Abstract
The effect of single and ply twists on the properties of a 15.5/2 carded yarn was studied, and a comparison made with the results of a similar study conducted on a 31/2 carded cotton yarn. In addition, the properties of a single yarn (15.5/1) were compared to those of an equivalent 2-ply yarn (31/2). Generally, the ply twist-strength curves for the 15.5/2 yarn were found to be similar to those for the 31/2 yarn. However, a change to a coarser yarn number caused definite differences in the twist level required for maximum strength and in the characteristics of the maximum strength plateaus. The elongation characteristics of the 15.5/2 and 31/2 yarns were also very similar, but the elongation values for the coarser yarns were higher than for the finer yarns. With decreasing yarn number, low single twist yarns reacted less sensitively elongationwise to high ply twist. For equivalent single and ply twist multiplier combinations, maximum ply yarn strength values were obtained with approximately the same twist combina tion for both the 15.5/2 and 31/2 yarns; elongation values increased as equivalent twist multiplier combinations increased, with the rate of increase being greater for the coarser yarn. For low and medium twist single yarns the percentage gain of ply over single yarn strength became less as the yarn became coarser. The equivalent ply yarn (31/2) was generally stronger and was, in most cases, lower in elongation than its single yarn counterpart (15.5/1). Ply yarn variability seemed to increase as the twist increased in the component single yarns.