POLYMER BLENDS AND NONWOVEN ARTICLES THEREFROM

摘要

This invention relates to a nonwoven article comprising a heterogeneous blend comprising: 1) from 60 to 99 weight percent of one or more semi-crystalline polymers (based upon the 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 2000 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 2000 dg/min; c) an intermolecular compositional 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; and d) an Mw/Mn of 1.5 to 4, and e) a propylene triad tacticity, as measured by ¹³C NMR, of 75% or greater; where the blend of the semi-crystalline and semi-amorphous polymers comprises less than 5 weight % filler, based upon the weight of the polymers and the filler, and the blend has: i) an MFR greater than 10 dg/min; and ii) a Permanent Set of greater than 65% (as measured on a 125 mil thick molded part); and where the nonwoven article has a Hand of 40 g or less at a fabric basis weight of 35 gsm.