SOIL RELEASE FINISH

SOIL RELEASE FINISH

What is stain?

A stain is a discoloration that distinguishes itself from the material on which it is found. It can be unintentional, in the case of domestic stains on fabric, cloth, or other material, or it can be intentional.

Synonyms: dirt, filth, grime, soil, grease, grunge

Various laundry techniques exist to attempt to remove or minimize existing stains, and stain removers are an important type of chemical in laundry detergents.

Stain resistance is an important characteristic in modern textile engineering.

What is repellency?

It forms a molecular barrier around the individual fibers to lower the critical surface tension (CST) so that the fabric does not attract stains or soil.

It results in-

-        Liquids bead up and roll off the fabric.

-        Spills can be blotted up quickly with a clean, dry, absorbent cloth.

-        Provides unmatched resistance to oil- and water-based stains.

WHAT IS RELEASE?

Release allows stains to be removed more easily during laundering than most common untreated fabrics.

It results in-

• Stains temporarily soak into the fabric.

• Hydrophilic “water-loving” portion of finish draws in detergent and water.

• Stains wash out more easily.

Introduction

Chemical finish that permit relatively easy removal of soils with ordinary laundering.

These finishes are necessary because hydrophobic fibers and resins have very low water absorbency. It accomplish the result of making the fiber more absorbent (hydrophilic), thus permitting better wettability for improved soil removal.

These finishes are applied at the same time the resins are applied to the textiles.

Most are durable to 40 to 50 launderings.

Soiling generally means smearing or staining of a large surface of the fabric with dust or dirt and oil or grease or both. The problem of soiling is not a new one. Natural fibers and synthetic fibers both attract dirt and get soiled but synthetic fibers attract soil to a grater extent than natural fibers; apart from this , they do not release soil easily during washing. Due to absorption and retention of soil , the whiteness and brightness of a fabric is spoiled and it appears yellowish and dirty.

Mechanism of Soiling

A fabric gets soiled mainly by three types of mechanism.

1. By mechanical adhesion of soil to the cloth by direct contact with a soiled surface or by rubbing of the garments against the skin or picking up dirt from liquors or from air ; fabric construction facilitates such adhesion as the soil gets entrapped in inter fiber and inter yarn spaces or even into the capillary spaces of the fiber where it gets firmly deposited. Also soil which is oily in nature can diffuse into the fiber.
2. By adhesion by electrical forces due to attraction of dust particles from air by electrically charged fiber surface. This phenomenon occurs mainly with synthetic fibers because of their low moisture regain. Positively charged fabric surface is soiled more than negatively charged surface.
3. By redeposition of soil during washing which occurs particularly with nylon and polyester fabrics; the redeposition on these fibers takes place because of their oleophilic nature. Another aspect of soiling is the effect of time lag between soiling and washing. When a soiled fabric is allowed to lie unwashed for many days, the soil diffuses inside the fiber and it becomes difficult to remove it.

Factors influencing Soiling

Moisture regain of the fiber is the most important factor that influences soiling. Natural fibers and regenerated cellulose rayons have high moisture regain and have little tendency to accumulate static electricity. Even if static electricity is generated, it is quickly dissipated to the atmosphere. Therefore, the problem of soiling and soil removal is not very acute in the case of fibers having high moisture regain. Synthetic fibers have low moisture regain, therefore they accumulate static electricity which attracts dirt and dust from atmosphere. Lower the moisture regain, higher is the attraction of soil. When the moisture regain of the fibers drops below 4%, soiling increases rapidly. Polyester has the lowest moisture regain (0.4%) among synthetic fibers; therefore it attracts maximum soil. Since these fibers are hydrophobic, they do not swell in water and the removal of soil from the fiber becomes difficult. In the case of blends with cellulosic fibers , whatever soil is removed from the cellulosic component during washing , gets redeposited on the synthetic fiber because the synthetic fiber being oleophilic, attracts oily matter from the dirty wash waters.

Electrostatic charge

This is also an important factor which influences soiling. Synthetic fibers accumulate static charge during manufacture and during wear. Charged fibers attract soil from the atmosphere, positively charged fabric attracting more soil than the negatively charged one.

