Finishing of cotton fabric with citric acid

Abstract

The finished cotton fabrics with crease resistant property can be obtained by using citric acid as a nonformaldehyde cross-linking agent with proper catalyst selection by pad-dry-cure method. Among a number of catalysts based on alkali metal salts of phosphorus-containing inorqanic acids, sodium hypophosphite has produced the satisfactory appearance properties of treated fabrics whereas monosodium phosphate, another catalyst, was found to be the effective extender for the more expensive sodium hypophosphite. The fabrics finished with 7% citric acid by using the ratio of citric acid to hypophosphite at 1:2 and curing at 160ํC for 90 seconds have produced 46% improvement of dry crease recovery angle with no reduction in whiteness and 69.4% of strength retention which was higher than those from finishing with the traditional formaldehyde-based resin. The increment of temperature and time of curing, however, will adversely affect breaking strength of the finished fabrics. The presence of ester groups in the treated fabric can be analysed by infrared spectroscopy technique.