Films, Compositions and Processes
Published November 29, 2005
An oriented polymeric film has been patented. It comprises at least one layer with a first material that is very highly crystalline polypropylene homopolymer (VHCPP), which has a very high intermolecular stereoregularity consisting of at least about 98% of isotactic polymer. The remainder of the material (if any) is atactic polymer. A second material comprises at least one polymer having a ring and ball softening point from 110° C. to 170° C. and/or a nucleating agent. The second material may also include at least two second materials comprising hydrogenated hydrocarbon resin(s) of different types and/or nucleating agent(s). The second material is added in an amount sufficient for the film to exhibit two or more of the following properties measured in any direction parallel to the film surface and, where necessary, normalized for a 20 micron thick film: WVTR less than about 6 g/24 hours/m2; OTR less than about 1,500 cm3/24 hours/m2; Young’s modulus from 4000 MPa to 5000 MPa, Flexural modulus from 0.4 N (mm2) to 0.7 N (mm2); haze less than about 1.1%; and/or a clarity greater than 97%.