| abstract |
(57) [Abstract] [Purpose] To provide a resin composition for impregnation which is excellent in heat resistance and electric properties after curing. [Structure] An impregnating resin composition containing 20 to 50 parts of a polyester resin, 1 to 25 parts of an epoxy resin, and 1 to 15 parts of a polyimide resin. Preferably, the polyester resin has isophthalic acid and maleic acid as the main components of the acid component, and the polyimide resin has at least potentially a double bond capable of crosslinking in the polyimide molecule. |