The influence of twist factor on the tensile characteristics on three combed cotton yarns spun from different kind of cottons has been investigated. Breaking strength, breaking extension, as well as specific strain resistance are the function of twist factor and kind of cotton from which the yarns are spun. With the increasing of tex twist factor from 26.9 up to 39.5 the breaking strength increases. The yarns spun with tex twist factor of 39.5 and 45.9 have the same breaking strength, i. e. there is no significante difference. With the increasing of twist factor the breaking extension increases as well for all yarns spun from different kind of cottons. The optimum tex twist factor with the combed cotton yarn of nominal count of 20 tex is a bit less than 45.9. At the same levels of twist factor the specific strain resistance drops more rapidly with the incrementt of the strain, and afterwords tends to stay at the same level or even to rise slightly. An average strain resistance of all yarns spun from different kind of cottons and twist factors occurs at the range from 70 up to 80 cN/fibre, whereas, to the break 42 up to 48 cN/fibre. Yarns spun from stronger and longer fibres exhibit higher breaking strength and breaking extension. The best fitting of the theoretical curves to the experimental results of the average specific strain resistance is obtained with an inverse curve with high coefficient of determination.

Tekstilna tehnologija