Tetracarboxylic Acids as Formaldehyde-Free Durable Press Finishing Agents

Abstract

1,2,3,4-Butanetetracarboxylic acid and all-cis-1,2,3,4-cyclopentanetetracarboxylic acid have been studied as durable press reagents for cotton. They quickly form ester-type crosslinks in the cellulose when applied to fabric by pad-dry-cure techniques. Weak bases have proven to be active catalysts, one of the most effective being mono-sodium phosphate. Durable press smoothness ratings of 3.8–4.4 were imparted by either tetracarboxylic acid. The amount of tetracarboxylic acid required could be decreased by two-thirds by having citric or tartaric acid present as a co-reactant additive. In durability to home laundering, finishes from butanetetracarboxylic acid far surpassed those from cyclopentanetetracarboxylic acid, and most of the durable press performance was retained through 65 washing and drying cycles with a wash temperature of 50°C (122°F) and a pH of 9.8 using a standard detergent. The strength retentions, bending moments, and wrinkle recovery angles of treated fabric were comparable to those imparted by dimethyloldihydroxyethyleneurea.