Improved surface segregation through the use of a block copolymer

摘要

A surface-segregatable, melt-extrudable thermoplastic composition is provided which includes (A) a thermoplastic polypropylene-polyethylene block copolymer in which the polyethylene blocks constitute from about 1 to about 10 percent by weight of the copolymer and (B) a defined trisiloxane polyether additive having a molecular weight of from about 350 to about 1,400, which additive is present in an amount of from about 0.1 to about 5 percent by weight, based on the amount of thermoplastic block copolymer. The use of the block copolymer unexpectedly permits the use of significantly reduced amounts of additive while still providing nonwoven webs which are immediately wettable and which do not become significantly less wettable over time.