Preparation of aqueous thermosetting electrical insulating varnishes, and use of the varnishes

US4429072A · kind A · utility

Assignee

• BASF SE

Inventors

• Udo Reiter · Telgte, DE
• Helmut Lehmann · Bad Nauheim, DE

Key dates

• Filing date: Sep 17, 1982
• Grant date: Jan 31, 1984
• Expiry date: Sep 17, 2002

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01B3/308
• WIPO field: Electrical machinery, apparatus, energy
• WIPO sector: Electrical engineering

Abstract

A process for the preparation of aqueous thermosetting electrical insulating varnishes, wherein polyester-imide precondensates are prepared by condensing aromatic tricarboxylic acid monoanhydrides, diamines, diols, triols containing an isocyanurate ring, and cyclic trimerization products of diisocyanates, whose free isocyanate groups are blocked, with or without aromatic dicarboxylic acids or their esterifiable derivatives, and are reacted, at from 50.degree. to 200.degree. C., with or without addition of from 1 to 10% by weight, based on polyester-imide, of a polar organic solvent, with ammonia or an organic amine, and then diluted with fully demineralized water, with or without addition of a water-soluble curing catalyst. The novel electrical insulating varnishes are used as wire enamels or impregnating varnishes.