Denim Washing

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Denim Washing Basic Steps and Guide..

Fashion is today incomplete without denim. Denim comes in all forms, looks and washes to match with everydress. It would be difficult to believe that the same denim was originally employed in clothing for the pants andoveralls worn by miners on the west coast(US). A number of technological factors have contributed to makingdenim the fashion icon that it is today including vast improvements in spinning, weaving, finishing etc. One ofthe most important part of creation of the beautiful denim jeans is the washing . Washing plays such an importantpart in the denim chain because of the umpteen effects that the consumers are looking for on their jeans . Letstalk a bit about denim washing

BASIC DENIM WASHING PRINCIPLES

Below is the brief introduction to common steps done & followed in denim garments washing in Laundries acrossthe world. Different kind & make of machines being used across the globe to hit similar results.

Every small step in denim washing makes a big difference because indigo dye has very poor wet & dry rubbingfastness. All parameters are critical to maintain for repetitive results. Eg Many laundries across the Globe ignorethe importance of pH M:L:R & R P M of machine.

Some important steps in the process of Denim Washing

1. Pre treatment ( Desizing, Rinsing, Scouring etc)2. Enzyme or Stone wash3. Clean up to adjust the desire effect4. Bleaching5. Tinting / Dyeing6. Softening & Much more..

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1.PRE TREATEMENT

This is very first & basic step but most important step of washing. Here the fate of denim garment is decided thatits going to appear good or bad. Good Pre treatments avoid streaking, stiffness & color loss. This processremoves impurities, starch & stains during handling of fabric.

This step is also called desizing ( Removal of Size applied during denim fabric making in weft yarn ). All the wovenfabric contains size on them due to reasons to strengthen the yarn for weaving.There are many types of sizesavailable in the market but they can be divided in two major groups.

1. Water Soluble (CMC or PVA based sizes ) and2. Dissolvable sizes in water ( Starch based ). Starch based sizes are most commonly used due to cheap

prices & readily availability.

Methods of Removing Sizes from Denim Jeans Washing with High Alkaline agents ( i.e. Soda ash )

Washing with High Acidic agents (i.e. Acetic acid )

Washing with Oxidative chemicals ( i.e. Hydrogen Peroxide )

Enzymatic desizing with Alfa amylase .. This is eco friendly & convenient .

2.Enzyme & Stone Washing Process Of Denim Garments

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There are four kind of Enzymes available in market for Denim Laundry business..

Amylase . Desizing Cellulase . For Salt & pepper effect , contrast Laccase. bio bleaching Catalase Peroxide killer

Enzyme is kind of protein that is obtained from fermentations method from naturally existing bacteria & fungi.The structure of Enzyme is a biological polymer and it can be found in every cell. Generally called as Cellulase & itworks on cotton( Cellulosic fiber ) only. Enzyme are living organisms which will attack a specific molecular group.

There are mainly three kind of Cellulase being used for Denim washing , Neutral, Acid and Bio polishing Enzyme.Enzyme are very sensitive with parameters in washing cycle i.e, pH , Temperature & time. If any of theseparameters are not up to the mark, result will not be accurate.

The reaction of enzyme can be easily controlled, its biodegradable products, so they eco friendly.

Bio Polishing Cellulase are being used to have protruded fiber removal from denim & oven fabric. This is alsowidely known as Anti pilling enzyme.

Any Cellulase used in process must be cleaned/killed after the process completion by simply disturbing theparameters ie. By raising high temp. or raising pH to alkaline where no Cellulase withstand.

Cellulase are available in 3 categories

Neutral

Acidic &

Hybrid enzymes.

Neutral enzyme gives better salt & pepper effect with very less back staining & its generally come sin powderform & also retains better strength of fabric than acidic Cellulase. Where as acidic cellulase give faster results butwith too heavy back staining & cuts down the indigo color, also affects the strength of fabrics.

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Now a days laundry people needs faster results in less time & money hence chemical suppliers combined Neutral& acid cellulase in such way that it works faster & with better results than acid cellulase with cost effectiveness &known as Hybrid enzyme.

Laccase is bio bleaching agent & alternative for conventional bleaching agents. This impart greyer cast to bluedenim & enhances salt & pepper effect. But due to high cost & low self life, laundries do not prefer it.

3.CLEAN UPAfter finishing Enzyme wash it is must to add clean up process for better results & garments appearance & thatcan be done in various ways & methods. As clean up is a must process to be carried out after every chemicalssteps done for any garments which allows next process to happen smoothly. All processes mentioned below kill/deactivate the active enzymes process which is necessary in order to protect/retain garment strength

a.Hydrogen peroxide in alkaline pH clean up enhances the brightness & rich blue tone of indigo. b.By using non ionic detergents in medium to high temperature c.By doing two good hot water rinse etc.

4.BLEACHING

This in one an important step in washing denim & can be done by various bleaching agents ..

a.Calcium hypo chlorite b.Sodium hypo chlorite c.Hydrogen peroxide d.Potassium permanganate

First two chemicals are commonly being used for every medium to vintage denim butwhen it comes to supervintage & light shade its advisable to use potassium permanganate bleach to cut the color faster till half way &then neutralize it & go with Liquid ( Hypo ) bleach to adjust the desired shade. This process helps to get Greyercast & also protects the lycra/spandex , retain elasticity.

