Hemp Wet Spinning Process

Hemp wet spinning draws drafted sliver (fibre bundle linear density 5–15 g/m) through a hot water trough (60–80°C) immediately before the front drafting rollers on a modified flax wet-spinning frame, softening hemicellulose and reducing inter-fibre friction to enable drafting ratios of 8–15× without fibre breakage. Ring-twisting at twist multiplier (TM) 3.5–5.0 produces yarn tenacity of 15–25 cN/tex at count Nm 8–30. Wet yarn is wound on bobbins and dried at 60–80°C before further processing. Water consumption is 15–25 L/kg yarn; bath temperature maintenance requires 0.3–0.5 kWh/kg yarn energy. Wet-spun hemp yarns exhibit 20–30% higher tenacity and 15–25% better evenness (Uster CV% 12–18 versus 18–25 for dry-spun) than dry-spun equivalents at the same count. Twist liveliness and residual stress in wet-spun yarn requires conditioning at 65% RH for 24–48 hours before weaving to prevent fabric distortion. Premium wet-spun hemp yarn at Nm 20–30 is used for apparel fabrics retailing at €15–40/m².