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Introduction 1

Before the emergence of chemical industries in the early 1800s, which made available

a number of inexpensive organic solvents, all textile processing, whether cleaning or dyeing

was carried in water.

As organic solvents become available e.g. as a byproduct from coal-gas industry, the

textile trade shown interest in cleaning purpose from these solvents. A Frenchman

accidentally came across the process, so earlier it was known as “ French Cleaning”. Later it

becomes “Dry Cleaning” and in Germany it is known as “Chemical Cleaning”.

Dry cleaning had already been applied to cleaning techniques, which made use of

absorbent earth material, Fuller’s Earth. It has been used since Roman times for removing

grease. This technique did not involve water hence it is known as “Dry Cleaning”.

The cleaning of textile materials is too complex and highly technical application

operation in which organic solvents and water is combined to achieve required results, very

sharp line is drawn between “wet cleaning” and “ dry cleaning”. It is just that it made use of

organic solvents for cleaning.

The advantages of dry cleaning include: -

• Garment could be clean whole.

• Faster process and less labor cost.

• Dyes, finishes applied on fabric are not affected.

• Pressing and finishing is very simple.

Mechanization: -

For a time, solvent cleaning process was carried out in copper bowls with hand,

traditionally used in wet cleaning. Pullars of Perth, Scotland was the first to introduce a

power driven machine.

History of dry cleaning since 1850s made and preferred many changes in solvent,

chemistry of cleaning, development of highly sophisticated machinery. Earlier dry cleaning

was done in centralized out locally, using small machines.



Decentralizations: -

Cause of decentralizations, one of them is Modern dyes; they have good fastness

properties so the danger of getting affected due to cleaning was very less. As we live in the

world, where textile and consumer goods are discarded and replaced rather than being

refurbished and retained.

Solvents: -

Solvents now used for dry cleaning are the latest in succession of solvents, which

began with water, camphene (turpentine) and benzene (from coal tar). At one time gasoline

was preferred in USA and benzene in Europe.

Standard petroleum solvent “Stoddard Solvent” adopted in 1928 in USA and was

accepted as dry cleaning solvent as ‘white spirit’ type. It was having higher Flash Point

(38ºC), which provide greater safety than gasoline. It was pure and odour-free.

Trichloroethylene was the first chlorinated hydrocarbon to be used; introduced in

1920 in Germany. It was followed by carbon tetrachloride and tetrachloroethylene

(perchloroethylene) CCl4 was very much toxic, but among these big impression is made by

Perchloroethylene known as “Perchloroethylene”.

In 1964, Fluorinated-Chlorinated hydrocarbon solvent like R113 introduced in

Europe, which was much effective than Perchloroethylene. It was not affecting pigments

dyes, rubber, furs, vinyl coated fibers and leathers. But the safest cleaning was still assigned

to Perchloroethylene. The industries, which are performing dry cleaning operations among

them 80%, use perchloroethylene, 15% use white spirit and very few use other solvents like

trichloroethylene or fluorinated-chlorinated hydrocarbon.

Why it is necessary to carry out the Dry Cleaning? 2

When you by expensive garments or clothing a label is put on it “Dry Clean only”.

Why the goods cannot be just tossed in to washing machine with water and detergent when it

is available easily. Why the “ Dry cleaning” is preferred?

What’s so special about fabrics like rayon, silk and wool blends? These materials may

shrink, change colors or lose their shapes if washed in water. Garments of rayon become

rumpled and misshaped because water is attracted to the hydrophilic fibers in this fabric.

When submerged in water, the fibers expand because water molecules form hydrogen bonds



with individual molecules also interfere with attractions between adjacent fibers and the

fabric as a whole can lose its strength.

Silk when sent for wet cleaning a little rubbing in wet condition will weaken the

fabric. Silk fabrics are used due to their lustrous appearance and durability. But wet cleaning

and rubbing will make silk fiber weaker and the fabric will not be in a condition so that it an

be used for longer tome.

Wool fabric also misshapes when it is wet cleaned. The wool absorbs water in large

quantity in the air gaps of the fiber and swell and when it is removed by squeezing the fabric

get shrunked and cannot be converted in to its original shape. The wet cleaning of wool cause

felting of fiber, some fibers broke due to it and that gives harsh feeling to wool, it also lost its

smoothness. So the dry cleaning of such goods is must. 3

Natural fibers like wool, silk and rayon dry-clean beautifully will not loose their

color, shape in dry cleaning. They will not shrink, distort and misshape due to dry cleaning.

Solvents and its additives: -

Solvents 4

As stated in earlier part many solvents were used for the purpose of cleaning. Starting

from petroleum solvent, turpentine, and benzene to chlorinated solvents like

trichloroethylene, tetrachloroethylene etc. and the latest invented solvents like Fluorinated-

Chlorinated hydrocarbons or organic solvents. The solvent, which we are going to use for

cleaning, should have certain characteristics and those are listed below.

• It should not affect the dyes, the textiles and the finishes.

• It should not be toxic.

• It should be stable at dry cleaning purpose.

• It should be suitable for automatic process.

• It should be easily recoverable and economical.

Although many solvents are used for dry cleaning very few are discussed above.

White spirit 4

It has been used for many years but lost its position as most extensively used solvent

in U.K. It is not synthetic chemical but is obtained from the distillation of crude mineral oils.

It is not single, chemically pure liquid but a mixture of hydrocarbons. Its composition may

vary according to the oil. As it is not a pure chemical a definite boiling point is not assigned



to it but a boiling point range is assigned to it. At atmospheric pressure it boils at 150ºC, but

at boiling proceeds temperature increase up to 200ºC. It gets decomposed a little when boiled

at ordinary atmospheric pressure and hence it is distilled under partial vacuum.

It has specific gravity 0.78 at ordinary temperature. It is less dense than water and

insoluble in water. It is among safest solvents on textile, dyes and finishes and it is non-

corrosive.

Major objection to use it that it is highly flammable, but with some precaution can be

used safely. As result of flammability and explosive nature of certain mixtures of white spirit,

certain precautions are to be taken during drying. It is not feasible to recover white spirit from

vapor-air mixture by condensation. The mixture allowed to escape in to the air outside the

premises or passed through a special carbon recovery plant.

Perchloroethylene 4

It is a synthetic organic chemical prepared from ethylene, which is again a by-product

of oil refining and chlorine. Its name is tetrachloroethylene and its formula is CCl2: CCl2.

It is used in small extent in U.K. but in greater extent in U.S.A. Shortcomings of

trichloroethylene led to its use on large scale. Its non-flammability and suitability for use in

automatic controlled machine increased its popularity.

Being a single and pure chemical it has a certain boiling point 121ºC. Its boiling point

is still higher if it is contaminated, as towards the end of distillation. And easily recovered

from distillation. And easily recovered from the air-vapor mixture obtained by dry garment,

which have been cleaned in it using condensation method. No need to take special precaution

except avoiding high temperature, it should not be heated above 60ºC. Non-flammability and

easy recovery is the cause of wide spread use in unit shop.

It is a dense liquid with a specific gravity 1.62 at room temperature and it is insoluble

in water.

A disadvantage of it, is its toxicity. It is not chronically toxic as carbon tetrachloride.

It is desirable to use in closed machines to minimize contamination of air; good ventilation

should be there and smoking should be prohibited in such areas.

Perchloroethylene is not safe on all textile materials as the white spirit. It affects some

textile and some finishes. Sometimes it gives harsh feel to material like leather, fur etc. It is

noncorrosive chemical. Although it is expensive but economical due to easy recovery from

drying and distillation.

Trichlorotrifluoroethane (Solvent F113)5



It is pure synthetic organic chemical and is prepared from perchloroethylene by

introduction of fluorine atoms in to the perchloroethylene molecule. Its formula is CCl2:

CCl2.

It is introduced in purpose of dry cleaning around 1960s.

