Patent ID: 6537652
Filing Date: 2003-03-25
Classification: C08J,H01G,Y10S,Y10T

Abstract:
A biaxially oriented film having at least one layer comprising polypropylene, characterized in that the polypropylene has a chain isotacticity index, measured by 13C-NMR spectroscopy (triad method), of at least 95%, an isotactic pentad fraction, measured by 13C-NMR spectroscopy, in the range of 85-95%, and a n-heptane-insoluble content of at least 97%, and in that the transverse shrinkage of the film (depending on the film thickness d) satisfies the following formula:<4.5 &mgr;m transverse shrinkage at 140Â° C. maximum 6.5% &Dgr; shrinkage at 140Â° C.âˆ’shrinkage at 120Â° C.=<3.5%â€ƒâ€ƒd: 4.5-12 &mgr;m transverse shrinkage at 140Â° C. maximum 5.5% &Dgr; shrinkage at 140Â° C.âˆ’shrinkage at 120Â° C.=<3.0% >12-20 &mgr;m transverse shrinkage at 140Â° C. maximum 4.5% &Dgr; shrinkage at 140Â° C.âˆ’shrinkage at 120Â° C.=<2.5%.