The film or casing is an ethylenically based plastic co- or ter-polymerized with a vinyl, acrylic or methacrylic acid derivative or with monomers such as vinyl acetate, ethylacrylate, methacrylate, methyl methacrylate and copolymers of styrene with butadiene, isoprene or other aliphatic monomers, films of polymers and copolymers of atactic polyalphaolefins, atactic polypropylenes, polyamides, poly