Multi-layered plastic sheeting having high clarity, strength, and resistance to water vapor transmission

摘要

A multiple-layered, autoclavable, flexible plastic sheet comprises (a) at least one first layer consisting essentially of 30 to 90 percent by weight of a block copolymer having thermoplastic rubbery characteristics and having rubbery olefin blocks and blocks of a polystyrene and from 10 to 70 percent by weight of a polyolefin derived principally from at least one of propylene, ethylene and 4-methylpentene-1, said polyolefin having a Vicat Softening Temperature of about 120 DEG C. and (b) at least one second layer consisting essentially of a polyolefin derived principally by from at least one of propylene, ethylene, and 4-methylpentene-1 and being of semi-crystalline characteristics to exhibit low permeability to water vapor, the first and second layers being bonded together in alternating arrangement.