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Formaldehyde, when applied with acid catalysis, is the most effective cellulose crosslinker available in that it produces the most crushproofing on a weight basis. However, formalization is accompanied by high strength loss in cotton.It has been postulated that the unfavorable crease recovery-strength relationship with formaldehyde is a function of the shortness of the acetal cross-link. It has also been postulated, naively, that longer cross-links could be derived from long chain dialdehydes, the crease recovery-strength relationship improving with increasing chain length.Work with the dialdehydes glyoxal (C 2 ). glutaraldehyde (C 5 ). and α-hydroxyadipaldehyde (C 6 ) yielded crease recovery-strength relationships similar, if not identical. to formaldehyde. This tinding is consistent with the known chemistry of the formaldehyde-cellulose reaction in that the acetal linkage controls the length of the cross-link.

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The pour crease recovery-strength relationship exhibited by cotton which has been reacted with formaldehyde by a dry curing process has been shown to be primarily a function of the formal linkage and not of the degradative effects of acid Inconsistencies in results obtained with formaldehyde are associated with the slow rate of hemiformal formation in the padding bath. Cotton in the wet state can be cross-linked by means of hemiacetal linkages with glyoxal, and it has been shown that the strength loss produced by cured dimethylol ethyleneurea at a given level of crease recovery is comparable to that obtained from uncured glyoxal in the absence of those degradative effects associated with the hot. acidic curing of thermosetting finishes The ratio of wet to dry crease recovery suggests that the areas of cellulose and/or the hydroxyl groups which are involved when cotton is cross-linked in glyoxal solutions are the same as those involved in the dry curing of cross-linkers A high wet to dry crease recovery ratio evidently requires that cross-linking at some stage take place in a state of swelling beyond that found during the application of typical aqueous cotton creaseproofing reagents. The thests that different areas and or hydroxyl groups are involved in the attamment of wet and dry crease recovery is further supported by experiments in which dry crease recovery was obtamed on cotton independently of the high wet crease recovery which had been established first