Melt-spinning process and melt-spinning apparatus for producing a crimped yarn

Abstract

A melt-spinning process and a melt-spinning apparatus produce a crimped yarn. By means of a spinning device, a filament bundle is generated from a thermoplastic polymer, is drawn after cooling and is compressed into a yarn plug in a stuffing chamber. The yarn plug is opened up into a crimped yarn and wound into a bobbin. In order to obtain as high a crimp resistance of the yarn as possible, amorphous fractions in the molecular structure of the yarn material are avoided after drawing. This is achieved by means of relaxation treatment after drawing and before compression, a minimum yarn pull force of >0.05 cN/dtex with a relaxation temperature in the range of 120° C. to 245° C. being maintained.

1 . A melt-spinning process for producing a crimped yarn, in which at least one filament bundle is generated from a thermoplastic polymer by the spinning of a plurality of filaments, in which the filament bundle is drawn after cooling and is compressed into a yarn plug in a stuffing chamber, and in which the yarn plug is opened up into a crimped yarn and wound into a bobbin, wherein, after drawing and before compression, the filament bundle undergoes relaxation treatment at a relaxation temperature in the range of 120° C. to 245° C. and with a minimum yarn pull force of >0.05 cN/dtex. 
     
     
         2 . The process as claimed in  claim 1 , wherein, during relaxation treatment, the yarn pull force acting on the filament bundle lies in the range of 0.1 cN/dtex to 2.0 cN/dtex, preferably in the range of 0.2 cN/dtex to 0.7 cN/dtex. 
     
     
         3 . The process as claimed in  claim 1 , wherein, for relaxation treatment, the filament bundle is guided in a plurality of loopings on a godet pair with heated godets and with conical godet casings. 
     
     
         4 . The process as claimed in  claim 1 , wherein, after relaxation treatment, the filament bundle undergoes fixing treatment at a fixing temperature in the range of 60° C. to 240° C., with a minimum yarn pull force of >0.05 cN/dtex being maintained. 
     
     
         5 . The process as claimed in  claim 4 , wherein, for fixing treatment, the filament bundle is guided in a plurality of loopings on a godet pair with cold godets. 
     
     
         6 . The process as claimed in  claim 1 , wherein, before compression, the filament bundle undergoes heat treatment at a treatment temperature lying below the relaxation temperature, with a minimum yarn pull force of >0.05 cN/dtex being maintained. 
     
     
         7 . The process as claimed in  claim 6 , wherein, for the heat treatment, the filament bundle is guided in a plurality of loopings on a godet pair with heated godets. 
     
     
         8 . The process as claimed in  claim 1 , wherein, for the compression, the filament bundle is conveyed into the stuffing chamber by an air stream of hot air or cold air. 
     
     
         9 . A melt-spinning apparatus for producing a crimped yarn, with a melt-spinning device, with a cooling device, with a drawing device, with a crimping device and with a winding device, the drawing device having a take-up godet pair with at least one heated godet and a drawing godet pair with two heated godets, wherein charactcrizcd in that the heated godets, of the drawing godet pair have in each case a stepped or conical godet casing, by means of which relaxation treatment can be carried out on a filament bundle guided in a plurality of loopings, with a minimum yarn tension of >0.05 cN/dtex and a relaxation temperature in the range of 120° C. to 245° C. 
     
     
         10 . The apparatus as claimed in  claim 9 , wherein, between the drawing device and the crimping device, at least one further godet pair is arranged, by means of which fixing treatment or heat treatment can be carried out on a filament bundle guided in a plurality of loopings. 
     
     
         11 . The apparatus as claimed in  claim 9 , wherein, between the drawing device and the crimping device a plurality of godet pairs are arranged, by means of which fixing treatment and heat treatment can be carried out on a filament bundle guided in a plurality of loopings. 
     
     
         12 . The apparatus as claimed in  claim 9 , wherein the crimping device has a conveying nozzle and a stuffing chamber arranged on the outlet side of the conveying nozzle. 
     
     
         13 . The apparatus as claimed in  claim 12 , wherein crimping device has a cooling drum for cooling a yarn plug guided out of the stuffing chamber. 
     
     
         14 . A crimped yarn which is made from a thermoplastic polymer and which is produced by means of a single-stage melt-spinning process as claimed in  claim 1 .