Submitted to: American Association Of Textile Chemists And Colorists Review
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/15/2003
Publication Date: 10/1/2003
Citation: Welch, C.M., Peters, J.G. 2003. Acid vs. Weak Base Catalysis in DP Finishing with BTCA or Citric Acid. American Association Of Textile Chemists And Colorists Review. 3(10):27-30.
Interpretive Summary: Efforts are in progress to replace formaldehyde-releasing agents now in widespread use for durable press treatment of cotton fabric and garments. It is officially recognized in the U. S. and worldwide that formaldehyde can produce cancers in animals, and is a probable cause of cancer in the respiratory and lymphatic systems of humans, as well as inducing allergic reactions in some individuals. Citric acid is an inexpensive durable press finishing agent that is nontoxic as an additive in food and beverages, is safe to apply in a textile mill, and is recognized as environmentally acceptable. Heretofore citric acid has not been as effective in textile finishing as required. There is a need for catalysts which can speed up the reaction of citric acid and similar durable press agents with cotton and thus obtain more effective garment processing. This paper compares two types of catalysts, and demonstrates superiority of a weakly alkaline type in affording greater wrinkle resistance, smooth drying performance, and fabric strength retention. The results will aid in development of still more active catalysts and improved formaldehyde-free durable press cotton textiles.
Technical Abstract: Direct comparison of hypophosphorous acid and sodium hypophosphite as curing catalysts has been made in formaldehyde-free durable press (DP) finishing of trouser weight cotton fabric with polycarboxylic acids. Trials were made at two temperature and curing times, with and without a fabric softener. Use of the acid catalyst caused excessive fabric breaking and tearing strength losses, and was consistently less effective than the sodium salt in imparting wrinkle resistance and smooth drying properties. Hypophosphorous acid as catalyst also increased the fabric bending moment and stiffness with epoxysilicone present as softener. However, the addition of moderate amounts of triethylamine made hypophosphorous acid nearly equivalent to sodium hypophosphite in catalytic effects. In an equilibrium mixture of sodium hypophosphite and the polycarboxylic acid, both types of catalysis may occur to accelerate production of anhydrides as intermediates and both may speed subsequent cellulose crosslinking.