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Hydrogen Peroxide is rarely used as bleaching agent when very less color loss required or if fabric is sulphur top.As it takes longer time to give desired effect.

Potassium Permanganate is also being used on 100% sulphur black denim fabric for bleaching/reducing agent toget unique effects. As its not production friendly till laundry have very expertise team to handle this program,otherwise it will result in many shades & cast.

Proper Neutralizations of bleaching process is very essential in order to get rid of fabric strength , bad smell fromgarment, yellowing & skin irritation etc

4.Tinting & Dyeing

Tinting is a process where very less amount of tint is involved & mainly direct dye is being used to do this process.This is being done to change hue/cast/tone of indigo. As soon as quantity of tint color increases & it cover upindigo, reaches the level of dyeing.

Tinting being used to give garments a used / vintage & muddy look. This process takes from 5 minutes to 15minutes time for better results followed by dye fixing & clean up of superficial dye.

Dyeing is being done on very light shade of Indigo, Ecru/ grey denim & Ready for dyeing denim.

There are various Types Of Dye . THe comparison of these dyes is given in the chart herebelow:

1-Direct Dyes

2-Reactive Dyes

3-Pigment Dyes

4-Sulphur Dyes

Direct Dyes Reactive Dyes Pigment Dyes Sulphur Dyes

Economical Costly Cost Efficient EconomicalWide range ofshades

Wide range ofshades

Styling ( limitedto dull shades)

Shades are dull

Short Cycles Long Cycle Short to longCycle

Short to longCycle, dependsupon shade

Ease of Water Machine Sulphur Odour

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application ConsumptionHigh

contamination,but hard toobtainconsistency,harsh hand feel

& harsh handfeel

SmoothAppearance

SmoothAppearance

SmoothAppearance

SmoothAppearance

5.SOFTENING PROCESSSoftening process of Denim is very critical. As denim is very heavy in compare with other fabrics hence its needssoftening. During this process there is a big problem -the discoloration of denim i.e change in shade or loss ofwhiteness, giving a yellow tint is commonly known as yellowing. By using normal softener will lead to ozoneproblem. Indigo dyed fabric are even more prone to yellowing.

As its a widespread problem & there in no single reason for its cause. Instead a number of condition can singly orin combination lead to the problem. Yellowing in not specific to certain fibers, finishes or washing processes. It isnot specific to chemicals or chemical treatment but certainly some of the factors among these can lead to theyellowing. As cotton & all organic polymers develop yellowing in time.

Light , acids, impurities, detergents & chemical contribute to yellowing problems.

Temperature of drying & curing can impart yellowing due to scorching of the cotton. Therefore good controlmust be used to minimize this type of damage.

Hence its advisable to use Antiozonate softener which prolong ozone reaction of Indigo & keep garment in goodcondition.

MINIMISATION OF YELLOWING RISK:

Its Impossible to eliminate yellowing but it is possible to prolong & reduce the conditions which causes classicalyellowing:

Ensure bleaching neutralization & rinsing is proper

Minimize back staining

Avoid use of chemicals which cause yellowing

Avoid leaving garment in open air for longer time

Control drying & curing temperatures

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Using right Antiozonate softener with right pH

Methods of Removing Sizes from Denim Jeans

Washing with High Alkaline agents (i.e. Soda ash)

Washing with High Acidic agents (i.e. Acetic acid)

Washing with Oxidative chemicals (i.e. Hydrogen Peroxide)

Enzymatic desizing with Alfa amylase.. This is eco friendly & convenient.

First three methods are difficult, risky and expensive method at laundry business because of this nearlyall of the market prefers enzymatic de-sizing.

Preventation of creases:

One of the main problems in laundry business is creases.

We can separate creases into 4 groups related to their reasons;

Mechanic based creases: these are the creases related to the ratio of water, loading capacity and rotation speed of drum. Chemical reaction based creases: These are the creases related to the wetting time of fabric or unevenness auxiliary applications

Fabric based creases:

These are the creases comes from the production of the fabric Storage based creases.

DESZNG RECPE

LQOUR RATIO: 1/6-1/10 (DEPENDNG ON MACHNE TYPE)

TIME : 10 MNUTES

LAVA ZYME DEZ0,5-1 GR/LT( amylase enzyme for removing of size)

LAVA WET W-LA0,5-1 GR/LT(wetting and scouring agent)

LAVA SPERSE KDS0,5-1 GR/LT(dispersing and washing agent)

SERA LUPE M-CF0,5-1 GR/LT(anti-crease agent)

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WETTING DISPERSING AGENT

Used in Desizing process. Must rapidly wet out jean. Prevents white lines caused by rigid creases. Permits penetration of Amylase to fully desize. Prevents back staining of loose indigo onto weft yarns and pockets. Also used in stonewash / after washing to reduce back staining.

BACK-STAINING:

Re-deposition of loose indigo, or indigo dyed short fibres, removed during desizing, stone-washing or enzyme washing.

Re-deposited Indigo, reduces the contrast between warp and un dyed weft Re-deposited indigo stains pockets and labels Re-deposited indigo is more prone to Ozone and yellowing

ANTI-CREASE (Lava Lupe M-CF)

Prevents crease formation during the washing procsess . Increases the loading capacity of the washing machine Reduses the stone spots risk during the stone wash procsess

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