STONEWASHING

STONEWASHING
Pumice stone usage in stonewash
One of such washing is known as Stonewash. In stonewashing the worn out look is given purposely. The fabric is washed along with pumice stones.
The stones and denim are spinned together in the large industrial washing machines. The longer they are spinned together the color of the fabric would get lighter with better contrasts. The time duration of this procedure is set beforehand so as to avoid the tear and wear of the fabric. Thereafter the fabric undergoes various other processes of rinsing, softening and finally tumbles drying. These stonewashed fabrics are used different uses like- garments making as well as for upholstery purpose.
Disadvantages of pumice stone usage
Stonewashing the denim with pumice stones has some disadvantages. For instance stones could cause wear and tear of the fabric, also it creates the problem of environmental disposition of waste of the grit produced by the stones. High labor costs are to be beared as the pumice stones and its dust particles produced are to be physically removed from the pockets of the garments and machines by the labors. Denim is required to be washed several times in order to completely get rid of the stones. The process of stonewashing also harms the big expensive laundry machines.
Alternate methods for stonewashing
To minimize such drawbacks, stonewashing of denim is carried out with the aid of enzymes. The method of giving the denim a stonewash look by use of enzymes like cellulase is known as- 'Enzymatic Stonewashing'. Here cellulases are used to provide that distressed worn out look to the denim fabric.
Cellulase Method
Cellulase is environment friendly in comparison to pumice stones. It reduces the percentage of damage caused to denim caused on it by tough effect of stones on them. As there is huge demand of garments with distressed jeans look, stonewashing with enzymes is being used increasingly. It is also known as bio-stonewashing. Enzymatic treatment has become another substitute for kilograms of stones, also the jeans stonewashed by this method has more longetivity. It ensures the same result with minimum amount of water, waste, time, volume and damage to machines.
As jeans are made up of cellulosic fibers, the use of cellulase enzyme is successful in giving the stonewash 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.
The production of stonewashed jeans has increased. Variations in finishes can be achieved by bio-stonewashing. Better fading of jeans could be achieved without causing harm to the fabric.
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 number of rinsing process after enzymes treatment is less than pumice stonewashing. There is reduced amount of waste produced and overall costs for stonewashing is also less.
Disadvantages of cellulase treatment
There are certain disadvantages of cellulase treatment. It could leave marks of backstaining like blue threads becoming more blue or white threads becoming blue. To get rid of such unwanted re-coloration of threads, the jeans are rigorously washed adding surfactants to it. This process could result to color-fading of jeans and there is added usage of water for the washing. Thus wastage of water and certain amount of backstaining could be experienced.
The primary target of stonewashing the denim with pumice stones or enzymes is to provide the garment worn out, old and aged look. Sometimes both stones and enzymes are used for the purpose.
Latest process of stonewash - Perlite
A new process of stonewashing has been introduced found by series of laboratory testings- Perlite.
Perlite is the form of naturally occurring silicon rock. It has the distinctive property of expanding to 4 to 20 times its initial volume when heated at a particular temperature. This happens because the raw perlite rock consists of 2-6% of water content in it. The crude perlite rock when heated at the temperature above 870 C it gets swollen up and tiny glass sealed bubbles are formed. Its original color which is black or gray changes to grayish white else white. This heated form of perlite is used for stonewash purpose.

It does the same function of stonewashing as stones. Perlite treatment reduces the rate of harm caused to large washing machines by pumice stones and gives the denim better supple and softer finish. Many jeans manufacturing companies instead of enzymatic treatment use perlite, it reduces the rate of wearing out of jeans when used. It gives throughout uniform worn out and old look to the denim and not just the upper part of the garment. There are many grades of perlite which differ in size are used for giving the stonewash finish to denim right from largest to finest grades, some are very tiny just like grounded earth.