Study On The Bleaching Technology Of High Whiteness And Low-strength Cotton Products

Cotton products have the characteristics of good moisture absorption,soft hand feeling,and excellent dyeing performance,which are favored by consumers.Traditional high temperature and strong alkali bleaching of cotton fiber can achieve the best bleaching effect,but the treatment of cotton fiber has large damage and low wax content retention rate,which has a greater impact on subsequent spinning;cotton non-woven fabric steaming and bleaching products have high whiteness,but It has the disadvantages of large damage,strong alkali waste liquid,and high energy consumption.The whiteness of cotton knitted fabrics after traditional cold-batch bleaching is high,which also has the shortcomings of large damage.Therefore,this project aims to improve the whiteness of bleached products,reduce the strength damage and bleaching temperature,and study three low-temperature bleaching processes,namely,the room temperature impregnation bleaching process of cotton fiber,the high whiteness of cotton knitted fabrics,and the cold pad bleaching of low strength damage.Process,a new cold-batch bleaching process for cotton non-woven fabrics,and determine the best process conditions,and determine the changes in the surface morphology of cotton fibers,cotton knitted fabrics,and cotton non-woven fabrics before and after bleaching by scanning electron microscope(SEM).The room temperature bleaching of cotton fiber is based on the impregnation process,and the single factor experiment is used to explore the effects of activator R60 concentration,bleaching synergist CF-15 concentration,Na OH concentration,H₂O₂dosage,dipping time,and dipping temperature on the whiteness and strength reduction rate of cotton fibers.,The influence of cotton wax content,and the best experimental conditions for cotton fiber room temperature dipping and bleaching process are obtained,namely activator R60 3g/L,synergist CF-15 2g/L,Na OH 15g/L,30%H₂O₂ 80ml/L,The bath ratio is 1:20,the immersion temperature is 30?,and the immersion time is 2h.Exploring the influence of activator R60,bleaching synergist CF-15,sodium pyrophosphate and the combination of the three on the stability of H₂O₂ in the oxygen bleaching system.The whiteness of cotton fiber after treatment;synergist CF-15 can cooperate with H₂O₂stabilizer—sodium pyrophosphate to stabilize H₂O₂in the bleaching solution,achieving the purpose of enhancing the bleaching effect and reducing strong damage.Compared with the traditional high-temperature bleaching process of cotton fiber,the whiteness of the room-temperature impregnation bleaching process is comparable,and the strength reduction rate and the cotton wax content are respectively 6.8%lower and0.1060%higher than that of the cotton fiber.Scanning electron microscopy(SEM)shows that the surface of cotton fiber is less etched after the room temperature immersion bleaching process,while the surface of cotton fiber is rough after the traditional high-temperature bleaching process.The bleaching of cotton knitted fabrics with high whiteness and low strength loss is based on the cold padding process.Through single factor experiments,the concentration of activator R60,bleaching synergist CF-15,Na OH concentration,H₂O₂ dosage,anthraquinone concentration,stacking are clarified.The influence of time and stacking temperature on the bleaching effect of cotton knitted fabrics.The best experimental conditions for cold reactor bleaching process with high whiteness and low strength loss are:activator R60 4g/L,bleach synergist CF-15 3g/L,Na OH 20g/L,30%H₂O₂ 100m L/L,anthracene Quinone 10g/L,stacking time 24h,stacking temperature 25?.Compared with the traditional cold pad bleaching process:the whiteness of the fabric after high whiteness,low strength loss cold pad bleaching is 5.15higher than that;the strength loss is 10.54%lower than that,and the hair efficiency performance of the two is equivalent.Experiments show that the addition of anthraquinone has no obvious effect on the whiteness,but it can greatly reduce the strength damage of the fabric.Through scanning electron microscope(SEM),it can be seen that the high whiteness,low-strength cold pad bleaching process has less damage to the cotton fiber.And this best technology is applied to cotton woven desizing cloth,the whiteness is 86.7,the strength reduction rate is 1.05%,and the wool effect is 11.0cm/30min.In addition,the air permeability,moisture permeability,whiteness stability,and hand feel of the high whiteness,low-intensity cold-batch bleaching process are better than those of the traditional cold-rolled-batch bleaching process.The cotton non-woven fabric is also based on the cold padding process,and orthogonal experiments are used to explore the influence of factors such as the concentration of activator R60,the concentration of bleaching synergist CF-15,the amount of H₂O₂ and the concentration of Na OH on the bleaching effect of cotton non-woven fabrics.The results show that the order of factors affecting whiteness is:H₂O₂ dosage>Na OH concentration>activator R60concentration>synergist CF-15 concentration;the order of factors affecting burst strength is:Na OH concentration>H₂O₂ dosage>activator R60 concentration>Concentration of synergist CF-15,combined with single factor experiment to determine the best process for new cold-batch bleaching of cotton non-woven fabrics:activator R60 3g/L,synergist CF-15 1g/L,Na OH5g/L,30%H₂O₂ 60m L/L,sodium pyrophosphate 4g/L,and stacked at 30°C for 12h.Comparing the whiteness,bursting strength,breathability,moisture absorption and hand feel of cotton non-woven fabrics between the steaming bleaching process and the new cold-batch bleaching process,the results show that the whiteness and strength reduction rate of the new cold-batch bleaching process are better than those of the steam bleaching process.The steam bleaching process is 1.2%higher and 5.04%lower,and has higher moisture absorption.In terms of air permeability,moisture permeability,and softness,the steam bleaching process is better than the new cold-batch bleaching process;from the stiffness,drape index,and wrinkle recovery In terms of efficiency and smoothness,the steam bleaching process is better than the new cold reactor bleaching process.