Fabric Structure

Fabric construction, yarn count, twist and the cross section of the fiber influence soiling. Smaller the denier, greater is the tendency to soil. A circular cross sectional fiber retains less soil than one with an irregular cross section. Higher the twist in the yarn, greater the soil retention. Fabric with protruding fibers assist soiling. Loosely woven and open knitted fabrics are more prone to soiling than closely woven fabrics but removal of soil from loosely woven fabrics is easy. Fabrics made from filament yarn do not get soiled as fast as those made from spun yarns.

Particle size of Soil

The smaller the size of the soil particles, grater is the soil retention by the fabric.

SOIL RELEASE FINISH

All fibers get soiled but most of them can be washed clean because soap, water or the detergent penetrates the fiber; but this is not so with polyester or polyester blended cotton. They are hydrophobic and often oleophilic or oil attracting. A soil release finish does not prevent soil from entering the fabric but it simply allows it to leave faster. It removes soil from the fabric and transfers it to the detergent; it protects the fiber from attack by soiling matter; it prevents redeposition of soil which has been dissolved or dispersed and lastly it prevents dust from being attracted and held by electrical charges on the fabric surface.

There are two types of soil release treatments available

1. Oleophobic treatments
2. Treatment with hydrophilic substances

In the first group it uses fluorocarbons which are oil repellent, soil resistant and release soil easily from the textile materials; one such compound is perfluoro-alkyl methacrylate used together with melamine formaldehyde condensate and paraffin wax. Many soil release finishes are based upon the use of organo silicon compounds which are applied by pad-dry-cure process. Thus the fabric may be padded with a mixture of methyl hydrogen polysiloxane and acetyl dimethyl benzyl ammonium chloride together with zinc acetate followed by drying and curing at 160 C for a few minutes. The new breed of soil release finishes confers hydrophilic character to the fiber surface.

Copolymers of ethyl acrylate with acrylic acid are used for soil release. Permalose T of ICI is applied (1-3%) to polyester and its blends by the pad-dry-cure process; it helps soil removal, prevents redeposition of soil during washing and prevents accumulation of static charges thereby reducing attraction of dust from the air. The finish is fast to washing and dry cleaning.

SOIL-RELEASE CHEMISTRY

Finishes providing soil release can be classified in numerous ways, by method of application, by fiber type, by chemical structure, electrical charge and so on. Here chemical structure is listed down-

Carboxy-based finishes

The composition of this finish is based on acrylic and methacrylic acid and ester copolymers. An ester to acid ratio of 70:30 is typical. This ratio seems to provide the proper blend of hydrophilicity and oleophobicity (hydrophilic-lipophilic balance, HLB) required for a soil release finish. The HLB scale is often used or the pre-selection of surfactants and ranges from about 0 (very hydrophobic) to nearly 20(very hydrophilic). For good soiling performance, HLB values of about 15 are favored. But this is only for rough orientation, because the important copolymer block arrangements are not expressed by these HLB values. Greater hydropilicity would strongly reduce durability to laundering. The ease of incorporating different acrylic monomers into copolymers has led to a wide variety of available finishes.other carboxy polymers that have been used as soil-release finishes include styrene-maleic anhydride copolymers and sodium carboxymethyl cellulose.

Hydroxy-based finishes

One of the earliest soil-release materials was starch, which functioned as a sacrifial treatment. Other starch- and cellulose based products that have been used as soil release agents include methyl cellulose, ethyl cellulose, hydroxypropyl starch,hydroxyethyl cellulose, hydroxypropylmethyl cellulose and hydrolyzed cellulose acetates. With some expectations these finished lack the laundering durability desired in finish expected to last of a garment and must be applied in combination with a binder or cross-linking agent.

