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.
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Originally published in New Cloth Market : December 2009
