Jute

We work with growers, yarn mills, laboratories and experts to produce rope for the specific application of prolonged human skin contact. Users are advised to pay strict attention to factors giving the best strength, and how to maintain integrity.

This begins with filament quality: where taken from the plant, how long, fine and free of impurities. Highest grade filaments are flexible and pliable: ideal for yarn used to twist rope intended to support a person safely. We do not use lower grade CB (carpet backing) yarns made specifically for Van de Wiele CRM, CRT or CRX looms.

Jute is a fertility exhausting plant requiring fresh alluvial soil. Inferior clay and sandy soils respectively produce sticky and coarse fibres. These require fertilizers that remain in the fibre, and even in the rope.

Jute is highly dependent on seasonal weather conditions in areas susceptible to global warming. Low pre–monsoon rainfall will affect planting and fibre quality. The best is grown within 24-37˚C with long periods at 34˚C.

After cropping, stems are softened by retting in slow moving, clear water at 34˚C within 8 days, before bacteria or acidity compromise the filaments. If the temperature varies >2˚C, this can double, and bacteria may be present. Fibres can pick up contaminants from low water quality.

After hand-stripping and natural drying, filaments are graded and folded into Morah bales for shipping. On arrival at the mill, manual hackling segregation sorts the longest, strongest filaments down through decreasing quality until only the dust remains.

Batching uses a mix of oil, water and emulsifier sprayed onto the jute, then piled for a specific time to soften filaments before yarn manufacturing. Filaments are carded to comb them parallel, then drawn to produce an average overlap into a ribbon-like slither ready for twisting. Optimum yarn twist, balancing coherence and obliquity is critical to strength. Loose twist is weaker, because slippage under load may cause catastrophic tear. Tight compromises linear orientation, causing shear.

Jute is hygroscopic, contracting when wet as filaments swell. With tension, as it dries, it returns to roughly the same length. Rope should not be made fully wet, but if so may be naturally dried under tension. This may also reduce oil and coating used in spinning yarn.

Oil and wax can be used in conditioning. They should not go rancid, or penetrate too much, making rope greasy and heavy. Jute fibre is like human hair; dry and brittle can be easily broken and damaged. Conditioning makes it pliant and flexible, aiding core strength.

Fresh jute is naturally hairy. This can only be reduced, but not eliminated. Use will pick up skin oils that will help ‘polish’ your rope over time.

©AMATSUNAWA GmbH 2021