Polymer filaments having profiled cross-section

Abstract

The invention provides a profiled polymer filament having an open hollow cross-sectional shape normal to the longitudinal axis of the filament, wherein the cross-section is dimensioned to prevent the filament from interlocking with a second filament of the same cross-section. The invention also provides methods of manufacture of such filaments by melt spinning a polyamide, and spinnerets suitable for use in melt spinning such filaments.

1 - 38 . (canceled)  
     
     
         39 . A spinneret for the production of profiled filaments by melt extrusion of a polymer into filaments, said spinneret comprisesing: 
 a plate having upper and lower surfaces connected by an assembly of capillaries;    and either (a) each capillary has an open hollow transverse cross-section, or (b) each capillary comprises two adjacent segments,    whereby the profiled filament cross section longitudinal to the axis of the filament is obtained as the molten polymer streams from each segment coalesce at a point between the segments, and    wherein the profiled filaments having an open hollow cross-sectional profile shape normal to the longitudinal axis of the filament, said cross-sectional profile shape having a central arcuate portion and first and second elongated leg portions, each of said leg portions having proximal and distal end portions, said proximal end portions joining to said central portion and said distal end portions joining to foot portions on each leg portion, said foot portions having a dimension F, said leg portions and said central arcuate portion defining an open portion, said leg portions oriented in a substantially parallel relationship, and said foot portions defining an aperture leading to said open portion; said aperture having a dimension D, wherein dimension D is less than dimension F.    
     
     
         40 . A spinneret according to  claim 39 , wherein: each capillary is comprised of two segments; each segment is comprised of a straight length portion having at each end a junction with a pair of projecting portions; at the first end, the pair of projecting portions are of equal area and each comprise a straight portion terminating in a round portion; at the second end the pair of projecting portions are of unequal area and each comprise a straight portion terminating in a round portion.  
     
     
         41 . A spinneret according to  claim 40 , wherein each segment is the mirror image of the other segment.  
     
     
         42 . A spinneret according to  claim 41 , wherein each segment is the non-superimposable mirror image of the other segment.  
     
     
         43 . A spinneret according to  claim 39 , wherein the capillaries themselves have an open hollow cross-section, each capillary having a cross sectional shape comprising: 
 a second straight portion and a third straight portion bifurcating from the first end of the first portion, wherein the second straight portion terminates in a round portion and the third straight portion extends to a first point of bifurcation;    a fourth straight portion and a fifth straight portion extending from said first point of bifurcation, wherein the fourth and fifth straight portions have unequal areas and each terminate in round portions;    a sixth straight portion and a seventh straight portion bifurcating from the second end of the first straight portion, wherein the sixth straight portion terminates in a round portion and the seventh straight portion extends to a second point of bifurcation; and    an eighth straight portion and a ninth straight portion extending from said second point of bifurcation, wherein the eighth and ninth straight portions having unequal areas and each terminate in round portions.