are a silicone-modified epoxy resin (A), a heat-resistant resin (B), and an inorganic filler containing low melting point glass powder (C), has excellent adhesion and melting properties as a resin. A silicone-modified epoxy resin (A) that is made by partially modifying an epoxy resin with good flowability with an organic silicone intermediate having good heat resistance, and a silicone-modified epoxy resin (A) that has good flowability and adhesion when melted, and has a crosslinking density of the resin system. Because one or more types of heat-resistant resin (B) with a thermal decomposition onset temperature of 200℃ or higher is used, which has the effect of increasing rigidity by increasing the temperature, only silicone-modified epoxy resin (A) is used as the resin. The resin has smoothness and adhesion that are equal to or better than those obtained when the resin is used, and the silicone-modified epoxy resin (A) is combined with a heat-resistant resin (B) that has the effect of increasing the crosslinking density of the resin. The adhesive strength at temperatures around 100°C to 300°C is greatly improved. Furthermore, the insulating coating layer obtained by heating, melting, and curing the mixture can be used in a temperature range from room temperature to around 350°C due to the good heat resistance characteristic of the organic silicone and heat-resistant resin used to modify the epoxy resin. It has good heat resistance for a long time, and in the temperature range from around 350℃ to 500℃ to 600℃, the heat-resistant resin (B), which is a substance with silicon-oxygen bonds that remains after the organic silicone is thermally dispersed, is completely Materials with carbon-carbon bonds that partially remain without being decomposed, inorganic powder, and low-melting glass that begins to soften and melt become enameled, so it has good heat resistance over a wide range of temperatures from room temperature to 500 to 600 degrees Celsius. have sex. In other words, organic silicone or heat-resistant resin
In the temperature range from around 350℃ to 500 to 600℃, where most of (B) is thermally decomposed and some substances with silicon atoms and oxygen bonds and substances with carbon-carbon bonds remain, silicon-oxygen bonds, Alternatively, although carbon-carbon bonds remain, the mechanical strength of the insulating layer is extremely weak if only these skeletons and inorganic powders are used.
If there is a low-melting glass powder that softens and melts in the temperature range from around 500 to 600 degrees Celsius, it will act as a binder with substances and inorganic powders that have silicon-oxygen bonds or carbon-carbon bonds, and these will become one. It is not until it becomes enameled that it becomes heat resistant at high temperatures. In the present invention, silicone-modified epoxy resin
By using heat-resistant resin (B) in combination with (A), it has better heat resistance than when using only silicone-modified epoxy resin (A), that is, from room temperature to 700℃, especially at high temperatures of 500℃.
Coating film hardness and adhesion at temperatures around ~700°C are further improved. This is due to the fact that the crosslinking density of the resin is improved by using heat-resistant resin (B), and even at high temperatures around 500℃ to 700℃, some of the heat-resistant resin (B) remains as a substance with carbon-carbon bonds. It is thought that this is because the crosslinking density was improved when the material remained and was integrally enameled with a substance having a silicon-oxygen bond, an inorganic powder, or a low-melting glass. The present invention will be explained below with reference to Examples. Example 1 Silicone-modified epoxy resin [25% by weight of bisphenol-type epoxy resin modified with a methoxy group-containing silicone intermediate. Melting point 70℃, epoxy equivalent 1300-1350〕 35 parts, Cresol novolac epoxy resin (EOCN102, manufactured by Nippon Kayaku) 10 parts, Low melting point glass powder (melting point 410℃-430℃) 20 parts, Silica powder 34 parts, Inorganic A mixture consisting of 1 part of pigment (red iron) and 3 parts of dicyandiamide (Epicure 108FF, manufactured by Yuka Ciel) was kneaded with two rolls to form a sheet, and this was crushed with a crusher to form a powder coating composition. I got something. The above coating composition was applied onto an iron piece preheated to 180°C using a fluidized dipping apparatus, and further cured at 200°C for 10 minutes to obtain a coating film with good smoothness and adhesion. The obtained iron piece was placed in an electric furnace set at 500°C, and after 24 hours it was taken out and evaluated. The evaluation results are shown in Table 1. In accordance with JISK6850, shearing of iron-iron test pieces bonded by heating and curing the above powder composition was performed under normal conditions, after treatment at 100℃ for 24 hours, after treatment at 300℃ for 24 hours, and after treatment at 500℃ for 24 hours. Adhesive strength was measured. The results are shown in Table 1. Example 2 In Example 1, instead of the cresol novolac epoxy resin, a resin with a melting point of 70°C and a hydroxyl equivalent of 105 was used.
A powder coating composition was obtained in the same manner except for using the novolak type phenolic resin. In the same manner as in Example 1, an iron piece was coated with the obtained coating composition and a test piece for measuring adhesive strength was bonded, and evaluation was made in the same manner as in Example 1. The evaluation results are shown in Table 1. Example 3 In Example 1, instead of cresol novolak epoxy resin, melting point 60°C, epoxy equivalent 350
A powder composition was obtained in the same manner except that an epoxy resin containing an oxazolidone ring was used. A coating composition obtained in the same manner as in Example 1 was used to coat an iron piece and adhere a test piece for measuring adhesive strength, and evaluation was performed in the same manner as in Example 1. The evaluation results are shown in Table 1. Example 4 25 parts of silicone-modified epoxy resin [35% by weight of bisphenol epoxy resin modified with hydroxyl group-containing silicone intermediate, melting point 60°C, epoxy equivalent 870-900], polybismaleimide resin (Kelimide 601, Mitsui Oil Co., Ltd.) (chemical product) 10 parts, low melting point glass powder (melting point 450°C to 470°C) 25 parts, alumina powder 39 parts, inorganic pigment (red iron) 1 part, imidazole (2-phenylimidazole, manufactured by Shikoku Kasei Co., Ltd.) 0.7 parts. The mixture was kneaded with two rolls to form a sheet, and this was pulverized with a pulverizer to obtain a powder coating composition. A coating composition obtained in the same manner as in Example 1 was used to coat an iron piece and adhere a test piece for measuring adhesive strength, and evaluation was performed in the same manner as in Example 1. The evaluation results are shown in Table 1. Example 5 A powder coating composition was obtained in the same manner as in Example 4 except that a bismaleimide triazine resin (BT2680, manufactured by Mitsubishi Gas Chemical) was used instead of the polybismaleimide resin. In the same manner as in Example 1, an iron piece was coated with the obtained coating composition and a test piece for measuring adhesive strength was bonded, and evaluation was made in the same manner as in Example 1. The evaluation results are shown in Table 1. Example 6 A powder coating composition was obtained in the same manner as in Example 4 except that a bitantoin type epoxy resin having a melting point of 55° C. and an epoxy equivalent of 200 was used instead of the polybismaleimide resin. In the same manner as in Example 1, an iron piece was coated with the obtained coating composition and a test piece for measuring adhesive strength was bonded, and evaluation was made in the same manner as in Example 1. The evaluation results are shown in Table 1. Example 7 The resin composition in Example 1 was changed to 25 parts of silicone-modified epoxy resin, 10 parts of cresol novolak epoxy resin (EOCN102, manufactured by Nippon Kayaku), and 10 parts of oxazolidone ring-containing epoxy resin (melting point 60°C, epoxy equivalent 350). A powder coating composition was obtained in the same manner except that the same amount was changed. In the same manner as in Example 1, an iron piece was coated with the obtained coating composition and a test piece for measuring adhesive strength was bonded, and evaluation was made in the same manner as in Example 1. The evaluation results are shown in Table 1. Comparative Example 1 A powder coating composition was obtained in the same manner as in Example 1 except that the resin formulation was changed to 45 parts of silicone-modified epoxy resin. In the same manner as in Example 1, an iron piece was coated with the obtained coating composition and a test piece for measuring adhesive strength was bonded, and evaluation was made in the same manner as in Example 1. The evaluation results are shown in Table 1. Comparative example 2 Bisphenol type epoxy resin (Epicote
1004, manufactured by Yuka Shell) 30 parts, cresol novolac epoxy resin (EOCN102, manufactured by Nippon Kayaku) 20 parts, calcium carbonate powder 49 parts, inorganic pigment (red iron) 1 part, imidazole (2-phenylimidazole, Shikoku Kasei) A mixture consisting of 2 parts (manufactured by the Company) was kneaded with two rolls to form a sheet, and this was pulverized with a pulverizer to obtain a powder coating composition. In the same manner as in Example 1, an iron piece was coated with the obtained coating composition and a test piece for measuring adhesive strength was bonded, and evaluation was made in the same manner as in Example 1. The evaluation results are shown in Table 1.