Ethoxy-based finishes

One important group of soil-release agents for polyester fibers is based on condensation copolymers of terephthalic acid with ethylene glycol and polyethylene glycol. The structure of this polyester –ether copolymer contains blocks of polyethylene terephthalate and polyxyethylene terephthalate that provide a structure that has regions of hydrophilicity interspersed with hydrophobic regions that have a strong attraction for the polyester surface. These products can provide extremely durable soil-release properties for polyester fabrics by either exhaust or pad applications with about 0.5% solids add-on. It is possible to exhaust apply these products during the dyeing process. A modification of the condensation copolymer compounds involves incorporating anionic character into the polymer chain by use of sulfonated monomers. High soil-release performance, excellent softness and combinability with fluorocarbon finishes may be achieved by special silicone/polyalkylene oxide copolymers.

Fluorine-based finishes

These unique polymers have the unusual property of being hydrophobic and oleophobhic in air and hydrophilic and oil-releasing during laundering process. This is called ‘dual-action’ mechanism. The hydrophilic blocks are shielded by the fluorocarbon segments when dry, presenting a repellent surface. After immersion in the wash bath, the hydrophilic blocks can swell and actually reverse the interfacial characteristics of the surface, yielding the hydrophilic surface necessary for oily soil release. Typically, these modified fluoropolymers are pad applied to fabrics in combination with the durable press crosslinking agents to increase the durability of the finish. The higher cost of the fluorochemical soil release agents compared to the acrylic copolymers is somewhat compensated by the low add-on required for soil-release performance. Mixtures of both polymers types provide a common compromise between efficiency and costs.

EVALUATION OF SOIL RELEASE

The ideal evaluation method for a soil-release finish would be to stain the fabric with the same material that will soil’s consumer’s clothes and then to wash the fabric with the detergents in the washing machine at the water temperatures that consumers will use. The American Association of Textile Chemists and Colorists (AATCC) has developed standardized procedures for evaluating soil-release finished that provide a strong indication of the actual finish performance in the real world.  Evaluation of soil-release effects after washing is mostly visually done by comparison with photographic standards, but also by reflectance measurements and other instrumental techniques, including microscopy.

Oily soil-release testing

It specifies all the parameters that strongly influence soil release of oily soils.

Soil redepositon

It is used to estimate the degree of soil redeposition likely to occur during laundering. The fabrics to be tested are exposed to a soiling medium during a laundering simulation with a standard detergent. The change in reflectance of the fabric before and after the testing is an indication of the redeposition potential of the fabric.

Moisture transport

The procedure is used to determine the degree of absorbency of fabrics finished with soil-release agents. Typically, near instantaneous wetting of the fabric with water (<1s) is expected from non-fluorine-containing soil-release finishes.

Chemical mechanisms of soil-release finishes

FACTORS AFFECTING SOIL REALESE FINISH

Ø  Nature of the soil

Ø  Kind of fibers

Ø  Nature of textile

Ø  Effects of preparation

Ø  Effects of dyeing and printing

Ø  Effects of other finishes

Ø  Washing conditions

PROPERTIES ACHIEVED BY SOIL RELEASE

Ø  Add care to garments.

Ø  Permits better wearability for improved soil release and soil removal.

Ø  Permits relatively easy removal of oil borne stains from permanent press garments.

Ø  Resists redepositing of soil when laundering.

Ø  Aids in making fabric more absorbent.

Ø  Provides greater comfort in hot weather.

Ø  Provides improved anti static properties.

ADVANTAGES OF SOIL RESISTANT

Ø  It protects the fibre from attack by soiling matter.

Ø  It prevents redeposition of soil which has been dissolved or dispersed

Ø  It prevents dust from being attracted and held by the electrical charges on the fabric surface.

Ø  The finish is fast to washing and dry-cleaning.

FINISHING AGENTS USED

•     FLUOROCARBONS

•      FLUOROCHEMICALS

•      PYRIDINUM COMPOUNDS

•      RESINS

•      SILICONE

•      TRIAZINE COMPOUNDS

•      WAX AND ITS DERIVATIVES

STAIN RESISTANT FINISH

Stain resistant fabric technology provides permanent stain repellency  and stain release properties.  Not only does this fabric repel stains, but it also releases the dirt and oils that cause stains. It helps garments stay cleaner, longer, because of the dual action of two robust and balanced technologies, working in the fabric for the life of your garment.

The stain repellent is applied on the outside of the fabric to allow most water- and oil-based stains to roll off. 

