FILMS FROM POLYMER BLENDS

摘要

This invention relates to a film comprising a heterogeneous blend of: 1) from 60 to 99 weight of the semi-crystalline and semi-amorphous polymers), each semi-crystalline polymer comprising propylene and from 0 to 5 weight % alpha-olefin comonomer (based upon the weight of the polymer), said semi-crystalline polymers each having a melting point between 100 and 170°C and a melt flow rate of 200 dg/min or less; and 2) from 1 to 40 weight % of one or more semi-amorphous polymers (based upon the weight of the semi-crystalline and semi-amorphous polymers), each semi-amorphous polymer comprising propylene and from 10 to 25 weight % of one or more C2 and or C4 to C10 alpha-olefin comonomers, said semi-amorphous polymers each having;. A)heat of fusion of 4 to 70 J/g; b) a melt flow rate of 0.1 to 200dg/min; c) an intermolecular composition distribution as determined by thermal fractionation in hexane such that 85% by weight or more of the polymer is isolated as one or two adjacent, soluble fractions with the balance of the polymer in immediately preceding or succeeding fractions; and wherein each of these fractions has a wt% comonomer content with a difference of no greater than 20 wt% relative to the average wt% comonomer content of the copolymer; d) an Mw(Mn of 1.5 to 4, e) a propylene triad tacticity, as measured by ¹³C NMR, of 75% or greater; where the blend has: I) a melt flow rate of 0.5 to 100 dg/min; and ii) 0 to 5 weight % filler, based upon the weight of the polymers and the filler; and iii) a haze of 20% or less measured on a 1 mm thick injection molded chip; and iv) a permanent set of greater than 65%; and where the film is 0.1 to 25 mil (2.5 to 635 micron) thick and has: a haze of 10% or less, a 1° Secant tensile modules of 100,000 to 30, 000 psi, an Elmendorf tear in the machine direction of 45 g/mil or more, an Elmendorf tear in the transverse direction of 45 g/mil more, a total energy impact of 3 J or more; and a 45 degree gloss of 82 or more.