| 摘要 |
<p>The present invention relates to bioriented polyethylene films having high water vapor transmission rates (WVTR) and methods for preparing the same. The film comprises a base layer and skin layers. The base layer comprises highly cavitated polyethylene, such as medium density polyethylene (MDPE) or high density polyethylene (HDPE). The cavitating agent in the base layer may be calcium carbonate. At least one skin layer comprises (i) a copolymer of ethylene and at least one other monomer and (ii) a hydrocarbon resin, such as a cyclopentadiene resin. This copolymer (i) may be an ethylene-propylene copolymer or an ethylene-propylene-butene-1 terpolymer. The film may have unidirectional tear properties in the machine direction. This film is particularly useful for packaging food products, such as pieces of candy.</p> |
