Abstract: Composite materials formed of bonded silicone elastomers and polyolefin films, for uses including catheters, closures for piercing by medical needles, and medical containers, the bonding between the normally inert unbondable materials being accomplished by corona discharge treatment of the polyolefin film and the use of an ethyl silicate, ethyl ortho silicate and tetra butyl titanate solution primer on the treated polyolefin adjacent the uncured silicone elastomer such that the materials may be securely bonded one to the other by curing through the application of heat and pressure.