Low temperature dyeing and shrinkage-resistance finishing of wool by composition of salt-ammonia and enzyme treatment

Wool top and knitted fabric were treated with ammonia in the presence of sodium chloride ( salt-ammonia process ). The effectiveness of salt-ammonia process traditionally used as pretreatment for low temperature dyeing has been investigated for conferring shrink-resistance of wool. The pretreatment of salt-ammonia process followed by enzymatic treatment has been proved that contribute to not only the enhancement of dyeing behaviour but also shrinkage-resistance in the present studies. A novel composition of salt-ammonia pretreatment, oxidized and reduced treatment as well as protease modification was recommended to achieve low temperature dyeing and shrinkage-resistance of wool. At the same time, the process conditions were optimized by orthogonal array and assessed by dye uptake rate, weight loss and area shrinkage. Laboratory experiments showed that the knitted fabric treated according to optimized conditions of the combined process, achieved not only improvement of dye abilities but also the strict requirement of machine-washable, representing a possible alternative to chlorination.