| 摘要 |
<p>The process comprises providing a first material constituted of discrete elements such as granules of polyester having an average molecular weight of 18000-40000 and an intrinsic viscosity of 0.6-1.2 dl/g, drying the first material, optionally mixing the raw materials to promote homogenization, extruding the first material through a die for forming a monolayer or a multilayer and the rapidly cooling, optionally coating a side of the film to impart specific properties to the film, biaxially stretching the film according to a draw ratio and a draw temperature to obtain a crystalline phase. The process comprises providing a first material constituted of discrete elements such as granules of polyester having an average molecular weight of 18000-40000 and an intrinsic viscosity of 0.6-1.2 dL/g, drying the first material, optionally mixing the raw materials to promote homogenization, extruding the first material through a die for forming a monolayer or a multilayer and the rapidly cooling, optionally coating a side of the film to impart specific properties to the film, biaxially stretching the film according to a draw ratio and a draw temperature to obtain a crystalline phase, thermosetting the film at a temperature of 180-250[deg] C, performing transverse relaxation of the film, winding the film and then performing cutting, coating, vacuum coating, annealing and/or UV, plasma or corona treatment, controlling the hydrolysis resistance and/or performance of the film, and increasing the thickness of crystallites to increase adhesion of film. The parameters of the steps are selected to control a thickness of the film or to increase a thickness of the film. The longitudinal stretching is performed at a draw ratio of 2-6, 2.5-5 or 2.8-4.5 and a draw temperature of 70-150[deg] C, 85-140[deg] C or 90-135[deg] C. The transverse stretching is performed at a draw ratio of 2-6, 3.5-5 and 3.5-4.5 and at a draw temperature of 95-150[deg] C, 105-145[deg] C and 110-140[deg] C. During the thermosetting process of the film, the rise in temperature is 4-14[deg] C/second. An independent claim is included for a biaxially oriented polyester film.</p> |