The release is applied within to prevent ground-in oil-based stains from remaining in the fabric. During laundering, the release component pulls water and detergent through the fabric to wash out the stain It allows liquid and food-based spills to bead up and be wiped right off. It allows oil-based stains to be easily released in the wash cycle.

PROPERTIES ACHIEVED BY STAIN RESISTANT

Ø  reduces rate of soil absorption, deposit and detention in fabric

Ø  Provides for good soil release properties

Ø  Prevents stains from spreading

Ø  Allows water and spills to form globules on fabric surface preventing penetration into the fiber

Ø  Resists water and water born stains

Ø  Adds soft silicone hand

Ø  Improves tear strength

ADVANTAGES OF STAIN RESISTANT

Ø  The Stain resistant treatment does not affect the hand of the fabric.

Ø  The Stain resistant treatment offers permanent protection to a variety of knitted and woven fabrics, including nylon, polyester, cotton, and cotton/poly blends.

MECHANISM COMMONLY USED IN INDUSTRY

1. USE OF FLUOROCARBONS

A durable stain resistant and soil release finish.

This finish imparts a fabric protector that enables the fabric to repel spills and stains on

contact. The stain resistant finishes apply a coating to the fibers. This treatment gives fabric a stiffer hand as well as some other performance problems. The fluorocarbon stain

resistant finish penetrates the individual fiber, becoming the part of the fiber.

The surface properties of the fabric is not altered.

Liquids can be blotted and soils wiped off and soils released during laundering.

2. NANOTECHNOLOGY

Nanotechnological processes for making stain-resistant fabric.

It involves a chemical treatment of the fabric to create a surface that repels water and also repels oil. Most stains come  as liquids (like orange juice). The liquid dries up and develop a stain.If the liquid can be kept from getting sucked up, a stain can be prevented from happening.

Using nanotechnology, unique and permanent stain resistant finishes are being developed. Nanotechnology is defined as the precise manipulation of individual atoms and molecules to create layered structures. Nanosize particles can exhibit unexpected properties— different from those of the bulk material. The basic premise is that properties can dramatically change when a substance’s size is reduced to the nanometer range.

It uses chemistry to make little tiny whiskers and other things that help to repel liquids.

First the fabric is treated with some acid and some hydrophobic polymers are pressed into the fabric.The fabric is then baked to make the whiskers.

Supposedly, little tiny whiskers of which about one-thousand can fit across a thread of fabric. The whiskers make the fabric hydrophobic. So, it is part of the fabric and makes the fabric stain repellent. Stains don’t stay and the whiskers don’t wash away either.

APPLICATIONS

Ø  High performance active apparel

Ø  Work wear

Ø  Military

Ø  Uniform

Ø  Travel apparel

Ø  Casual men's and women's.sportswear

Ø  Wall spaces for hospitality  and commercial interior  design use--fabrics for this market are possess flame retardant and stain release/repel properties.

Ø  Nurses scrubs 

Basic washes in denim fabric

THE HISTORY OF DENIMS
A popular conception of the etymology of the word denim is that it is a contraction or derivative of the French term, serge de Nîmes. Denim was traditionally colored blue with indigo dye to make blue "jeans," though "jean" then denoted a different, lighter cotton textile; the contemporary use of jean comes from the French word for Genoa, Italy (Gênes), from which the first denim trousers were made.
A similarly woven traditional American cotton textile is the diagonal warp-striped hickory cloth that was once associated with railroad men’s overalls, in which blue or black contrasting with undyed white threads form the woven pattern. Hickory cloth was characterized as being as rugged as hickory wood—not to mention the fact that it was deemed to be worn mainly by "hicks"—although neither may be the origin of that term [from a nickname for "Richard"]. Records of a group of New Yorkers headed for the California gold fields in 1849 show that they took along four "hickory shirts" apiece. Hickory cloth would later furnish the material for some "fatigue" pantaloons and shirts in the American Civil War.


INTRODUCTION
Denim is a rugged cotton twill textile, in which the weft passes under two (twi- "double") or more warp fibers, producing the familiar diagonal ribbing identifiable on the reverse of the fabric.


