Improvements in the melt spinning of fine denier synthetic filament yarn

摘要

PICT:0661999/IV (a)/1 Fine denier filament yarns are obtained by melt spinning a synthetic polymeric substance through a multihole spinneret into a stream of inert gas passing through a spinning cell and maintained at a temperature sufficient to cool the molten substance to below its solidification temperature so as to form a plurality of fine denier filaments which are gathered together to form a yarn and steadied by means of a convergence yarn guide as soon as the filaments solidify and become substantially non-tacky. The fine denier filament yarns are those in the range of 3.0-1.0 or lower denier per filament. Preferably, air or other gas is passed as a cooling medium across the path of the moving filamentary material adjacent the spinneret. The convergence guide serves to minimize the effects of any pulsations in the cooling medium as well as any momentary tension fluctuations occasioned by the take-up mechanism. The yarn from the convergence guide may pass through the cell to a second guide and thence to a conditioning apparatus. As shown, filaments are melt-spun through spinneret 4 and gathered together to form a yarn 5 by means of convergence guide 6. The spinning cell 7 is provided with means, not shown, for passing a current of cooling fluid in non-turbulent manner at right-angles to the direction of travel of the filaments, e.g. it may be constructed as described in Specification 533,304. The yarn passes to another guide 8, then through a moisture-conditioning chamber 9, and finally to a wind-up device. In an example, polyhexamethylene adipamide is melted and maintained at 285 DEG C. in an atmosphere of nitrogen. The molten polymer is pumped through a filter pack comprising sand layers and screens and then through a spinneret with 70 holes, each of diameter 0.0009 inch. A cross-flow cooling chamber is placed 1 inch below the base of the spinneret. The filaments solidify at about 21 inches from the spinneret and at this point they are brought together as a yarn by passing through a thread guide. The process is applicable to the production of yarns of polyamides, polyesters, polyethers, polyacetals, polyester-polyamides, polyethylenes, polyvinyl compounds, polystyrene, and polyacrylates. Specifications 471,590 and 577,436 also are referred to.