JPS625451B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a photocurable prepreg. More specifically, it relates to photo-curable prepreg, which is flexible in a semi-cured state and easily hardens and becomes fixed when exposed to light, for interlayer insulation of coils for electrical equipment, or insulation of slots, leads, etc. be. The method of insulating coils for electrical equipment using semi-cured prepreg insulating sheets or prepreg insulating tapes does not require operations such as brushing or impregnating with insulating varnish, so it is effective in terms of cost and manufacturing time. This is an extremely advantageous method for producing this prepreg, and an epoxy resin composition is used to prepare a prepreg resin, which is an epoxy resin with excellent properties for the cured product, and a latent curing agent such as a sifted boron amine complex salt or dicyandiamide. is widely used. In addition, as base materials for prepreg, inorganic fiber base materials such as glass cloth, organic fiber base materials such as polyethylene terephthalate cloth, heat shrink films, paper, mica sheets, etc. are used. However, this semi-cured prepreg must be heated when curing, so it cannot be used for adherends that change or decompose when heated, and The adhesion and moldability of the adherend was often extremely uncertain due to tape displacement due to deformation of the adherend and flow of the semi-cured resin. In addition, in the case of adherends with large heat capacity, the temperature required for the curing reaction (usually 100 to 150
It took a considerable amount of time for the temperature to rise to .degree. The present inventors have conducted intensive research to eliminate the above-mentioned drawbacks and provide a photocurable prepreg that is semi-cured, flexible, and easily cures and becomes fixed when cured by light irradiation. , we have completed the present invention. That is, the present invention uses a multilayer structure of laminated mica paper containing polymeric fibrids and aromatic polyamide paper as a base, and reacts a quinazolone ring-containing dicarboxylic acid compound and an epoxy compound thereto. This invention relates to a photocurable prepreg obtained by coating or impregnating a photocurable resin composition obtained by reacting a quinazolone-modified epoxy resin with an unsaturated monobasic acid, and then heating and drying the base material, the prepreg being used for electrical equipment. By using a photocurable prepreg made of a specific base material and a photocurable resin composition when insulating coils, etc., heating is not necessarily required as in the case of using conventional prepreg. It cannot be used for adherends that change in quality or decompose when heated, and may cause deformation of the adherend due to heating or slippage of the tape due to the flow of the semi-cured resin. The above-mentioned disadvantages such as extremely uncertain fixation formability are completely eliminated, and it is semi-cured and flexible, and does not require heating during curing.
It has the extremely remarkable effect of being easily hardened and fixed by light irradiation. Furthermore, in this photocurable prepreg, there is no need to heat the adherend to a temperature necessary for a thermosetting reaction, and the curing time can be extremely shortened, resulting in an energy saving effect. Additionally, the prepreg of the present invention cures when exposed to a source of ultraviolet light (e.g. sunlight, low to high pressure mercury lamp, xenon lamp, etc.), and permanently crosslinks when not exposed to ultraviolet light. It has the characteristics of excellent storage stability and a long shelf life without causing any damage. Furthermore, by introducing a quinazolone ring into the photocurable resin composition, a prepreg with excellent heat resistance can be obtained. On the other hand, the base material used here, which has a multilayer structure of laminated mica paper containing polymer fibrids as a fusing agent and aromatic polyamide paper, is characterized by higher heat resistance than conventional polyester mat, etc. The photocurable prepreg of the present invention obtained from this and the photocurable resin composition provides an insulator with high heat resistance. The photocurable resin composition used in the photocurable prepreg of the present invention is prepared by reacting 1 equivalent of a quinazolone ring-containing dicarboxylic acid compound with 1.2 to 5 equivalents of an epoxy resin to obtain a quinazolone-modified epoxy resin. It can be easily obtained by heating and reacting an epoxy resin and an unsaturated monobasic acid in the presence of an esterification catalyst, a vinyl polymerization inhibitor, a solvent, and a vinyl