This invention discloses a highly efficient selective UV-absorbing film based on polyvinyl
acetal and its preparation method, belonging to the technical field of
polymer functional membrane materials. The UV-absorbing film comprises the following components in parts by weight: 55-95 parts of matrix resin, 5-45 parts of
plasticizer, 0.005-1.2 parts of core
UV absorber, 0.01-0.3 parts of auxiliary
UV absorber, 0.01-0.8 parts of composite
antioxidant, 0.01-0.8 parts of light stabilizer, and 0.0025-0.0065 parts of
metal ion additive. The core
UV absorber is an
alkyl-modified benzoxazinone compound, and the composite
antioxidant is a combination of a hindered phenolic resin as the main
antioxidant and a
thiophosphate ester as the auxiliary antioxidant. This invention achieves highly efficient blocking of UV-B
radiation and
high transmittance of UV-A
radiation. Simultaneously, the
film material has advantages such as low initial yellowing, excellent long-term anti-yellowing performance, good
thermal stability, good compatibility with the matrix, and no exudation. The present invention also provides a method for preparing the core UV absorber and a method for preparing the membrane, which are simple processes and suitable for industrial production.