| 摘要 |
1317558 Film fibrillation SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ NV 26 May 1970 [26 June 1969] 32364/69 Heading B5B In a continuous process for the manufacture of synthetic fibres, from a molecularly orientable thermoplastic synthetic organic polymer in which a polymer film web is profiled using a profiling element, the resulting profiled web being split subsequently into individual fibres by longitudinal stretching of the profiled web, the ridged portion of the profiling element 4 is in the form of a band 5 bounded on each longitudinal edge by a ridge 6, and, immediately beyond said ridge, by a plain unridged portion 7 of width sufficient to prevent a groove formed in the film web of polymer from running into an edge thereof as a result of any lateral movement of said film web of polymer. The ridged portion of the profiling element may comprise ridges of unequal pitch 9, 10 such that the ultimate grooved web breaks down into a plurality of fibres of at least two substantially different deniers. As shown, the profiling element may be a driven profiling roller having circumferential parallel closely spaced ridges. Preferably, the width of the plain unridged portion 7 of the profiling element is such as to provide edge portions of the web of polymer which can be readily removed; ¢ to 2 inches width is suitable. The depth of the plain unridged portion may be equal to the depth of the portions between adjacent ridges of the profiling element; and beyond each plain unridged portion the surface of the profiling element may rise very slightly higher than the height of the ridges to form a shoulder 11. The ridged roller form suitably embodies a ridged portion which has ridges 9 of small pitch separated by a small number of ridges 10 of greater pitch; thus the small pitch ridges may have a pitch of 0À0125 inch and a depth of 0À0077 inch and the large pitch ridges may have a pitch of 0À020 inch and a depth of 0À0077 inch. The production of polypropylene fibres is exemplified. |
