Fabrics Crabbing

A worsted polyester/wool blended fabric is prepared by crabbing or blowing and then Scoured Dry Heat-set (on pin stenter) -> Brushed and Cropped Press or Decatise. 

Acrylic/wool blended fibre fabrics may be prepared according to established practice for wool, except that precautions are taken to allow for the thermoplastic properties for the acrylic fibres. Relaxation is done to remove the inherent strain. Worsted fabrics are crabbed and then scoured in either a Dolly at temperature not exceeding 40 C or in winch. 

Diacetate and triacetate are both used in blends with wool. Scouring and milling can be conducted with the minimum quantity of alkali at temperatures not exceeding 50 C and care should be taken to avoid excessive mechanical friction on the fabric. Fabrics made from triacetate/wool blends should be given a crabbing treatment before dyeing. 

A continuous crabbing by overheated water without rubber belt (Fig. 5-27) gives permanent effect with brighter appearance. The notable improvement of the fabric quality is due to the calendering effect in water at 110 C. There is no need for use of expensive rubber belts. Fig. 5-28 shows a continuous multiset crabbing machine. 

Crabbing. Crabbing is a wet-processing procedure which employs hot and finally cold water, together with mechanical tensioning, and finally drying for the purpose of equalizing tensions in the fabric. 

Crabbing n. The process of heating wool or hair fabrics, under tension, in a hot or boihng liquid, then cooling under tension, to provide the fabric with dimensional stability for further wet processing. 

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