5-LAYERED COEXTRUDED BIAXIALLY STRETCHED TUBULAR FILM HAVING AT LEAST 3 POLYAMIDE LAYERS

摘要

PURPOSE: To improve insulation performance against oxygen and moisture by providing at least three polyamide layers as well as olefin (co)polymer layers between the polyamide layers, in a film in the title suitable for packaging food such as sausage meat and soft cheese. CONSTITUTION: At least three polyamide layers are provided in a coextruded biaxially stretched tubular film consisting of at least five layers for covering an article packaging in the liquid state or paste state, especially food with filled material or for post treatment. These three layers forms the core layer, inner layer and outer layer, between which olefin (co)polymer layers are provided. For polyamide layers aliphatic polyamide such as polyamide-6 or a copolyamide containing a relative large percentage of caprolactam is used, and for olefin layers an ethylene- or propylene-based copolymer containing functional groups, preferably for a layer between the inner and core layers.