Polypropylene blends and processes for producing polymeric compositions

摘要

Polymer blends of polypropylene homopolymer and propylene-α-olefin interpolymer. Processes for producing polymeric compositions comprising control-cooling heated blends of polypropylene and propylene-α-olefin interpolymer. Such polymeric compositions can be employed in forming coated wires and cables.

主权项

1. A process for preparing a thermoplastic polymeric composition, said process comprising:
(a) heating a polymer blend comprising a polypropylene homopolymer and a propylene-α-olefin interpolymer to a melt temperature of (1) greater than 140° C., (2) at least the melting temperature of the polypropylene homopolymer, or (3) at least the melting temperature of the propylene-α-olefin interpolymer, whichever of (1) through (3) is greatest, for a time sufficient to form a polymer melt blend; and (b) cooling said polymer melt blend from said melt temperature down to ambient temperature, wherein said cooling comprises:
(i) non-control-cooling said polymer melt blend from said melt temperature to an initial cooled temperature in the range of from 140 to 125° C.,(ii) control-cooling said polymer melt blend at an average cooling rate in the range of from 0.1 to 30° C. per minute from said initial cooled temperature to an intermediate cooled temperature in the range of from 110 to 100° C., and(iii) cooling, by either control-cooling or non-control-cooling, said polymer melt blend from said intermediate cooled temperature to ambient temperature, thereby forming said polymeric composition.