Abstract: A novel method and apparatus for manufacturing magnet wire in a continuous process by which coatings of a flowable resin material may be applied concentrically to a moving elongated filament in thicknesses of about 16 mils or less. The filament can be a bare copper or aluminum conductor having round or rectangular configuration or an insulated conductor upon which a top or an intermediate coat of material is desirably applied. Coatings of one-half mil and one mil also can be applied by the method of the invention. By the method and apparatus of the invention, magnet wire can be manufactured by continuously drawing the wire to size, annealing the wire, if necessary, insulating the wire with one or more coats of flowable resin material, curing the resin material, if necessary, hardening the resin material, and spooling the wire for shipment, without interruption at speeds limited only by the filament pay-off and take-up devices used.

Abstract: A novel apparatus for manufacturing magnet wire in a continuous process by which coatings of a flowable resin material may be applied concentrically to a moving elongated filament in thickness of about 16 mils or less. The filament can be a bare copper or aluminum conductor having round or rectangular configuration or an insulated conductor upon which a top or an intermediate coat of material is desirably applied. Coatings of one-half mil and one mil also can be applied by the method of the invention. By the apparatus of the invention, magnet wire can be manufactured by continuously drawing the wire to size, annealing the wire, if necessary, insulating the wire with one or more coats of flowable resin material, curing the resin material, if necessary, hardening the resin material, and spooling the wire for shipment, without interruption at speeds limited only by the filament pay-off and take-up devices used.

Abstract: A modified polyamide-imide resin and method for making the same. The composition comprises the reaction product of an aromatic tricarboxylic acid anhydride reactant, an aromatic diisocyanate reactant and an aliphatic dicarboxylic acid reactant in a solution comprising an aprotic solvent at a temperature ranging from about 70.degree. C. to about 155.degree. C. The tricarboxylic acid anhydride reactant is present in an amount which is greater than about 25 mol percent of the total of the tricarboxylic acid anhydride-aliphatic dicarboxylic acid reactants.The method comprises the steps of dissolving the aromatic tricarboxylic acid anhydride and aliphatic dicarboxylic acid reactants and an excess of the aromatic diisocyanate reactants in aprotic solvent thereby forming a reaction solution. The aromatic tricarboxylic acid anhydride is present in an amount which is greater than about 25 mol percent of the total of the tricarboxylic acid anhydride-aliphatic dicarboxylic acid reactants.

Abstract: A modified completely imidized aromatic polyamide-imide resin which can be applied from conventional phenolic solvents such as cresylic acid, phenols, cresols and the like. The method of the invention includes reacting an aromatic diisocyanate and an aromatic tricarboxylic acid anhydride in an aprotic solvent, modifying the reaction product with an aliphatic dicarboxylic acid, and diluting the same to an appropriate degree with a solvent. Solutions of the resin having relatively low viscosity and a relatively high resin content can also be made by the method of the invention. The modified polyamide-imide resin of the invention has thermal stability and toughness approaching non-modified aromatic polyamide-imide resins and are fully useful as such resins as insulation materials in the electrical industry.