Denim Dry Processes – P.P. Spray, Tagging, Ozone wash
Zahirul Islam BUTEX
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Denim Dry Processes – P.P. Spray, Tagging, Ozone wash
7. P. P. Spray : Potassium permanganate is sprayed in specific parts of the garment to fade color and bring a bright effect on the hand scraped area. It is often done on Denim, Twill, poplin, corduroy fabrics. It is done after the first wash. Liquid potassium permanganate color is pink but after applied to garment turns to muddy brown or grey on drying. Sometimes acetic acid or phosphoric acid is mixed to increase its intensity. It is always followed by the neutralization by Na-meta bysulphate or other neutralizing agents. The concentration of potassium permanganate will control the extent of brightness or effect.
Stock Solution preparation :
- water taken 1 litre , say
- Potassium permanganate ( .4- 15 gm/L ) ( standard stock soln = .4 % )
- Acetic acid ( as per need )
Indigo dyed fabrics treated with low concentration whereas sulphur black dyed fabrics need high concentration to treat.
Machines / Apparatus and requirements required :
- P. Spray Cabin
- Spray gun
- Air Dummy
- Water circulation system
- Musks, Gloves , safety shoes and apron
- Electricity
Process is given below :
- Garments are taken to P.P.Cabin and mounted on Air dummy filled with compressed air so the garment is full fit to be exposed.
- Different size dummy is used for different garment sizes and styles like men’s trouser and shirts
- The cabin booths are fitted with proper air exhaust system .
- The treatment room where the spray is done , the chemical mixed air is passed through water shower
- Water dissolves the p. p. and clean air is blown out to open.
- The p. p. is sprayed on the garments.
Control parameters :
- Distance : Less distance will give more defined and sharp effect and more distant will give less bright and mild effect.
- Air to water ratio of gun : Low air pressure will result in droping soln on the garments instead of spraying which will result in bright spot.
- Concentration: This will control the extent of fading.
Safety measures :
- Hand gloves, apron and masks should be worn
- Don’t forget to switch exhaust blower and water circulation system
8. P. P. Rubbing :
- It is often required for development purpose
- A towel or fabric is soaked in potassium permanganate solution and then rubbed on the fabric
- which fades or increases the brightness .
- It is also followed by neutralization.
- The solution made for p.p. rubbing is same like p. p . spray.
- It brings more high low effect and it is difficult control and done manually by hand.
9 . P.P. Spot / Bleach spot :
- To get white or yellowish spot randomly in garments P.P.Spot or Bleach spot is used.
- Potassium permanganate solution is perpared and droping the solution randomly where spot is desired .
- After neutralization spot appears as white spot.
- But when bleach solution is droped on the garments , by oxidation it brings yellowish spot on the garments.
10 . Tagging :
- Tagging is done at unwashed condition of garments.
- It is done by tag gun or plastic staple machine which binds or fold the edge of the garments
- Manually by niddle and thread
- After wash the effect is visible
- Sometimes it creates hole on the edge
11 . Ozone Wash : Ozone wash is a new technology and used to change color after washing. Normal washing needs water , chemicals , time and mechanical action to wash but ozone wash replaces all those things in wet washing and saves energy and resources. Ozone machine used for ozone wash. It uses oxygen gas and makes ozone gas for the process.
Control Parameters :
- Ozone gas concentration
- Moisture content
- Time of exposer to ozone
Process of ozone wash :
- Ozone machine converts the oxygen gas into ozone gas
- The garments to be washed , thrown to the ozone machine and run the machine
- After some time , the garments is checked whether it maches with the desired effect or not
- Finally effect is visible
Benefits of ozone wash :
- Saves chemicals , water , time and wash cycle
- Change shade without any wet process
- Stength of fabric remains same as before
- Clean the surface of tinted garments
- Used for changing light shade
- Remove back stain from garments
- Creates same effect as bleaching wash
- Better working environment for workers
- Used as disinfectant
- Ecofriendly as it does not dischare any hazadous gas
Safety : One bio product is produced call esertin which is harmful for human body
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Zahirul Islam BUTEX
Latest posts by Zahirul Islam BUTEX (see all)
- Denim Wet Process | Bleach Wash | Acid Wash - June 14, 2020
- Acid Wash / Random Wash - May 8, 2020
- Denim Wet Process | Enzyme Wash - April 15, 2020
