| 摘要 |
1306214 Profiled films SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ NV 26 May 1970 [26 June 1969] 32365/69 Headings B5A and B5B [Also in Division B6] In a process for forming a profiled film web of a molecularly-orientable synthetic organic polymer a moving sheet-like mass 2 of the polymer is brought into contact, at a temperature above its crystalline melting point, with a profiling element (e.g. a ridged roller 3) having a ridged surface adapted to form a plurality of closely-spaced longitudinal grooves on one surface of the sheet, the profiled film web 2<SP>1</SP> so formed being drawn away from the profiling element at a speed faster than the sheet-like mass is supplied thereto so as to effect a melt draw-down of the web prior to the web being cooled to a temperature below its crystalline melting point. As illustrated the profiling element preferably includes an unridged backup roller 4 and the cooling and draw-down of the profiled web is achieved by a movable element which is internally water-cooled and driven at a speed faster than the surface speed of the profiling element. The chilled profiled film web may be converted into filaments or fibres by longitudinally stretching the film at a stretch ratio and under conditions such that it fibrillates under conventional fibrillation treatments. In an example a sheet of polypropylene is extruded, profiled, cooled and stretched at 145‹ C. a ratio of 8 : 1 between two sets of Godet rollers. The filaments so produced had an average denier of 22. |
