Novel Mercerizing Technique to Establish "True" Length of Cotton Yarn

Abstract

A procedure is suggested for the determination of the length at which the yarn in a skein can be regarded as straightened but not stretched. This procedure requires the determination of the tensions developed in a series of mercerizings of skeins of yam which are alike but are set in the mercerizing apparatus at lengths which differ by small percentages. When the maximum tensions attained are suitably plotted, a change in slope in the curve indicates a point which corresponds with the desired length. A unit measuring-tension for the precise measurement of skeins of yarn which are, for example, to be used subsequently for chemical treatment, can then be derived. More specifically, a suitable tension for measuring has been found to be 1.2 lb. per lea of 120 yds. of 40 2 yarn of mercerizing twist. Equivalent tensions can be calculated readily for other sizes of skein and many other yarns. The change in slope appears, further, to pinpoint a fun damental change in the response of cotton yarn under increasing tension just as it begins to stretch. It is suggested also that a measuring-tension for single threads derived from results with skeins may be suitable for determining the initial lengths of yarns for some of the common physical tests such as those for elongation and twist.