Packaging material esp for food products - consisting of laminate of several polymer films having low gas permeability

摘要

Packaging matl., esp. for food prods., consists of a laminate of several bonded polymer films, each film having a gas permeability of at most 10 (expressed as the cm3 of gas diffusing through a surface of 254 cm3 of a film having a thickness of 10 mu, during 24 hrs. at 22-5 degrees C, 50% relative humidity, and a pressure of 1 atmos.). The permeability of the laminate is essentially less than the permeability of one of the films divided by the no. of films, when all the films have the same thickness. Very low permeability for gases such as oxygen and carbon dioxide. This permeability can be controlled by varying the no. and type of films. Pref. the films consist of PVC, vinyl chloride) vinylidene chloride copolymer, polyacrylonitrile styrene/acrylonitrile copolymer, polyester, regenerated cellulose, oriented polypropylene, polyethylene, nylon or polyvinylidene chloride.