HEAT-STABLE BIAXIALLY ORIENTED POLYPROPYLENE FILMS

In one example embodiment, disclosed is a biaxially oriented multilayer film, which may include a first tie layer and a second tie layer, wherein each has an inside surface and an outside surface. The film's core layer may consist of: (i) at least 50 wt. % high-crystalline polypropylene; (ii) both cyclic olefin copolymer and polypropylene homopolymer, or, polypropylene heterophasic copolymer; (iii) and, optionally, additives, wherein the core layer is between the inside surface of the first tie layer and the inside surface of the second tie layer. The film may also include a first skin layer on the outside surface of the first tie layer and a second skin layer on the outside surface of the second tie layer, wherein shrinkage is less than 3.5% in a transverse direction for the biaxially oriented multilayer film after subjecting the biaxially oriented multilayer film to 135° C. for 7 min at 1 atm.