Coextruded polyolefin films having improved barrier properties

摘要

The barrier properties of a coextruded film having a surface layer comprising a crystalline polyolefin can be improved substantially by incorporating a precise amount of a partially incompatible wax into the polyolefin. The film has an interior layer comprising a polymer that prevents migration of the wax to the other surface of the film so that wax does not interfere with the printability or heat sealability of the other surface. The wax-containing polyolefin layer also protects the interior layer from adverse effects of moisture, such as when the interior layer comprises EVOH. An interior layer of EVOH may be sandwiched between wax-containing polyolefin layers to fully protect it from moisture.