monomer, if necessary. When the amount of the epoxy resin blended is less than 1.2 equivalents, the molecular weight of the resin obtained becomes large, solubility decreases, and the softening point increases, resulting in poor workability. On the other hand, if it exceeds 5 equivalents, the resulting resin will not have satisfactory heat resistance, so it is desirable to keep it within the above range. The quinazolone ring-containing dicarboxylic acid compound used here includes, for example, the general formula (In the formula, R is an aliphatic or aromatic divalent group.) Preferred examples include those represented by the following. In addition, examples of polyfunctional epoxy compounds used in the production of quinazolone-modified epoxy resins include bisphenol A diglysyl sol eral type Epicote 826, Epicote 827, and Epicote 828 (all epoxy resins manufactured by Ciel Chemical Co., Ltd., trade names). , GY-252, GY-260 (all epoxy resins manufactured by Teva Geigy, trade names), DER330,
DER331, DER332 (both epoxy resins manufactured by Dow Chemical Company, trade names), novolac type
DEN431, DEN438 (all epoxy resins manufactured by Dow Chemical Company, trade names), aliphatic type CY-
179 (epoxy resin manufactured by Ciba Geigy, trade name). Furthermore, unsaturated monobasic acids that can be used in the present invention include acrylic acid, methacrylic acid, sorbic acid,
Examples include cinnamic acid. In addition, in the reaction of polyfunctional epoxy compounds and unsaturated monobasic acids, quaternary ammonium salts, tertiary
By using a catalyst such as a grade amine, the reaction can be carried out more smoothly. Hydroquinone, parabenzoquinone, hydroquinone monomethyl ether, phenothiazine,
Thiosemicarbasite, acetone thiocarbazone copper salt, etc. can be added usually in a range of 0.001 to 1.0% by weight. Furthermore, curing can be further facilitated by adding 0.1 to 5 parts by weight of the following photosensitizers to 100 parts by weight of the photocurable resin composition. . Examples of the photosensitizer include benzoin and its derivatives (for example, benzoin methyl ether,
ethyl ether, isopropyl ether, etc.); quinone compounds such as anthraquinone and naphthoquinone; organic sulfur compounds such as diphenyl sulfide; peroxides such as benzoin peroxide; These include nitrogen compounds and photoreducible dyes (for example, methylene blue, p-toluenesulfonate ion, etc.). Furthermore, if necessary, a vinyl monomer may be added to the photocurable resin composition. Examples of the vinyl monomer include styrene, vinyltoluene, diallyl phthalate, diallyl isophthalate, triallyl isocyanurate, triallyl cyanurate, triallyl trimellitate, vinyl acetate, (meth)acrylic acid esters, and (meth)acrylic acid esters. Examples include acid esters. The blending amount of these vinyl monomers is preferably 20% (wt%, same hereinafter) or less of the total. That is, if it exceeds 20%, the adhesiveness of the prepreg becomes high, resulting in poor workability and storage stability. In the photocurable prepreg of the present invention, a new base material having a multilayer structure in which laminated mica paper containing polymeric fibrils and aromatic polyamide paper are bonded together by heat fusion as a fusion agent is used. The composition ratio of laminated mica paper and aromatic polyamide paper in the base material is 100 parts of laminated mica paper to 20 parts of aromatic polyamide paper, from the viewpoint of the mechanical strength of the resulting photocurable prepreg and various properties of the cured product.
~120 parts is preferred. If the composition ratio of aromatic polyamide paper in the base material is less than 20 parts per 100 parts of laminated mica paper, the mechanical strength as a prepreg will be poor,
If it is wound around a coil etc., cracks will occur and it cannot be used for practical purposes, and if it is larger than 120 parts, it tends to not adhere firmly between the base materials when it is heated and hardened after being wound around a coil etc. Both are unfavorable because they can be seen. As mentioned above, examples of the laminated mica paper used in the photocurable prepreg of the present invention include laminated mica papers containing polymer fibrids as a fusion agent, and representative examples thereof include:
For example, mica foil of 30 to 5000 μm and polymeric fibrids are dispersed in water, and paper is made using a circular wire or fourdrinier paper machine to obtain laminated mica paper. Examples of the polymer fibrils contained in the laminated mica paper as a fusing agent include short fibers (ie, fibrids) of aromatic polyamide, polyacrylontrile, and the like. The content of polymer fibrids in the laminated mica paper is usually 1 to 10%, more preferably 1 to 5%.
