| Ramie is an ancient and elegant fiber with the cultural connotation, which holds the important historical situation in the natural fiber phylogeny of our country. The ramie fabric is straight, rough, cool, breathable, anti-bacterial, hygienically, etc., and its advantages and unique style is unmatched by other fibers. Today more and more people pay attention to protecting environment and advocate returning to nature, so the ramie products will become one of the preferred green products. However, for the ramie fiber molecular, crystalline and orientation is high, bending and flexure rigidity is big and the surface cohesion is poor, which makes ramie yarn hairiness more, hard and long, thereby the breakages on weaving are increased and the weaving efficiency is reduced. It affects the promotion of ramie products, and especially on the use of the high-grade thin comfortable fabrics.The key to improve the ramie weaving efficiency is to reduce the yarn hairiness. In this thesis, the question of reducing the ramie yarn hairiness of the production was researched, the effect of the processes such as spinning, winding, sizing in improving the ramie yarn hairiness was analyzed, and the property of the ramie fiber and yarn, the generation and harm of hairiness were discussed.The sizing is the key process of reducing ramie yarns hairiness, but the traditional ramie yarn is sized mostly by using the high PVA ration size, which will result in serious environmental pollution inevitably. For this problem, based on the adhesion theories , this topic chose the adhesive of the PVA1788, the grafted starch st-g-Pam and the modified polyacrylamide Pam as additives, using the sizing process of double-soak and double-press with the first-weight and later-light to sizing of the pure ramie yarn, in order to improve adhering and soaking performance of the slurry.In order to select the optimal sizing formula, firstly a group of formulas with the same proportion (PVA: st-g-Pam: Pam = 7:1:2) and different concentrations(6%→8%→10%→12%) was designed to sizing of ramie yarn, and the best concentration was determined to be 10% by analyzing the quality indexes of the slurry and sized yarn comprehensively. Secondly a group of formulas with the same concentration(10%) and different proportions that the PVA was reduced and the grafted starch and the modified polyacrylamide were increased gradually.The performance indexes of sized yarn such as moisture regain, sizing loading, breaking strength, breaking elongation, hairiness index and abrasion frequency, etc. were tested and analyzed. The testing results were evaluated comprehensively by fuzzy decision and it was concluded that: the 7# formula (concentration of 10%, PVA1788: st-g-Pam: Pam = 5:3:2) was the optimal in order to improve weaving efficiency, meanwhile the 16# formula (concentration of 12%, PVA1788: st-g-Pam: Pam = 2:7:1) was the best in order to protect environment.Then, the adhering and soaking performance of the two best formulas slurry were discussed by observing the surface morphology by SEM and analyzing the reflects of friction on sized yarn hairiness, and it was concluded that the 7# was better than 16# formula.Finally, after the simulation weaving without weft insertion, it was found that the breakages and after-growth hairinesses of 7# and 16# were less than 0#(concentration of 12%, PVA1799:modified starch=2.5:7.5). The two best formulas were applied to the mass production, and the results showed that the weaving efficiency was greatly improved when compared with the workshop formula (60%). The weaving efficiency of the 7# formula was up to 75%, and the 16# was up to 68%.
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