| 摘要 |
PROBLEM TO BE SOLVED: To obtain a carbon dioxide gas-selectively permeable composition which gives a molding highly safe in terms of food hygiene and having a high ratio of carbon dioxide gas permeability to oxygen gas permeability by mixing a basic amino acid with a polyalcohol so that the resultant mixture has a specified isoelectric point. SOLUTION: This composition is a mixture of at least one basic amino acid selected from lysine, arginine and histidine and at least one polyalcohol selected from polyvinyl alcohol and starch and has an isoelectric point of 7.5 or higher. The mixing ratio is preferably such that the molar ratio of the amino or imino group, which provides the basicity, of the basic amino acid to the hydroxyl group of the polyalcohol is (0.025/1)-(2.0/1). When this composition is formed, e.g. by solution casting, into a film having a thickness of 0.01-100μm, the ratio (PCO2/PO2) of carbon dioxide gas permeability (PCO2) to oxygen gas permeability (PO2) of the film is 15 or higher. Thus formed film is laminated to a thermoplastic film to give a laminated film for food packaging.
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