It is very volatile liquid, it must be used in enclosed machines similar to those used

for perchloroethylene. Cleaning operation, centrifugal extraction and the garment drying

process all take place in a same cage. The machines used for it are more intricate than used

for perchloroethylene, to have low consumption of F113, as it is an expensive solvent. Price

of it is four times more than that of perchloroethylene so low solvent usage is prime

importance.

Solvent F113 possesses good grease dissolving properties but not as effective as

perchloroethylene in solubilising certain oils. Its solvent power is similar to that of white

spirit. The low solvent power is somewhat beneficial to more sensitive fabric. Some soluble

dyestuff and pigments are fast to F113 than perchloroethylene. For e.g. pigment bonded to

the surface using adhesive dissolves or softens in perchloroethylene. It is cleaned

satisfactorily in F113.

Volatility of solvent F113 is very high. It evaporates readily in open vessel. Its odour

is not unpleasant as it is less strong than that of perchloroethylene. Evaporation of solvent

F113 is very easy during drying and very less temperature is required. So less risk of harm to

heat sensitive fabrics.

There is no standard system of recovery of solvent F113 after drying. A system based

on vacuum evaporation can be used for it. Carbon recovery may also be used.

It is a pure chemical with boiling point 47ºC, boiling point raises if it is contaminated

with detergent and fatty matter. It has specific gravity 1.58 at 20ºC and is miscible with

water. It is stable and does not tend to break in the machine. It is non-flammable.

The combination of all features ensures that it is useful for totally enclosed unit shop

machines.

Danes Study Case For Hydrocarbons 6

Results show that hydrocarbons can replace CFC113 for the treatment of ordinary

clothing and can be reduced to large extent perchloroethylene cleaning, it consumes 60% less

solvent. Cost of machine is four times that of CFC machine but lifetime is longer and

maintenance is low. The cost of machine is high due to safety devices and cooling facilities

for the machine.



Trichloro-FluroMethane: - (Solvent F11) 5

It is the most recent arrival in dry cleaning. It’s pure synthetic solvent, an organic

chemical (CCl3F). It is introduced in U.K. in 1969.

It possesses good grease dissolving properties. It’s solvent power lies between that of

perchloroethylene and F113. It is compatible with wide range of textile materials. It is not

safe towards sensitive materials as F113.

Its volatility is very high. It cannot be kept in open vessel. Its boiling point is 24ºC.

Specially designed machines are used for it. Solvent needs to be cooled; machine should have

refrigeration system for stock tanks all times.

It is distilled easily due to high volatility. This is value in cleaning suede, skins, furs

etc. Garments dried at such a low temperature do not suffer from creasing or linting and any

residual stains are not fixed; as may occur in hot machine.

Solvent F11 has a faint odour and leaks cannot be detected easily. It is having low

toxicity. Solvent F11 induce corrosion of some metals. Machines are constructed with such

metals so they are resistant to potential corrosion, usually stainless steel. They are relatively

expensive. The solvent is expensive but fairly economical; in use. It is nonflammable.

Solvent is used widely in Germany and U.K. Various other solvents are incorporated

in dry cleaning in addition to the solvents mentioned above solvent such as petroleum

solvents, liquid carbon dioxide etc. are used.

Petroleum based Solvents 7

These solvents are flammable and if sufficient vapors of fuels are present it burn

readily with just a small ignition.

These solvents have higher flash points and safer machines are now in market. Its

flash point is 55ºC and they are thermally stable at operating conditions. Several

improvements for safety can be done. Inert gases such as nitrogen are used to displace

oxygen. Operation under vacuum to remove oxygen.

But these are used less due to fire hazards, they provide better condition for bacteria

growth, it requires higher drying time, less effective in removing oil, grease as compared to

Perchloroethylene.

Liquid Carbon dioxide 8

It is recently develop and commercially available since 1998. During the process

clothes are immersed in liquid CO2, under pressure. In a vessel load is agitated inside the



basket by high velocity jet fluid, to remove soil. Once cleaning is finished, load is

decomposed, CO2 is vaporized and dry garments are removed.

CO2 has lower viscosity, better cleaning as it removes small particles. It is non-polar

and effective to remove soil such as oil or grease. It is eco-friendly, shorter cycle time, more

effective in cleaning suede, leather and fur.

Disadvantage of it is redeposition of stain removed, protein stains not removed easily

such as grass, lipstick or chocolate. Machines are expensive than perchloroethylene

machines.

A research is going on so as to replace toxic perchloroethylene. Four commercial

solvents dibasic esters, isooctane, isopropyl acetate and limonene were found to perform

better than perchloroethylene in some but not all respect. Limonone was very effective to

remove engine oil and isopropyl acetate to remove sebum soil. 9

Solvent Additives: -

In addition to solvents certain other chemicals are used during dry cleaning. This

chemical assists the dry cleaning process and helps the dry cleaning solvent for the cleaning

purpose. To avoid the static charge, to avoid the redeposition of dirt and to avoid the bacteria

formation in garment these chemicals are added.

Dry cleaning compositions with antistatic benefits 41

Dry cleaning compositions are formulated with antistatic agents. The compositions contain

water, butoxy propoxy propanol , optionally 2,3-octanediol and surfactants and also antistatic

agents. Such as sulphonated polystyrene or sulphonated polystyrene/maleic anhydride

polymers to provide antistatic benefits to garments. The compositions is placed on a carrier

and tumbled in hot air dryer with garments.

Dry cleaning with Enzymes 42

Dry cleaning compositions comprising lipase, protease and amylase are applied to soiled

fabrics in the presence of an organic solvents e.g. buyoxy propoxy propanol to clean the

fabrics. A preferred mode features an enzyme containing dry cleaning compositions, which is

releasable contained in a sheet substrate. This sheet is tumbled with fabrics/garments in a

conventional domestic tumbler dryer to clean them.



Soaps and Detergents 1

For many years in 1800s, solvent was used without any additives. When turpentine,

benzene or gasoline fail to do the job separate spotting work and wet cleaning methods were

developed.

First use of additive in solvent although it was a soap not to improve detergency but to

control the build up of electrostatic potential in the mechanically processed load, the

discharges which can cause great hazard in presence of highly flammable solvents. Neutral

magnesia soap prevents electric excitation of the solvent, which proves very good for

cleaning purpose.

Super fatted soap becomes popular for improving the cleaning performance of

solvent. It served to suspend loosened soil and to emulsify very small amounts of water that

could be added for better soil removal. At the end soap and soil is removed by filter and for

each batch fresh amount of soap is added.

The aim of using soap is to control static build up in the load through increased

conductance of the solvent solution, good suspension of loosened soil and increased

detergency for water-soluble dirt.

Synthetic detergents are everywhere used and universally accepted. They are used to

remove oils from the fabric. The detergents are mostly oil-soluble type detergents.

Precautions taken before Dry cleaning 10

Great technological advancement is made in improvement of natural fiber as well as

creation of synthetic. They are blended to have the best properties of both. Certain special

finishes are applied onto fabric, like water repellency, permanent press quality etc. All things

have to be considered before dry cleaning.

• Many beautiful fibers lack durability and should be purchased with understanding.

e.g. cashmere, camel’s hair etc. angora is lustrous fiber but can shrink extremely

although most careful cleaning is done.

• Lightly woven wool, loosely knit sweaters get distorted in wear and cleaning.

• Leather and suede needs special process to preserve their finish, feel and color.

They might become stiff in cleaning so taken for cleaning at owner’s risk.

• Suede or flocked finished material develops bare spots in wear and cleaning.

• Tailored garments contain interfacings in the color are fused rather than stitched,

blisters and wrinkles might be developed after cleaning.



• Some bonded fabrics may separate or there may be shrinkage, puckering,

stiffening etc.

• Acrylic knits are inclined to stretch when wet or exposed to steam during

finishing.• Some dyes, pigments, prints may fade in dry cleaning.

• It is also important to see how buttons, beads, sequins and other decorations hold

up to dry cleaning. Buttons and beads made of polystyrene may soften during dry

cleaning.

• Belts or items like cardboard stiffeners or glue require special attention.