As a result, a laminated mica paper can be obtained that provides a cured product with good impregnation properties with the photocurable resin composition and good fusion properties with the aromatic polyamide paper. If the content of polymer fibrids in the laminated mica paper is less than 1%, it will be difficult to heat-fuse it with aromatic polyamide paper, and if it is more than 10%, the photocurable resin composition will Impregnating properties deteriorate, and as a result, the electrical properties and mechanical properties of the resulting cured product deteriorate, both of which are unfavorable. In the photocurable prepreg of the present invention, the aromatic polyamide paper to be heat-sealed to the laminated mica paper is, for example, isophthalic acid-m-phenylenediamine copolymer, terephthalic acid-γ-phenylenediamine copolymer, etc. Examples of such paper include aramid paper (Mitsubishi Paper Mills Co., Ltd.) and Nomex paper (DuPont Co., Ltd., trade name). Therefore, the photocurable prepreg of the present invention is made by applying an organic solvent solution of the photocurable resin composition to a base material having a multilayer structure of laminated mica paper and aromatic polyamide paper containing polymeric fibrils as a fusion agent. After coating or impregnating, it is heated and dried to obtain a semi-cured product. The resulting photocurable prepreg has a long shelf life, high mechanical strength, and does not crack or wrinkle even when wound into a coil or the like. Furthermore, the conditions for heating and drying the base material coated or impregnated with the organic solvent solution of the photocurable resin composition are as follows:
A drying temperature of 50 to 200° C. and a drying time of 1 to 60 minutes is used, thereby obtaining a photocurable prepreg that provides a cured product with excellent electrical and mechanical properties. Drying temperature is higher than 200℃ and drying time is 60℃
If it is longer than 1 minute, the curing of the resulting photocurable prepreg progresses too much, resulting in wrinkles and cracks after coil winding, and insufficient fusion properties. Furthermore, when the drying temperature is lower than 50° C. and the drying time is shorter than 1 minute, the volatilization of the solvent is insufficient and the adhesiveness becomes large, resulting in poor workability as a prepreg, and both are unfavorable. The resulting photocurable prepreg can be easily cured and fixed by irradiation with light without being heated after being wound around a conductor such as a coil, and has good heat resistance, mechanical properties, and electrical properties. Gives a cured product. Next, the present invention will be explained in more detail with reference to Examples. Quinazolone ring-containing dicarboxylic acid compounds used in Examples of the present invention are shown below. Example 1 28.6 g (0.1 equivalent) of a quinazolone ring-containing dicarboxylic acid compound represented by the structural formula QC-1 and 95 g of Epicote 828 (trade name of Ciel Chemical), a bisphenol A type epoxy resin with an epoxy equivalent of 190.
(0.5 equivalent) and heated to 150℃ using 0.01g of benzyltriethylammonium chloride as a catalyst.
A quinazolone-modified epoxy resin with an epoxy equivalent of 310 was obtained by a time reaction. To 600 g of this quinazolone-modified epoxy resin, 150 g of methacrylic acid was added and reacted at 130° C. for 2 hours to obtain an unsaturated polyester with an acid value of 8. 0.5 g of benzoin ethyl ether was added to 100 g of the unsaturated polyester obtained here to synthesize a photocurable resin composition. Next, aromatic polyamide paper [Mitsubishi Paper Mills Co., Ltd. thickness]
0.1 mm] and laminated mica paper [polymer fibrid content 3%, polymer fibrid composition diisophthalic acid-diaminodiphenylmethane copolymer (polyamide): thickness 0.1 mm] (weight ratio per 1 ^m2 : aroma Group polyamide paper/laminated mica paper = 20/100) was thermally fused to obtain a two-layer heat-resistant mica paper (i.e., base material), and the photocurable resin composition was applied to this base material at a temperature of 100°C. A prepreg sheet was produced by heat treatment for 40 minutes. In order to understand the mechanical properties of this prepreg sheet, four 25 mm x 25 mm photocurable prepreg sheets were heated to about 80°C and exposed to a 2.5 KW mercury lamp for about 10 minutes. The adhesive strength of the cured sheet obtained using this sample was measured at a temperature of 20°C using an Instron tensile tester. In addition, the obtained photocurable prepreg sheet was
A bundle of 10 formal flat rectangular copper wires of mm x 5 mm x 50 mm was wound 4 times in a lapper winding (or sushi winding) on a coil conductor, and then heated to 80°C and placed in a 2.5 KW mercury lamp for 10 strands. The electrical characteristics (dissipation tangent (tanδ), temperature characteristics,
dielectric breakdown voltage) was measured. The measurement results are shown in Table 1. Note that the dielectric loss tangent temperature characteristics are measured at the measured voltage of the obtained insulated coil at temperatures of 20°C and 200°C.
