Superheated Water Hydrolyzed Keratin: A New Application as a Foaming Agent in Foam Dyeing of Cotton and Wool Fabrics

摘要

src="http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ascecg/2017/ascecg.2017.5.issue-10/acssuschemeng.7b02064/20170926/images/medium/sc-2017-02064y_0011.gif">A large amount of wool produced in the EU region is coarse and of low quality. The limited or nonutilization of such coarse wool leads to landfilling causing environmental pollution. In this paper, we studied the properties of keratin hydrolyzate, produced by a sustainable hydrolysis process, to be used as a foaming agent in foam dyeing of cotton and wool fabrics. This is a preliminary step on the way to find possible applications which overcome the environmental problem of wool waste and byproducts. We report for the first time the use of keratin hydrolyzate as a foaming auxiliary in the textile dyeing process. The surface tension, molecular weight, foam stability, blow ratio, and bubble size of keratin hydrolyzate in aqueous solutions with and without dyeing auxiliaries were determined. The dyeing influential parameter such as wet pickup was studied to identify their effect on dye fixation and color strength. The foam dyeing was compared with conventional cold-pad batch and pad-steam processes for cotton and wool, respectively. In the investigated variant, keratin hydrolyzate shows a reduction in surface tension, good foam stability along with dyeing auxiliaries, a blow ratio of about 10:1, and 0.02–0.1 mm diameter bubble sizes. These results make possible its application as a foaming agent. Cotton and wool fabrics were dyed using reactive and acid dyes respectively, on a horizontal padding mangle. In both cases, hydrolyzed keratin acts as a carrier for dye molecules and the mechanism of dyeing depends on the respective pH of the dye solution, keratin, and fiber. Foam dyeing of cotton resulted in comparable color strength, while wool shows higher color strength when compared with conventional dyeing processes. Washing and rubbing fastness of cotton and wool foam dyed fabrics are similar to the respective conventional dyed fabrics. The combinations of sustainable keratin hydrolyzate production and its use as an eco-friendly, biodegradable foaming agent in less add on foam dyeing technology resulted not only in saving of large amounts of water and energy but also will be helpful in minimizing a load on effluent and the environment.