Study On The Dugumming And Spinning Technology Of Yunnan Flax

The flax fabric has been consumer’s favorite because of its good moisture absorption,heat dissipation,air permeability,comfortable and cool.However,the world’s annual production of flax is only 300 thousand tons,it’s difficult to meet the market demand,meanwhile the production and development of China flax is not ideal,and people are facing with the current of raw material shortages,import-dependent.The Yunnan Flax has abundant sources of raw materials,and cheap in price.But it has too much gum content,short in length and difference among the fibers intrinsic quality.If it can be researched deeply for degumming of the Yunnan Flax to make the product performance close to regular flax,it can substitute regular flax partly,alleviate the current shortage of flax raw materials,decrease costs,and have good social and economic advantages.The following contents are mainly studied in this dissertation:chemical composition of the Yunnan flax is tested,physical and chemical properties are analyzed,a suitable degumming plan is found combined with the degumming mechanism,and the corresponding plan of degumming is studied,finally the Yunnan Flax and cotton blending spinning technology under the conditions of the laboratory are studied,then the blend yarn’s mechanical properties under the different twist factor are explored,the corresponding critical twist factor is obtained.The results are as follows:（1）The chemical composition of Yunnan flax is cellulose 66.06%,fat waxiness 3.07%, water-soluble matter 4.54%,pectin 2.37%,hemicellulose 15.88%,lignin 8.08%;and regular flax cellulose 71.38%,fat waxiness 1.52%,soluble matter 4.78%,pectin 3.65%,hemicellulose, 14.80%,lignin 2.87%.Comparison between the two is found:Yunnan Flax contains less than regular flax in cellulose,pectin content,fairly in water soluble matter,higher than regular flax in lignin,fat waxiness,hemicellulose.（2） A suitable chemical degumming plan of Yunnan flax is explored:sample preparation→pickling→washed→the same water-bath of alkali and oxygen→hit fiber→pickling washed→dehydration→offer the oil→cut off oil and water→Drying→mechanical loosening.（3） Single-factor experiments of four important factors on the impact of chemical degumming（dosage of sodium hydroxide,hydrogen peroxide,scouring temperature,scouring time）are done to analyze and determine the four factors range:sodium hydroxide 2%～6% （compared to the fiber,the same below）,hydrogen peroxide 4%～8%,scouring temperature 70℃～90℃,scouring the time 90min～180min.Based on the scope of the above-mentioned factors, L9（3⁴） orthogonal experiment is designed to obtain the optimum chemical degumming optimization plan.After rang,variance analysis,and verification test,the optimum process parameters are determined:sodium hydroxide 4%,hydrogen peroxide 6%,scouring temperature 90℃,and scouring time 90min.（4） The Bio-degumming of Yunnan Flax is studied,when the fibers are treated by a single enzyme preparation,laccase treated fibers has the lowest rate of residual glue,and cellulase the highest.Complex enzyme treatment is better than a single enzyme preparation,and laccase and xylan enzyme（acid） composite is better than xylan enzyme（alkaline） and pectinase complex.The orthogonal experimental of complex enzyme preparation is designed to obtain the optimum processing parameters:Laccase 2%,xylan enzyme（acid） 1.0%,temperature 50℃,time 180min. On this process conditions,if H₂O₂ 2%,NaOH 0.5%～2.5%of the scouring are added,the degumming effect can reach the optimal chemical degumming process impact,which can reduce the chemical use significantly and has good conservation of environment.（5） Under the laboratory conditions,the blended spinning experiments with Yunnan Flax which is obtained by the optimum process parameters of chemical degumming and cotton are done.The results indicate:The accession of emulsion has excellent moisture retention to the fibers in the pre-treatment process.While,whether the moisture retention is good or bad depends on the kind of oils.The parameter of spinning is as follows:Roving twist factorα_t=110,thin spindle speed 7000r/min,critical twist factor of 30tex Yunnan Flax 30/cotton 70α_t=410,its fracture strength is 12.682cN/tex;critical twist factor of 30tex Yunnan Flax 50/cotton 50α_t=460,fracture strength 10.891cN/tex.If the fineness of Yunnan Flax/cotton blended yarn is same,the breaking strength,breaking elongation rate,etc of the blended yarn decline gradually with the increase of the Yunnan Flax.Under the same conditions,performance comparison between Regular Flax/cotton and the Yunnan Flax/cotton blended yarns is done,the results indicate physical properties of the two are closed to each other,and the Yunnan Flax can partially replace Regular Flax.