Mechanical Separation
Coarse short flax fibres obtained by direct mechanical stripping of unretted or semi-retted stems constitute a secondary raw material used for non-woven textiles and coarse yarn. This by-product, referred to as decorticated tow, is separated from the long line fibres during the initial processing of flax straw. Industrial decorticators use fluted rollers to break the woody stem and scutching blades to beat away the shives.
The resulting material bypasses the traditional retting process entirely, which preserves the natural lignin and hemicellulose content but leaves the fibre bundle stiff and unrefined.
Fiber Quality
Structural stiffness restricts the use of decorticated tow in fine apparel yarns. It contains a high proportion of residual bark and woody shive fragments that resist bleaching and chemical softening. Mills test these batches for trash content using gravity separators before deciding whether to direct them to industrial twine spinning or paper manufacture.
Production Standard
Standardised grading systems in Chinese linen mills classify this material based on the weight percentage of residual woody matter. The buyer’s acceptance sheet records the shive content and average fibre length before the material leaves the extraction facility. Low-grade tow cannot enter the fine-spinning line without causing frequent thread breaks.
