VRI 777 solventless polyester varnish is a thixotropic semi-rigid resin system primarily for vacuum impregnation of both from wound and random wound motors. VRI 777 solventless polyester varnish is a thixotropic semi-rigid resin system primarily for vacuum impregnation of both from wound and random wound motors. Its high thermal capability coupled with its excellent electrical properties over a wide temperature range makes this resin suitable for AC and DC applications in the higher voltage ranges in both form wound motors and transformer.