Denim washing
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Denim washing is a finishing process that adds value and creates special appearances. There are chemical and mechanical washing methods. Chemical methods include enzyme washing, acid washing, and bleaching which use chemicals like enzymes and acids to break down indigo dye for color effects. Mechanical methods like stone washing use abrasive materials like pumice stones to create worn effects. Other techniques are sand blasting, whiskering, and laser treatments. Process parameters like chemical concentration, stone quantity, and treatment time affect the results. Washing adds value but also has costs for chemicals, machinery, and labor.
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Denim washing
- 1. DENIM WASHING(A value addition process)Submitted to- submitted by-Mr. Vasant Kothari Mr. Harmendarkothari M.F.Tech-2
- 2. ContentsIntroductionTypes of washesChemical washesMechanical washesCost References
- 3. IntroductionDenim washing is know as one of the finishing treatment that has vast usage because of creating special appearance and updating clothesThere is different methods of denim washing.
- 4. On the base of chemical use
- 5. On the bases of water use
- 6. A. Chemical washes-1. Enzyme Wash(Bio Stoning)-Cellulase enzymes are natural proteins which are used
- 7. It attacks on 1,4-beta-glucoside bond of cellulose molecule e.g. Denim ax PB/BT
- 8. optimized pH and temperature = maximum activity of the enzyme
- 9. 2. Acid Wash- 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.Results depends on:--Fabric -chemical used(conc.)-Stone(quantity) -machine used
- 10. Limitations of acid wash: Tendency to be yellowish
- 11. incomplete reduction gives create problemRemedy: Manganese is effectively removed during laundering with addition of reducing agent(sodium bisulfate,1-5gpl, 50 deg. Cent.,20mins)-
- 12. 3.Denim Bleach-To decolorize the dark shade into light shade by destroying indigo. INDIGO --------------------------. ISATIN(oxidative bleaching agent)Chemicals-sodium hypochlorite
- 13. KMnO4
- 14. Hydrogen peroxide Discoloration produced is usually more apparent depending :-On strength of the bleach liquor
- 15. On bleach liquor quantity
- 17. On treatment time.Drawback- Harmful to human health and causes corrosion to stainless steel.
- 18. 3-E Bleaching concept for denim- Bleaching with sulphiric acid derivatives, and recently with laccase(enzyme).
- 19. Technology in based on a Laccase(a redox enzyme using mol. Oxygen as electron acceptor) and mediator.
- 20. eg. DeniLite(enzyme + PPT)Other chemical washes-
- 21. B. Mechanical washes-Stone washing-Pumice stones give the additional effect of a faded or worn lookStone wt. /fabric wt. = 0.5 to 3 /1Dia.of stone-1-7 cmPumice stone
- 22. 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.
- 23. 2. Sand blasting:-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.product lookprocess
- 24. 3.Whiskering-(Cat's Whiskers)Industrially done with laser, sandblasting, machine sanding, hand sanding and rods.'knee whiskers' -whiskers on the sides of knees ‘honeycombs' -crease marks on the back of the kneehoneycombWhiskers on skirt
- 26. Laser technologygrindingScrubbingTagging on pockets
- 27. Costing-