Relations between Specific Volume,Count,and Twist of Spun Nylon Yarns

Abstract

Measurements of count, twist, and diameter were made on 500 specimens from 20 spun nylon yarns, covering counts from 10s to 40s and twist factors from 2 to 8, and used to study the specific volumes of these yarns. It was shown that in hard-twisted yarns the packing was about 7% less effective than in an ideal ring structure. In soft-twisted yarns, the specific volume was much greater. The effect of tension on yarn diameter was investigated in preliminary tests. The correlation between twist t and count N was also considered, and the constants k and m in the relation t = kN ^m were calculated. The value of m was shown to vary with twist factor in a way which could be explained by the torque-twist relations of yarns.