Patent ID: 7540834

Claim:
A process for making a backseamed casing, comprising: (A) preparing a multilayer heat-shrinkable film comprising: (i) a first outer layer serving as an inside casing layer, the first outer layer comprising a first polyolefin comprising at least one member selected from the group consisting of: (a) ethylene/unsaturated acid copolymer, propylene/unsaturated acid copolymer, and butene/unsaturated acid copolymer, wherein the unsaturated acid is present in an amount of at least 4 weight percent, based on the weight of the copolymer; and (b) anhydride-containing polyolefin comprising an anhydride-functionality, wherein the anhydride functionality is present in an amount of at least 1 weight percent, based on the weight of the anhydride-containing polyolefin; (ii) a second layer comprising at least one member selected from the group consisting of polyester and a first polyamide; and (iii) a third layer serving as an outside casing layer, the third layer comprising at least one member selected from the group consisting of second polyolefin, polystyrene, and a second polyamide; and wherein the second layer is between the first layer and the third layer, with the film having has a thickness of at least 5% of a total thickness of the heat-shrinkable casing film; (B) wrapping the film longitudinally around a forming shoe with opposing length film sheet edges being overlapped or abutted with one another; (C) sealing the film longitudinally to form a backseam; followed by (D) forwarding the film.