| 摘要 |
PURPOSE:To obtain a desired good quality polyvinyl chloride-coated polyester film at low cost by a method wherein coating is done during a process for making a biaxially stretched polyester film and the heat treatment of a coating layer is done simultaneously with the thermosetting of the polyester film. CONSTITUTION:Vinyl chloride-vinyl acetate copolymer emulsion, which is prepared by a method wherein fine silica powder dispersed in water in advance is added so as to form 0.1% of solid, followed by addition of water to prepare 40% of solid and well agitated, is applied on one side of an unstretched film, which is obtained by being melt-extruded from a T-die, with an air knife in the thickness, which is about 10mum after drying, and about 1mum after stretching. In order not to impair the stretchability of the film, the film is dried by hot air in such a state that the temperature of film at the application part is 50 deg.C or lower at the outlet of a drying oven and, in succession, charged in a simultaneous, biaxial stretching machine and, after being preheated at 100 deg.C, simultaneously and biaxially stretchedand thermoset at 230 deg.C, and at the same time polyvinyl chloride is heat-treated. Finally, after cooling, the resultant polyvinyl chloride-based resin-coated polyester film is reeled out. |
