Abstract: Mixtures of reactive thermosetting resins which are stable at ambient temperature, latent catalyst complexes for hardening said mixtures, processes for their manufacture, and heat-hardened resins obtained from said mixtures. Mixtures of heat-reactive thermosetting resins which are stable at ambient temperature for use in impregnating insulation for electrical materials or in the preparation of molding products or composite materials, comprising liquid oligo- or poly-isocyanate compounds and liquid epoxy resins and a latent hardening catalyst which is inert at ambient temperature and is composed of an addition complex of an amine compound from the group consisting of the amines, the alkylhydrazines and the imidazoles, and a boron halide. They additionally comprise a small quantity of maleic anhydride or the boron halide is boron tribromide with no addition of maleic anhydride. Latent catalyst complexes of these mixtures, formed by the addition complexes of BBr.sub.

Abstract: Process for insulating by impregnation an electric winding with isocyanurate and oxazolidone cycles resins, in which one wraps around the conductors a glass cloth and porous mica paper tape loaded with a quaternary ammonium salt catalyzing the condensation of the isocyanate and epoxy compounds into isocyanurate and oxazolidone cycles, one impregnates the tape with a varnish containing an isocyanate compound and a liquid epoxy resin, then one subjects the impregnated tape to a varnish polymerization thermal treatment. One uses as a quaternary ammonium salt a benzyl-trialkylammonium halide with an alkyl chain containing at the most 3 carbon atoms.

Abstract: A method of insulating electrical conductors wherein a tape of porous mica paper and of glass felt or cloth or plastic material film is wound round the conductors, wherein the tape is impregnated with a varnish comprising a polymerizable liquid resin, and wherein the impregnated tape is polymerized by heat treatment, the method including the improvement whereby an adhesive powder is initially added to the tape to provide adhesion between the porous mica paper and the glass felt or cloth or the plastic material film, said adhesive powder comprising a polymer having chains of oxazolidone groups containing groups with epoxy terminations, and whereby the polymerizable liquid resin of the varnish essentially contains isocyanate groups which are transformed into isocyanurate groups during polymerization.

Abstract: Process for insulating by impregnation an electric winding with isocyanurate and oxazolidone cycles resins, in which one wraps around the conductors a glass cloth and porous mica paper tape loaded with a quaternary ammonium salt catalyzing the condensation of the isocyanate and epoxy compounds into isocyanurate and oxazolidone cycles, one impregnates the tape with a varnish containing an isocyanate compound and a liquid epoxy resin, then one subjects the impregnated tape to a varnish polymerization thermal treatment. One uses as a quaternary ammonium salt a benzyl-trialkylammonium halide with an alkyl chain containing at the most 3 carbon atoms.

Abstract: Insulation process by impregnation of electric leads using isocyanate and oxazolidone cycle resins in which a glass cloth and porous mica paper tape is wound around the leads, the tape is impregnated with a quaternary ammonium salt, catalyzing condensation of isocyanate and epoxy derivatives in isocyanurate and oxazolidone cycles and with a varnish comprising a liquid epoxy resin and an isocyanate derivative, then the impregnated tape undergoes a heat treatment for polymerization of the varnish.As quaternary ammonium salt, is used a benzyltrialkylammonium halide with alkyl chain containing at most 3 carbon atoms, the tape is first impregnated with benzyltrialkylammonium halide and liquid epoxy resin, it is dried at a temperature equal to 135.degree. C. at maximum and then it is impregnated with isocyanate derivative based varnish before undergoing the polymerizing heat treatment.

Abstract: An electrically conductive part with an insulation material which withstands high temperatures and a method of manufacturing such a part. Its conductive core is formed by drawing a copper billet coated with a copper-aluminium alloy.