The polymeric material suitable for use herein may comprise homopolymers, copolymers, or terpolymers having the above-mentioned glass temperature and molecular weights such as acrylic polymers, styrene polymers, vinyl polymers, and copolymers and terpolymers thereof including copolymers of butyl acrylate and methyl acrylate, acrylonitrite-butadiene-styrene terpolymers, copolymers of vinyl isobutyl