JPS6142401B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an insulated coil, and particularly to an insulated coil that requires heat resistance. BACKGROUND ART Heat resistance is required for insulated coils for AC or DC rotating machines or stationary equipment as equipment becomes smaller and capacity increases. By the way, this type of insulated coil is generally constructed as follows. That is, a heat-resistant insulating base material such as a thin insulating material made of a small amount of resin and laminated with mica pieces or glass cloth is wound around the coil body to form a coating layer, and this coating layer is coated with a solvent-free epoxy resin composition. The impregnated resin is impregnated to sufficiently fill the gaps between the coil wires and in the coating layer, and the impregnated resin is dried and hardened to integrate the coating layer and the impregnated resin to form an insulating structure. However, what is important in terms of the insulation function of such an insulated coil is its service life that can sufficiently withstand temperature rises due to energization of equipment, in other words, its heat-resistant life. As mentioned above, in the so-called insulated coil for dry electrical equipment, the insulating structure is composed of a combination of an inorganic or organic heat-resistant insulating base material and a thermosetting resin (eg, epoxy resin). However, the heat resistance life of this insulating structure is determined not only by the heat resistance of the individual insulating materials used in combination, but also by comprehensive heat resistance life evaluation. That is, the heat-resistant life of an insulating structure varies greatly depending on the combination of insulating materials, and in particular, depends on the heat-resistant resin used, and in some cases may be realized as a synergistic effect. However, the above-mentioned epoxy resin has good compatibility with mica, asbestos, glass cloth, polyimide film, etc., which serve as insulation base materials, and can form a well-balanced insulation structure when viewed comprehensively as an insulation coil. However, its heat resistance is Class F (maximum allowable temperature 155
℃), and the heat resistance is still not sufficient. As described above, the present inventors have focused on the importance of thermosetting resins in the insulation structure of coils for dry electrical equipment, and as a result of their studies, they have found that an insulator having an insulation structure with excellent heat resistance and a long lifespan. It is intended to provide coils. That is, the present invention provides for heat-resistant insulating substrates such as aramid paper, polyimide film, glass-backed film, film-backed mica tape, aramid mica sheet, glass cloth, or glass varnish cloth, with the following methods: (a) Alkenyphenols, alkenyl A composition comprising at least one phenyl ether, (b) a maleimide compound, (c) an epoxy compound, and (d) a carboxylic acid anhydride has excellent compatibility and heat resistance. This is based on the knowledge of To explain the present invention in detail below, the present invention comprises a coil main body, a heat-resistant insulating base material layer wound around the outer periphery of the coil main body, and a cured resin layer impregnated and integrated with the heat-resistant insulating base material layer. The cured resin layer comprises (a) at least one selected from alkenyl phenols and alkenyl phenyl ethers, (b) a maleimide compound, (c) an epoxy compound, and (d) a carboxylic acid anhydride. This is an insulated coil characterized by having a composition of Examples of the insulating base material forming the base of the insulating structure in the present invention include aramid paper, polyimide film, glass-backed mica tape, film-backed mica tape, aramid mica sheet, glass cloth, and glass varnish cloth. To explain in detail about the resin composition that is one component of the insulating structure in the present invention, the alkenyl phenol that is one component of the resin composition is generally heated at a temperature of 180 to 200°C.
It can be obtained by heat treatment at a high temperature of 100% to cause Claisen transition. Furthermore, alkenyl phenyl ether can be easily obtained by condensing a phenol compound with an alkenyl or a ride using an alkali catalyst such as caustic soda. Phenol compounds that can be used to synthesize such alkenyl phenyl ethers include monovalent phenols such as phenol, cresol, xylenol, p-tert-butylphenol, and 44'-dihydroxydiphenylpropane. (Bisphenol A), 33'-dihydroxy-diphenylpropane, 44'-dihydroxydiphenyl ether, hydroquinone, resorcinol, catechol, 44'-dihydroxy-22'-dimethyl-diphenyl ether, 44'-dihydroxydiphenyl sulfone , 44′-dihydroxydiphenyl sulfide, 44′-dihydroxydiphenyl ethane,
Examples include polyhydric phenols such as 44'-dihydroxydiphenyl ketone, phenolic resin, and cresol resin. These phenolic compounds may be used alone or in combination of two or more. All of the above alkenyl phenyl ethers can be converted into corresponding alkenyl phenols by Claisen rearrangement, and can be mixed into the resin composition of the present invention. Furthermore, as alkenylphenols, condensates of monoalkenylphenols such as allylphenol and allylcresol with formalin can also be used, as well as natural products such as eukenol, isoeugenol, and eugenol methyl ether, or derivatives thereof. You can also use It is also effective to use a mixture of these alkenyl phenols and alkenyl phenyl ethers. In addition, the maleimide compound which is the other main component of the resin composition according to the present invention includes phenylmaleimide, methylphenylmaleimide, methoxyphenylmaleimide, monochlorophenylmaleimide, hydroxyphenylmaleimide, and acetoxyphenylmaleimide. Monoimides such as NN'-ethylene dimaleimide, NN'-hexamethylene bismaleimide, NN'-dodecamethylene bismaleimide, NN'-dodecamethylene bismaleimide,
NN'-m-xylylene bismaleimide, NN'-p
-Xylylene bismaleimide, NN'-1.3-bismethylenecyclohexane bismaleimide, NN'-
1.4-bismethylenecyclohexane bismaleimide, N-N'-2.4-tolylene bismaleimide,
NN′-2.6-tolylene bismaleimide, NN′-diphenylmethane bismaleimide, NN′-diphenylsulfone bismaleimide, NN′-diphenylsulfide bismaleimide, NN′-p-benzophenone bismaleimide, NN′-diphenyl ether bismaleimide, NN′-(methylene-ditetrahydrophenyl)bismaleimide, NN′-(3-ethyl)44′-diphenylmethane bismaleimide,