[Table] In Table 1, the appearance was judged visually, and the coating hardness and adhesion were judged by applying a hammer impact to the test piece after being treated at 500°C for 24 hours, after being left to cool to room temperature. From Table 1, it is clear that Examples 1 to 7 provide coating compositions with improved heat resistance and adhesive strength.

Claims (1)

[Claims] 1 Component A: An epoxy resin modified in a range of 10 to 50% by weight with an organic silicone intermediate having a functional group capable of reacting with an epoxy resin having a hydroxyl group, a melting point of 40 to 90°C, and an epoxy equivalent. but
400 to 2000 silicone-modified epoxy resin, B component: novolak type epoxy resin, phenol resin, oxazolidone ring and/or isocyanurate ring-containing resin, imide group-containing resin,
A heat-resistant resin that is one or more selected from the group of triazine ring-containing resins and hydantoin ring-containing resins, and has a melting point of 40 to 180 °C and a thermal decomposition initiation temperature of 200 °C or higher, component C: 400 to An inorganic filler containing 10% by weight or more of low melting point glass with a melting point of 500°C, the main constituents of which are A, B and C, with a mixing ratio of (A):(B)=90 by weight. :Ten~
A heat-resistant electrical insulating coating composition consisting of 50:50 and (A)+(B):(C)=20:80 to 60:40.