• The fabric stained should not be ironed before cleaning because some of the stains

get fixed due to heat setting treatment.Dry Cleaning Operations 14

Marking : -

The garment is first sent to the “Marking Department”. A stamp is put on it, with a tag

and a code is kept on it for further identification.

Sorting : -

It is done in “Sorting Department”. Clothes are classified to have a single type of load

in one hamper. In a single hamper load up to 45Kg is kept in one batch. The load is classified

on the basis as given further: -

• White and light colored clothes.

• Dark colored clothes.

• White and light colored woolens.

• Dark colored woolens.

• Draperies and furniture covers.

• Raincoats and furniture cover.

Remove all the buttons and check all the pockets.

Stain Removal Or Spot cleaning : -

If smaller stains are found and if those can be cleaned easily with by just applying

stain removers the requirement of dry cleaning is less or mild cleaning process also will be

sufficient for complete cleaning. 11



Stain removal is an art. Initially cloth is examined whether overall soiling, localized

soiling or combination of the two is present. Soil properties are checked whether it is solvent

soluble, water soluble or insoluble soil like carbon or dust particles.

Spot and stain removal- Basic requirements 12

• Appropriate concentrations of stain remover.

• Stain removers reacts slowly with stain and so work carefully and have patience.

• Ageing and heat can set stain permanently so avoid it.

• Use correct method.

• Chemicals should be used cautiously to avoid fabric damage.

• Proper knowledge of fibers, its properties and the characteristic of the stain

removal should be known.

Various methods for removing stains are used for e.g. Dip method, Steam method,

Drop method and Sponge method. Based on these methods different types of fabrics and the

stain different spot cleaning methods are discussed. 13

Group I – Hydrophobic Stains:

Staining materials containing fats, oils, waxes and other oily types stains make up the

34 members of this group; typical examples are crayon, grease, hand lotion, lubricating oils,margarine or liquid floor waxes. Removal starts with dry cleaning solvent since many of

these materials contains compounds, which can be easily dissolved in non-polar solvents. The

stains usually require only local treatment, so that only a little solvent is used (20). If stain

removal is incomplete after the solvent treatment, a dry spotter is used. Gentle rubbing

usually loosens insoluble pigments, which may be present.

The application of coconut oil or mineral oil, referred to as “Lubrication” in the dry

cleaner’s vernacular, prevents wear and chafing of the fabric area if the stain is mechanically

worked on with a spatula or brush. If the stain is still visible thereafter, a wet spotter is used.

Addition of a small amount of ammonia may be helpful by increasing fiber swelling of

hydrophilic textile polymers, and thus help remove pigment soil. Colored residues may

require mild chlorine bleach. In these experiments, chlorine bleach, diluted 1:3, was applied

to the stain with a dropper and allowed to remain for no more than 2 min. thereafter the

remaining bleach was flushed out with water and white vinegar to prevent damage to the

fabric.



Group II – Food Stains Containing Oils And Fats:

This group contains 14 stains, such as salad dressing, gravy, chocolate, catsup and

mayonnaise. Since oil is often in the bonding agents in the solid pigments in soil and the fiber

surface, dry cleaning solvents are tried first. If removal is not satisfactory, wet cleaners are

used. Since many of these stains are “built-up” types and have high solid contents, a few

drops of concentrated liquid dishwashing or light duty detergent give better results than wet

spotting agent described for Group I. However, these more concentrated reagents require

thorough rinsing, which is tedious if the fabric is nonwashable. Some stains may still need an

additional treatment with an enzyme product. If the fabric is washable, soaking in a warm

solution of an enzyme product ( 1 tablespoon / 1 qt water) for 30 min is sufficient.

Nonwashable fabrics are best treated locally with a more concentrated solution (½ teaspoon

per ½ cup of water) for about 30 min.

While the use of enzymes has a long history in dry-cleaning spotting departments,

consumers learned about their use as a detergent additive only recently. Enzymes convert

albumin, starch and sugar into simpler more soluble compounds, which can be removed

readily from fabrics. They are safe on all fabrics and dyes that are not affected by water (3).

The properties of specific enzymes used for stain removal are summarized by Moss (4).

Enzymes in laundry products are as safe and as mild for consumer use as comparable no

enzyme products (20).

Group III – Proteins And Starches:

Of the 12 stains in this group, blood, egg white, fish slime mucus and starch are

typical. The first step is treatment with warm water and detergent. If unsatisfactory, an

enzyme detergent treatment, as discussed for Group II, follows. In some cases bloodstains

require peroxide bleach. Hydrogen peroxide (3%) is applied to wet stain along with a small

amount of ammonia. Oxygen bleach is used for this group of stains, since chlorine bleach

may leads to yellow stains if residual protein remains on the fabric.

Group IV – Plastics And Resins:

Of the 16 stains in this group, examples are household cement, plastic glue and

varnish. The constituents of these stains are insoluble in water but may be soluble in an

organic solvent, so dry cleaning solvents and dry spotter are tried first. Some of the stains i.e.



paint and cement are soluble in amyl acetate this solvent does not swell or dissolve some

dyes. Fabrics should be tested for colorfastness before amyl acetate is applied.

Plastic stains require repeated treatments. Resins, which are cross-linked polymers,

only swell in solvents. However, in the swollen state, they can often be removed satisfactorily

from textile substrates. We have not found any adverse effect on durable press resin finishes

when using these stain removal processes and chemicals. Colored traces may be removed by

bleaching.

Group V – Tannin, Glucose (With Or Without Natural Dyes):

Most of the 27 stains in this group are fruit stains like grape, strawberry and cherry;

but beets, wine and coffee are included. These stains contain tannin, a light tan to dark brown

glucose derivative that has limited solubility in water but is particularly soluble in alcohol; an

alcohol treatment is included in this method. Tannin contains on protein fibers are difficult

and some times impossible to remove. Reducing sugar stains are also in this group and some

of the most common are glucose, fructose and maltose around in beverages. These stains are

usually invisible when fresh but turn brown when heated and caramelized. Specific

information on caramelized sugar stains has been reported (3).

Caramelized stains cannot be completely removed from protein fibers, but an enzyme

treatment followed by chlorine bleach may give acceptable removal.

Group VI – Water-Soluble Body Waste, Deodorants:

Of the 14 stains in this group, perspiration, urine and body deodorants are typical. Since the

pH of body discharges depend on the age of the stain, treatments with aqueous alkaline or

acid detergent solution should be tried. Mercurochrome, merthiolate and picric acid are in

this group. Sponging and flushing with alcohol is often effective, but the treatment may have

to be repeated several times. These dyes have an affinity to protein fibers. Traces on other

fiber substrates may be removed with chlorine bleach.

Group VII – Inks, Dyes And Pigments:

This group mainly consists of dyes and inks; inks are classified as dry or wet. Dry

inks usually consist of pigments, oil soluble dyes, solvents and a binder; examples are

printing ink, ballpoint pen ink, typewriter ink and carbon paper ink. Wet ink consists of

water, iron tannate and gallic acid, dyes, pigment and gum arabic. It is difficult to find fully

satisfactory and simple removal method for inks, since consumer cannot differentiate or

recognize the type of ink present. Therefore, a simplified sequence of treatments with



detergents and solvents was developed and used in this study. If the first steps are

unsuccessful, chlorine bleach can be applied.

Group VIII – Asphalt, Oxidizing Oils And Gums:

The stains tested in this group are highly viscous and hydrophobic. In the first step,

excess material is removed carefully with dull side of knife. Then dry cleaning solvent and

dry spotter are used. This treatment is repeated until the stain disappears or no more can be

removed. The removal of these stains is governed by the solubility properties of the staining

material and complete removal is not possible.

Group IX – Medicinal Stains:

Argyrol, iodine, penicillin, photo developer and silver nitrate make up this group.

Argyrol, an organic salt of silver albuminate (3), is dark brown. Enzyme pretreatment is most

effective in removing the protein part of this stain. After enzyme treatment, the remaining

part of the Argyrol stain is treated as the other stains in this group. Tincture of iodine converts

metallic silver-to-silver iodide, and this changed into a soluble complex iron by sodium

thiosulfate and ammonia, which converts it, and excess iodine on other stains, into soluble

sodium iodide, which is easily flushed from the fabric. The reason for the success of this

method in removal of penicillin stains, which contain no silver, is not known.

