Improvements in or relating to methods for the production of polypropylene filamentary structures and filamentary structures produced thereby

摘要

1,139,328. Melt spinning polypropylenes. ALLIED CHEMICAL CORP. 4 May, 1966 [21 June, 1965; 21 Oct., 1965], No. 19775/66. Heading B5B. Undrawn polypropylene filaments having a denier of 50 to 50,000 and a density below 2À86 Î 10SP-7/SP D+0À88145, or below 2À90 Î 10SP-7/SP D +0À88120, or below 2À92 x 10SP-7/SP D + 0À88034, where D is the denier, may be formed by melt extruding polypropylene in the form of one or more filamentary structures and quenching the said structures by passing them through a liquid quencing medium maintained at a temperature below 3‹ C. The temperature of the liquid may be below - 20‹ C. or below - 75‹ C. The quenched filaments may then be drawn at a draw ratio of 8 to 14: 1 at 20‹ to 150‹ C., preferably 120‹ to 140‹ C. The temperature of the melt is at least 185‹ C. and preferably within the range 200‹ to 300‹ C.