In this essay we will discuss about the process of dry cleaning of a fabric.
Washing or cleansing of fabrics may be possible by two processes:
(1) Wet cleaning:
Cleansing with water and soap or detergent.
(2) Dry cleaning:
Cleansing with grease solvents and absorbent other then soap solution and water. Some fine, rich and expensive fabrics lose their lustre, shining appearance and rich texture when they are washed with soap and water. So in order to preserve these expensive fabrics, dry cleaning is the best method of laundering clothes. Previously, Dry-cleaning was known as “French cleaning” and “Chemical cleaning”.
In Dry-Cleaning soap and water are replaced by “Dry Cleaning Reagent”, which are available in two forms:
(1) Grease Absorbent
(2) Grease Solvents.
(1) Grease Absorbents:
Different types of grease absorbents like fuller’s earth, bran, French chalk. Talcum powders, salt, breadcrumbs, baked flour and powdered sulphur are used for cleaning of the fabric by dry cleaning methods. This method is suitable to remove grease spots from all kinds of materials. These absorbents are useful for cleaning grease marks on light coloured fabrics.
One of these grease absorbent powders is sprinkled on the grease or dirty portions of the fabric. The fabric is then folded and kept for half an hour to allow the powder to absorb the grease. Then shake and brush out until all the absorbent powders are removed. Since the grease holds the dirt the garment is now easy to clean by proper brushing. These powders are suitable for spot cleaning. They are not so effective for cleaning heavily soiled garments.
(2) Grease Solvents:
These are available in liquid ferment which easily penetrate the garment and clean it. These solvents are easily evaporated in air. Some grease solvents like petrol, benzin and methylated spirit are inflammable while carbon tetrachloride, trichloroethylene etc. are non-inflammable. Some of these grease solvents which are widely used for dry cleaning are petrol, ether, methylated, spirit, chloroform, carbon tetrachloride, trichloroethylene, turpentine, and a product known as solvent. Inflammable solvents must be used with much care.
The precautions are:
1. They should not be used in a room containing flame.
2. Do not dry the fabric under the sunrays.
3. Iron the fabric when completely dried.
4. The solvents should be kept away from flame or hot objects.
Preparation before cleaning:
The fabric must be prepared for dry cleaning.
The preparation consists of:
(a) Examination of the fabric.
(b) Mending wherever necessary.
(c) Removal of buttons, zips,-emptying of pockets.
(d) Shaking or Brushing thoroughly to remove all the loose dust and dirt.
(e) Stain Removal: After removal of stains the fabric should be dried before the dry cleaning processes.
Methods of cleaning:
There are three methods of dry cleaning:
1. Immersion method.
2. Spot cleaning by sponging method.
3. Absorbent method by grease absorbents.
1. Immersion Method:
In this method, a grease solvent is required. The fabric or garment is immersed in grease solvent in order to dissolve the grease, Generally, the fabric is thoroughly wetted and cleaned in plenty of petrol which is commonly used as grease solvent in dry-cleaning process.
The requirements for this method are:
1. A container with tight fitting lid for petrol and the fabric.
2. A wooden spoon with a long handle.
3. A wooden rod or a suction washer.
4. A basin.
A cylinder shaped container with a narrow mouth should be taken for this purpose. There must be a lid to fit the mouth of the container. So that after filling it with a lot of patrol, the container should be closed with the lid tightly and the evaporation of petrol will be reduced. The dry cleaning pump can also be used for cleaning of fabrics in the container. The use of this pump will prevent the evaporation of petrol and also keep out of danger from catching fire.
Method of Use:
Sufficient petrol is to be poured into the container which can immerse the fabric completely. Press it down with a wooden rod. After thorough stirring, close the lid and shake the container for a continuous motion inside it. A suction washer may also be used in place of a wooden rod. Allow 15 to 20 minutes for this process. The time depends upon the size of the garment and the quantity of dirt.
Then wrap the garment round and round the wooden rod and press it on the rod with a wooden spoon to squeeze out excess amount of petrol from it. Put the garment in a basin and press it one side with the help of wooden spoon to remove more amount of petrol. Hang the fabric to dry in a shady place outside in the open for one day.
The place should be away from sun and fire. The fabric should not be ironed until the odour of petrol remains in the garment. After cleaning, the used up petrol is to be filtered through blotting paper or a piece of muslin. Keep it in the bottle with tight fitting lid which can be used again for the second time.
2. Spot Cleaning by Sponging Method:
The dirty spots or the stains can be easily removed by this method.
The requirements for this method are:
1. An ironing table covered with blanket and sheet,
2. A bottle of petrol,
3. A small bowl,
4. Blotting paper,
5. A piece of fine muslin cloth or cotton.
The more dirty parts of the garment are to be cleaned first by this method, for e.g. the neck, armpit, yolk, cuffs of the coat or any soiled and greasy part of sarees etc.
Method of use:
The ironing table is to be prepared by covering the blanket with the sheet. Spread the piece of blotting paper on this table. Place the soiled part of the garment on the blotting paper in such a way that the grease part of the garment should come in direct contact with the blotting paper. Wet the cotton or a fine piece of muslin cloth with petrol and damp the soiled part of the fabric by sponging on the upper most side.
