Research on enzyme pretreatment process of colored cotton/linen/white cotton blended knitted fabrics
Research on enzyme pretreatment process of colored cotton/linen/white cotton blended knitted fabrics
Natural colored cotton is naturally soft in color, simple and elegant, elastic and comfortable to wear; linen is hygroscopic and breathable, antibacterial, antistatic, antiseptic, easy to wash, and has a simple and natural style. However, colored cotton fibers are short in length, and linen fibers are long but have high length unevenness and poor cohesion, while white cotton fibers are long and have high length uniformity. Adding white cotton can greatly improve the spinning effect and yarn quality. Colored cotton/linen/white cotton blended knitted fabric absorbs the advantages of colored cotton, linen and inner cotton. The fabric is soft and body-like, cool and comfortable, and the color is natural and childish.
Because colored cotton and flax contain high pectin and lipid wax components, and flax fibers have greater stiffness, colored cotton/flax/white cotton blended knitted fabrics have shortcomings such as rough and stiff feel and poor hygroscopicity. This article uses scouring enzyme to replace conventional scouring, which greatly improves the moisture absorption and softness of the fabric and is more in line with the environmental protection characteristics of colored cotton.
1 Analysis of impurity content of colored cotton/linen/white cotton blended knitted fabrics
Although natural colored cotton, linen and white cotton are all fiber cord fibers, there are differences in their physical properties and content of each component. A comparison of the main impurity contents that affect the hygroscopic properties of colored cotton/linen/white cotton blended knitted fabrics is shown in Table 1. Because the 25 brown colored cotton/35 linen/40 self-cotton blended yarn was used in this experiment, deductive calculations show that the pectin content in the raw material is about 3.04%, the lignin content is about 3.43%, and the fat and wax content is about 3.04%. The content is about 1.43%. Among them, pectin and lipid wax mainly affect the moisture absorption performance of fabrics.
2The action mechanism of scouring enzymes in fiber refining
Refining enzyme 301L is a compound product of various enzyme preparations based on alkaline pectinase. Its refining mechanism is similar to pectinase.
The traditional scouring mechanism is to use a large amount of caustic soda solution to saponify the wax first, then emulsify and wash it to remove it, and at the same time remove the minerals and pectin. The mechanism of enzyme refining is to hydrolyze pectin first, which facilitates the removal of remaining wax. During the pectinase refining process, pectinase and pectin first form a complex (complex), and then hydrolyze it. In this way, the originally insoluble pectin is broken down. After breaking away from the fiber, the hydrolyzed pectin becomes dispersed. After the pectin dissolves from the primary cell wall layer on the fiber surface, it provides a channel for the detergent to remove wax. This process will continue to repeat. Until pectinase stops working due to some condition. The reaction between pectinase and insoluble pectin not only makes the pectin into a free state, but also makes other surface impurities fall off to achieve the purpose of refining.
3Experimental part
(omitted)
4Results and Discussion
4.1 Effect of enzyme dosage on scouring effect of scouring enzyme
Refining enzyme scouring process conditions: liquor ratio l: 20, temperature 50°C, time 30 minutes. pH value is 8, penetrant 2g/L, change enzyme dosage, and perform scouring.
As the dosage of enzyme increases, the reduction rate increases; the gross effect increases; the bursting strength decreases; and the bending length becomes shorter. This is because as the dosage of enzyme increases, the concentration of enzyme in the solution increases, the reaction speed between scouring enzyme and pectin and wax is accelerated, and the impurity removal effect is good. Therefore, the weight reduction rate of the fabric increases and the wool effect increases. However, when the dosage of enzyme reaches a certain value, The increase in wool effect is not obvious, the improvement in fabric softness is not obvious, but the fabric strength decreases greatly.
4.2 Effect of pH value on the scouring effect of scouring enzyme
Refining enzyme scouring process conditions: liquor ratio 1:20, temperature 5O℃, time 3Omin, enzyme dosage 1g/L, penetrant 2g/L, change pH value.
pH value can affect the binding of refining enzymes to substrates. The dissociation of enzyme and substrate is only under specific pH conditions, suitable for them to combine with each other and catalyze, so that the enzymatic reaction speed reaches a maximum value. This pH value is called the optimal pH of the enzyme (optimumpH ). When the pH value of the solution is higher or lower than the optimal pH, the activity of the enzyme will be reduced, and when it is far from the optimal pH value, it may even lead to denaturation and inactivation of the enzyme.
