Abstract: A polymer having dihydropyridine rings or dihydrotriazine rings as main constitutional units, an ethynyl- or cyanato-terminated Schiff's compound which is a starting material for producing the polymer, and applications of the polymer.

Abstract: An electrically insulated coil manufactured with a composition comprising a poly-functional epoxy resin having at least three of p-(2,3-epoxy propoxy) phenyl groups and a bi-functional epoxy resin as a binding resin for a reinforced insulating base sheet and as an impregnation resin has no peeling off in its insulating layers and is capable to be used continuously under the temperature at 200.degree. C. or above.

Abstract: A thermosetting resin composition comprising (A) at least one polyfunctional epoxy compound and (B) at least one polyfunctional nitrile compound and a prepolymer thereof can give a cured product having excellent heat resistance and mechanical properties such as flexibility.

Abstract: A crosslinkable compound obtained by reacting an aromatic hydrocarbon-formaldehyde resin with an .alpha.,.beta.-unsaturated monocarboxylic acid or an ester thereof has no odor or very slight odor. Said crosslinkable compound can be radical polymerized at a low temperature to give a cured article having excellent electrical insulating properties. Said crosslinkable compound can also be used as one component of a resin composition containing an unsaturated polyester resin or a polybutadiene resin modified with acrylic or methacrylic acid to give an odorless or low-odor resin composition suitable for producing reinforced plastics, paints and varnishes, adhesives, electrical parts, etc.

Abstract: A crosslinkable compound obtained by reacting an aromatic hydrocarbon-formaldehyde resin with an .alpha.,.beta.-unsaturated monocarboxylic acid or an ester thereof has no odor or very slight odor. Said crosslinkable compound can be radical polymerized at a low temperature to give a cured article having excellent electrical insulating properties. Said crosslinkable compound can also be used as one component of a resin composition containing an unsaturated polyester resin or a polybutadiene resin modified with acrylic or methacrylic acid to give an odorless or low-odor resin composition suitable for producing reinforced plastics, paints and varnishes, adhesives, electrical parts, etc.

Abstract: A thermosettable, polymerizable resin composition comprising a polyepoxide and a polyisocyanate which is normally catalyzed by a basic curing catalyst for forming oxazolidone rings and isocyanurate rings or uredione rings is remarkably stabilized at low temperatures by incorporating a small amount of an organic electron acceptor, such as, picric acid, quinone, chloranil, or cyanoacetate ester into the composition. Since the specific electron acceptors effectively inhibit the polymerization of the reactive components in the composition at low temperatures, a shelf life of the composition is remarkably prolonged.