It was measured using the high-pressure Schering bridge method at 0.5KV. [Using a shearing bridge made by Yokogawa Electric Corporation] The breakdown voltage was determined by measuring the obtained insulated coil (initial stage) and the insulated coil (after deterioration) obtained by thermally degrading the insulated coil at 220°C for 20 days. 1 at 250℃
Measurements were made in oil at a constant pressure increase rate of KV/sec. [Using a withstand voltage tester manufactured by Aikoku Denki Co., Ltd.] Example 2 Aromatic polyamide paper [Mitsubishi Paper Mills Co., Ltd., thickness 0.1
mm] and laminated mica paper [polymer fibrid content: 5%, polymer fibrid constituents: isophthalic acid-diaminodiphenylsothane (polyamide): thickness 0.3 mm] (weight ratio aromatic per ^m2 ) A base material with a two-layer structure was obtained by heat-sealing polyamide paper/laminated mica paper = 20/100. In addition to using the obtained two-layer structure base material,
A semi-cured photocurable prepreg sheet was produced in the same manner as in Example 1, and the adhesive strength of the obtained photocurable prepreg sheet was measured. Further, an insulated coil was manufactured in the same manner as in Example 1 except that the obtained photocurable prepreg sheet was used, and the electrical properties of the obtained insulated coil were measured. The measurement results are shown in Table 1. Example 3 Aromatic polyamide [manufactured by Mitsubishi Paper Mills Co., Ltd.: thickness 0.1
mm] and laminated mica paper [Polymer fibrid content: 1%, Polymer fibrid constituents: Acrylonitrile-methyl methacrylate copolymer:
0.1 mm thick] (weight ratio per 1 m ² : aromatic polyamide paper/laminated mica paper = 60/60) was heat-sealed to obtain a base material with a two-layer structure. Next, a semi-cured photocurable prepreg sheet was produced in the same manner as in Example 1, except that the obtained two-layer structure base material was used, and the adhesive strength of the obtained photocurable prepreg sheet was measured. did. Further, an insulated coil was manufactured in the same manner as in Example 1 except that the obtained photocurable prepreg sheet was used, and the electrical properties of the obtained insulated coil were measured. These results are shown in Table 1. Example 4 28.6 g (0.1 equivalent) of a quinazolone ring-containing dicarboxylic acid represented by QC-2 and Epicote, a bisphenol A type epoxy resin with an epoxy equivalent of 190.
828 (trade name of Ciel Chemical) was mixed with 57.0 g (0.3 equivalents) and reacted with 0.01 g of benzyltriethylammonium bromide as a catalyst at 150° C. for 1 hour to obtain a quinazolone-modified epoxy resin with an epoxy equivalent of 430. To 800 g of this quinazolone-modified epoxy resin, 140 g of methacrylic acid was added and reacted at 120° C. for 2 hours to obtain an unsaturated polyester with an acid value of 5. 0.5 g of benzoin ethyl ether was added to 100 g of the unsaturated polyester obtained here to synthesize a photocurable resin composition. Next, a semi-cured photocurable prepreg sheet was produced in the same manner as in Example 1, except that the obtained curable resin composition and the same two-layer structure base material as used in Example 3 were used. . The adhesive strength of the obtained photocurable prepreg sheet was measured in the same manner as in Example 1. The measurement results are shown in Table 1. Comparative example 1 DEN438 (Dow Chemical Co., Ltd.: epoxy equivalent) 60
g and ECN1273 (Ciba Geigy Co., Ltd. epoxy equivalent)
225) and 3 g of boron trifluoride monoethylamine complex salt were dissolved in a mixed solvent of acetone/toluene (45/55) to obtain an organic solvent solution of an epoxy resin composition. Next, the epoxy resin composition was applied to the same two-layer structure base material used in Example 1, and the temperature was increased.
A prepreg sheet was produced by drying at 100°C for 5 minutes and then at 110°C for 8 minutes. Then, the adhesive strength of the obtained prepreg sheet was measured in the same manner as in Example 1. Furthermore, an insulated coil was manufactured in the same manner as in Example 1 except that the obtained prepreg sheet was used, and the electrical properties and appearance of the obtained insulated coil were measured. The measurement results are shown in Table 1. Comparative Example 2 An organic solvent solution of the epoxy resin composition obtained in Comparative Example 1 was applied to aromatic polyamide paper (manufactured by DuPont, trade name "Nomex Paper": thickness 0.1 mm),
A prepreg sheet was produced by drying at a temperature of 105°C for 10 minutes. Then, the adhesive strength of the obtained prepreg sheet was measured in the same manner as in Example 1. Further, an insulated coil was manufactured in the same manner as in Example 1 except that the obtained prepreg sheet was used, and the electrical properties and appearance quality of the obtained insulated coil were measured. The results are shown in Table 1.

[Table] The photocurable prepreg of the present invention can easily obtain an insulating structure excellent in the above properties by winding it around a conductor such as a coil and then irradiating it with light, which is extremely advantageous industrially. be.

Claims (1)

[Claims] 1. A base material made by heat-sealing a laminated mica paper containing polymeric fibrils as a fusion agent and an aromatic polyamide paper, and a quinazolone ring-containing dicarboxylic acid compound and an epoxy compound being reacted. A photocurable prepreg made into a semi-cured state by coating or impregnating a photocurable resin composition obtained by reacting the obtained quinazolone-modified epoxy resin with an unsaturated monobasic acid. 2. The photocurable prepreg according to claim 1, wherein the composition ratio of the laminated mica paper and the aromatic polyamide paper is 20 to 120 parts by weight based on 100 parts by weight of the laminated mica.