The application of microbial enzyme in the finishing of denim fabric is beneficial to environmental protection. This is because, first, these enzymes are natural non pathogenic microorganisms, which can quickly biodegrade themselves, so they will not cause waste accumulation; Second, in the industrial fermentation process, the fermentation biomass of the main waste can be used as an organic fertilizer for recycling in the surrounding environment.
There are two kinds of microbial enzymes used in textile denim finishing. One is amylase, which is used in desizing process; The other is cellulase, which can degrade cellulose. It is a kind of protein that plays a special catalytic role in the glucose bond of cellulose. Its enzyme molecule is more than 1000 times larger than that of water molecule. Therefore, it can not penetrate into the interior of cotton fiber. Hydrolysis is only carried out on the surface of cellulose and will not cause serious damage to denim fabric.
Enzyme can be used in the finishing of jeans. The process can be divided into two steps: enzyme desizing and enzyme stone washing. In desizing process, amylase can effectively remove the size on denim fabric, prevent the occurrence of streaks and defects, and improve the quality rate of clothing. The application of enzyme to stone washing is called biological stone washing, that is, enzyme is used to replace pumice, which avoids the heavy labor of carrying, storing and treating pumice. Pumice treatment of contaminated clothing, contaminated workshop floor and sewer problems will no longer exist.
1、 Enzymatic desizing process
Amylase acts on the starch part of the size, so that long chain and insoluble starch molecules are degraded into small segments, which are easy to be dissolved and removed. The general process conditions are as follows:
Amylase concentration is 1-2g / L, pH value is 6-7, temperature is 55-65c, time is 10-15min, bath ratio is more than 1:10, and can reduce the rolling speed of the washing machine, which is beneficial to reduce the generation of mechanical friction and streak defects.
2、 Biological enzyme stone washing process
Cellulose enzyme acts on the cotton yarn to hydrolyze the fiber on the surface of the yarn, so that the indigo dye layer on the surface becomes loose, and then it can be easily removed under the action of mechanical friction, so as to achieve the same effect of pumice grinding. The general process conditions are as follows:
The dosage of cellulase is 10-15g for neutral enzyme and 20-30g for acid enzyme. When the enzyme is combined with pumice, the dosage can be reduced by 50%; The pH value of neutral enzyme should be controlled at 6-7, and that of acidic enzyme should be controlled at 4-5; The temperature is 45-55c; The bath ratio is about 1:5, and the time is controlled between 40-120min according to the needs of clothing.