7.4.5 Aftertreatment

Softening
After pretreatment and dyeing, most textile materials are hard and brittle. Applying softeners gives them a soft and pleasant grip. Examples of softeners are hygroscopic products and lubricants; these are applied by impregnation.

Making crease/ wrinkle recovering
Fabrics made of hemp, flax, cotton and viscose can be made less sensitive to wrinkling. This is done by applying chemicals that cross-link or bind with the fibres to form a layer that makes the textile less sensitive to wrinkling. Application can be done by impregnation or coating.

Calendering
Fabrics are pressed between two or more pressing drums to make them more closed, glossy and smooth or to give them a relief pattern.

Sanforising
Making shrink proof, named after its inventor Sanford L. Cluett. Under the influence of moisture and heat, the compressive shrinkage of the ensures the shrinkage is fixed.

Liquid ammonia treatment
This treatment (Figure below) is an alternative to mercerizing, caustifying of cellulose textiles where an overall substrate improvement is sought in terms of: better dyeability, more lustre, higher dimensional stability, improvement of basic physical properties (e.g. strength, abrasion) and better touch. Traditional processes based on high concentrations of sodium hydroxide may lead to undesirable substrate degradation and ecological impact (wastewater). Treatment of the textile in liquid ammonia (Beau-Fixe®) involves a continuous 4-step process and can be performed in contract at Veramtex (Brussels).

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Process for liquid ammonia treatment of textiles (Beau-fixe^®). Scheme Veramtex.

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Effect of liquid ammonia treatment on shape stability of hemp tissue. Photo HOGENT.

[1] https://www.veramtex.com/beaufixe. https://www.veramtex.com/wa_files/brochurebb_nl.pdf