Stone wash. Stonewash sometime referred as Enzyme wash is most common in denim wearing. Typical in denim, due to its unique fabric construction gets antique look with time passing. An old jean is famous for the white and blue texture that appears on warp and weft of garment. In fashion it is required on fresh articles and enzyme wash is designed to create this effect on garments.
As the name implies, freshly dyed jeans are loaded into large washing machines and tumbled with stones. Adding pumice stones gives the additional effect of a faded or worn look. The pumice abrades the surface of the jeans like sandpaper, removing some dye particles from the surfaces of the yarn. Pumice has been used since the introduction of stone washed jeans in the early eighty.
Â Stone washing with pumic has some disadvantages. The intensity of the abrasion process is difficult to control. Small will not give the desired look. Too much can damage the fabric, mostly at the hems and waistbands. The effect in a load of jeans is never consistent, with a noteworthy percentage always getting bust by
too much abrasion. The process is also non-selective. Everything in the washing machines gets abraded, including the metal buttons and rivets on the jeans as well as the drum of the washing machine. This significantly reduces the quality of the products and the life of the equipment, and increases production expenses. Environmental regulations have put severe stress on the textiles industry to control pollution by wastewater treatment and disposing of the slush (used pumic).
A technique known as “Bio-stoning” was introduced in Europe in start of 1990â€™s and then quickly adopted in rest of the world the following year. Bio-stoning is an action of enzymes to garment similar to pumice stone. Enzymes have been used in the textiles industry to remove starch and wax residues from raw materials and to give fabric a uniform finish.. The enzymes used in biostoning are known as “cellulases.”
The gene for the cellulase enzyme was first isolated from the fungus Trichoderma reesei and then put into bacteria for mass production.Â Cellulases digest cellulose, the main component of cotton and other natural plant fibers. Cellulose is a long, glucose polymer used as structural support in plant cell walls. Cellulases attacks the exposed cellulose on the exterior of each cotton fiber and break some of the molecular bonds so that only the dye particles are loosened from the denim surface while the interior of the cotton fibers are left intact.
In the early days, one problem with biostoning was “back staining.” Back staining happens when loosened dye particles redeposit onto the back surface of the fabric. But by maintaining the pH of the wash load between 6-8, it has successfully been controlled.Â Today, biostoning can achieve the same effect as traditional stone washing, but without the damaging abrasion of the fabric and equipment.
Cellulases and other enzymes used in the textile industry are available in a number of different varieties, each with its own special properties. This added dimension gives fashion designers the flexibility to create a wider range of shades and finishing effects. By selectively modifying the surface of the denim without damaging the fabric integrity, designers have a more liberal pallet to create new fashions possibilities. For example, colorful logos can be printed onto metal buttons or leather labels without the fear of them being abraded away by pumice. And intricate designer accents made of non-cellulose fibers such as nylon or polyester will remain even after cellulase treatment.
Biostoning is by far the most economical and environmentally friendly way to treat denim.
- Waste, pollution, quality variability, and imperfections are all reduced. And unlike pumice or acid, which get used up during the wash, enzymes can be recycled.
- A small dose of enzymes can replace several dozen pounds of pumice stones. So productivity can be increased by 30-50% because the space formerly taken up by the pumice stones in the washing machines can now be filled with more jeans.
- And there is no need for the time-consuming and expensive task of removing stone fragments from the jeans once the wash is done.
- There is also no pumice dust to endanger employee health or gritty sediment to clog drains. Nearly all jeans made today are finished by biostoning.
In stone wash, pumice stone is used in washer with garments to create effect. To enhance the effect of stone some time enzyme is added. usually conditions are mild for enzyme wash. But in some cases hot bath (temp. 40 C to 60 C) is used for enzyme wash
General Recipe Steps
- Stoning and/or Bio-stoning
- Soap Rinsing
- Softner Application
There are always handsome chances of deposition of indigo back to garment during desizing. To avoid this phenomenon, some agents are used, classified as Anti-Backstaining Agents (ABS). These ABS are derivatives of detergents and act as leveling agents
In case of sand blasting you may need to apply some oxidizing agent to improve the effects of fading.
One method is to apply Hydrogen peroxide in washer, that removes the unfixed indigo partials from blasted area and make the contrast more bright and visible. Mild quantity of peroxide didnâ€™t affect the shade much but rather act as a cleaning agent.
some cases Potassium Permanganate is applied on blasted area with spray gun of paint brush. This is commonly used where the fading effect is desired to high intensity. As compare to peroxide this method will result much brightness and whiteness.
It is always recommended to apply soap in hot bath. High temperature not only increases the penetration of water particles to fabric but also the activity rate of soap molecules.