Abstract: A flexible mica tape having a low gel time is prepared from a composition of an epoxy resin, an organotin salt, and catechol or pyrogallol. A mica sheet is immersed in the composition and the solvent is evaporated to form a tack-free A-staged resin. A conductor is wound with the tape and is impregnated with an impregnating resin using vacuum-pressure impregnation.

Abstract: A flexible mica tape having a low gel time is prepared from a composition of an epoxy resin, an organotin salt, and catechol or pyrogallol. A mica sheet is immersed in the composition and the solvent is evaporated to form a tack-free A-staged resin. A conductor is wound with the tape and is impregnated with an impregnating resin using vacuum-pressure impregnation.

Abstract: An epoxy-styrene, solventless resin impregnating varnish, having an atmospheric catalyzed pot life at room temperature of at least 45 days, is made by mixing: (1) the product of the reaction of (a) 1 part of an epoxy resin mixture, comprising solid epoxy resin and liquid epoxy resin wherein the weight ratio of solid epoxy: liquid epoxy is between 1:1 to 1:10; with (b) between about 0.01 part to 0.06 part of maleic anhydride and (c) a catalyst; under such conditions that the epoxy diester formed has an acid number of between about 0.5 to 3.0; with (2) a coreactive vinyl monomer; and between about 0.0003 part to 0.004 part of a room temperature stabilizer (3) between about 0.3 part to 1.2 part of a polycarboxylic anhydride, which is soluble in the mixture of (1) and (2) and an amount of free radical catalyst that is effective to provide a catalytic effect on the impregnating varnish and to cure it at temperatures of over about 85.degree. C., and with (4) between 0.0005 part to 0.

Abstract: A highly fluid, solventless, resinous, impregnating and coating composition, suitable as a high voltage insulation for electrical members, is made from an admixture containing: 100 parts of an epoxy resin, about 25 to 200 parts of an acid anhydride reactive with the epoxy resin, and about 0.002 to 1.00 part of a selected metal carbonyl, acting as a latent accelerator.

Abstract: Anaerobic resins are cured in a gaseous atmosphere which does not contain oxygen. An insulated conductor is placed in a vacuum and is impregnated with an anaerobic resin under pressure. The conductor is then placed in a non-oxygen containing atmosphere, such as nitrogen, which cures the resin.

Abstract: A resinous composition, suitable as a high voltage insulation for electrical members, is made from an admixture containing: 100 parts of an epoxy resin, about 25 to 200 parts of an acid anhydride reactive with the epoxy resin, about 0.01 to 2.0 parts of chromium or zirconium acetylacetonate, acting as a latent accelerator and about 0.3 to 30 parts of a selected organic carboxylic acid, acting as a co-accelerator.

Abstract: A highly fluid, solventless, resinous, impregnating and coating composition, suitable as a high voltage insulation for electrical members, is made from an admixture containing: 100 parts of an epoxy resin, about 25 to 200 parts of an acid anhydride reactive with the epoxy resin, and about 0.002 to 1.00 part of a selected metal acetylacetonate, acting as a latent accelerator.

Abstract: An epoxy-styrene, solventless resin impregnating varnish, having an atmospheric catalyzed pot life at room temperature of at least 45 days, is made by mixing: (1) the product of the reaction of (a) 1 part of an epoxy resin mixture, comprising solid epoxy resin and liquid epoxy resin wherein the weight ratio of solid epoxy: liquid epoxy is between 1:1 to 1:10; with (b) between about 0.01 part to 0.06 part of maleic anhydride and (c) a catalyst under such conditions that the epoxy diester formed has an acid number of between about 0.5 to 3.0; with (2) a coreactive vinyl monomer; and between about 0.0003 part to 0.004 part of a room temperature stabilizer; (3) between about 0.3 part to 1.2 part of a polycarboxylic anhydride, which is soluble in the mixture of (1) and (2), and an amount of free radical catalyst that is effective to provide a catalytic effect on the impregnating varnish and to cure it at temperatures of over about 85.degree. C., and with (4) between 0.0005 part to 0.

Abstract: Resins, made by admixing polyacrylic resin and epoxy resin in a weight ratio of polyacrylic:epoxy of 10:0.1 to 100 are cured in a diffusion gas atmosphere. An insulated conductor is coated with the polyacrylic-epoxy resin and cured without heat in a contacting gas atmosphere, such as nitrogen, carbon dioxide, argon, helium, methane, or hydrogen.

Abstract: A highly fluid, solventless, resinous, impregnating and coating composition, suitable as a high voltage insulation for electrical members, is made from an admixture containing: 100 parts of an epoxy resin, about 25 to 200 parts of an acid anhydride reactive with the epoxy resin, and about 0.002 to 1.00 part of a selected metal acetylacetonate, acting as a latent accelerator.

Abstract: A solventless impregnating composition is disclosed which is made by forming a mixture of a liquid diepoxide and about 10 to about 80 phr of a diglycidyl ether of a glycol. To this mixture is added a titanate catalyst in an amount sufficient to cure the composition.

Abstract: A resinous composition, suitable as a high voltage insulation for electrical members, is made from an admixture containing: 100 parts of an epoxy resin, about 25 to 200 parts of an acid anhydride reactive with the epoxy resin, about 0.01 to 2.0 parts of chromium or zirconium acetylacetonate, acting as a latent accelerator and about 0.3 to 30 parts of a selected organic carboxylic acid, acting as a co-accelerator.

Abstract: A flexible, nontacky prepreg for use in bonding high voltage coils and inner cooling channels which comprises a fibrous mat material containing a high molecular weight epoxy and a sterically hindered anhydride. The resin comprises approximately 25 to 500% by weight of the fibrous mat material.

Abstract: A resinous composition, suitable for insulating electrical members, is made from a mixture containing about 100 parts of an epoxy resin, about 55 to 165 parts of an acid anhydride, an effective amount of a latent catalyst and about 1 to 20 parts of a carboxylic acid stabilizer selected from the group of acetic, propionic, butyric, isobutyric, valeric, caproic, heptanoic and hexanoic acids.

Abstract: A resinous composition is made by: admixing (1) an organo-tin compound, having the structural formula: R.sub.1 R.sub.2 R.sub.3 SnX, where R.sub.1, R.sub.2 and R.sub.3 are organic groups, and X is a halide, hydroxide, acetate, butyrate, propionate, or dimethyl phosphate group, effective as a latent catalyst, (2) an amount of a reactive low viscosity epoxide diluent effective to dissolve the organo-tin compound without substantial heating, and (3) a cycloaliphatic epoxide or a glycidyl ester epoxide; wherein the weight ratio of cycloaliphatic epoxide or glycidyl ester epoxide: reactive epoxide diluent is between about 1:0.10 to 1:0.90, in the epoxide mixture; and about 0.00005 part to 0.0005 part by weight of organo-tin compound is used for each 1 part by weight of epoxide mixture.This resinous composition can be impregnated into a sheet material and cured to form insulation for an electrical member.

Abstract: A flexible, nontacky prepreg for use in bonding high voltage coils and inner cooling channels which comprises a fibrous mat material containing a high molecular weight epoxy and a sterically hindered anhydride. The resin comprises approximately 25 to 500% by weight of the fibrous mat material.