GAS-BARRIER FILM AND PROCESS FOR PRODUCING THE SAME

摘要

A gas-barrier film is produced by covering at least one side of a base film, such as a polyester film, with a transparent inorganic layer such as a silicon oxide and then with a barrier resin coating layer such as a vinylidene chloride copolymer or an ethylene-vinyl alcohol copolymer. A heat-sealing layer may be formed on the barrier resin coating layer or the other side of the base film. The thickness (n1) of the inorganic layer is 0.01 - 0.5 mu m and that (n2) of the coating layer is 0.05 - 15 mu m, the ratio of n2 to n1 being 0.1 to 1,500. The obtained film withstand the lowering of the gas-barrier properties even when acted upon by an external mechanical force such as crumpling. The film is suitable for preserving food for long, because it can retain high transparency and gas-barrier properties even when it has a thin covering layer and is heated by retorting or in a microwave oven.