APO—Copolymer Systems for Cotton1

A study of the treatment of cotton fabric with APO-thiourea and urea copolymers followed by cross-linking with dihydroxydimethylolethyleneurea (DHDMEU) has been undertaken. The two-step treatment, simulating a durable-press process, effected a desirable balance between appearance and service properties of the fabric. Dry and wet wrinkle recovery values of 300° and 260°, respectively, and vash-wear ratings of 5 (tumble dry) and 4 (line-dry) were obtained on printcloth at 60% to 70% strength retention. Repeated laundering and tumble-drying of simulated garments indicated relatively little abrasive wear with little or no reduction in crease retention, compared to garments made from fabric treated in the regular manner with DHDMEU. The following mechanism is suggested. The APO and urea or thiourea form copolymers in the fiber. Urea and thiourea, apart from acting as swelling agents, compete with cellulose hydroxyls for the aziridinyl rings and, thereby, repress premature cross-linking. During the subsequent DHDMEU treatment, cross links are formed, presumably between cellulose and polymer deposit as well as between cellulose chains, resulting in a greater mobility of the chains within the fiber than obtained in standard cellulose-cellulose cross-linking.