Influence of additives on the formation of unsaturated PCAs produced during durable-press curing with citric acid

To impart durable-press properties to cellulosic material, the fabrics have been treated with a finishing bath containing a polycarboxylic acid in com bination with an appropriate catalyst. When citric acid (CA) was applied as crosslinking agent discoloration of the fabric was observed. Special addit ives were included into the formulation to improve the whiteness index. Iso cratic HPLC was used to identify and quantify the unsaturated polycarboxyli c acids that are produced during the curing process of CA-treated cotton fa brics. The influence of different catalysts (sodium hypophosphite, sodium d ihydrogen phosphate, disodium hydrogen phosphate, tetrasodium pyrophosphate , trisodium phosphate) and of various types of additives, such as triethano l amine (TEA), N,N,bis(hydroxyethyl)glycine (BICINE), boric acid and polyet hylene glycol 200 (PEG 200), on the content of CA and the amount of unsatur ated PCAs in the wash liquor and on the fabric has been investigated. A sig nificant reduction of the unsaturated polycarboxylic acids was observed whe n an additive was incorporated into the pad bath.