Profile: Perma-Flex Mold Co. is engaged in the production of rubber molds and castings. Our product line includes RTV-2 slicones, polyurethanes, polysulfide and latex gum rubber. Our polyurethane rubber elastomer is a versatile polyurethane elastomer for making rubber molds, flexible blocks, and cases. Our Green-Sil® CMC® formulations are designed to make high strength RTV silicone rubber molds to cast gypsum plasters and cements.