Chemical Degumming Thresholds for Cottonized Hemp Fiber Tariff Entry
Chemical degumming reduces hemp Klason lignin below 1.5 percent and dtex below 2.5, triggering HS 5302.90 tariff reclassification and trade remedy duties.
Fiber Linear Density Dtex
Linear Metric
Mass distribution along a continuous length establishes the fundamental metric for grading textile raw materials. In flax fiber evaluation, fiber linear density dtex expresses the mass in grams per ten thousand meters of individual fibers or bundles. Quality testing laboratories in Chinese spinning mills record this parameter on raw material intake logs to classify long line flax versus tow fibers.
Finer fibers displaying lower dtex values permit more individual fibers per yarn cross-section, which yields higher tensile strength and improved yarn evenness. Coarser fibers with higher dtex numbers generate stiff yarns suitable only for heavyweight industrial fabrics or coarse upholstery goods.
Draft Ratio
Fine linear density values allow spinning machinery to apply higher draft ratios without causing strand slippage. Mill technicians adjust drafting roller settings based on fiber dtex data recorded in daily spinning preparation reports. Proper roller spacing prevents thin places and yarn breaks on high-speed ring spinning frames.
Deviations in fiber mass cause uneven drafting forces, generating slubs that diminish fabric appearance.
Yarn Grading
Uniform decitex measurements across fiber lots ensure consistent yarn strength and compliance with buyer contract specifications. Mill certificates log average fiber dtex before releasing yarn lots to weaving departments. Material failing dtex target ranges is downgraded to lower yarn counts.
Fiber linear density dtex dictates spinning limits for fine linen fabrics.