Introduction<br />Denim washing is know as one of the finishing treatment that has vast usage because of creating special appearance and updating clothes<br />There is different methods of denim washing.<br />
A. Chemical washes-<br />1. Enzyme Wash(Bio Stoning)-<br /><ul><li>Cellulase enzymes are natural proteins which are used
It attacks on 1,4-beta-glucoside bond of cellulose molecule</li></ul> e.g. Denim ax PB/BT<br />
optimized pH and temperature = maximum activity of the enzyme<br />
2. Acid Wash-<br /> It is done by tumbling the garments with pumice stones presoaked in a solution of sodium hypochlorite or potassium permanganate for localized bleaching resulting in a non uniform sharp blue/white contrast.<br />Results depends on:-<br />-Fabric -chemical used(conc.)<br />-Stone(quantity) -machine used<br />
Limitations of acid wash:<br /><ul><li> Tendency to be yellowish
incomplete reduction gives create problem</li></ul>Remedy:<br /> Manganese is effectively removed during laundering with addition of reducing agent(sodium bisulfate,1-5gpl, 50 deg. Cent.,20mins)<br />-<br />
3.Denim Bleach-<br />To decolorize the dark shade into light shade by destroying indigo.<br /> INDIGO --------------------------. ISATIN<br />(oxidative bleaching agent)<br />Chemicals-<br /><ul><li>sodium hypochlorite
On treatment time.</li></ul>Drawback-<br /> Harmful to human health and causes corrosion to stainless steel.<br />
3-E Bleaching concept for denim-<br /><ul><li> Bleaching with sulphiric acid derivatives, and recently with laccase(enzyme).
Technology in based on a Laccase(a redox enzyme using mol. Oxygen as electron acceptor) and mediator.
eg. DeniLite(enzyme + PPT)</li></li></ul><li>Other chemical washes-<br />
B. Mechanical washes-<br />Stone washing-<br />Pumice stones give the additional effect of a faded or worn look<br />Stone wt. /fabric wt. = 0.5 to 3 /1<br />Dia.of stone-1-7 cm<br />Pumice stone<br />
Recommended Specification for Stones-Moisture content-less than 5%Surface properties-less than 5% finesApparent Density-0.5-0.75gm/cm3Abrasion loss-35%Impurities –when exceed 10% they increase apparent density1 gm/cm3, the stone will not float in water during process.<br />
2. Sand blasting:-<br />Sand blasting technique is based on blasting an abrasive material in granular, powdered or other form through a nozzle at very high speed and pressure onto specific areas of the garment surface.<br />product look<br />process<br />
3.Whiskering-(Cat's Whiskers)<br />Industrially done with laser, sandblasting, machine sanding, hand sanding and rods.<br />'knee whiskers' -whiskers on the sides of knees <br />‘honeycombs' -crease marks on the back of the knee<br />honeycomb<br />Whiskers on skirt<br />