The Improvement of Luster of Cotton

Abstract

The results of swelling treatments which go beyond mercerizing at ordinary temperature indicate that there is an upper limit to the swelling of cotton, with increased luster as the objec tive. If this is exceeded, as it is with strong sulfuric acid or zinc chloride, and probably is with mercerization with caustic below 0°C, the luster is decreased, because the surface of the indi vidual fiber is roughened. Drastic shrinkage of yarn volume, combined with film formation and disappearance of fuzz, can leave the fabric very sheer and transparent, attributes often correlated with luster. Me chanical action on the plastic cellulose, or on films of cellulose or hydroxyethyl cellulose de posited from solution, can give increased luster through flattening and mechanical stabilization in the flattened form. These cellulose-affecting treatments tend to leave the fabric stiff, if they go beyond normal mercerizing. Other additive finishes act on luster either through film formation or by stabilizing mechani cal effects and controlling fabric structure. The more flexible thermoplastic resins can, with mechanical smoothing, produce an increase in the physical measurement of luster. However, this effect is less than that of mechanically smoothing the fabric without the thermoplastic resins, so the chief advantages lie in the other effects of these finishes, such as possible greater stability of the mechanical finish with the resin present. In the higher ranges of luster, the eye can discriminate between luster arising from film formation or flattening, and the type of luster arising from yarn and fabric structure and from mercerizing.