Spinneret for extruding self-crimping hollow fibers, self-crimping hollow fibers, and method for producing self-crimping hollow fibers

Abstract

The invention relates to a spinneret for extruding self-crimping hollow fibers including at least one capillary. The at least one capillary has at least one segmented opening, which has at least two opening segments spaced apart from each other in the cross-section. A first opening segment of the at least two opening segments has a first opening-segment width and a second opening segment of the at least two opening segments has a second opening-segment width. The second opening-segment width is wider than the first opening-segment width.

1 . A spinneret for extruding self-crimping hollow fibers,
 comprising at least one capillary, wherein   said at least one capillary has at least one segmented opening, which has at least two opening segments spaced apart from each other in cross-section, wherein   a first opening segment of said at least two opening segments has a first opening-segment width and a second opening segment of said at least two opening segments has a second opening-segment width, the second opening-segment width being wider than the first opening-segment width.   
     
     
         2 . The spinneret according to  claim 1 , wherein the opening-segment width of the second opening segment is by at least 10%, preferably at least 20% wider than the opening-segment width of the first opening segment. 
     
     
         3 . The spinneret according to  claim 1 , wherein the opening-segment width of the second opening segment is by 10% to 50%, preferably 20% to 40% wider than the opening-segment width of the first opening segment. 
     
     
         4 . The spinneret according to  claim 1 , wherein that the opening segments have a curved shape. 
     
     
         5 . The spinneret according to  claim 1 , wherein the opening segments are concentrically curved. 
     
     
         6 . The spinneret according to  claim 1 , wherein the at least two opening segments each have a substantially semicircular shape. 
     
     
         7 . The spinneret according to  claim 1 , wherein the respective opening segments comprise two longitudinal sides and two transverse sides, wherein the distance between the transverse sides of the mutually adjacent opening segments is selected in such a manner that the hollow-fiber wall portions extruded from the opening segments are fused to each other on the transverse sides after exiting from the opening segments. 
     
     
         8 . A self-crimping hollow fiber comprising a hollow-fiber wall extruded by means of a spinneret, comprising
 a hollow-fiber wall, wherein   the hollow-fiber wall in cross section comprises at least two hollow-fiber wall portions, wherein   a first one of said at least two hollow-fiber wall portions has a first wall thickness and a second one of said at least two hollow-fiber wall portions has a second wall thickness, the second wall thickness being larger than the first wall thickness.   
     
     
         9 . The self-crimping hollow fiber according to  claim 8 , wherein the first hollow-fiber wall portion and the second hollow-fiber wall portion each have a constant wall thickness. 
     
     
         10 . The self-crimping hollow fiber according to  claim 8 , wherein the first hollow-fiber wall portion and the second hollow-fiber wall portion are connected to each other by fusion. 
     
     
         11 . The self-crimping hollow fiber according to  claim 8 , wherein the wall thickness of the second hollow-fiber wall portion is by at least 10% and preferably at least 20% larger than the wall thickness of the first hollow-fiber wall portion. 
     
     
         12 . The self-crimping hollow fiber according to  claim 8 , wherein the wall thickness of the second hollow-fiber wall portion is by 10% to 50% and preferably by 20% to 40% larger than the wall thickness of the first hollow-fiber wall portion. 
     
     
         13 . The self-crimping hollow fiber according to  claim 8 , wherein the hollow-fiber wall portions are curved, the second hollow-fiber wall portion having a stronger curvature than the first hollow-fiber wall portion. 
     
     
         14 . A method for producing self-crimping hollow fibers a spinneret, by
 extruding polymeric material from an opening, segmented in cross section, of a capillary of a spinneret, said opening comprising at least two opening segments having different opening-segment widths,   wherein, from said at least two opening segments, at least two hollow-fiber wall portions are extruded, wherein, from a respective opening segment, respectively one hollow-fiber wall portion is extruded,   fusing the extruded hollow-fiber wall portions to each other after exit from said opening, while forming a hollow fiber having a hollow-fiber wall which in cross section comprises at least two hollow-fiber wall portions with different wall thicknesses.   
     
     
         15 . The method according to  claim 14 , wherein after said fusion connection, the hollow fiber is heated.