Oxygen barrier film, food packaging material comprising same, and method for producing oxygen barrier film

An oxygen barrier film comprising:

• a base layer;
• and
• an organic-inorganic hybrid layer located on the base layer and including a natural hydrogel and a silane coupling agent, and
• wherein the natural hydrogel comprises protein,
• wherein the protein is a whey protein,
• wherein
• the organic-inorganic hybrid layer has a structure in which the silane coupling agent is dispersed and crosslinked in the natural hydrogel having a three-dimensional network structure,
• a weight ratio of solids of the protein to the silane coupling agent is 10:1 to 1:10,
• the silane coupling agent is dispersed and crosslinked with the protein of the natural hydrogel by bonding which includes C—N bond and C—H bond, and
• the silane coupling agent is an aminosilane, and the protein and the aminosilane are combined to form the crosslinked three-dimensional network structure with an amide bond,
• wherein
• the organic-inorganic hybrid layer further includes a filler which is disposed in pores between the crosslinked three-dimensional network structures, and a content of the filler is 5 parts by weight to 15 parts by weight, per 100 parts by weight of a pre-composition for the organic-inorganic hybrid layer, and
• the filler is a sorbitol,
• wherein
• the aminosilane and the filler are added into an aqueous protein solution to prepare the pre-composition for the organic-inorganic hybrid layer,
• the pre-composition for the organic-inorganic hybrid layer is heat-treated and then cooled to prepare a composition for the organic-inorganic hybrid layer, and
• the composition for the organic-inorganic hybrid layer is applied onto the base layer to prepare the oxygen barrier film,
• and
• wherein
• the pre-composition for the organic-inorganic layer is heat-treated under a condition of 80° C. to 90° C. for 2 hours to 3 hours and then cooled, and
• the organic-inorganic hybrid layer shows, in an infrared spectroscopy measurement, predetermined levels of peaks at 900 to 1200 cm−1 corresponding to the C—N bond and at 2800 to 3000 cm−1 corresponding to the C—H bond.