Abstract: A process to increase resistance to tearing in a heat-resettable material involves extruding a polymer of a specified crosslinking density to produce a plastic web. After cooling the plastic web is heated by creating a temperature decreasing towards its core and stretched at core temperature below crystalline melting temperature of partially crystalline and crystalline polymers resulting in a distribution of orientation over the full section of the plastic web. Resistance to tearing will be essentially increased in this manner based on a simple, low-cost production process.

Abstract: A thermomorphic covering layer is applied to a heat-shrinkable body of thermoplastic material, e.g. a heat-shrinking sleeve adapted to surround and seal a cable splice so that when the heat-shrinking temperature is reached, the thermomorphic covering melts to form a continuous protective layer on the sleeve. It contains glass fibers or an insecticide or microbicide to protect the sleeve against pest deterioration.