Alternate twist ply yarn with low residual twist

Abstract

ATP yarns having high twist efficiency (low residual twist) as well as methods for increasing the self plying action that occurs in ATP yarn processing. The self plying action and the ATP yarn structure may be improved by increasing the convergence angle of the singles twist yarns to above 50 degrees (compared to current values of 0 to 35 degrees). The increased convergence angle permits an increase in the ply twist above the level possible by self plying alone. This results in a yarn with reduced residual singles twist. An array of singles torque jets and an optional ply torque jet has been developed to achieve a high convergence angle. The angle between the singles torque jet axes can be varied from 0 to 180 degrees.

1 . An alternate twist ply yarn with a twist efficiency greater than 0.70. 
     
     
         2 . An alternate twist ply yarn as claimed in  claim 1 , with a twist efficiency of 0.75 to 1.25. 
     
     
         3 . An alternate twist ply yarn as claimed in  claim 1 , with a twist efficiency of 0.85 to 1.15. 
     
     
         4 . An alternate twist ply yarn as claimed in  claim 1 , with a twist efficiency of 0.95 to 1.05. 
     
     
         5 . A method for making the yarn of  claim 1  comprising the steps of:
 twisting singles in lengthwise alternating directions using a convergence angle of at least 50°; and 
 bonding yarns at a twist reversal point. 
 
     
     
         6 . A method as claimed in  claim 5 , wherein the convergence angle is 50-180°. 
     
     
         7 . A method as claimed in  claim 5 , wherein the convergence angle is 70-150°. 
     
     
         8 . A method as claimed in  claim 5 , wherein the convergence angle is 90-120°. 
     
     
         9 . A method as claimed in  claim 5 , wherein at least one yarn ply torque jet is employed in said twisting step. 
     
     
         10 . A method as claimed in  claim 9 , wherein at least two singles torque jets are employed in said twisting step. 
     
     
         11 . A yarn torque jet assembly comprising at least two singles torque jets and wherein an angle between axes of two of said singles torque jets is from 0-180°. 
     
     
         12 . A yarn torque jet assembly as claimed in  claim 11 , wherein the angle between axes of at least two of said singles torque jets is from 50-180°. 
     
     
         13 . A yarn torque jet assembly as claimed in  claim 11 , wherein the angle between axes of at least two of said singles torque jets is from 70-150°. 
     
     
         14 . A yarn torque jet assembly as claimed in  claim 11 , wherein the angle between axes of at least two of said singles torque jets is from 90-120°. 
     
     
         15 . A yarn torque jet assembly as claimed in  claim 11 , further comprising a guide which ensures that a yarn convergence angle is different from the angle between the axis of said at least two singles torque jets. 
     
     
         16 . A yarn torque assembly as claimed in  claim 11 , further comprising a ply torque jet located downstream of said at least two singles torque jets.