Gas-barrier resin composition and use thereof

1. A gas-barrier resin composition, comprising: a gas-barrier resin (A) having an oxygen permeability coefficient of 1.0×10 −14 (cm 3 ·cm/cm 2 ·s·Pa) or less wherein said gas-barrier resin (A) is a vinyl alcohol-based resin (A1); and a copolymer (B) containing monomer structural units represented by the formula (1), the formula (2), and the formula (3):

wherein R 1 represents a hydrogen atom or a methyl group; R 2 represents a hydrocarbon group having 1 to 20 carbon atoms that may be substituted with a halogen atom, a hydroxy group, an alkoxy group, or an amino group; 1, m, and n represent numerical values representing molar proportions of the respective monomer structural units, and n may represent 0; and p represents an integer of from 1 to 4, wherein a ratio of a mass of the copolymer (B) to a total mass of the gas-barrier resin (A) and the copolymer (B) is from 1 mass % to 40 mass %,

wherein, in the copolymer (B), the molar proportion 1 of the monomer structural unit represented by the formula (1), the molar proportion m of the monomer structural unit represented by the formula (2), and the molar proportion n of the monomer structural unit represented by the formula (3) satisfy the following expression:

50≥{( m+n )/( l+m+n )}×100≥5.

2. The gas-barrier resin composition according to claim 1 , wherein the hydrocarbon group having 1 to 20 carbon atoms represented by R 2 is an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms.

3. The gas-barrier resin composition according to claim 1 , wherein, in the copolymer (B), the molar proportion m of the monomer structural unit represented by the formula (2) and the molar proportion n of the monomer structural unit represented by the formula (3) satisfy the following expression: 100≥{m/(m+n)}×100≥50.

4. The gas-barrier resin composition according to claim 1 , wherein, in the monomer structural unit represented by the formula (3) in the copolymer (B), n=0.

5. The gas-barrier resin composition according to claim 1 , wherein the copolymer (B) has a number-average molecular weight (Mn) of from 1,000 to 1,000,000, and a ratio Mw/Mn between a weight-average molecular weight (Mw) and the number-average molecular weight (Mn) of from 1.5 to 4.0.

6. The gas-barrier resin composition according claim 1 , wherein, in the formula (2) and the formula (3), R 1 represents a hydrogen atom and p represents 1.

7. The gas-barrier resin composition according to claim 1 , wherein the vinyl alcohol-based resin (A1) is an ethylene-vinyl alcohol-based copolymer containing 10 mol % to 60 mol % of an ethylene structural unit.

8. A container, comprising, as a barrier layer, the gas-barrier resin composition of claim 1 .

9. A resin molded article, which is obtained by molding the gas-barrier resin composition of claim 1 .

10. The resin molded article according to claim 9 , wherein the molding is an injection molding method or an extrusion molding method.

11. The resin molded article according to claim 9 , wherein the resin molded article is any one of a sheet, a film, a tube, a pipe, a bottle, or a tank.

12. A method of modifying a gas-barrier resin, comprising mixing a copolymer containing monomer structural units represented by the formula (1), the formula (2), and the formula (3):

wherein R 1 represents a hydrogen atom or a methyl group; R 1 represents a hydrocarbon group having 1 to 20 carbon atoms that may be substituted with a halogen atom, a hydroxy group, an alkoxy group, or an amino group; 1, m, and n represent numerical values representing molar proportions of the respective monomer structural units, and n may represent 0; and p represents an integer of from 1 to 4,

into a gas-barrier resin (A) having an oxygen permeability coefficient of 1.0×10 −14 (cm 3 ·cm/cm 2 ·s·Pa) or less, wherein said gas-barrier resin (A) is a vinyl alcohol-based resin (A1),

wherein, in the copolymer, the molar proportion 1 of the monomer structural unit represented by the formula (1), the molar proportion m of the monomer structural unit represented by the formula (2), and the molar proportion n of the monomer structural unit represented by the formula (3) satisfy the following expression:

50≥{( m+n )/( l+m+n )}×100≥5.