Ciric acid in crease-proof finishing and its impact on coloration changes on cotton fabrics

Possibility is discussed of using citric acid as a new, environment-friendly crease-proof finishing agent, one containing no formaldehyde. For the purpose of investigation, cotton fabric is treated with citric acid (CA) and catalyst Na-hypophosphite (SHP). The impact of secondary phosphonate based catalysts is also monitored, as well as the impact of the treatment on coloration changes of cotton fabric previously dyed with reactive dyes containing various reactive groups. Isocratic HPLC method is used to determine quantitatively the amount of CA that reacts with cotton fabric tested. This chromatographic method indicates that deeper coloration results in lower amount of CA linked to the cellulosic material, which means there is a definite impact of reactive dyestuff on the reduction of free reactive groups in cellulose. Spectrophotometric measurements indicate that hypophosphite as a catalyst has the greatest impact on coloration changes, as it is a strong reducing agent and acts upon the chromogene in the dyestuff.