Study On The Spinning Process Of Ramie Stretch-Breaking Slivers With Different Length

Ramie conventional spinning processing has some disadvantage, such as complex and long process passages, high raw material waste and lower yarn quality because lots of overlength and multiple length staple fiber exist in ramie fiber which causes the serious uneven fiber length. In this dissertation, the stretch-breaking used in ramie processing is investigated. Instead of opening and carding processing, stretch-breaking causes less fiber damage, reduction of overlength and multiple length staple fiber, and decreasing the nep forming, which is helpful for the end yarn quality of ramie.The topic of this dissertation is that I will do further study based on the former's research in ramie fiber. Discussing the situation that drawing fiber with different length spin in different spinning system (bast fiber spinning system, wool spinning system, mid-fiber spinning system) and studying the influence of fiber length and processing parameter.The main points and conclusions as follows:(1) Study the influence of stretch breaking effect with changing parameters of main draft gauge, pre-drawing gauge and pressure.With the same pressure and main draft gauge, setting the main draft gauge and pre-drawing gauge reasonablely can effectively increase the length uniformity, reduce the staple fiber rate. With the increasing of pressure, the long staple rate decreased gradually when gauge are constant, which effect cut fiber rate and average length in a certain degree.(2) Study the influence of stretch breaking effect with changing stretch breaking times.After two times stretch-breaking, the number of string, nep and bundling are obviously less than one time. Compare to two times, just the number of bundling is slightly lower with three times stretch-breaking.(3) Study the influence of stretch breaking effect with changing pretreatment.The damage of ramie fiber is less, but oil evenness needed to be further control to improve bundling rate by water dresser pretreatment. Fiber cluster rate can be controlled efficiently with rotary hammer opening and knife wheel processing, but fiber will be damaged seriously, which is not good at improving row yielding.(4) Compare the stretch breaking strip and combing strip quality of stretch breaking spinning with the conventional spinning ones.In stretch breaking technology, the strip's CV% and long staple rate lower obviously than the conventional one with less string and more nep. Bundling in combing strip is slightly more than conventional one, while nep is less. After combing process. long staple rate reduce by 50% at least, and cut fiber rate can meet the conventional standard. (5) Study the performance index of stretch breaking yarn with different fiber length and discuss their critical twist factor.In the same condition, for the stretch breaking yarn spun by average 85mm fiber length, yarn breaking tenacity is the best while the lowest strength unevenness belongs to the stretch breaking yarn spun by average 80mm fiber length. They both almost have the same CV% with the conventional one and less hairiness by 20%. The yarn spun by average 75mm fiber length is the worst with more hairiness。The critical twist factor respectively is 105-110 for 75mm,100-105 for 80mm,95-100 for 85mm.(6) Stretch breaking technology apply to wool spinning system, mid-fiber spinning system.In wool spinning system, most of yarn performance is better than the conventional one, including yarn breaking tenacity, slub and thin nip, nep, except for CV%. The application in mid-fiber spinning system was progressing not very well. Because for average 60mm fiber length, long staple rate was too high to draft completely while stretch breaking strip had not enough cohesive force for average 55mm fiber length, which both will be effect the final yarn performance.In the article, I mainly discuss and study the better parameter of stretch breaking technology, test and compare the quality of semi-finished products and end products in the whole stretch breaking process. Proving that the ramie stretch breaking spinning can be apply to bast fiber spinning system and wool spinning system. But the application in mid-fiber spinning system should make further study.