Study On The Spinning Process Of Ramie With Cotton Fiber Length

In recent years, the spinning process of ramie with cotton fiber length has been studied. The combed slivers in conventional spinning process were stretch-broken into slivers with cotton length fibers, and then processed on cotton spinning system, such as drawing, roving and ring spinning, with high uniformity in fiber length and high spinning efficiency. The result showed that the uniformity of yarn and the spinning efficiency had been improved. However, there were sitll some overlength and multiple length fibers residual in the stretch-broken slivers, which would greatly influence the spinning process. What was more, the ramie fibers need to be processd to combed slivers on ramie spinning system, which are relatively outdated, with low spinning efficiency. So the spinning process of ramie with cotton fiber length, still need to be studied, to realize the innovation of ramie processing.In this thesis, the degummed ramie was used, instead of combed slivers, to be cut-off or stretch-broken, researches have been done as follows:(1) The comparison research of cut-off ramie and stretch-broken ramie.The degummed ramie fibers were cut-off or stretch-broken into cotton type fibers, respectively with average fiber length of about 30 mm, 35 mm, 40 mm, 45 mm and 50 mm. Then, the properties of cut-off and stretch-broken ramie fibers were compared, such as length, fineness and tensile property.(2) The optimization of combing technology for ramie processed on cotton comber.The pre-drawn slivers of cut-off 40 mm and stretch-broken 40 mm ramie fibers were respectively processed on cotton comber as representative, to find the best combing technology for each kind of ramie fiber. The combing technology for ramie, such as the total number of cylinder needles, the density of top comb needles, the detaching distance and the clockwise rotating time of detaching roller, was optimized by the properties of fibers and the processibility of combing, such as the short fibre content, the average fiber length, the fiber length irregularity, the corn content, the hard article content and the noil rate.(3) The comparison research of spinning technology and yarn quality of cut-off ramie and stretch-broken ramie.The cut-off 40 mm, cut-off 45 mm, stretch-broken 35 mm and stretch-broken 40 mm ramie fibers were respectively processed on cotton spinning system, and the processing technology of each procedure, such as drawing, roving and ring spinning, as well as the end yarn quality were analysed and compared.The results found are shown as follows:(1) As the increasing of cutting length or main stretch-broken gauge, the average fiber length of cut-off ramie or stretch-broken ramie increases gradually. When the cutting length is same with the main stretch-broken gauge, the amount of long fibers in stretch-broken ramie is higher, while the amount of short fibers in cut-off ramie is higher.(2) When the cutting length is same with the main stretch-broken gauge, the amount of corns in stretch-broken ramie is higher. The content of strings in cut-off ramie increases more quickly than that in the stretch-broken ramie when the cutting length and main stretch-broken gauge increase.(3) The linear density, breaking strength, breaking elongation and breaking work of stretch-broken ramie fiber are much less than that of cut-off ramie fiber, when the stretch-breaking gauge become smaller, the linear density, breaking strength, breaking elongation and breaking work of stretch-broken ramie fiber all become smaller, while the linear density and tensile properties change little when the cutting length changes.(4) Under the experimental conditions, the combing technology of ramie fibers is as follows: The total number of cylinder needles of cut-off 40 mm, cut-off 45 mm, stretch-broken 35 mm and stretch-broken 40 mm ramie fibers is all 14196. The density of top comb needles of cut-off 40 mm, cut-off 45 mm, stretch-broken 35 mm and stretch-broken 40 mm ramie fibers is all 26 needles/cm. The detaching distance of cut-off 40 mm and stretch-broken 35 mm is both 9.6mm, while that of cut-off 45 mm and stretch-broken 40 mm is both 10.4mm. The clockwise rotating time of detaching roller of cut-off 40 mm and stretch-broken 35 mm is both 15 scale mark, while that of cut-off 45 mm and stretch-broken 40 mm is both 14.5 scale mark.(5) For the drawing of cotton type ramie, the time of drawing should be two, the draft ratio of second drawing should be bigger than that of breaker-drawing, also the press should be big. For the roving of cotton type ramie, the twist multiplier should be large and the break draft should be small, to make the fibers adhesive together. For the ring spinning of cotton type ramie, the nip gauge should be zero to make a better control of fibers.(6) Generally, the cut-off 45 mm and stretch-broken 40 mm combed ramie yarns have the shorter spinning process flow, lower cost of raw material, and greater spinning efficiency than the traditional combed ramie yarn.