Use of Sulphamic Acid or its Ammonium Salt as Catalyst in Wrinkle-Resistant Finishing of Cotton Textiles

Abstract

Crosslinking of cotton cellulose with DMEU and DMDHEU were studied using amido sulphuric acid (sulphamic acid) either alone or in combination with MgCl2-6H2O or citric acid. Ammonium sulphamate was also examined as a catalyst, and different techniques of application studied include pad-dry-cure, steam-cure, and rapid-cure treatments. Sulphamic acid was found to be an effective catalyst for crosslinking of cellulose and enables satisfactory levels of wrinkle-recovery improvement and wash-n-wear ratings, irrespective of the method of application used. Among the three methods of application studied, improvement in dry wrinkle recovery obtained with both single-stage rapid-cure and steam-cure methods is less as compared with that obtained by the pad-dry-cure technique, while improvement in wet wrinkle recovery is always higher with steam-cure and rapid-cure as compared with pad-dry-cure method. Unlike MgCl2-6H2O + citric acid mixed-catalyst systems, where synergistic behavior is noticed in catalytic activity of the crosslinking reaction, no additional improvement in wrinkle-recovery angle is observed when sulphamic acid is used in conjunction either with citric acid or MgCl2-6H2O, irrespective of the relative proportions of the two components in the mixture. In the case of ammonium sulpharnate as catalyst, rapid-cure technique fails to impart satisfactory levels of wrinkle-recovery improvement, but with pad-dry-cure technique it enables slightly better strength retention for a given level of wrinkle-recovery improvement as compared with sulpharnic acid or MgCl2-6H2O.