Nonphosphorus Catalysts for Formaldehyde-Free DP Finishing of Cotton with 1,2,3,4-Butanetetracarboxylic Acid

Abstract

In place of the phosphorus-containing catalysts normally required in 1,2,3,4-bu tanetetracarboxylic acid (BTCA) treatment of cotton, aromatic N-heterocyclic com pounds were used to accelerate formaldehyde-free durable press finishing. Imidazole and its derivatives with alkyl groups in various positions were effective catalysts for the esterification reaction of BTCA with cellulose. Such catalysts improved the retention of mechanical properties of the treated fabric relative to results with sodium hypo phosphite at similar durable press ratings and wrinkle recovery angles. This can be due in part to the polar characteristics of these compounds, which allow ready pen etration of BTCA during the treatment. The proposed reaction mechanism is the for mation of an acylimidazolium salt as the cellulose-reactive intermediate, in addition to general base catalysis. Analyses by Fourier transform infrared spectra and nitrogen measurement confirmed the absence of permanent linkages between imidazole or its derivatives and cellulose. Ester/acid carbonyl groups were also quantatively measured using Fourier spectra.