Heat shrinkable film using a blend of polypropylene impact copolymer, syndiotactic polypropylene and/or polypropylene random copolymer

摘要

It has been discovered that the properties of heat shrinkable sheet or film materials of ethylene/propylene rubber impact-modified heterophasic copolymer (ICP) can be improved by blending the ICP with a second polyolefin. The second polyolefin may be a syndiotactic polypropylene (sPP), a random copolymer (RCP) of propylene and a comonomer (e.g. ethylene and/or butene) made using a Ziegler-Natta or metallocene catalyst. A cavitating agent may be optionally included. The heat shrinkable sheet or film materials may also be biaxially oriented. Property differences in films made with the inclusion of the second polyolefin and possibly the cavitating agent include, but are not necessarily limited to, reduction in yield stress, increased density, decreased cavitation, increased light transmittance, increased shrinkage, among other physical and mechanical properties.