Finishing Denimwashing 120209233253 Phpapp01

7/29/2019 Finishing Denimwashing 120209233253 Phpapp01

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DENIM Finishing

&

WashingD. Praveen Nagarajan


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STONE WASH

* Most denims are stone washed.

When wash technique was developed,denims were washed with actual stonesbut research and development has

changed the whole scenario.Now-a-days pumice stones are used toachieve soft as well as desirable look.

Many types of man-made stones, of

different shapes and sizes are available inthe market. Though they are expensivethey provide more consistent quality ofdenim.


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STONE WASH

Pumice stones are available in different sizes and shapes.Selection of pumice stone depends upon end products e.g.,

large and hard tones for heavy weight denim

smaller and softer stones for light weight denim

Recommended stone to fabric weight ratio is 0.5-3:1

Stone weight 0.5 to 3

---------------- = ----------

Fabric weight 1

Stone to fabric weight ratio depends upon the degree ofabrasion desired in the in the washed denim.

Stone wash cycle consists of several stages


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STONE WASH

BACK STAINING AND COLOUR REDEPOSITION:

Back Staining and colour redeposition can pose aproblem and could be reduced by:

* Addition of dispersing agent to wash cycle

* Intermediate replacement of wash liquor forexample stone wash for 30 minutes, drop,

Rinse, then again additional stone wash for 20

minutes, drop, rinse etc.* Use of an alkaline detergent such as sodium

perborate with an optical brighter as an after-wash


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Stone Wash Cycle

Loading of denim garment and stones

Desizing for about 15 minutes- Detergent plusenzymes, or - Oxidative desize

Rinsing

Stone wash- 30 to 60 min

Rinsing

Softening

Extraction

Unloading and removal of stones from garment

Tumble drying


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DISADVANTAGES OF STONE WASHING

* Increased work of removing stone dust fromfinished garment after washing is completed

* Quality of abrasion process is difficult to control

everything during washing gets abraded, includingthe metal buttons, rivets, drums of machine andthe garment itself, which causes reduction in life ofthe washing machine as well as garments.

* Problem of water pollution due to presence ofstone dust and treating the waste water anddisposing of the sludge.


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ENZYME WASH

In enzymes washing, cellulose* enzymes(a protein like substance) are used.

Since colour in the denim fabric is actuallyon the surface of the yarn, when denim iswashed in a cellulose enzyme bath theindigo dye is removed along with the fibre.

These enzymes actually eat away dyedcellulose fibre, from the surface thus createa stone washed look.


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BRIEF INTRODUCTION TO ENZYME AND

ENZYMATIC REACTION

* Enzymes are found in plant, animals and micro-organism, where they play an important role in thefunction of cells

* Enzymes are proteins which catalyze specific

chemical reactions and are known as bio-catalysts* Enzymes enable higher reaction rates with lower

energy consumption in comparison to othertraditional catalysts.

* Enzymes are designed for acting in living cells,hence they can work at atmospheric pressure andin mild conditions of temperature and pH.


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ENZYME WASH CYCLE

Loading of denim Garments (addition of Stones is optional)

Desizing with- alpha-amylase Enzyme, or- Oxidativedesize

Rinsing

Adjusting pH to 4.5 to 5.0 with- acetic acid, or- buffersystem

Heating to 50 to 60 C

Addition of cellulose enzyme

Tumbling for 30 to 60 minutes

Hot rinsing at > 65 C

Cold washing

Softening

Dry tumbling


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Activity of cellulose enzyme is judged by itsability to degrade the cellulose to glucose.

The activity of cellulose enzyme depends

on temperature and pH.Optimum activity of acid cellulose enzymemay be achieved at a pH of 4.5 to 5.0 anda temperature of 60 C.

Their optimum activity, however, dependson the type of enzyme and the processwhere it is applied.


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ADVANTAGES OF ENZYME WASH

Ease of handling, storage and disposal makes enzymes achoice catalyst for any processing industry

Most economical due to more water saving

* Reduction in pollution, waste, quality variation

* Enzymes can be recycled unlike pumice stones or acids

* Several dozen pounds of pumice stones can be replacedwith a small quantity of enzymes

* Reduce labour engagement as there is no need for theexpensive and time consuming tasks of removing stonefragments from the garments once the wash is completed

* Reduce wear and tear of washing machine components andgarments


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ACID WASH

It is usually done by dry tumbling the denimgarments with pumice stones that are pre-soakedin a solution of sodium hypochlorite (5 to 10%); orpotassium permanganate (3 to 6%) in order tofacilitate localized bleaching that results in a non-

uniform sharp blue/white contrast.

After tumbling colour contrast can further beenhanced by way of giving subsequent opticalbrightening treatment.

Acid wash is also known as snow, marble, fogwhite, ice and frosted wash.


