PURPOSE: To maintain the freshness by keeping a food such as raw eggs, etc., in a carbondeoxide gas-enriched atmosphere which is obtained by a gas released from a carbon deoxide gas controlled releasing type film of sheet.
CONSTITUTION: A carbon deoxide gas controlled releasing type film or sheet has spaces in which carbon deoxide gas is filled. The carbon deoxide gas- permeability of the film or sheet at 25°C is 500cc/100in2.mil.atm.24hr or higher. For the method to provide spaces on the film or sheet, e.g. two sheet with different shapes are laminated. Also, for the method to fill carbon deoxide gas in the spaces, preferably, a carbon deoxide gas with, e.g. 30-80% concentration is incubated for 6-24 hours. The material of the film or sheet is, e.g. polyethylene, polystyrene, fluorine-contained resin or hard vinyl chloride, etc. As the spaces in which the carbon deoxide gas is filled, e.g. the one which can be used as a cushion material and air mat as shown by a sketch is preferable.
MIURA YOSHIE
INOUE ICHIRO