Cleaning: -

During cleaning operation the load is kept in the basket and then the solvent is

circulated. The solvent flow rate is decided from size of load, type of load and the stains.

Delicate clothes are kept in a net bag and then cleaning is carried out. The load is treated

from 5 to 45 minutes and during that mechanical agitation, immersion and agitation of load in

solvent is done. The soil is loosened, some of the stains are dissolved and then the solvent

containing dirt is removed.

Extraction: -

Remove excess solvents from the fabric. In now a day, in machines cleaning and

extraction is carried out in same cylinder. In older machines, which were petroleum based

there a separate extractor was used. Extraction helps to recover solvent, to remove solvent

containing soil and stains and also helps in drying. If greater amount of solvent is present in

the load then drying time will be more.



Drying: -

The material after cleaning process is to be dried to remove solvent completely.

Drying operations and mechanizations depends on solvent used. If more volatile liquids are

used then drying time required will be lesser and if it is less volatile then the time required for

drying will increase. If solvent is flammable and material is heat sensitive, drying is done

gradually. For drying load is kept in perforated drum and hot air is passed and sucked out

repeatedly to dry the goods. The temperature of air is around 70ºC.

Filtering and Distillation: -

Solvents used for dry cleaning are very much expensive, some are very much volatile,

so the losses are more. To make process economical the recovery of solvent is more

important feature of dry cleaning. So the solvents are distilled and reused. Some solvents are

toxic and flammable so to reduce the other hazards and health hazards the vapors of such

solvents are condensed and again solvent is obtained.

Filtration is done continuously during dry cleaning is to remove soil, lint and other

materials picked up from load. Filter is the heart of the circulating system which supply

continuously conditioned solvent. When new load is processed, additional filter powder is

added and carried off in the solvent to the filter screens. Filter is washed to remove cake of

accumulated powder and dirt and backwashed and cleaned. Secondary filters avoid the

redepositon of dirt.

Inspection: -

Check all the garments one by one for the perfect cleaning. The spotter does

inspection. The spotter should have good knowledge of fibers, fabrics and their properties.

Spotter needs to have extra knowledge of fabric construction, knowledge of different solvents

and their effect on the fabric. If some of the stain remains spotter must have the skill to

remove it neatly and completely so as to satisfy customer.

Finishing: -

The fabrics before delivery is finished to restore its original shape, size, feel,

appearance etc. Extent of finishing depends on fabric type, dyes used on fabric and the

severity of the solvent in which fabric is dry-cleaned.

Clean garment is pressed and if some of the finishes are disturbed then, if possible

again those treatments are given. For e.g. water proofing, mothproofing, softener etc.



Packing: -

Before packing all the garments are separated from codes attached initially. All

buttons are stitched back again. Package is ready for delivery.

Dry cleaning Process: -

Dry cleaning solvents, various steps, what care should be taken we have seen it all the

things but what is exactly happening in dry cleaning is illustrated in this section. As we

described earlier load is sort out and various dry cleaning processes are carried out depending

on the type of good.

Dry- Cleaning Of Garments Using Gas-Jet Agitation 15

Substantial amount of particulate soil sin garments can be removed by agitation in gas

jet in a solvent-free, low-pressure environment. The ability of the present gas-jet agitation

system to remove particulate soils from garments and fabrics rivals H at of Conventional dry

cleaning process, which agitates the garments and fabrics while immersed in solvent. Thus

the dry cleaning operation may consist of solvent immersion step for removing soluble soils

and gas-jet agitation to remove particulates. Considerable savings in equipment and operating

cost may be realized in the practice of the invention; since solvent flow rates need to be

boosted to provide necessary agitation for particulate soil removed. The savings achievable

by using gas-jet agitation system are more pronounced in dense phase gas dry cleaning

system, which requires pressurized environments to maintain a liquefied solvent. It has no

moving parts and is relatively less expensive fabricate and maintain. Common inexpensive

gases can be used like CO2, nitrogen or air. So the process will be eco-friendly.

Emulsion Process For Cleaning Of Textile 16

Utilization of non-aqueous solvents in soil removal is important development in

textile in the emulsion process “Perchloroethylene” is used. It is advantageous as it dissolves

waxes, fats and various polymers. Less heat is required to dry the fabric, which is cleaned

using perchloroethylene than that cleaned with water. Perchloroethylene wetted the fabric

easily, less swelling of fiber and hence mechanical deformation is less severe. The

chlorinated solvents are expensive and cause pollution problem, so their recovery should be

higher.

In this process household white fabric with durable press finish is cleaned using an

emulsion of water-perchloroethylene. The emulsion process also serves the purpose of

reducing phosphate pollution of water and removal of soil from durable press finish fabric.



The process eliminates need of phosphate in cleansing and so help to eliminate one of the

greatest sources of water pollution.

Removal of oily soil by aqueous cleaning is tough and not satisfactory hence the

emulsion process is used. In the cleaning process various paths are considered depending on

fabric type.

• Agitation for 12 minutes and heating up to 86 F.

• Agitation for 6 minutes and heating up to 100-150 F.

In the emulsion, soap is also added, it is neutral soap with sodium metasilicate as a

builder. Synthetic detergent is used which contain very less amount of phosphate.

Emulsion 86 F: -

It contains perchloroethylene, detergent, hydrogen peroxide, sodium metasilicate and

then pH is maintained to 9.8. emulsion is well shaken and it should not separate for almost 24

hours.

Emulsion 130 F: -

This is also same as emulsion 86 F; the difference is that temperature in this method is

130 F.

Perchloroethylene is the main solvent. Its recovery is done by distillation. Water-

Perchloroethylene azeotrope is distilled to separate perchloroethylene. The care should be

taken during distillation that, if peroxide is there in perchloroethylene then distillation of the

azeotrope is difficult and hazardous.

General principle of cleaning is the same that immersed the load in solvent, agitate it

with high speed, fluid jets or mechanical action is taken to remove soil.

Removal of Moisture from Solvent 17

This is a method in which organic solvent is combined with water, so as a result of

distillation water is removed quickly. A porous membrane is used which acts to coalesce the

moisture, so the liquids passage through to it is easy.

Solvent Circuit 18

This process is used for solvents having low boiling point. Particularly for

monofluoro trichloromethane (CFCl3), which boils at 23ºC. Load is immersed in solvent, then

the load is agitated mechanically, when impurities are removed liquid is drained off and then

purification of liquid is done for reuse.



Reduction of Solvent Losses 19

The process makes use of volatile solvents for removal of soil and grease. Textiles

loaded in a rotatable drum, drum is kept in rotation, and then air is evacuated. In this method

Fluorinated-Chlorinated hydrocarbon is used to react with soil.

Dry cleaning and Disinfectant Process 20

This is method for disinfections of textile during dry cleaning, in particular the

process applied for dry cleaning of textile from the medical field, mostly the hospital textiles

and also applicable to normal professional dry cleaning.

Biological contaminants, pathogenic germs, as for instance, bacteria, spore etc. that

cause the problem. Germ free textiles might get contaminated due to these germs in next

cycle. Cross-infection by microorganisms of uninfected articles is avoided. In the process

solvent is heated up to that temperature where it kills germs. The heating is optimum, it is

such that heat should not be too much so that it will damage the goods and it should not be

lesser so the germs will remain alive in the fabric. To avoid the damaging of goods due to

heat, the solvent is cooled immediately.

H2O2 Treatment for Cleaning 21

Peroxide treatment used in dirty dry cleaning bath based on aliphatic hydrocarbon or

chlorinated solvent, to prevent longer distillation operation.

Dirty dry cleaning baths previously considered unfit for use without distillation is

heated with H2O2. Dual action takes place here, bleaching, which reduces light nuclei for

agglomeration, so particles in large size are filtered out.

