▎ 摘　　要

NOVELTY - A modified polyvinyl alcohol coating film comprises a base film, a functional bottom coating, and a polyvinyl alcohol coating layer. USE - Modified polyvinyl alcohol coating film. ADVANTAGE - The cross-linked structure formed by functional monomers restricts the movement of molecular segments, reduces the free volume, reduces or blocks the diffusion path of oxygen molecules, and fills the gaps of the cured molecular segments with inorganic materials to further reduce the free volume. The diffusion path of water vapor molecules is extended. The barrier to water vapor molecules is improved. The functional bottom coating has excellent compatibility with polyvinyl alcohol coating, and strong binding force. The use of the coating improves the oxygen and water vapor barrier ability of the polyvinyl alcohol coating film, the adhesion of the polyvinyl alcohol coating to the substrate, and the application of the polyvinyl alcohol film. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a preparation method of modified polyvinyl alcohol coating film, which involves (1) preparing functional bottom coating and polyvinyl alcohol coating layer, where the coating viscosity is 300-1000 cps, (2) using micro-concave reverse coating method, uniformly coating the functional bottom coating on the base film, where the mesh number is 100-200 mesh and the linear speed ratio is 0.7-1.6, (3) drying a coating film by an oven at 130-200degreesC for 15-75 seconds, (4) coating the polyvinyl alcohol coating layer by normal coating method, (5) drying the modified polyvinyl alcohol coating film by the oven at 100-150degreesC for 20-70 seconds, and (6) rewinding the roll, put in a curing chamber, and curing at 40-60degrees Celsius for 0.5-6 days.