NN'-(3.3'-dimethyl)4.4'-diphenylmethane bismaleimide, NN'(3.3'-dimethyl)diphenylmethane bismaleimide, NN'-(3.3'-dichloro)-4.4'-diphenylmethane bismaleimide , NN'-tolidine bismaleimide, NN'-isophorone bismaleimide, NN'-pp'-diphenyldimethylsilyl bismaleimide, and other bifunctional maleimide compounds, as well as reaction products of aniline and formalin (polyamine compounds), 3.4. There are reaction products of 4'-triaminodiphenylmethane, triaminophenol, etc. and maleic anhydride. Therefore, these polyvalent maleimide compounds may be used alone or in a mixed system of two or more. Examples of epoxy compounds constituting other components of the resin composition according to the present invention include the following. Namely, bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolak type epoxy resin, cresol novolak type epoxy resin, alicyclic epoxy resin, heterocyclic epoxy such as triglycidyl isocyanurate and hydatoin epoxy. resins, hydrogenated bisphenol A type epoxy resins, aliphatic epoxy resins such as propylene glycol-diglycidyl ether and pentaerythritol-polyglycidyl ether, epoxy resins obtained by the reaction of aliphatic or aromatic carboxylic acids with epichlorohydrin. , a spiro ring-containing epoxy resin, a glycidyl ether type epoxy resin which is a reaction product of an orthoallyl-phenol novolak compound and epichlorohydrin, a diallyl bisphenol compound having an allyl group at the ortho position of each hydroxyl group of bisphenol A, and epichlorohydrin. Examples include glycidyl ether type epoxy resin, which is a reaction product with ludolin. Furthermore, the carboxylic acid anhydride which constitutes one component of the resin composition according to the present invention is a compound as shown below which is usually used as a curing agent for epoxy resin. Namely, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, 3-(or 4)methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, nadic anhydride, methyl-nadic anhydride, dodecylsuccinic anhydride, succinic anhydride. Acids, methylsuccinic anhydride, octadecylsuccinic anhydride, phthalic anhydride, maleic anhydride, benzophenonetetracarboxylic dianhydride, butanetetracarboxylic dianhydride, pyromellitic anhydride, ester of trimellitic acid and ethylene glycol carboxylic acid anhydride (dianhydride), and esterified product of trimellitic acid and glycerin (trianhydride). On the other hand, it is preferable to use it in an amount of 0.2 to 1.2 equivalents. The resin composition according to the present invention may be made of only the above four essential components, but in order to accelerate the curing reaction and obtain a cured product with good properties within a short time, a radical polymerization initiator or an epoxy resin curing promoter may be used. Agents may be added as appropriate. Examples of radical polymerization initiators for promoting the curing reaction include benzoyl peroxide, di-t-butyl peroxide, dicumyl peroxide, MEK-peroxide, t-butyl peroxybenzoate, and azobisisobutyl peroxide. Examples include lonitrile. Examples of curing accelerators for epoxy resins include boron trifluoride amine complexes such as boron trifluoride monoethylamine complexes and piperidine trifluoride complexes, tertiary amines such as triethylamine, benzyldimethylamine, hexamine, and dimethylaniline, and tetramethyl Quaternary ammonium salts such as ammonium bromide, borate compounds such as triphenyl borate and tricresyl borate, imidazole compounds such as N-methylimidazole, N-ethylimidazole, N-phenylimidazole and N-vinylimidazole, zinc acetate Examples include metal salts and metal complexes such as sodium acetate, cobalt naphthenate, titanium acetylacetonate, iron acetylacetonate, nickel acetylacetonate, sodium methylate, sodium ethioate, and tetrabutoxytitanium. Furthermore, the resin composition according to the present invention can be used, for example, in styrene, α-methylstyrene, vinyltoluene, divinylbenzene, N
- Vinylpyrrolidone, acrylate, methacrylate, acrylonitrile, methyl vinyl ketone,
diallyl phthalate, triallyl cyanurate,
triallyl isocyanurate, allyl glycidyl ether, spiroacetal resin, furan resin,
Additives such as coupling agents, surfactants, antioxidants, pigments, and dyes, fillers such as silica powder, glass fibers or beads, aluminum hydroxide, calcium carbonate, magnesium oxide, titanium oxide, and mold release agents are selected as appropriate. However, it may also be added. As mentioned above, the resin composition according to the present invention is usually 40%
Aramid paper, polyimide film, glass-backed mica tape, film-backed mica tape, aramit It has good impregnation properties for wound materials such as mica sheets, glass cloth, and glass varnish cloth, and dense filling and impregnation can be easily achieved. In addition, it has excellent adhesion and compatibility with the insulating base material, etc., so it can be firmly integrated even when cured, and in combination with the above-mentioned good impregnability, it can form a dense cured layer or insulating structure without residual bubbles. . To further explain this point, in the present invention, maleimide compounds, alkenyl phenols, and alkenyl phenol ethers in the resin component forming the insulating structure have extremely high copolymerizability, have good compatibility with epoxy resins and organic acid anhydrides, and have low It is a liquid polyimide resin with high viscosity and long pot life. However, since the resin composition of the lever has a low viscosity, it has good impregnation properties into coils wound with thin insulating materials such as glass fiber products, mica products, or film products, and has excellent adhesion with these materials. When cured, it integrates with these materials and significantly improves its heat resistance as an insulating material. For example, it has heat resistance and heat resistance life equivalent to class C insulation, which far exceeds an insulation structure impregnated with epoxy resin. and maintains excellent electrical insulation properties. Next, examples of the present invention will be described. Example 1 Diallyl bisphenol A, orthoallyl phenol borak compound, bisphenol A diallyl ether, bismaleimido diphenylmethane,
P-tolylmaleimide, O-anisylmaleimide, bisphenol A type epoxy resin Epicoat
828 (trade name, Ciel Corporation), Epicote 152 (trade name, Ciel Corporation), methyltetrahydrophthalic anhydride, benzyldimethylamine (abbreviated as BOMA), and dicumyl peroxide (abbreviated as DCP) are shown in Table-1. First, five types of resin compositions were prepared by selecting composition ratios (parts by weight). The resin compositions prepared above were poured into molds and heated at 120°C for 5 hours and at 180°C for 15 hours to obtain cured resin plates with a thickness of 2 mm. Table 1 shows the results of measurements such as heating loss and electrical properties for each of the cured resin plates thus obtained.

