. "Among these are polyethylene, polypropylene homopolymer, random copolymers of propylene containing up to 10 percent of another olefin, block copolymers of propylene containing up to 25 percent of another olefin, nylon-6, nylon-66, polyethylene terephthalate, other high molecular weight thermoplastic polyesters, and vinyl polymers such as polyvinyl chloride." . . .