Natural auxiliaries for textile processing
The purpose of auxiliaries is to facilitate a textile process and/or increase its efficiency. They serve as sizing materials, lubricants, wetting agents, emulsifiers, agents accelerating or decelerating the dyeing rate, thickeners, binders, etc. often with considerable overlap in the functions and abilities of a specific chemical. Compounds used encompass many different chemical classes, some of which are affected by enzymes and thus can be regarded as substrates, and some of which remain unaffected. Owing to environment and economical concerns, auxiliaries are used as sparingly as possible.
Once the respective process is terminated they are to be removed completely from the treated material; however, traces could still be present and interfere negatively with subsequent processing steps
Natural sizing compounds, coating materials and thickeners
Sizing compounds and lubricants are applied to yarns before fabric formation to protect the integrity of the yarns. While increasingly faster weaving processes demand more enduring sizes, acrylic-based compounds, natural sizes that can be decomposed are still on the market.
Such compounds comprise starch and starch derivatives, as well as soluble. Cellulose derivatives, with waxes often admixed.Desizing with amylases is one of the oldest enzymatic processes used in the textile industry. A comprehensive description of the process can be found in Uhlig (1998).
Starch has also been very useful as a thickener in printing pastes and as a component of adhesives. In printing processes, starches are applied to guarantee a defined design and to avoid spreading of the printing paste. In the paper industry, starches increase sheet strength and, as coatings, improve the writing and printing properties of high quality paper.
Originally published in New Cloth Market : December 2009