Study On The Process Of No Chlorinatiao And Bleaching Of Linen Roving

The roving boiling and bleaching process in linen spinning is to remove non-cellulosic materials such as lignin,pectin and hemicellulose,and to improve the fiber splitting degree and improve the yarn quality of the spun yarn.The roving and bleaching method commonly used in factories is sodium chlorite boil and bleaching with hydrogen peroxide.The main reagent in the sodium chlorite boil is sodium chlorite,which is used to remove lignin.Sodium chlorite has problems such as polluting the environment and damaging human health.Therefore,it is very important to find a new environmentally friendly reagent instead of sodium chlorite.The specific content of this paper is as follows:(1)Contrast test with formic acid scouring and chlorine dioxide scouring and sodium chlorite scouring,wherein the lignin content is 1.8055% after scouring with sodium chlorite and 1.9935% after formic acid scouring and 1.784% after chlorine scouring.At the same time,the removal effect of other non-cellulosic materials such as pectin is equivalent,and the scouring of sodium chlorite is more harmful to the fiber.The other two methods have less damage to the fiber,indicating that both formic acid scouring with chlorine dioxide scouring can be used instead of sodium chlorite scouring to remove lignin and other substances in flax.The effect of chlorine dioxide scouring is similar to that of formic acid scouring,and the environmental pollution is low.However,considering the presence of chlorine,there is still a small amount of organic halide in the scouring liquid.This subject uses formic acid for chlorination-free scouring.(2)For the process exploration of the formic acid scouring,a single factor test was first carried out to explore the influence of formic acid concentration,hydrogen peroxide concentration,formic acid/acetic acid mixed solution concentration,formic acid/acetic acid mass ratio,boiling time and boiling temperature on flax roving boiling and bleaching effect.A single formic acid solution was applied to the flax roving,and the residual amount of lignin was 2.22%,and the removal effect was not satisfactory.After adding hydrogen peroxide to the formic acid solution,the residual amount of lignin is 1.89%,and the formed formic acid/ peroxyformic acid system can better remove lignin.Within a certain range,the peroxyformic acid/ peracetic acid system obtained by adding acetic acid can better promote the removal of non-cellulosic materials such as lignin and pectin in the flax roving,and the removal effect is more with the increase of the amount of formic acid.(3)Further,the formic acid scouring process was optimized by a quadratic general rotation combination design test.The optimum process formula was a formic acid/acetic acid mixed solution concentration of 284 g/L,a formic acid/acetic acid mass ratio of 4.2:5.8,and a H2O2 concentration of 7.13 g./L.The verification test data showed that the formic acid method had a gel content of 1.01% and a lignin content of 1.64%.At this time,the pectin content decreased by 38.9% and the lignin content decreased by 65.7%,indicating that formic acid scouring is feasible for removing non-cellulosic materials such as lignin and pectin,and can improve the fiber splitting degree while ensuring the roving breaking strength.(4)Finally,the oxygen bleaching process was tested.It mainly explores the effect of sodium carbonate concentration and hydrogen peroxide concentration.The residual amount of glue and lignin is used as the index,combined with the breaking strength and fibrosis,to achieve the optimal ratio of flax roving with biological content after boiling and get better process parameters: sodium carbonate concentration of 4.05 g / L,hydrogen peroxide concentration of 5.05 g / L(bath ratio 1:15).After boiling and bleaching,the roving breaking strength is 1731 c N,the fibrosis is 1133 Nm,the pectin content is 0.85%,which has reached the target content of 0.85%,and the lignin content is 0.93%,which is quite close to the target content of 0.9%.In summary,formic acid and acetic acid act as environmentally friendly reagents for flax roving boiling and bleaching,achieving the effect of sodium chlorite boil and bleaching with hydrogen peroxide,reducing environmental pollution.It provides a scientific basis for the subsequent chlorination-free bleaching of linen roving.