Denim washing

DENIM WASHING(A value addition process)

Submitted to- submitted by-Mr. Vasant Kothari Mr. Harmendar kothari M.F.Tech-2

Contents

I. IntroductionII. Types of washesIII. Chemical washesIV. Mechanical washesV. Cost VI. References

Introduction

• Denim washing is know as one of the finishing treatment that has vast usage because of creating special appearance and updating clothes

• There is different methods of denim washing.

Types of washes

Mechanical washes

Stone wash

Whiskering

Sand blasting

Chemical washes

Enzyme wash

Bleach wash

Acid wash spray

On the base of chemical use

Types of washes

Dry wash

whiskering

Laser technology

Damage

Grinding

scrubbing

Wet wash

Stone wash

Enzyme wash

Bleach wash

PPC spray

Tinting

Acid wash

On the bases of water use

A. Chemical washes-

1. Enzyme Wash(Bio Stoning)- Cellulase enzymes are natural proteins which are

used It attacks on 1,4-beta-glucoside bond of cellulose

molecule e.g. Denim ax PB/BT

Cellulase enzyme

Acid cellulase Neutral cellulase

optimized pH and temperature = maximum activity of the enzyme

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

Limitations of acid wash: Tendency to be yellowish incomplete reduction gives create problem

Remedy: Manganese is effectively removed during

laundering with addition of reducing agent(sodium bisulfate,1-5gpl, 50 deg. Cent.,20mins)

-

3.Denim Bleach- To decolorize the dark shade into light shade by

destroying indigo. INDIGO --------------------------. ISATIN (oxidative bleaching agent)Chemicals- sodium hypochlorite KMnO4Hydrogen peroxide

Discoloration produced is usually more apparent depending :-

On strength of the bleach liquorOn bleach liquor quantityOn temperature andOn treatment time.Drawback- Harmful to human health and causes corrosion to

stainless steel.

3-E Bleaching concept for denim-

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)

Other chemical washes-

RINSE WASH

Ozone fading

Over dye- tinting

Sun washing

Quick wash denim

Water jet fading

Vintage etc.

B. Mechanical washes-

1. Stone washing- Pumice stones give the additional effect of a faded

or worn look

• Stone wt. /fabric wt. = 0.5 to 3 /1• Dia.of stone-1-7 cm

Pumice stone

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.

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

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 knee

Whiskers on skirt

honeycomb

• Other mechanical washes-

LASER TECHNOLOGY

SUPER STONEWASH

Scrapping

Grindings-

grinding

Laser technology

Scrubbing

Tagging on pockets

Costing-WASH COST($)

Whiskering .40

scrapping .35

Tagging .15-.30

Damage .10 -.50

Sand blasting(band)

Silicosis( Levi’s and H&M)

Pocket edge & hem grinding

.10

WASH COST($)

Enzyme wash .70

Acid wash 1 $

Enzyme stone Bleach wash

.95

Tieing- 0.15

Stone wash .70

PPC spray .25

Tinting .10

Laser technology 1$

Ozone wash- 3 min-0.20 30 mins-0.60

Enzyme stone wash .85

1.www.fibre2fashion.com2.Washing Report of Arvind Mills3.Denim garment washing process-ATIRA4.Denim garment processing –Express Textile(march 2003)5.Garment washing & finishing- Pearl Academy of Fashion