All properties such as weight loss rate, gross effect, bursting strength and bending length are better at pH values of 7, 8 and 9 than at pH values of 6 and 1O. It can be seen that scouring enzyme has better activity and good impurity removal effect under neutral to weakly alkaline conditions. Therefore, the fabric wool effect is better when the pH is 7, 8, and 9. When the pH value becomes larger, the strength damage of the fabric becomes greater and the softness performance becomes worse. This is the damage caused by the alkali in the solution to the fabric rather than the effect of the scouring enzyme treatment.
43The effect of temperature on the scouring effect of scouring enzyme
Refining enzyme scouring process conditions: liquor ratio 1:20, time 30min, enzyme dosage 1g/L, pH value 7, penetrant 2g/L, changing temperature.
Temperature is another important factor that affects the activity of refining enzymes. Different biological enzymes are suitable for different temperatures. When the temperature is between 5O and 60°C, the weight loss rate reaches a certain value, and the gross efficiency, bursting strength and bending length are all relatively small. Well, at this time, the scouring enzyme treatment effect is better. This is because as the temperature increases, the number of activated molecules of the refining enzyme increases and the reaction speed accelerates. However, when the temperature continues to increase, the enzyme protein fork will gradually denature and become inactive, and the treatment effect of the refining enzyme will become worse. For scouring enzyme treatment, at 60°C, the fabric performance is better and the treatment effect is excellent.
4.4 Effect of time on the scouring effect of scouring enzyme
The process conditions for scouring enzyme scouring are: liquor ratio 1:20, temperature 6O°C, enzyme dosage 1g/L, penetrant 2g/L, pH value 7, and variable scouring time.
As the cooking time increases, the wool effect increases and the bending length changes.�� is large, although the hygroscopicity and softness of the fabric have improved, the improvement is not obvious. On the contrary, the bursting strength of the fabric has dropped greatly. This is because the fabric has been exposed to a higher temperature solution for a long time, and the fibers have been damaged, resulting in a decrease in the bursting strength of the fabric.
45Determination of refining enzyme refining process conditions
Based on the analysis of the influence of the above single factors on the refining enzyme treatment effect, four factors, enzyme dosage, pH value, temperature and time, were selected to conduct an orthogonal experiment at three levels.
The main purpose of scouring is to remove natural impurities, reduce the impurity content of the fabric, and improve the wettability of the fabric. Therefore, in the scouring enzyme orthogonal experiment, three indicators, including wool effect, fabric bursting strength and bending length, were selected as the evaluation criteria. Among them, gross effect is the main indicator. In addition, the greater the scouring enzyme concentration, the higher the temperature, the longer the time, the higher the production cost, and the greater the decrease in the bursting strength of the fabric. Therefore (continued on page 84), after comprehensive consideration of various factors, the optimized process finally obtained by using the intuitive analysis method of orthogonal experiments is: the concentration of refining enzyme is 1.5g/L, the pH value is 8, and the temperature is 6O℃ , time 45min. Penetrant 2g/L, liquor ratio 1:20.
5Conclusion
(1) Enzyme dosage, pH value, temperature and time all have a certain impact on the scouring effect of scouring enzyme. As the dosage of enzyme increases, the weight reduction rate increases, the wool effect increases, the bursting strength decreases, the bending length becomes shorter, and the softness of the fabric is improved; when the pH value is in neutral to weakly alkaline conditions, the scouring effect of scouring enzyme Good; as the temperature increases, the wool effect of the fabric first increases and then decreases, the bursting strength first decreases and then increases, the bending length first decreases and then becomes longer. When the temperature is 50~60℃, the scouring enzyme scouring effect is better. Good; as the scouring time increases, the wool effect and softness of the fabric improve, but the improvement effect is not obvious, and the bursting strength of the fabric decreases greatly.
(2) Through orthogonal experiments, the optimal process conditions were obtained: the concentration of refining enzyme is 1.5g/L, the pH value is 8, the temperature is 6O℃, and the time is 45min. Penetrant 2g/L, liquor ratio 1:20. UOjtDNE
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