The Nature of Wet Crease Recovery in Cotton—A Review

Abstract

Intro4uction, Unfinished cotton fabrics that have heen desizecl, ' scoured, and bleached are usually less resilient when wet tjiati when conditioned to &dquo;dryness&dquo; at 65% RH at 25° C. Thus 80 X 80 fabric has been found to have dry conditioned recovery angles of 195°' (warp plus filling) and 165 (W + F) when wet.On occasion, other memlers of this laboratory have observed cotton fahric in which the dry and wet crease recovery angles were of equal value and one sample at least with the wet recovery angle higher than the dry value. These anomalies are helieved to le due to the severity of, or the lack of severity of, the purification process and perhaps to the structure and history of the fabrics. It has been, experimentally shown that numerous reagents cause an elevation of both the dry and wet recovery angles, and the reagents which have been successful in textile finishing for wash-wear have heen dior '. poly functional. However, in the field o~ epoxide and formaldehyde finishing it has been found possiblẽ to elevate the wet crease angle without changing the dry angle very much, although sometimes with epoxide-treated fabrics the dry angle is definitely less than that of the untreated control. Gross deposition of re~n to cause &dquo;spot welding&dquo; of fibers or l~cril>l~eral deposition, as described by Steele 1701 I and Marsh [41], will not be considered in tliis discttssion. although noted in passing.From the number of references in the literature to wet crease recovery alone it would appear that the phenomenon has been rather widely observed over a considerable period of time. And since there is such a variety of reagents that can cause it under many different conditions of reaction, it is possible that what is being observed are several effects superimposed upon one another. The two most common reagents capable of making cotton crease resistant in the wet state alone are formaldehyde (or donors of it) and epichlorohydrin (or its precursors). However, as this review will show, the choice of a reagent is not limited to these two.IZeference will also 1>e made to effects of alkali alone on cotton, and, as will be pointed out, strong alkali (15-25% NaOH ) is used as a &dquo;catalyst&dquo; in preparing various cellulose derivatives, particularly the ethers. It is possible to cause improvement in 1 One of the laboratories of the Southern Utilization Research and Development Division,