DENIM WASHING
Denim washing is the aesthetic finish given to the denim fabric to enhance the appeal and to provide strength.
Dry denim, as opposed to washed denim, is a denim fabric that is not washed after being dyed during its production.
Much of the appeal of dry denim lies in the fact that with time the fabric will fade in a manner similar to that which artificially distressed denim attempts to replicate. With dry denim, however, such fading is affected by the body of the person who wears the jeans and the activities of their daily life. This creates what many feel to be a more natural, unique look than pre-distressed denim.


DENIM WASHES ARE OF TWO TYPES:


1. Mechanical washes
- Stone wash
- Microsanding


2. Chemical washes
- Denim bleaching
- Enzyme wash
- Acid wash


CHEMICAL WASHES


Denim bleach
In this process a strong oxidative bleaching agent such as sodium hypochlorite or KMnO4 is added during the washing with or without stone addition.
Discoloration produced is usually more apparent depending on strength of the bleach liquor quantity, temperature and treatment time.
It is preferable to have strong bleach with short treatment time.
Care should be taken for the bleached goods so that they should be adequately antichlored or after washed with peroxide to minimize yellowing. Materials should be carefully sorted before processing for color uniformity.


Process cycle:


Limitations:
- Process is difficult to control i.e. difficult to reach the same level of bleaching in repeated runs.
- When desired level of bleaching reached the time span available to stop the bleaching is very narrow. Due to harshness of chemical, it may cause damage to cellulose resulting in severe strength losses and/or breaks or pinholes at the seam, pocket, etc.
- Harmful to human health and causes corrosion to stainless steel.
- Required antichlor treatment.
- Problem of yellowing is very frequent due to residual chlorine.
- Chlorinated organic substances occur as abundant products in bleaching, and pass into the effluent where they cause severe environmental pollution.


Enzyme Wash
It is environmentally friendly wash. It involves the Application of organic enzymes that eat away at the fabric, i.e. the cellulose.


When the desired color is achieved, the enzymes can be stopped by changing the alkalinity of the bath or its temperature. Post treatment includes final rinsing and softening cycle. The effects produced by the cellulose enzyme are---
1. Use of cellulase making the seams, hems, and pockets more noticeable
2. Salt pepper effect is color contrast effect.
3. Faded garment with acid cellulase enzyme provides less color contrast in proportion to garment washed with neutral cellulase enzymes.
Garment load size of the machine is 35-40 jeans per machine and it cannot be overloaded.


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.
In this wash the color contrast of the denim fabric can be enhanced by optical brightening. The advantage of this process is that it saves water as addition of water is not required.


Process cycle


Limitations of acid wash:
- Acid washed, indigo dyed denim has a tendency to yellow after wet processing.
- The major cause is residual manganese due to incomplete neutralization, washing or rinsing.


Remedy:
- Manganese is effectively removed during laundering with addition of ethelene-diamine-tetra-acetic acid as chelating agent.
- Acid washing jeans avoided some of problems of stone wash, but came with added dangers, expenses, and pollution.


MECHANICAL WASHES


Stone wash:
In the process of stone washing, freshly dyed jeans are loaded into large washing machines and tumbled with pumice stones to achieve a soft hand and desirable look.
Variations in composition, hardness, size shape and porosity make these stones multifunctional. The process is quite expensive and requires high capital investment.
Pumice stones give the additional effect of a faded or worn look as it abrades the surface of the jeans like sandpaper, removing some dye particles from the surfaces of the yarn.


Process cycle:


Selection of stone
Stone should be selected of the proper hardness, shape, and size for the particular end product. It should be noted that large, hard stones last longer and may be suited for heavy weight fabrics only.
Smaller, softer stones would be used for light weight fabrics and more delicate items.
Stone wt. /fabric wt. = 0.5 to 3 /1
It depends on the degree of abrasion needed to achieve the desired result. Stones can be reused until they completely disintegrate or washed down the drain.


Problems caused by stones:
-Damage to wash machineries and garment due to stone to machine and machine to stone abrasion
-Increase in labor to remove dust from finished garments.
-Water pollution during disposal of used liquor.
-Back staining and re deposition.


