Patent attributes
This invention relates to homogeneous blends of: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 200 dg/min or less; and2) 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 5 to 12 weight % of one or more C2 and or C4 to C10 alpha-olefin comonomers, said semi-amorphous polymers each having:a) 10 to 50 percent crystallinity or less;b) a melt flow rate of 200 dg/min or less;c) a DSC melting point (second melt Tm) of 130° C. or less;d) 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;e) an Mw/Mn of 1.5 to 4,f) a triad tacticity of three propylene units, as measured by 13C NMR, of 75% or greater,for use in films, fibers, non-wovens, molded articles and the like.
