Lyocell bamboo fiber MVS yarn and the development of knitted fabricLAN Hong-yan1, FANG Lei1, ZHANG Yan-hui2(1. Shanghai Wool & Jute Textile Research and Technology Institute, Shanghai 200082, China)(2. Shanghai Textile Research Institute, Shanghai 200082, China)Abstract: In the paper are introduced the making background of Lyocell bamboo fiber and its fiber properties as well as MVS principle with the properties of Lyocell bamboo MVS yam discussed. Through USTER yam eveness testing and use of scanning electron microscope, it shows that the yam is of good wrapping structure and good yam evenness and less hairiness. Compared to traditional knitted goods, knitted fabric made of this yarn is touched more soft and comfortable, show ing better anti-pilling property. Knitted goods made of Lyocell bamboo MVS yarn have a prospect future market and benefit the environment.Key words: blended yam; knitgoods; vortex spinning; property; yam spinning; weavingBamboo pulp fiber is of good hygroscopicity and breathability. Product made of this has good drapability and offers comfortable and cool feelings when people wear, especially that its unique natural antibacterial property meets the healthy and comfortable trend that people pursuit, and this kind of fiber is being mostly applied during recent years in such fields as garment material, nonwoven fabric, bedclothes, hygienic products and so on. But the physical and mechanical properties of viscose fiber are poor and this kind of fiber meets large distortion in water which easily causes brittle fracture and poor size stability during wet processing of the fabric. In addition, the production process of viscose fiber has polluted environment seriously. On such background, Shanghai Lyocell Fiber Development CO., Ltd. develops Lyocell fiber made of bamboo pulp raw material Lyocell bamboo pulp fiber and has realized industrialized production. Lyocell bamboo pulp fiber produced at present possesses much better physical & mechanical properties and wearability than viscose bamboo pulp fiber. No pollution will be caused to the environment during the production process and this fiber can be thoroughly degraded under natural environmental condition. The production of Lyocell bamboo pulp fiber is characterized by sustainable development feature and it is regenerated cellulose fiber of new generation. Lyocell bamboo pulp fibers arising complies with the development direction of strengthening non-cotton natural fiber development and utilization advocated by textile industry of our country 1.MVS machine of Murata No.861 type is adopted by this article and the yarn property made of Lyocell bamboo pulp fiber has been explored. 100% Loycell bamboo pulp fiber yarn of wrapping structure including core fiber has been developed with its relevant properties tested in this article, which has provided basis and reference for speeding up process improvement and development & utilization of functional fiberLyocell bamboo pulp fiber with independent intellectual property rights of our country.1. Properties of Lyocell Bamboo Pulp FiberThe production process of Lyocell bamboo pulp fiber adopts non-toxic N-methyl morpholine-N-oxide (NMMO) as solvent without any chemical reaction happens or wastewater or waste gas discharged during the production process, and no chemical residue harmful to human body will be contained in the product. This fiber can render you smooth feelings upon touching and possess good glossiness, great strength, high wet modulus and natural antibacterial property and have both advantages of natural fiber and synthetic fiber. Please refer to Table 1 for property comparison between Lyocell bamboo fiber and other fibers.Table 1 Property Comparison between Lyocell Bamboo Fiber and Other FibersItemFineness/dtexDry BreakingStrength/cN dtex-1Wet Breaking Strength/cN* dtex-1WetModulus/cN* dtex-1Residual SulfurContent/mg * dtex-1Lyocell bamboo pulp fiber1.73.33.82.83.2Bamboo pulp fiber1.72.21.1-20Viscose fiber1.72.22.61.01.5-20Modal1.73.43.61.92.11120Cotton fiber1.72.02.42.63.010-Dacron1.74.05.24.05.2-2. Spinning Principle of MVSMVS is a new type spinning technology which uses high speed rotating airflow to spin. This process applies aerodynamic principles to make high speed rotating vortex generate radial split force, axial suction force and tangential twisting force on fiber strand, thus the fiber in the strand can be stretched and form free end during twisting process and true twist yarn will be produced. Please refer to Fig.1 for the spinning principle 2卜.Vortex YarnDraftingFig.1 MVS PrincipleMVS feeds fiber rod directly to MVS spinning machine after 3 drawings, and the yarn coming out will be directly wrapped into conical package with good shape. The roving process in traditional spinning line has been eliminated and rotary machine twisting parts