Method for improving glossiness and ink color fastness of printed color films and its application thereof

A method for improving glossiness and ink color fastness of a printed color film, wherein the printed color film is a composite biaxially oriented polypropylene (BOPP) film, and the method comprises the following steps:

• pre-treating outer and inner surfaces of the composite BOPP film, wherein the composite BOPP film comprises (i) a surface layer comprising a blended film of a first polypropylene (PP) copolymer, silica, a phenyl-modified silicone and hydrogenated petroleum resin, (ii) a core layer comprising a blended film of a PP homopolymer, an antistatic agent and the hydrogenated petroleum resin, and (iii) an inner layer comprising a blended film of a second PP copolymer, the phenyl-modified silicone and the hydrogenated petroleum resin;
• coating the outer and inner surfaces of the composite BOPP film with a surface-modifying coating agent and drying it at a temperature of 80-100° C., wherein the surface-modifying coating agent includes a waterborne silane coupling agent, an ethyl orthosilicate, a solid acid and water in a mass ratio of (5-10):(50-100):(5-10):(300-400), the waterborne silane coupling agent is one of methyl trichlorosilane (MTS) or an amino silane, and the solid acid is ethylenediaminetetraacetic acid;
• and
• printing the outer surface of the composite BOPP film with a water-based colored ink, and drying to obtain the printed color film.