Effect Of Two-step Softing And Spinning Process On Performance Of Flax/Cotton Blended Yarn

Flax fiber has the characteristics of fast moisture absorption and desorption,anti-fouling and antistatic,antibacterial and health care.It is widely used in clothing and home textile fabrics.It is deeply loved by consumers and has a strong market demand.However,due to the poor length uniformity,containing more impurities and other shortcomings,the pure spinning of flax short fiber is more difficult and can be spun coarse.In order to improve the utilization of short fiber and solve the problem of shortage of raw materials,flax short fiber is often blended with other fibers into yarn.Flax and cotton fibers are both natural fibers.The blended yarn of the two fibers combines the characteristics of flax fiber and cotton fiber,and the two fibers form complementary advantages.On the basis of developing blended yarn,the spinnability of flax staple fiber is improved by physical or chemical methods.At present,flax fiber is generally treated before spinning,but the spinnability of flax fiber becomes worse with the moisture release of fiber in the subsequent spinning process.This paper aims to explore the effect of twostep softing process on improving the spinnability of flax staple fiber.Firstly,the raw materials of flax short fiber were treated by head softing,the effect of softing additives on fiber properties was studied,and the softing additives were optimized.Then,the two-step softing process was carried out on the blended sliver output by the blowing-carding process after mixing,and the influence of the two-step softing process on the linear performance of flax/cotton blended yarn with different blending ratios was explored.At the same time,based on the two-step softing process,the effect of compacted spinning technology on the performance of flax/cotton blended yarn and the corresponding process optimization were studied.Firstly,the effect of softing agent formula on the properties of flax short fiber was explored.After softing treatment,the surface roughness of the fiber can be improved and the moisture retention of the fiber can be increased.The softing agent is evenly distributed in the inner and outer layers of the fiber,which can achieve the purpose of improving the fiber quality.Five kinds of health additives and a group of blank control groups were designed.The flax short fiber was treated with oil health process,and the health additives were optimized.By testing the chemical composition and physical properties of flax fiber before and after softing,the effect of softing agent formula on fiber properties was analyzed.The results showed that the properties of flax short fiber were better when silicone oil 2.0%,antistatic agent 0.5%,emulsified oil 2.0%and water 95.5%.Compared with the control group,the pectin removal rate increased by 46.5%,the breaking strength increased by 39.5%,the elongation at break increased by 22.0%,and the bending resistance decreased by 25.0%.Optimizing the scheme of softing additives is of great significance to improve the performance of flax short fiber.Secondly,the optimization of flax cotton blended yarn softing process and performance research.The mixing method of raw materials in the softing process is optimized,and the two mixing methods of fiber mixing and strip mixing are compared.The 50/50 flax/cotton blended yarn is spun by one-step oil supply and two-step oil supply softing process.Based on the fiber mixing form,the effects of two-step softing process on the properties of 20/80,40/60,50/50,60/40 and 80/20 flax/cotton blended yarns were investigated.The results show that the twostep oil-feeding yarn properties of flax/cotton blended yarns with different blending ratios are better than the one-step softing process under the same conditions,which plays an important role in improving yarn strength and elongation,reducing yarn hairiness and improving yarn evenness.Thirdly,the effect of compacted spinning on the quality improvement of flax/cotton blended yarn and the effect of compacted spinning on the performance of flax/cotton blended yarn and the optimization of compacted negative pressure were explored.Firstly,the spinning method of compact spinning is preferred,and the spinning range of flax/cotton blended yarn with different blending ratios is explored.Under the experimental conditions of this paper,the limit fineness of 20/80,40/60,50/50,60/40,80/20 flax/cotton blended yarn is about 10 tex,12 tex,20 tex,30 tex,49 tex.The influence of twist on the performance of limit fineness yarn of flax/cotton blended yarn with different blending ratio was studied,and the yarn twist factor was optimized.The results show that when the twist factor is 360,the strength and elongation of each blended yarn are higher and the hairiness level is lower.According to the preferred yarn twist factor,the effect of negative pressure on the performance of flax/cotton blended yarn was investigated.By comparing the yarn properties under different negative pressures,the negative pressure was optimized.The results show that the optimum negative pressure of blended yarn does not change obviously with the yarn count when the flax content is low.When the flax content reaches 50% or more,the optimal negative pressure of the blended yarn is obviously affected by the yarn count.Among them,the optimal negative pressure of 10 tex 20/80flax/cotton blended yarn is 2000 Pa;the optimum negative pressure of 58.3 tex 50/50,60/40,80/20 flax/cotton blended yarn is 3500 Pa.Finally,the feasibility of pure linen yarn was explored,and the effects of two-step softing process,twist and negative pressure on the performance of pure flax yarn were studied.The results show that the two-step softing process can improve the performance of pure flax yarn.The 58.3 tex pure flax yarn is spun,the optimal twist factor is 420,and the optimal negative pressure is 3500 Pa.Optimizing flax fiber softing process is of great significance to improve the spinnability and yarn properties of short flax fiber.