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ACID WASH CYCLE

Loading of garment With pumice tones

Desizing for about 10 to 15 minutes

DryingDry tumbling for 10 to 30 minutes

Cooling without Addition of water

Per-oxide washOptical Brightening

Softening Treatment


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DENIM BLEACHING

In this technique, decolouration is done by way ofadding strong oxidative bleaching agent likesodium hypochlorite or potassium permanganateduring washing.

Washing maybe done with or without stones* Extent of decolouration of denim depends upon

strength of bleaches, liquor quantity and treatmenttime

* Proper after wash or anti-chloring (incase ofsodium hypochlorite bleaching agent) of bleacheddenim to minimize subsequent yellowing andtendering of denim


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Wash Cycle of Denim

Loading of Garment with or Without stones

Desizing

RinsingBleaching for 15 to 30Minutes

Rinsing with Cold water

Optical brightening

Softening Treatment

Washed denim


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SOME UNCOMMON DENIMS

BUBBLE GUM DENIM

General name for Lycra containingdenim that has between 35 to 50%

stretch


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COLOURED DENIM

Jeans used to be blue and nothingelse.

But, now-a-days, denim fabric isavailable in different colours also.

This fabric is woven with dyed yarn

either wrap or weft.Coloured denim can also be obtainedby piece dyeing process.


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CRUSHED DENIM

Textured effect achieved through a specialfabric construction coupled with wet

processing.Fabric is woven with an over twist weftyarn.

On washing the yarn shrinks, acquiring a

goffre look.The effect can also be improved by bleach

and stone wash.


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DENIM FROM FOX FIBRE

Denim fabric manufactured by colouredcotton fibre that grows naturally developed

and patented by California cotton breederSally Fox.

Available in Coyote brown with red andgreen shades Grown in Texas, Arozona

and California.NITRA, India has also done work on thisline.


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MARBEL DENIM

It is an another name for acid wash.Some crushed denims, if strongly

bleached, are also called marble.


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ECRU DENIM

The denim, which is not having dyedyarn i.e. only grey yarn in warp &

weft.


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REVERSE DENIM

Where the face side and reverse sidelook alike

SHOT GUN DENIM

Denims that have been shot with a

gun and sometimes washed to theextreme condition resulting in smallholes.


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THERMO DENIM / DOUBLE DENIM

In which a light weight fabric either plain,fancy or coloured is glued to the denim.

After washing the glue comes off andtrouser looks like they have been lined.

VINTAGE DENIM

A denim treatment that applies heavy stonewashing or a cellulose enzyme wash withor without bleach for an old and wornoutlook


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PETROLEUM WASH

Developed in 1992 by US brandWilliwear.

A left hand denim is enzyme washeduntil it has lost most of the colour.

It is then overdyed and put through a

silicone wash, which gives it an oilycoating and, in turn a super-soft,butter like hand.


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PINTO WASH DENIM

This fabric was developed accidentally. In 1969,warehouses of Cone Mills, USA flooded with water due tohurricane.

Millions of yards of denim were soaked with water.When the fabric was dried, an uneven dyeing defectdeveloped on the fabric.

To cover up huge losses, a merchandiser of Cone Millscame up with an idea.

He suggested to run the fabric through a solution to remove

the dye, which resulted faded appearance.This new fabric became very popular and called Pinto WashDenim.


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SANDING DENIM

Abrading fabric with sand-paper for

peach skin hand

SALT WATER DENIM

Washed with a high sodium contentfinish for increasing abrasion levels


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SNOW WASH

A variation of acid wash that imparts

bright white highlights

SUN WASHING

A very light shade can be achieved bybleaching and toning which looks as if

the sun faded the fabric


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SAND BLASTING

This process refers to a physical process which createslocalized abrasion or colour change on the denim similar tothe effect seen on well used jeans.

In this process the garments are first stone washed to thedegree required and than sand blasted in certain areas suchas knees and elbows.

The common blasting substance used are metal granules.

The other method used to get a similar look is by spraying asolution, containing sodium hypochlorite or potassium

paramagnet.After spraying the desired areas on the garment they areneutralized, rinsed softened and dried.


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SUPER STONE WASH

A prolonged stone wash treatment givenfor more than six hours.

Washing is done in drum washer.

The chemical agents required for hardwash are soda ash and soap.

Steam is required upto 60-80 C minimumfor one hour to finish the process.

In the second stage acetic acid washtreatment is used, then the garments areneutralized and rinsed


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PEACH SKIN EFFECT DENIM

This effect is created by treating the fabric in order to form afine protruding, hair-like covering resembling the surface of apeach.

The effect can be achieved by a careful selection of thefabric and a tightly controlled wash with a combination ofneutral cellulose enzyme and stone.

This treatment is often carried out on ecru jeans that are tobe garment dyed.

The extent of the surface effect depends on the fabric usedas well as on the cellulose dose and treatment time.

If an equally high amount of acid cellulose is used, thesurface will turn out very smooth with absolutely no fuzz onthe face.


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Thank You

Finishing Denimwashing 120209233253 Phpapp01

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