Fluidized Bed Fabric Cleaning 22

Utilizes a fluidized bed or carrier comprised of very finely divided solid particulates,

which are apparently dry and free flowing. Carrier made up of particulates, maintain fluidized

state. 50% of particulate mass is adsorbed on to the surfaces of finely divided solid particles.

Liquid for cleaning consists of aqueous emulsion of odorless kerosene or cleaners naphtha.

Non-Solvent Process 23

A soiled article and suitable quantity of substantially dry cleaning agents includes

carrier and a suitable quantity of cleanser. Soiled article and cleaning agent are agitated

together for sufficient time, to permit removal of substantial amount of soil from the article.

When cleaning is complex the cleaning agent is separated from the article.

Three-Step Process 24

A three-step method is described for dry cleaning fabrics are as follows: -



• Contacting fabric with a bath consisting of dry cleaning solvent and a detergent

about 1 to 20 minutes, then removing the liquid from wheel by draining or

extraction.

•

Contacting fabric with a bath consisting of a dry cleaning solvent and a detergentabout 1 to 20 minutes, then removing liquid by draining or extraction.

• Contacting fabric with a bath consisting of a dry cleaning solvent and a detergent

about 1 to 20 minutes, then removing liquid by draining or extraction.

Reduction of Non-volatiles in Solvent Recycle 25

In this method, dry cleaning fabrics, where vaporized solvent from the cleaning

operation is extracted, condensed and stored for use as solvent rinse before final extraction

and fabric drying part of the cleaning cycle. Distilled solvent acts as a rinse for the fabric,

being cleaned thus diluting the amount of non-volatile material, which remained in the fabric

after first extraction.

Metal Passivators 26

The method is concerned for decreasing the amounts of metallic ion impurities in to

solvent system generally employed in dry cleaning process. Polyvalent metal ions have

detrimental effect on effectiveness and efficiency of dry cleaning operations. The results are

obtained by taking reflectance reading of cloth sample. Reduction of polyvalent materials

improves the brightness. Samples cleaned with it give high reflectance reading.

Towards Environmental Dry Cleaning 27

As the dry cleaning is becoming more and more commercial, the hazards and

pollution causing through these industry is continuously observed. The environmental

reasons cause diversification in solvent, so new organic solvents are about to introduce this

does not mean that other solvents like ‘Perchloroethylene’ are banned. But in future

perchloroethylene can be used if its loss in to air and ground water is reduced. Residuals of

perchloroethylene in fabric are also important it is removed by hanging the garment in air and

as it is volatile it gets removed quickly. Solvents with higher flash points are used to avoid

hazard due to fire. Reduce the solvent loss. Liquid and supercritical CO2 is eco-friendly. Rate

of removal of dirt, due to liquid CO2 is good but unpolar dirt is not removed sufficiently.

Surfactants are added to dissolve polar substance. For environmental cleaning, water is main

solvent instead of organic solvents.



Mechanization: -

As we have seen earlier initial dry cleaning steps includes marking, sorting and pre-

spotting in these three steps no need of any significant machine as such, the processes are

more or less manual operations. But the further steps like cleaning, extraction, drying,

filtering and distillation required specially designed machines. Finishing also requires some

machines but those are not very much complicated.

Dry cleaning machines have evolved over a period of time to better protect worker

safety, health and the environment. As the solvents used in it are very much expensive, the

loss of solvent is undesirable. Most of the solvents are volatile and their exposure to

atmosphere can cause economic loss and so various closed machines are developed for better

recovery of solvent, to make the process economical. Dry cleaning machines encompass five

generations currently used in industries. 28

1 st Generation: - (transfer machines)

These are older and less expensive machines. Require manual transfer of solvent

laden clothing between separate washer and dryer. These machines were in use until the late

1960s.

2nd Generation: - dry-to-dry (vented)

These machines are nonrefrigerated, dry-to-dry machines, using one-step process to

eliminate clothing transfer. Clothes enter and exit the machine dry. Machines vent residual

solvents vapors directly to the atmosphere.

3rd Generation: - dry-to-dry (nonvented)

These machines were introduced with refrigerated condensers in late 1970s and early

1980s. These are essentially closed system, open to atmosphere only at that time, when the

door of machine is open. Recirculate the heated air through a vapor recovery system and back

to drying drum. Machines provide considerable solvent savings and reductions in

perchloroethylene emissions.

4th Generations: - dry-to-dry (nonvented with secondary vapor control)

These are more or less like 3rd generation machines; it relies on both refrigerated

condenser and carbon absorber to reduce the perchloroethylene emissions. These are effective

at recovering solvent vapors.

5th Generations: - dry-to-dry (nonvented with secondary vapor control and drum monitor)

Machines are similar to 4th generation machines; these are used widely in Germany.

They also have monitor inside the machine drum and an interlocking system to avoid losses.



Machine Design: -

Any dry cleaning machine consists of a rotating, perforated basket (or cage), which

holds the fabric to be cleaned. The cage is connected by a number of pipes to a series of

tanks, which service solvent for the machine.

The way in which solvent used and recovered modifies the machine design. Solvent

utilization will decide the extent of cleaning so it is important to know each part. 4

Design of Cage: -

Mechanical action is the important part of cleaning process; it is rarely sufficient to

immerse the garment in the solvent. It is manipulated to produce following effects: -

Squeezing : -

Immersion in solvent dissolves or loosens some soil. Squeezing action expels liquid

from the fabric and liquid carries some soil.

Agitation: -

Squeezing is seldom sufficient, since when the pressure is released the dirty liquid

tend to be drawn back to the fabric. If agitation is provided, dirty liquid mixes with and is

displaced by cleaner liquid so less chance of dirt redeposition.

Rubbing : -

In hand washing, if article is heavily soiled it may be scrubbed or one part may be

rubbed against another part.

It is an advantage that modifying mechanical process, the cleaning efficiency will

improve. In some case small rotating propellers are fixed in the side tub, which produces

swirling and turbulence of water and movement of the garment. A series of beaters attached

to central shaft, which rotates anticlockwise or clockwise. Garments are placed in perforated

cage, which rotates inside casing. The principle is same.

Types of Machines 5

There are two types of machines one is Side Loading Machines and the recent ones

are End Loading Machines.

Side Loading Machines: -

It consists of metal container which consists of metal cage in which garments are

placed. The cage is long cylinder and placed with cylindrical axis horizontally. Curved wall

of cylinder is perforated but the ends of cylinder are solid.

At the inner circumference of cylinder, 3 to 4 lifters are situated. These lifters project

several inches in to the cage. Cage is fitted in to casing which is slightly greater in size and



diameter; so small amount of clearance between them. Inner cylinder is the cleaning cage,

mounted on shafts, which pass through bearings.

Mechanism of Cleaning Process: -

During cleaning, the inner cage loaded with fabrics is rotated at low speed and solvent

is pumped in to the cage. If solvent is immediately drained then fresh solvent is added

quickly, it is known as “dip-less” washing or continuous rinsing.

If solvent is pumped to build up a depth of liquor in casing and the fabric is agitated in

it i.e. in “trough” of solvent, it is standing dip operation. High dip means large volume of

solvent, while dip less operations consists of addition of fresh solvent.

Lifters play an important role, it help solvent to move relative to the fabrics. They also

come in contact of cloth at the bottom of cage and lift them up and again put them back in

solvent. It also provides a squeezing action. In high dip, less squeezing as compared to dip-

less operation.

Agitation of liquid and rubbing action is induced by drawing out material, rotation of

the cage, sliding under or over other articles.

Extent of mechanical action depends on size of cage, size of load, speed of rotation,

size and shape of lifters as well. Overloading can cause poor cleaning, redeposition of dirt or

graying of fabric. If machine is under loaded then soil-removing efficiency will be low so the

rubbing action is low if the volume of fabrics in cage is low. Increase in load can cause

redeposition of dirt. Most machines are operated at load 2.5 to 3.5 lb/cubic feet. The way in

which article is lift and fall is also important. Rotation speed also plays important role. Speed

is low, cleaning efficiency less, too high speed then the fabric dropping in solvent will be

less, so the cleaning will get reduced. It allows the cage to be turned round on its horizontal

axis and it is power driven.

Curved wall of outer casing is fitted with a door, which is hinged and lifts smaller

door in the cage, so the material can be loaded in to the cage easily.

Suitable gearing attached to shaft so it can be rotated slowly or quickly or either the

motion can be in a clockwise or anticlockwise can be done.

Pipes are fitted to outer casing so solvent can flow in casing and when required

drained away from bottom. Pipes should be arranged such that, solvent cannot flow in to the

machine and then out through the drain without circulating over entire length.

End Loading Machine: -



The type of machine possesses many of the features of side loading machine. It

consists of a perforated cylinder placed with its cylindrical axis horizontal. In this short

section of cylinder is used, so the length is less than the diameter of the cylinder. One end of

it is closed completely. Other end has a lip, which partially closes, leaves a circular aperture.

So the garments can be introduced without having any door to cage. Cage is lifted in slightly

larger cylinder forming the casing. A shaft holds inner cylinder. In front of casing a door,

which coincides with opening in the cage, allows the fabric to be put in and taken out of

machine. Pipes are introduced, to introduce and drain away the solvent.

It has only one shaft, careful fabrication is done to withstand with strain. Same cage

can be used for extraction and drying as well. Machine is used exclusively for

perchloroethylene and fluorinated solvent. Drying is done in separate machine, so squeezing

action will be poor.

Some cages are rotated in one direction only and it can lead to formation of rope of

article. Problem is avoided by rotating drum in clockwise and then anticlockwise direction.

Solvent circulation is also important to remove dirt; it plays important role in dip-less

technique as the solvent is continuously changed.

Further we listed some special features of the machines used in commercial dry

cleaning purpose.

Removal of moisture from solvent 17

The basic principle of cleaning is same but the machine provides a special membrane

having 10 to 110 pores per linear inch, which collects moisture, helps in cleaning.

Solvent circuit 18

It is used for those solvents, which have very low boiling point. The special feature of

this machine is separating chamber, which split mixture of air and solvent vapor by the mere

action of gravity. As it is used for chemicals having low boiling point hence a mechanical

refrigeration unit is provided.

Reduction of solvent losses 19

It is always beneficial to reduce the solvent losses for an economical process. Special

features of the machines are device for partial evacuation so squeezing will be more effective

to remove soil. Volatile solvents vapors are directed toward a condenser for later reuse.

Dry cleaning and Disinfectant Process 20

As method name suggests, the textile garment is heated to kill germs. The special

feature of the machine is thermal sensors. As overheating can cause fabric damage and lesser



heating will not be able to clean the garments completely and will be unable to make them

germ free. Thermal sensors help in this operation. They remove overheated solvent to avoid

fabric damage. This process needs additional germ killing chemicals to make solvent pure

and clean for later reuse.

Dry cleaning Machine with Absorber 39

As the name suggests an absorber is provided in the machine for the recovery of

solvent. Such a machines are used for low boiling points solvents. Absorber efficiency

reduces if solvent of high concentration is in use. Disadvantage of the machine is it also,

adsorbs air with solvent. Air contains some moisture so the moisture content is increased in

the system, which causes creasing.

Dry cleaning and Fluid Decontamination Apparatus 40

The machine is installed so that the solvent containing dirt and soil from first article

should be easily and readily available for the next batch of articles. Here cleaning of fluid

take place after passing through each batch and recirculation of it goes on. Disadvantage of

machine is limited life at cleaners, which is reduced continuously by blocking due to the soil

and dirt. To clean the cleaners every time made the operation cost slightly higher. So a

special designed apparatus used which increases service life of cleaners, periodically

removing solids from cleaners. Sometimes backwash also helps.

Non Solvent Process 23

It consists of an air-impermeable chamber for carrying articles; it has a perforated drum

open at one end and rotatable at horizontal axis. It has an evacuating device to remove air

from articles to make cleaning efficient. Air impermeable chamber substantially evaporates

loss of impregnated cleanser and maintain effective cleaning.

Suprema- Dry to Dry – Perc Machine – ITALY 31

It is latest machine, computer controlled operations. It has advantageous features like high

solvent recovery up to 99.5%, which reduces workable cost. In this continuous or batch wise

cleaning can be done. It consists of all apparatus required for cleaning, filtering, distillation,

condensing and separation of contaminants from solvent. It vibrates less when higher speed

extraction is done. It has ecological friendly dual lint filter.

Care of Solvent 29

Solvent used for cleaning get contaminated due to:

• Oily, greasy and fatty substance dissolved in it,



• Insoluble solid dust particle dispersed in it.

Filter is used to remove dust and dispersed impurities but soluble soils cannot be removed.

Distillation is carried out for it or a specially designed filter cartridge is used.

Filtration

29

In this contaminated solvent passed through a filter candle or screen, it permits

solvent passage but holds dirt particle. In some filters porous surface is finely woven fabric or

a metal mesh is also can be used.

Deposition of dirt on filter reduces passage of solvent so filter powders are added,

which are irregular in shape and having large surface area. They deposit on filter bed made it

porous so solvent passage is easier. They avoid blocking of filter due to dirt.

Filter powders used in cleaning are minute particles, composed of fossilized remains

of tiny aquatic plants known as diatoms or it is referred as diatomaceous earths. Sometimes

powder added initially i.e. precoating to avoid blocking of filter due to dirt. Subsequent

addition of powder with each load is done, so the powder mixes and dilutes the dirt carried by

solvent.

A filter known as scrambler filter where a filter medium consists of flexible mesh

tube, precoated. Solvent circulation continues with each new load. 15 loads can be treated

with each load. Filter powder improves efficiency of filtering and prolonging the period for

which filter can be used. Sometimes flow of solvent is reversed to push the cake away from

filter. It is known as back washing. Filtration is simpler and quicker way to remove solid dirt

from contaminated solvents, so clear solvents are ready for reuse. Filters do not remove

soluble material but some of the cartridge filter made with activated earth can absorb non-

volatile soluble soil. They are used to reduce the necessity of distillation. Cartridge filters are

disposable after use.

Distillation 29

Distillation plays important role for recovery of solvent. It is done in a separate

apparatus and it is not at all a part of fabric cleaning.

Distillation is effective to remove solvent soluble and insoluble material from solvent.

Distillation is expensive as compared to filtration. Especially solvents with higher boiling

point require extensive heat. Certain amount of distillation is required to keep solvent in good

condition. By this process solvent recovery is done which helps to make the process

economical.



High-Speed Extraction (Hydro extraction) 29

It is the removal of solvent from dry cleaned fabric by “spin drying”. After washing

and cleaning solvent is drained but the fabric still consists an appreciable amount of solvent.

If such articles are removed and hang in air, solvent will fall down under the force of gravity.

Centrifugation of such article can remove appreciable amount of solvent, same thing is done

in the cage; in which articles are rotated at high speed. As the inner drum is perforated,

solvent will move in outer case and drained for reuse. Gravity is the important factor in it. A

‘g’ factor is very important which is decided by diameter of cage and the speed of rotation.

More is the diameter more will be the extraction. Same thing for the rotational speed.

Another important factors deciding extraction are extent of perforation, and time of

extraction. As the time progresses, the amount of liquid removed will reduce. During

extraction fabrics are pressurized. Some fabrics crease easily and so extract them with care.

Excessive creasing can cause removal of finishing treatments. For this operation a domestic

spin dryer is used.

Drying 29

Even after high-speed extraction some of the solvents remain in garments in considerable

amount. It is known as ‘hydro retention’.

Solvent remained in cloth depends on its specific gravity, so the amount of white spirit is

around 20% and that of perchloroethylene is just hanging the garments in air for drying is not

feasible on the grounds of safety; space and economy.

A tumble dryer is used for it. Tumbler is separate or an integral part of cleaning

machine .Hot air is passed through a revolving cage where fabrics are tumbling. Air

evaporates solvent and leaves the cage through an exit duct.

When expensive and volatile solvents like perchloroethylene or F113 is used, hot vapors

of it cooled and condensed to have same solvent for reuse. Air is returned to heater battery

and the cycle is repeated.

For F113 hot air gives effective drying while in volatile F11 drying is done at lower

temperature and under vacuum.

In some of the perchloroethylene machines, heat extracted from hot solvent is

recirculated by the heat pump to reduce energy requirements. It cannot be applied to white

spirit due to danger of explosion. Additional recovery of perchloroethylene can be done using

a bed of activated carbon and recovered by subsequent streaming of the bed.



Do not allow the fabric to become too hot, it can distort the fabric, it can residual stains

or can cause difficulties in finishing. Temperature should not allow exceeding 60ºC and

sometime it is 40ºC to avoid certain harmful effects.

Finishing 30

Retexturing And Shower Resistance

People say that dry cleaning takes the “”body” out of fabric, however it is not true.

Before delivery and after cleaning retexturing of fabric is important. In retexturing some

softeners, resins or dressings are put on to give garment a firm but soft handle. It also

enhances crease retention after finishing. Some time it is done to improve stain and water

resistance.

In the case of rainwear, garments are made shower resistant. In some cases garment is

made waterproof.

The machines and processes for finishing are very simple. For ironing pressing, grid

head press is used for woolen and a hot head press for silk is used.

(Water-proofing) Retexturing / Shower resistance can be done easily by Stock Tank

Method where articles are tumbled in the finishes and treated few minutes. In Direct Method

the finishes are directly injected in cage and then possible extraction and drying is done.

Sometimes finishes are applied with Spraying Method, atomized jets are used for that

purpose and then drying is done in normal fashion.

After cleaning: -

Customer is not always satisfied with the clothes come back from the cleaner, even if

all the suggestions are followed carefully observe the cloth and if same problem contact

drycleaner immediately. Some of the problems are curable. Wools and some synthetics show

pilling, the appearance of tiny balls on the fabric surface. 33

Dry cleaning is important because of significant economy in energy cost, less

mechanized deformation as the fiber swelling is less as compared to wet cleaning, so

obviously longer life of garment is expected and a good Durable press. When whiteness

retention and wear life of dry cleaned garments is checked then it showed soil content was

reduced and it kept on decreasing with subsequent cleaning. Due to soil redeposition, the dry

cleaned fabrics tend to become unattractive after 15 cycles. Durable press finish of fabric is

very good after dry cleaning. 34

Wool fabric can shrink during dry cleaning by mechanism of relaxation and felting.

Relaxation will cause if fabric is not properly sponged before making in to a garment. Due to



fibers, scaly surface felting shrinkage is the unique properly of wool. Due to scaly surface

friction occurs and it cause interlocking of the fibers. After dry cleaning opens fiber structure,

which increase air permeability. Dry cleaning did not weaken the wool fabric KES

PropertiesThe Kawabata Evaluation System (KES) is the most accurate measurement

concept. It shows some of the wool properties are altered. But one noticeable change is the

increase in thickness of fabric, which affects compression properties. Bending stiffness

properties showed a little change. 35

The dry cleaning gives good appearance to fabric, it gives back its luster. It removes

yellowness of fabric, removes bacteria, insects and make the fabric perfectly cleaned. The

weakened fibers are flushed away in cleaning and the garment becomes more porous in

nature. 34

Hazardous Effects of the solvents used in Dry Cleaning and Safety Measures 32

The process of dry cleaning starts almost 150 years ago and with the development in

machines, solvents and other things safety is also a very much important factor now days. A

certain rules and regulations are assigned to all these industries and they have to obey them.

Any violation of such rules can cause serious accidents, hazardous effect on human health or

it can cause pollution of environment.

The measure reason of pollution and hazardous effect is solvent. Various solvents

are used in the industry for cleaning purpose. The most commonly used solvent is

perchloroethylene. Other solvents like white spirit, trichloroethylenene are also used.

Petroleum solvents are safer if its health effects are concerned. But the main hazard

is many of the petroleum solvents are flammable and if some how such incidence takes place

the fire will consume all the materials present in the plant. It can cause dangerous fire; it will

be such a dangerous that it can cause life of people working over there.

The care taken in such a plant or unit where petroleum solvents are used, no source

of fire ignition is allowed, smoking is strictly prohibited in such units.

The plants, which use 1,1,1-trichloroethane for cleaning they were banned because

of its ozone depletion potential in the upper atmosphere.

In industries the contact with chlorinated solvent is avoided for safety purposes.

Mostly the chlorinated solvents are non-flammable, odorless and volatile.

Mostly used solvent is Perchloroehylene. It is volatile and odorless; so spreading of

such solvents in vapor form cannot be known easily. The prolonged contact with vapor of

such solvent could be fatal. The human beings comes in contact with perchloroehylene is due



to inhalation. Basic rule of safety measures said that the chemicals used should be odorless

but continuous effect of perchloroethylene can affect human health.

Short term effects: -

These effects are caused due to small exposure to perchloroethylene for short time.

Like anesthesia, headache, dizziness, sleepiness, fatigue, tremors, nausea, vomiting and

unconsciousness.

Long term effects: -

These effects are caused due to exposure to large doses for prolonged time inhalation

of high concentration can cause. Physical or mental shock can cause alteration of heart

rhythms or even heart failure.

Ingestion: -

Ingestion of chlorinated solvent cause severe burning and necrosis of mouth &

throat. To avoid all these things, avoid inhalation of such solvent, avoid contact with body. If

solvent is ingested then evacuation of contents from stomach is the only way. To avoid

contact personal contact use PVC gloves and clothing. Its contact with skin can make skin

hard, dry and even full cracks will be also developed. Solvents like benzene are carcinogenic

so it is banned.

The Preventive Measures to Avoid such hazards are: -

Material Substitution: -

Use another solvent other than chlorinated solvent. Use other safer solvent.

Isolation: -

Dry cleaning units should be located in stand-alone buildings to reduce risk of

contamination. Isolate the dry cleaning machines from other machines.

Machine Design: -

Machine loading and unloading can be a greater cause of exposure. In modern

machine carbon absorber is used to reduce exposures. Maintenance of machine should be

proper for better performance of it.

Ventilation: -

Proper ventilators should be provided to avoid exposure to PERC. Capturing and

removing contaminants should accomplish the control. Local ventilation, to avoid exposure

of

such chemicals to workers. General ventilation to add fresh air and to change air completely

after each 5 minutes.



Alternatives to Dry Cleaning Method: -

As we seen earlier the solvents used in dry cleaning like perchloroehylene are

having hazardous effects on human health. The pollution is also increasing due to some of the

solvents. Solvents like 1,1,1-trichloroethane cause depletion of Ozone layer. Petroleum

solvents are dangerous to use due to their flammability characters. To avoid the hazardous

health effect, to avoid pollution and to methods and solvents are invented.

These processes and solvents make dry cleaning more economical, safer and hand over the

advantage of better cleaning.

Aquatex- An aqeous Alternative to Solvents in Dry cleaning 36

This is a no-toxic aqueous cleaning system, which overcome the potential health

hazard of chlorinated solvent like perchloroethylene. The system uses water in

microprocessor-controlled washing and special detergents and finishing agents are developed.

The system range consists of four products viz; Aquatex detergent and finish for fiber

garments. Aquatex leather detergent, for leather finished product. Aquatex system not only

cleans the fiber but takes care of delicate fibers also. Finishing provides aesthetic appeal,

body and fullness of handle as expected by consumer.

It is formed from synergistic blend of four surfactants, which gives superior cleaning.

Surfactant blend penetrate fabric weave and removes soil. A complexing agent effectively

removes trace impurities. Protective auxillaries minimize any damage of the fabric. Aquatex

finish restores firmness and handle of garment. Aquatex leather finish consists of naturally

occurring vegetable oils and ester, which restore oil to leather and gives leather a supple and

neutral feel.

