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