Dimensionally stable yarns

Abstract

An undrawn yarn is produced at increased quench delay and increased take-up speed to achieve improved ultimate elongation at a given crystallinity. Particularly preferred aspects include products comprising such yarns and methods for producing same.

1 . A method of producing an undrawn yarn having a predetermined crystallinity, comprising: 
 extruding a molten polymer through a spinneret plate to form a plurality of filaments; and    passing the plurality of filaments through a heated sleeve to thereby provide a quench delay, and taking up the plurality of filaments at a take-up speed;    wherein the quench delay and the take-up speed are selected such that an ultimate elongation of the undrawn yarn increases at the predetermined crystallinity when the quench delay increases.    
   
   
       2 . The method of  claim 1  wherein the predetermined crystallinity is between 10% and 40%, and wherein the undrawn yarn has a linear density of at least 300 dtex.  
   
   
       3 . The method of  claim 2  wherein the polymer comprises poly(ethylene terephthalate).  
   
   
       4 . The method of  claim 1  wherein the quench delay in the heated sleeve is increased by increasing a length of the heated sleeve.  
   
   
       5 . The method of  claim 1  wherein the length of the sleeve is at least 300 mm.  
   
   
       6 . The method of  claim 1  wherein the quench delay in the heated sleeve is increased by increasing a temperature in the heated sleeve.  
   
   
       7 . The method of  claim 1  wherein the take-up speed for the plurality of filaments is at least 3000 m/min.  
   
   
       8 . A method of producing an undrawn yarn, comprising extruding a molten polymer through a spinneret plate to form a plurality of filaments, delaying quenching of the plurality of filaments in a heated sleeve, and taking up the plurality of filaments at a take-up speed TU (m/min) using a quench delay such that the crystallinity of the undrawn yarn is less than 0.017×TU-39.  
   
   
       9 . The method of  claim 8  wherein the polymer comprises a polyester, and wherein the yarn has a linear density of at least 300 dtex.  
   
   
       10 . The method of  claim 8  wherein the heated sleeve has a length of at least 300 mm and wherein a temperature in the heated sleeve is at least 250° C.  
   
   
       11 . The method of  claim 8  wherein the take-up speed is between 3000 m/min and 5000 m/min.  
   
   
       12 . The method of  claim 8  further comprising drawing the plurality of filaments after taking up to form a drawn yarn.  
   
   
       13 . The method of  claim 12  further comprising providing an overfinish to the drawn yarn.  
   
   
       14 . The method of  claim 13  further comprising at least partially enclosing the overfinished drawn yarn in a rubber-containing composition.