Gas-barrier laminate for hydrothermal treatment

1. A gas-barrier laminate for hydrothermal treatment, comprising a base plastic film, a coating layer formed on at least one surface of the base plastic film, an inorganic thin film formed on a surface of the coating layer which is made of a metal compound and/or silicon compound, and a heat-sealable plastic film laminated on the inorganic thin film or the base plastic film, wherein

the coating layer comprises

a crosslinking aqueous resin comprising at least one group selected from the group consisting of a melamine group and a carbodiimide group,

an aqueous polyurethane-based resin which is the reaction product of a polycarbonate-based polyhydroxy compound and a polyisocyanate compound, and

an aqueous acrylic resin;

the amount of the crosslinking aqueous resin is 10 to 60% by weight of the coating layer in terms of a solid content thereof; and

the inorganic thin film before laminating the heat-sealable plastic film thereon has a rubbing strength of not less than 20 times as measured under a load of 70 g, and the coating layer has a hardness of 0.15 to 0.40 GPa.

2. The gas-barrier laminate according to claim 1 , wherein the base plastic film is made of a plastic material selected from the group consisting of polyesters, polyamides, polypropylene, polyvinyl acetate and partially hydrolyzed products of ethylene-vinyl acetate copolymers.

3. The gas-barrier laminate according to claim 1 , wherein the aqueous acrylic resin is a water-soluble acrylic resin.

4. The gas-barrier laminate according to claim 1 , wherein the metal compound and/or silicon compound is silicon oxide and/or aluminum oxide, or a metal oxide containing these oxides.

5. The gas-barrier laminate according to claim 1 , wherein the inorganic thin film has a thickness of 5 to 50 nm.

6. The gas-barrier laminate according to claim 1 , wherein the inorganic thin film has a surface roughness Rms of not less than 1.5 nm.

7. The gas-barrier laminate according to claim 1 , wherein the heat-sealable plastic film is laminated on the inorganic thin film.

8. The gas-barrier laminate according to claim 7 , further comprising an adhesive layer formed between the inorganic thin film and the heat-sealable plastic film.

9. The gas-barrier laminate according to claim 1 , wherein the heat-sealable plastic film formed on the inorganic thin film or the base plastic film is an unstretched polypropylene film having a thickness of 50 μm, and a gas-barrier laminate after subjected to hydrothermal treatment at 120° C. for 30 min has an oxygen transmission rate of not more than 5 cc/m 2 /day/atm.

10. A gas-barrier laminate for hydrothermal treatment, comprising a base plastic film, a coating layer formed on at least one surface of the base plastic film, an inorganic thin film formed on a surface of the coating layer which is made of a metal compound and/or silicon compound, and a heat-sealable plastic film laminated on the inorganic thin film or the base plastic film, wherein

the coating layer comprises

a crosslinking aqueous resin comprising at least one group selected from the group consisting of an oxazoline group and a carbodiimide group,

an aqueous polyurethane-based resin which is the reaction product of a polycarbonate-based polyhydroxy compound and a polyisocyanate compound, and

a water-soluble acrylic resin;

the inorganic thin film before laminating the heat-sealable plastic film thereon has a rubbing strength of not less than 20 times as measured under a load of 70 g, and

the coating layer has a hardness of 0.25 to 0.30 GPa.