Bamboo - 21st century eco fiber : Application in towel sector(Part-2)

Bamboo - 21st century eco fiber : Application in towel sector

By : Dr. Subrata Das

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Interested to read Part-1? Its here Read Part-1

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Eco friendly process to produce bamboo fiber

The chemical manufacturing process used to produce lyocell from wood cellulose can be modified to use bamboo cellulose. The lyocell process, also used to manufacture tencel, uses N-methylmorpholine-N-oxide (NMMO) as a solvent to dissolve the bamboo cellulose into a viscose solution. Hydrogen peroxide is added as a stabilizer and the solution is forced through spinnerets into a hardening bath which causes the thin streams of viscose bamboo solution to harden into bamboo cellulose fiber threads. The hardening bath is usually a solution of water and methanol, ethanol or a similar alcohol. The regenerated bamboo fiber threads can be spun into bamboo yarn for weaving into fabric.

This lyocell processing is substantially healthier and more eco-friendly because N-methylmorpholine-N-oxide is supposedly non-toxic to humans and the chemical manufacturing processes are closed-loop so 99.5% of the chemicals used during the processing are captured and recycled to be used again. Only trace amounts escape into the atmosphere or into waste waters and waste products. Other chemical manufacturing processes for bamboo fabric are appearing such as using acetic anhydride and acetic acid with sulfuric acid as a catalyst to form acetate fiber which is then spun into a yarn.

Nanotechnology in bamboo clothing industry

New nano-technologies are also being introduced into the bamboo clothing industry. It based on a bamboo clothing line made from nano-particles of bamboo charcoal. In this process, bamboo is dried and burned in 800 degree C ovens until it is reduced to charcoal. The bamboo is processed and converted into fine nano particles which are then embedded into cotton, polyester or nylon fibers. This conventional fiber yarn that contains trapped bamboo charcoal nano particles is then woven into fabrics mostly socks and blankets now. It is reported that the active bamboo charcoal ingredients will only remain active in the clothing for about six months of active use.

Dyeing and Finishing

Light singeing, enzyme desizing, moderate bleaching and semi-mercerizing should be applied to the bamboo textile substrate prior to its dyeing and finishing process. It is better to avoid drastic conditions and use low mechanical tension.

Singeing: Bamboo fabric can be singed in moderate condition.

Desizing: Desizing rate should be over 80%.

Scouring: Pure bamboo normally needs no scouring; sometimes washing with a little alkaline soap may serve the purpose. The scouring process should be made in terms if fiber blend contains cotton. When pure bamboo fabrics are scoured, the alkali should not be over 10 g/liter but can be applied in accordance with the thickness of fabrics.

Bleaching: The processing should be made in terms of the specification and thickness of fabrics. Mercerizing: Fabrics of bamboo fibers normally should not need mercerizing due to their sound luster and poor anti-alkaline properties. However, in some cases, to increase their absorbance capacity to dyestuff, it can be mercerized.

Dyeing: Reactive dyestuffs are used during dyeing process - alkali should not be over 20 g/liter; temperature should not be over 100 C. During drying process, low temperature and light tension are applied.

Yarn dyeing: Alkali should not be over 8 g/l in yarn dyeing. Chemically-manufactured bamboo rayon has some wonderful properties which are adored by conventional and eco-aware designers and consumers involved in towel sector:

Water Absorbent

In textile form, bamboo retains many of the properties it has as a plant. Bamboo is highly water absorbent, able to take up three times its weight in water. In bamboo fiber towel, this translates to an excellent wicking ability that will pull moisture away from the skin so that it can evaporate.

Soft Feel

Bamboo fiber towel is softer and smoother than cotton and can be comfortable directly next to the skin. Many people who experience allergic reactions to other natural fibers, such as wool or hemp, do not complain of this issue with bamboo. The fiber is naturally smooth and round without chemical treatment, meaning that there are no sharp spurs to irritate the skin. Strong and stable strength both vertically and horizontally plus a good dependence which leads to natural look and elegance.

To be continued……

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