RETORTABLE EASY OPENING SEALS FOR FILM EXTRUSION

摘要

The multilayer film comprises a first outer layer which is heat sealable. The first outer layer comprises from 95 to 100 percent (by weight of the first outer layer) of a first polymer, said first polymer being derived from propylene monomer and optionally one or more comonomers selected from the group consisting of ethylene and C4-C8 alpha olefins. The first polymer should have a melting point of at least 125 C. The multilayer film further comprises an inner portion adjacent to the first outer layer. The inner portion may be a single layer or may comprise several layers. At least one layer of the inner portion comprises an elastomeric propylene based polymer (“EPBP”). Further at least one layer of the inner portion comprises a second polymer, wherein the second polymer is selected from the group consisting of high pressure low density polyethylene, high density polyethylene, ethylene acrylic acid copolymers, ethylene (meth)acrylic acid copolymers and combinations thereof. The second polymer may be together with the EPBP in the same layer or may be in a separate layer. It is also contemplated that the inner portion may optionally comprise one or more additional layers, which may or may not contain EPBP or the second polymer. The multilayer film further comprises a second outer layer arranged so that the inner portion is encapsulated between the first outer layer and the second outer layer. The second outer layer comprises a third polymer, wherein said third polymer is selected from the group consisting of homopolymer polypropylene, random copolymer polypropylene and impact copolymer polypropylene and blends thereof.

主权项

1. A multilayer film comprising:
a. a first outer layer which is heat sealable, said first outer layer comprising from 95 to 100 percent by weight of the first outer layer of a first polymer, said first polymer being derived from propylene and optionally one or more comonomers selected from the group consisting of ethylene and C4-C8 alpha olefins, said first polymer having a melting point of at least 125° C.; b. an inner portion adjacent to the first outer layer, said inner portion comprising (i) from 5 to 80 percent by weight of the inner portion of an elastomeric propylene based polymer; (ii) from 30 to 70 percent by weight of the inner portion of a random copolymer derived from propylene and one or more additional comonomers selected from the group consisting of ethylene, and C4-C8 alpha olefins; and (iii) from 20 to 60 percent by weight of the inner portion of a second polymer, wherein the second polymer is selected from the group consisting of high pressure low density polyethylene, high density polyethylene, ethylene acrylic acid copolymers, ethylene (meth) acrylic acid copolymers and combinations thereof; c. optionally one or more additional layers; and d. a second outer layer arranged so that the inner portion is encapsulated between the first outer layer and the second outer layer, said second outer layer comprising a third polymer, wherein said third polymer is selected from the group consisting of homopolymer polypropylene, random copolymer polypropylene and impact copolymer polypropylene and blends thereof.