Insulation of electrical conductor - with thermosetting polyester resin

摘要

Insulation of an electrical conductor with a thermosetting non-linear polyester resin(s) is effected by (a) passing the conductor one or more times through molten resin(s) at a temp. between 80 degrees and 250 degrees C in a heatable enclosed varnishing chamber and then (b) curing the resin on the conductor at a higher temp, the resin(s) used having a viscosity at 250 degrees C 8000cP. The resin (or at least one when a mixt. is used) is pref. a polyester resin obtd. from an aromatic carboxylic acid(s) and contg. amide and/or imided gps. The resin is pref. a mixt. of highly condensed resins with those of low condensation. Up to 20 wt. % solvent (based on the resin) may be present to reduce viscosity.