Bamboo Lyocell Fiber

Lyocell fiber is a new cellulose fiber from wood pulp raw material, and reputed as the 21st century's environmental-friendly fiber. It has been developed with N-methylmorpholine-N-oxide (NMMO) solvent and new spinning technology. This research has taken China's special high-yield resource - bamboo as its raw material and bamboo Lyocell fiber is developed successfully through the synthesis of solvent, selection of the suitable species of bamboo pulp, and improvement of dissolution and spinning technology. The industrialization of this fiber will play a very important role in relieving the tension of oil resource and promoting the sustainable development of fabric and fiber industry.Bamboo is a fast growing plant with very high-yield, therefore, it is an important raw material of cellulose. There are hundreds of bamboo species in China. It is found that N. affinis possesses the high cellulose content, and proper fiber molecule weight, indicating that N. affinis is a suitable raw material for the production of Lyocell fiber.In this research, dissolution and double-screw spinning equipment was designed by the author (Patent No. 03104084.5), and production techniques such as dissolving bamboo fibre with NMMO, extrusion, extension, solidification in water, spinning, washing and drying were applied. Then, Lyocell fibre with high quality could be obtained. The invention patent of processing method has been approved (Patent No. CN 01117634.2)The method of producing Lyocell fiber through bamboo pulp is more environmental-friendly than that through wood pulp, and it can widen the application field and enhance the level of comprehensive application of bamboo. There was no similar report at home and abroad.Methylmorpholine is oxidized into NMMO. H₂O₂ is used as the oxidant in this reaction, however, the oxidation reaction is quite slow, releasing a lot of heat, under the room temperature. Increasing temperature can speed up the reaction, meanwhile the released heat also accelerates the reaction rate, which turns out to be difficult to control the reaction and results in the explosion. Adding catalyst can speed up the reaction rate in a low temperature, however, it results in some difficulties in spinning and solvent recycling and in separating the catalyst from the solution. An organic solvent B is used, which enables the oxidation reaction under a mild condition. Meanwhile the organic solution can be separated easily.Recycling of NMMO is the key point of the industrialization of bamboo Lyocell fiber. A concentrated method from diluted NMMO solution has been developed. A 0.3% NMMO solution is concentrated into an enriched solution of above 10% quickly and effectively by active charcoal's absorption and sodium hydrate's desorption. National invention patent about this method has been applied and its application No. is 02150127.0.The fibre solubility and determination method of NMMO were studied, as well as the determination conditions of NMMO with HPLC method were found.