| 摘要 |
A thin transparent coated film comprises a base sheet of polyvinyl alcohol having a hydrolysis of at least 99,6% and an adherent waterproof polymeric coating on at least one side thereof. The base sheet may be coated on both sides. The polyvinyl alcohol may have a hydrolysis of at least 99,7%. The base sheet may have a thickness of 0,0001-0,01 inch. The waterproof coating may be of copolymers such as vinylidene chloride-acrylonitrile, vinylidene chloride-vinyl chloride, and methyl methacrylate-ethyl acrylate-terpolymers such as methyl methacrylate-ethyl acrylate-itaconic acid; homopolymers such as polyethylene, and polyvinyl chloride; or natural resins and derivatives such as nitrocellulose. An intermediate coating layer may be present or a bonding agent may be included in the polymeric coating to improve adherence of the waterproof coating e.g. polysiloxane or a terpolymer of vinyl chloride, vinyl acetate and maleic anhydride. Specifications 960,203, 260,204 and 260,206 are referred to. |
