| 摘要 |
An organic thermoplastic film is coated with a solution in an organic solvent of a heat-sealable polymer containing finely-divided polymethyl methacrylate particles, the particles being large enough to confer slip properties but not so large that they cause haze, the organic solvent being a non-solvent for polymethyl methacrylate and for the material of which the film is made, and the coating dried to remove the solvent. The bulk of the particles may have a size in the range of 0,1-2 microns, especially 0,1-0,7 microns, and the thermoplastic film may consist of a linear polyester, preferably polyethylene terephthalate, or a poly-a -olefine, e.g. polythene or polypropylene. Heat-sealable polymers mentioned include polyvinyl acetate, partially hydrolysed polyvinyl acetate, butadiene/acrylonitrile copolymers, butadiene/styrene copolymers, copolymers of vinylidene chloride with vinyl chloride or alkyl acrylate, copolymers of vinyl acetate with vinyl chloride or ethylene, copolymers of vinyl chloride with ethylene, and especially copolymers of vinylidene chloride and acrylonitrile (e.g. 80-95% / 20-5% copolymers). Specification 707,549 is referred to. |