UV Laser Cleaning 37

Use of ultraviolet lasers is for surface cleaning and it is used widely as the potential

for generating clean surfaces without using environmentally hazardous solvent and the ability

to create improved material.

It is developed to remove even smaller particles from substrates to avoid hazardous

waste. Unwanted residues, small particulates are not developed in this method. It reduces

water consumption in large scale. Smallest fiber also can be cleaned with this method, no

modification in machines are required; just using high pulse rate and double the frequency,

the cleaning can be done. The method provides 100% cleaning efficiency for particulate

contaminants as small as 0.3μm. Efficiency laser cleaning occurs using multiple pulses and it



is best when solvent assisted. 100 % cleaning is achieved without laser induced surface

damage or micro roughening.

UV laser cleaning of glass substrate is significant discovery; UV laser irradiation

renders the glass surface resistant to the redhesion of particulate contaminants which

otherwise adheres strongly, if the glass fiber is cleanedwith isopropanol/ethanol/methanol

solvent using multiple wipe technique.

Aquq Clean System Or Wet Cleaning 38

Wet cleaning swells natural and hydrophilic fibers and they can wrinkle, shrink and

lose their shape and strength. But controlling the factors in wet cleaning can do the

satisfactory cleaning.

Pollution due to chlorinated solvents is the main problem with dry cleaning. aqua

clean system doesn’t cause such a problem. Use of formulated, biodegradable detergents

helps to avoid any kind of pollution. Increased extraction from fabric before drying will help

the fabric as the fiber swelling will be less and it will not lead to shrinkage of fabric. Closely

monitoring heat and moisture content during drying also helps to enhance the life of fabric.

Lower mechanical action during cleaning should be there. For e.g. squeezing and rubbing as

it can form crease on the fabric. Taking care of all the factors, Aqua Clean System is

developed. It used special biodegradable detergents. Sophisticated microprocessor is used to

precisely monitor time, temperature, water level and other critical factors. Its dryer is also

performing precise controlled drying. Precise control is the key of the wet cleaning.

Advantages of wet cleaning: -

• Fewer health and safety hazardous;

• Soil contamination and large emissions of air pollutants eliminated;

• More pleasant smell than solvent;

• Less cost of cleaning compared to ‘PERC’;

• Burden of strict health, safety and environmental regulations reduced.

This method also has some disadvantages, as it cannot replace perchloroethylene cleaning

completely. Shrinkage and change in shape of fibers like wool, silk and rayon. Large quantity

of water is consumed. Highly skilled worker, more will be the labor cost. It is more labor-

intensive method.



Conclusion: -

Dry cleaning is by definition, cleaning with solvents and little or no water. Dry

cleaning is advantageous as it cleans fabric with ease and no need to put extra effort to clean

the fabric. The efficiency of the process to clean the fabric is very good as compared to

goods, which are laundered, but at the same time dry cleaning is expensive than laundering.

The fabrics which are dry-cleaned are generally expensive and delicate; so great care

has to be taken to clean the fabric with this method. Dry cleaning is very good for the fabrics

made of wool, silk, rayon etc. As it removes dirt gently from them. The process does not give

harsh feel to the fabric and make it more air permeable. The life of fabric is in no danger if

dry cleaning is carried out but it rebuilds the ‘body’ of the fabric. Proper dry cleaning

improves fabric appearance and makes it lustrous. Dry cleaning do not harm the tensile

strength of the fabric.

There are certain alternatives to dry cleaning method using solvent, such as wet

cleaning or UV laser cleaning but these methods cannot replace the dry cleaning with solvent

as either these processes are not that much efficient as dry cleaning or sometimes the

processes are very much expensive.

Dry cleaning is under threat of ban due to toxic chemicals such as

‘perchloroethylene’. But the solution lies with careful operations and proper recycling of such

solvents to reduce their concentrations in the atmosphere.

Careful dry cleaning operation is very good as it does not harm the fabric, does not

swell them, does not change their dimensions and also does not harm the colors and certain

finishes. Specially designed machines helps to handle the delicate fabric and to avoid the

exposure of workers to toxic chemicals. Pollutants are reduced by better recovery of solvent.

So overall the ‘Dry Cleaning’ process is very good for the fabric and to increase its wear life.

References: -

1. Albert E. Johnson. Dry Cleaning , CIBA Review 1964/1.

2. www.otoons.de/group and www.msnbc.com

3. www.americleaners.com and www.dri-kleen.com.uk

4. Guide of Cleaners and Launderers. 1981.

5. Intermediate Dry Cleaning Technology.

6. Danes Study Of Hydrocarbons, Laundry and Cleaning News- 1994.



Volume no. -16 (15). Page No.- 119.

7. www.ieindustrialservices.com

8. innovativeenvironmental.homepageCHMS.

9. T. Rydeberg. Journal of Textile Institute 1994

85, No.- 3. Page No. 402- 405.

10. www.epa.gov/garment

www.bbb.com

11. A.Hebeshish, K. El-Zoghby and S.Haleem, American Dyestuff Reporter.

12. U.V.Arvindekar and D.V.Alat./UDCT , Textile Dyer and Printer.

September 3, 1980. Page No. 29-31.

13. Manfred Wentz, A.C.Lloyd and Andrew Watt IV. Textile Chemist and Colorist.

October- 1975. Page No. – 30- 34.

14. Noemia Disouza. Dry Cleaning Operations.

15. E.M Wilkerson and A.Y.Townsend, U.S.Patent- 5925192.

16. Seham Zaki Mousa, David B. Russel and Elizabeth Flowers Thomas.

December- 1973. Volume No. – 5 (12). Page No. 24 –28.

17. I. Victor. U.S.Patent- 3,395,086.

July 30, 1968.

18. M.R.Burger. U.S.Patent- 3,617,208.

November 2, 1971.

19. H.Fijhring, J.H.Sieber. U.S.Patent- 3,613,135.

October 19, 1971.

20. H.Fijhring, K.Wunderlich. U.S.Patent- 3,459,490.

August 5, 1969.

21. H.M.Castrantas, R.E.Keay and D.G.Mackellar. U.S.Patent- 3,677,955.

July 18, 1972.

22. A.E.Levan, D.Tatum. U.S.Patent- 3,577,214.

May 4, 1971.

23. D.R.Dixon, A.D.Coppock. U.S.Patent- 3,512,923.

May 19, 1970.

24. J.J.Giampalami, Jr., I.K.Telegdy, M.Wirth. U.S.Patent- 3,659,211.

September 5, 1972.

25. H.S.Gilbert. U.S.Patent- 3,384,445.



May 21, 1968.

26. H.S.Gilbert. U.S.Patent- 3,335,091.

August 8, 1967.

27. Joseph Kurz. Textile Asia.

June 1999. Page No.-36-37.

28. www.epa.gov/ebtpages

indiindudrycleaningindustry.html

29. Lyle. Dry Cleaning Process.

30. drycleanequip.com

www.duval-uk.com.ment.net

31. Ramsons, Perc Machines, Garment Text- 2001.

32. OSHA web, www.house.gov/smbiz

www.epa.gov

33. George L. Brodmann, Textile Chemist and Colorist.

May 1975. Volume No.- 7. Page No.- 20- 23.

34. Saadia S. Mohamed, American Dyestuff Reporter .

April 1982.

35. Mary Ellen Wiczynski and Manfred Wentz.

March 1988. Volume No.- 20. Page No.- 30-34.

36. Abstracted by: Mrs. N.Pawar, Textile Horizon.

June/ July-1996. Page No.-36.

37. Prof. Debkane.www.ics.mq.edu.au/gen/person/debkane.html

38. www.deq.state.va.us/osha

39. H.Fijhring and J.H. Sieber. U.S.Patent- 3,538,615.

November 10, 1970.

40. M.R.Estabrook. U.S.Patent- 3,510,890.

May 12, 1970.

41. Addition of Antistatic Agents abstract by P& G,Roetkar T.C. EPA.

42. Addition of enzymes abstract by P&G Trinh T. and Siklosi M.P. EPA

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