Auxiliaries serve as sizing materials, lubricants, wetting agents, emulsifiers, agents accelerating or decelerating the dyeing rate, thickeners, binders, etc.
They overlap in the functions and abilities of a specific chemical to facilitate a textile process and/or increase its efficiency.
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.
The compounds that are 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.