The dye removed from denim material after the treatment with cellulose or by a conventional washing process may cause "back staining” or "redeposition”. Re-coloration of blue threads and blue coloration of white threads, resulting in less contrast between blue and white threads.


Remedy of back staining ---
- Adding dispersion/suspension agent to wash cycle.
- Intermediate replacement of wash liquor.
- Using alkaline detergent like sodium per borate with optical brightener as after wash.


Limitations of stone washing:
- Quality of the abrasion process is difficult to control Outcome of a load of jeans is never uniform, little percentage always getting ruined by too much abrasion.
- The process is non-selective.
- Metal buttons and rivets on the jeans in the washing machines get abraded.
- This reduces quality of the products and life of equipment, and increases production costs.
- Stones may turn into powder during the process of making the garment grayish in color and rough too
- Provides rougher feel than enzyme wash
- Stone may lead the harm to the machine parts


Microsanding
There are 3 ways for this technique:
• Sandblasting
• Machine sanding
• Hand sanding or hand brushing


Used in various ways:
- Flat surfaces (tables, ironing boards)
- On the dummy (inflatable dummies, sometimes standing, sometimes flat, sometimes 'seated')
- Various templates can be used to create a 3D effect.


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 to be treated to give the desired distressed/ abraded/used look.
- It is purely mechanical process, not using any chemicals.
- It is a water free process therefore no drying required.
- Variety of distressed or abraded looks possible.
- Any number of designs could be created by special techniques.


WHISKERING
- Also known as ‘Cat's Whiskers’
- Crease lines around the crotch.
- Industrially done with laser, sandblasting, machine sanding, hand sanding and abrasive rods.
- Also used for 'knee whiskers' (whiskers on the sides of knees) and 'honeycombs' (crease marks on the back of the knee)


Other chemical washes:
• Rinse wash
• Cellulase wash
• Ozone fading
• Snow wash
• Salt water denim
• Flat finish
• Over dye
• Sun washing
• Super dark stone


RINSE WASH
- Chemically bleaching jeans so that the color fades away
- Breaks down the fibers of jeans and creates white streaks or spots on denim
- Gives a unique rugged look, also called snow wash
- Earlier involved the use of pumice stone
- Presently process involves spraying chemical and removing it immediately
- Come in colors like blue, black, green, brown, grey etc.


CELLULASE WASH
- This is done to achieve a wash down appearance without the use of stones or with reduced quantities of stones.
- Cellulase enzymes are selective only to the cellulose and will not degrade starch.
- Under certain conditions, their ability to react with cellulose (cotton) will result in surface fiber removal (weight loss).
- This will give the garments a washed appearance and soft hand.


Factors influencing cellulase performance
-pH
-Temperature
-Time
-Dose
-Mechanical action


OZONE FADING
-By using this technique, the garment can be bleached.
-Bleaching of denim garment is done in washing machine with ozone dissolved in water.
-Denim garments can also be bleached or faded by using ozone gas in closed chamber.
-In the presence of UV light, there is an interaction between the hydrocarbons, oxides of nitrogen and oxygen that causes release of ozone.
- Indigo dyestuff tends to fade or turn yellow due to ozone reaction.


The advantages associated with this process are:
- Color removal is possible without losing strength.
- This method is very simple and environmentally friendly because after laundering, ozonized water can easily be deozonized by UV radiation.


FLAT FINISH
It is a special process done to impart fabric with an even wash down effect and very clean surface. Originally liquid ammonia was used, but now use mercerization plus calendering processes to achieve the flat surface.
Mercerization swells up the cotton fibers and allows the calendering to press flat the surface.
They consider this as an imitation process to the use of ammonia, which is toxic and not allowed in commercial use in most countries


OVERDYE
-Dyeing over the fabric or jeans to add another tone of color
-Most often used is a 'yellowy' overdye to create a 'dirty' look
-Also can be applied with spray gun or paintbrush for local coloring


SUNWASHING
- A very light shade by bleaching and stoning
- Looks as if the sun faded the fabric


SUPER DARK STONE
- Commercial term for an extra dark indigo color
- Results from a double-dyeing technique


SNOW WASH DENIM
Denim treated with a variation of acid wash that imparts bright white highlights.


QUICK WASH DENIM
• Aims at minimizing wash cycle time
• Results in more economical washes and solving many other washing problems faced by launderes during fashion wash cycles
• The yarns are ring dyed using indigo giving 25 to 30% less fixed dye to obtain a given shade
• During wash cycle,indigo dye can be removed quickly,giving washed look
Advantages of quick wash denim
1. Streaks develop in garments after washing process due to differences in dye concentration of denim fabrics are avoided using a modified alkali-ph controlled system giving uniformity of shade.
2. Amount of indigo dye required is less thus making it an economical process
3. Time required for washing is 20-30% less than that required for conventional denim.
4. Lesser enzymes and oxidising agent used
5. Environment friendly process
6. Back staining is minimised due to less concentration of of indigo dye in the wash liqour.


Other Mechanical washing
Whiskering
Shot gun denim
Water jet fading
Super stone wash
Ice wash
Thermo denim
Laser technology finish


WATERJET FADING
-Hydrojet treatment is used for enhancing the surface finish, texture, durability of denim garment.
-Hydroject treatment involves exposing one or both surfaces of the garment through hydrojet nozzles.
-The degree of colour washout, clarity of patterns, and softness of the resulting fabric are related to the type of dye in the fabric and the amount and manner of fluid impact energy applied to the fabric.
-As this process is not involved with any chemical, it is pollution free.


LASER TECHNOLOGY
-It is a computer controlled process for denim fading.
-This technique enables patterns to be created such as lines and/or dots, images, text or even pictures.
-It is water free fading of denim.
-Being an automatic system, chances of human error are slim.
-Also called spray painting in denims.
- This technique has relatively high cost.


SUPER STONEWASH
-Prolonged stonewashing, up to six hours or more.


ICE WASH
-Ice washing in denim fabrics is done to remove more than half the dye during washing


THERMO-DENIM
Also called double denim. A lightweight fabric (either plain, fancy or colored) is glued to the denim. The glue comes off after washing and the trousers look like they've been lined


VINTAGE
- Applies heavy stonewashing or a cellulose enzyme wash, with or without bleach
-Gives an old and worn look


CHEMICALS ON DENIMS


1. Bleach fast Indigo
-Value addition to denim
-Retains indigo on certain parts
-Kind of resist effect
-Chemical applied by brush, cured at 150ºC
-Ex. Indigofix AXN


2. Anti-depositing agent
-Prevents “back staining” of fabric by loose indigo during washing
-Improves contrast in denim
-Used in stone wash step


3. Dye stuffs with softener
-To carry dyeing and softening in one step
-Soft and supple hand
-Saves time, money and energy as added to final rinse
-Gives used and worn out effect


4. Anti creasing agent
-Provides fabric to fabric lubrication
-Prevents formation of crack marks and streaks
-Minimizes abrasion and gives strength


5. Wrinkle formation
- Creating smooth and permanent wrinkle
- Cross linking concept
- Ex. DMDHEU
- White pigment
- Can be applied by brush, spray or screen
-  Then cured at 150ºC
- Washed and treated with softener


6. White pigment
• Can be applied by brush, spray or screen
• Then cured at 150ºC
• Washed and treated with softener


CONCLUSION
Denim is unique in its singular connection with one colour. The warp yarn is traditionally dyed with the blue pigment obtained from indigo dye. Until the introduction of synthetic dyes, at the end of the 19th century, indigo was the most significant natural dye known to mankind, linked with practical fabrics and work clothing. The durability of indigo as a color and it's darkness of tone made it a good choice, when frequent washing was not possible.
The old mass market has segmented, fragmented, shattered into a multitude of mini, micro and niche markets. The last generation has a vast quantity of brands to choose from, a different perception of the cult value of owning small insider labels and a fanatical loyalty only to what's hot on a daily basis.
Freed of all social and creative restrictions, denim is assuming any number of disguises and contexts to be worn in and has broken through almost any limitation on price. It can also be found in home collections, appearing in cushions, bed spreads and furniture-coverings.