【table】

[Table] In addition, the above resin compositions (A to E) and as comparative examples, epoxy resin (containing acid anhydride curing agent)... Comparative Example 1, and polyimide resin... Comparative Example 2 were prepared as impregnated resins. Meanwhile epoxy silane treated thickness
0.18mm glass tape on 5x12x330mm copper body
Prepare a model bar wound 4 times in a 1/2 layer, impregnate this wound layer with each of the above resin compositions, and heat at 150°C.
Insulating structures were formed by heating for 3 hours and 180°C for 15 hours. The dielectric loss tangent and dielectric strength at room temperature, 160℃, and 120℃ of the model bar with an insulating structure formed in this way, as well as the dielectric strength (room temperature) after heat aging at 260℃ or 240℃ for 40 days.
The results of each measurement were as shown in Table 2.

[Table] Furthermore, a field coil (white coil) was created by selecting copper as the conductor and wrapping it with 0.18 mm thick glass tape treated with epoxy silane four times in a 1/2 overlap. These field coils were impregnated with the resin composition A in resin, resin composition D, and polyimide resin, respectively, under vacuum pressure and at 150°C for 3 hours and at 180°C.
After heating and curing for 15 hours, 15 field coils were each made for heat resistance life evaluation. Next, regarding these field coils, IEC _pub210 - ₁
We selected the three recommended temperatures and heating cycles and conducted tests according to IEEE304 using the current heating method (5 samples for each temperature). In other words, after applying the specified vibration for each heating cycle, we allowed it to absorb moisture for 48 hours under 100% relative humidity, and performed a withstand voltage test at 3KV for 1 minute to determine the life time until dielectric breakdown occurs (5 coils The life time at these three temperatures was extrapolated to determine the life temperature equivalent to 20,000 hours.
℃, while in the case of the comparative example it was 196℃. Example 2 A model bar coil was created by wrapping aramid paper or the like six times around a 5 x 12 x 330 mm copper body with 1/2 overlap. Next, each of these model bar coils was impregnated with a resin composition having the same composition as resin composition B in the implementation, and then heated at 120°C for 5 hours and at 150°C.
Heat cured for 3 hours and 180℃ x 15 hours,
Further, post-curing was performed at 220°C for 6 hours. The model coil with the insulating structure obtained above was placed in an oven at 280℃ and left to heat, then taken out at 500 hours, 800 hours, and 1000 hours.
Table 3 shows the results of measuring the dielectric breakdown voltage (at room temperature) after absorbing moisture for 48 hours under % relative humidity.

【table】

Claims (1)

[Claims] 1. Consists of a coil body, a heat-resistant insulating base material layer wound around the outer periphery of the coil body, and a cured resin layer impregnated and integrated with the heat-resistant insulating base material layer; The resin layer contains (a) at least one selected from alkenyl phenols and alkenyl phenyl ethers, (b) a maleimide compound, (c) an epoxy compound, and (d) a carboxylic acid anhydride. An insulated coil characterized by: