Abstract: A thermosetting resin composition comprising:[A] a polyfunctional epoxy resin produced from a reaction between a mixture of at least two polyhydric phenols selected from (a) bis(4-hydroxyphenyl)methane, (b) bis(4-hydroxyphenyl)ethane, (c) bis(4-hydroxyphenyl)-propane, (d) tris(4-hydroxyphenyl)alkane and (e) tetra(4-hydroxyphenyl)alkane, and epichlorohydrin, and[B] an acid anhydride curing agent; and a coil and a panel formed of said composition.

Abstract: Electric windings comprising an electric conductor and a plurality of cured insulating layers wrapping around the conductor, said cured insulating layers being obtained by bonding two or more insulating materials with a binder solution containing a mixture of a condensation polymerization type silicone resin containing hydroxyl groups in the molecule and an addition polymerization type silicone resin to form a composite insulating material, wrapping the composite insulating material around the conductor, impregnating the wrapped composite insulating material with an impregnating varnish of an epoxy-isocyanate resin and curing the impregnated composite insulating material, have excellent water resistance in addition to excellent thermal resistance, and mechanical properties.

Abstract: Electric machine windings produced by wrapping a composite insulating material around an electrical conductor, said composite insulating material having been prepared by bonding two or more insulating materials with a silicone resin containing hydroxyl groups in the molecular structure, impregnating said composite insulating material with an insulating varnish comprising 1 equivalent of a polyfunctional epoxy compound and 2.5 to 25 equivalents of a polyfunctional isocyanate compound and curing said varnish, have excellent insulation properties under high temperatures and high humidity and thermal resistance of class H or more.

Abstract: A thermosetting resin composition comprising a polyfunctional epoxy compound such as diglycidyl ether of bisphenol A, a polyfunctional isocyanate such as diphenylmethane diisocyanate, a curing agent and a polybutadiene type homopolymer having terminal hydroxyl groups or copolymer having terminal amino groups, or a reaction product of a polyfunctional epoxy compound or an epoxy compound having halogen atom(s) and a polybutadiene type homopolymer or copolymer having terminal hydroxyl groups or terminal carboxyl groups can produce cured articles excellent in heat resistance, crack resistance and fire resistance.

Abstract: A thermosetting resin composition comprising a polyfunctional epoxy compound such as diglycidyl ether of bisphenol A, a polyfunctional isocyanate such as diphenylmethane diisocyanate, a curing agent and polybutadiene type polymer having terminal hydroxyl groups can produce cured articles excellent in heat resistance and crack resistance.

Abstract: Thermosetting resins are produced by blending 1 equivalent of a polyoxazolidone terminated by two vicinal epoxy groups and containing at least two oxazolidone rings with at least 1 equivalent of a polyfunctional isocyanate compound, adding 0.01 to 10% by weight of a catalyst which forms isocyanurate rings and oxazolidone rings based on the total amount of the polyoxazolidone and the isocyanate compound, and then heating the resulting composition to polymerize the composition by forming isocyanurate rings and oxazolidone rings. The resin compositions have excellent mechanical properties, and particularly excellent flexibility, and excellent thermal resistance.