What is Cellulase Wash?
There are three methods to remove surface fibers from 100% cotton woven and knit goods, namely singeing in the greige state and bio-polishing. The third method is home laundering the fabrics using detergent that contains a cellulase enzyme. The application of cellulase enzymes is well known to the majority of industrial laundries and the big brands and retailers are also very much aware of their sustainability aspects.
Cellulase is environmental friendly compared to pumice stones. Cellulase enzymes are natural proteins. It reduces the percentage of damage caused to denim by the rough effect of stones on them. Cellulase attacks primarily on the surface of the cellulose fiber, leaving the interior of the fiber as it is, by removing the indigo present in the surface layer of the fiber. This method is also known as bio-stone-washing. Enzymatic treatment has become another substitute for stones; also, the jeans stone-washed by this method have more shelf life. It ensures the same result with minimum amount of water, waste, time, volume and damage to machines.
Cellulase enzymes have gained acceptance in the garment wash industry as a means to achieve a washed down appearance without the use of stones or with reduced quantities of stones. These enzymes are different from the alpha-amylase enzymes used for starch removal in which they are selective only to the cellulose and will not degrade starch. Under certain conditions, their ability to react with cellulose (cotton) will result in surface fiber removal (weight loss). This will give the garments a washed appearance and soft hand. Cellulase enzyme is classified into two classes, namely, acid cellulase and neutral cellulase.
- Acid cellulase: It works best in the pH range of 4.5–5.5 and exhibits optimum activity at 50°C
- Neutral cellulase: It works best at pH 6; however, its activity is not adversely affected in the range of pH 6–8 and shows maximum activity at 55°C.
As jeans are made up of cellulosic fibers, the use of cellulase enzyme is successful in giving a stone wash look. This enzyme breaks down the surface cellulose fibers and removes them without causing harm to the jeans. Better finishing and look is achieved even with indigo-dyed denim. In cellulase enzymatic wash, the denim is given an enzyme bath. Here, certain amount of indigo dye and cellulose fibers are removed from the surface of the fabric.
As enzymes are like yeast in nature, they eat the cellulose present in denims. When the jeans get the preferred color, enzymatic reaction is stopped by changing the alkalinity of the bath or else the water is heated. Thereafter, the fabric undergoes rinsing and softening process. The numbers of rinsing processes after the enzyme treatment are lesser than pumice stone-washing. There is a reduced amount of waste produced and the overall costs for stonewashing are also less.
Working Procedure of Cellulase Wash:
- Load stones in machine (normally 0.5 – 2.0 part weight stones: 1 part weight garments) if applicable.
- Load garments.
- Desize with alpha amylase enzyme and detergent.
- Rinse.
- Add cellulose enzyme (amount, pH, temperature, and cycle time dependent upon type of fabric and desired effects; manufacturer’s recommendations should be followed).
- Adjust pH as recommended.
- Tumble 30-90 minutes.
- Drain.
- *Rinse well (70◦C).
- Drain.
- Rinse well (70◦C).
- Drain. Separate garments from stones if used (garments can be transferred to another machine).
- Apply softener.
- Extract and unload.
- De-stone and tumble dry.
- Press, if required.
After step 7, a chlorine bleach may be used as described in Stone Wash with Chlorine.
* The increase in temperature serves to deactivate the cellulose. pH adjustment to 9.0-10.0 with soda ash can also be incorporated. Some operations use both the increases in pH and temperature.
Advantages of Cellulase Wash:
Usage of cellulase has some distinct advantages, such as:
- Cellulase is economical and environmentally friendly as compared with stone washing using pumice stones. The percentage of fabric damages is reduced with cellulase treatment. The enzymatic treatment of denim fabric ensures the same result but consumes less water and time, resulting in less waste and damage to machines. The pollution, quality variability and imperfections are also reduced in enzymatic treatment.
- Enzymes can be recycled.
- The productivity of washing is increased due to the space formerly taken up by the pumice stones; the same washing machines can handle more jeans.
- The time consumption for removing stone fragments from the denim garments is eliminated in the case of cellulase treatment.
- The duration or number of rinse washing after enzyme treatment is less than pumice stone washing.
- A small quantity of enzyme can replace several kilograms of pumice stones during washing, which ultimately leads to less damage to garments and machines.
- Washed garments with a softer feel and better appearance is achieved in cellulase treatment.
Disadvantages of Cellulase Wash:
There are certain disadvantages of the cellulase treatment. It could leave marks of back-staining, such as blue threads becoming more blue or white threads becoming blue. To get rid of such unwanted recoloration of threads, the jeans are rigorously washed by adding surfactants to it. This process could result in color fading of jeans and there is added usage of water for the washing. Thus, wastage of water and certain amount of back-staining could be experienced. The primary target of stone-washing the denim with pumice stones or enzymes is to provide the garment a worn-out, old and aged look. Sometimes, both stones and enzymes are used for the purpose.
You may also like:
- Denim Enzyme Wash Process
- Stone Washing Process of Denim Fabric
- Bio-Stone Washing with Celluloses for Denim
- Enzyme Stone Wash Process of Garments
Founder & Editor of Textile Learner. He is a Textile Consultant, Blogger & Entrepreneur. Mr. Kiron is working as a textile consultant in several local and international companies. He is also a contributor of Wikipedia.
