VRI 709 is a unique semi-rigid Solventless Polyester Resin designed for dipping and vacuum pressure impregnation. It has good catalyzed tank stability, high thermal capability and good moisture resistance. VRI 709 has been specifically formulated to have good bond strength while retaining a degree of flexibility for resistance to thermal shock. - Permafil® 709 is a unique semi-rigid Solventless Polyester Resin designed for dipping and vacuum pressure impregnation Application. It has Excellent tank stability, higher flash point than resin utilizing styrene or vinyl toluene as monomers.