Effect of pre-draft ratio and twist on the stretch of Lycra elastic yarn

The changes of elastic recovery of two kinds of Lycra elastic yarns(one spun on fancy twisting machine of cotton spinning system and the other on Sirofil spinning frame) were reviewed by changing the pre-draft ratio and twist.The relevant experimental data were used lo establish the function model between the stretch of the elastic yarn and pre-draft ratio and twist.The effect of the pre-draft ratio and twist on the stretch of the elastic fancy yarn and Sirofil elastic yarn was summarized with how to rationally distribute draft and twist factor discussed.