| 摘要 |
A base thermoplastic film, has a coextruded or coated heat seal layer formed from a polymer blend which provides good peel-apart heat seals. When the film is sealed to itself, the seal opens by separation at the original seal surface without film tear, or by delamination of the sealant material from the primary base film substrate without the formation of strands extending between the two base film. The heat seal layer which may be on one or both sides of the base layer comprises a ternary blend of a random ethylene-propylene copolymer, a butene polymer and a low density polyethylene. The films are cast, and oriented in the solid state up to about two times in the machine direction and six times or more in the transverse direction to give films having good dead-fold and water vapor transmission rate characteristics making them highly suited for packaging, particularly for dry foods. |
