| abstract |
A film selectively permeable to carbon dioxide which comprises chitosan having a degree of deacetylation of 70 mol% or higher and in which the ratio of the carbon dioxide transmission (CO2TR) to the oxygen transmission (O2TR), (CO2TR/O2TR), is 15 or higher. The film is insoluble in water, is highly safe from the standpoint of food hygiene, and has such selective gas permeability that the ratio of carbon dioxide transmission to oxygen transmission is high. It can be economically obtained. |