The sponging is to be done in a circular manner, beginning from the outermost part of the soiled portion to the central part. This process is to be continued until the soil or grease is liberated from the cloth and is absorbed by the blotting paper which is placed under the soiled part of the garment. Repeat this process to remove grease from other parts of the fabric. Then dry the fabric outside in a shady place for one day before ironing.
3. Absorption Method by Grease Absorbents:
By this method very soiled parts are cleaned. After examining the fabric the most soiled parts are to be detected for removal by this method.
The following things are required for absorption method:
1. An ironing table covered with blanket and sheet.
2. A piece of blotting paper.
3. Absorbent powder.
4. Some solvent.
5. A soft brush.
Generally two methods are adopted:
1. By using absorbent powders.
2. By the application of paste made by absorbent powders and a solvent.
1. Methods of Using Absorbent Powders:
Prepare the ironing table with blanket and sheet. Spread the blotting paper on the table. Place the soiled part of the garment on the blotting paper in such a way that the soiled side should face upwards. Then spread the absorbent powder on the soiled portion. Rub it lightly and allow the garment in that condition for half an hour to 45 minutes. The Grease absorbent powders now absorb the grease and liberate the dirt. Then shake off the powder and brush it thoroughly to remove the powder completely from the fabric with the liberated dirt. Take it for ironing.
2. Methods of Application of Paste:
This method is applied for part cleaning of the fabric. In this process a paste is to be made by mixing a solvent and absorbent powder. Spread the soiled garment on the blotting paper in the ironing table, with the soiled side uppermost. Apply the paste on the soiled portion and leave it for half an hour to one hour. Then scrap off the paste by which the dirt can also be removed that is absorbed by the paste. Brush it thoroughly and dry in open air for one day as solvent is used. Take it for ironing.
Advantages of Dry Cleaning:
1. Many expensive silk and woolen fabrics can be easily washed by dry-cleaning method which becomes impossible with soap and water.
2. Velvet and pile fabrics can be easily dry cleaner.
3. There is no shrinkage of fabric after the whole process of dry-cleaning.
4. All types of grease and stains are easily removed by this method.
5. Fabrics which are given different chemical and mechanical finishes can be easily cleaned by dry cleaning method without any damage to the finished fabrics.
6. Dry cleaning is the best method for the garments with special pleats as it does not remove the setting of pleats.
Disadvantages of Dry Cleaning:
1. Dry cleaning method is very expensive.
2. The smell of inflammable solvents remain for a longer period of time which becomes uncomfortable.
3. If precautions are not taken, there is a chance of catching fire by the inflammable grease solvents like petrol.
4. It requires special type of skill and equipment.
5. Solvents cannot remove the dirt which are dissolved in water. It only removes the grease.
6. The solvents of the dry cleaning dissolves rubber wax, plastic and resin materials attached to the fabric.
7. The vapors of the solvents used may have harmful effect on the person who is washing.
Precautions of Dry Cleaning:
The following precautions are to be taken while adopting the method of Dry cleaning:
1. Wash in a well ventilated place.
2. Avoid inhaling the vapors of solvents for a longer period of time.
3. Wash only a few garment at a time.
4. Use and store solvents in a cool dry place. Avoid heat and fire from the storing place
5. After cleaning with inflammable solvents hang the garment in open air for one day away from heat, fire and sunlight.
6. Keep the used solvents in airtight containers and proper labeling should be done for future use.
7. Use dry cleaning equipment of standard companies to avoid accidents.
8. Ironing is to be done after the smell of solvents disappear.
9. The whole process should be carried out as quickly as possible to avoid evaporation of solvents.
Bleaching is the process by which colouring matter is removed from the fabric and makes it white. If bleaching agents are used on white fabrics they make them bright. In laundry work bleaching is used for removal of stains which are not responding to ordinary washing.
Bleaches are of two types:
1. Oxidizing Bleaches,
2. Reducing Bleaches.
1. Oxidizing Bleaches:
These bleaches provide oxygen which combines with the stain to form a colourless compound. All fibers are affected by oxidizing bleaches. So the bleach must be in contact with the fabric until the stain is removed. Longer contact may weaken the fabric.
Some of the oxidizing bleaches are as follows:
1. Sunlight and open air.
2. Sodium perborate.
3. Hydrogen peroxide.
4. Sodium Hypochlorite
5. Potassium paramaganet.
1. Sunlight and Open Air:
This is the oldest method of bleaching cotton and linen fabric. This is also the easiest and cheapest method for removing the colouring matter specially from white fabrics, when they come in contact with oxygen. The oxygen from the air and grass liberated by the sunlight and in conjunction with moisture is the active bleaching agent.
When an article is laid on grass or spread over a bush in sunlight, additional bleaching is due to the chlorophyll in the leaves. Most of the Indian housewives dry their clothes after washing or removal of stain in the sunrays which is strong oxidizing bleach.
2. Sodium Perborate:
It is also used as bleaching agent. Sodium perborate is produced from borax, caustic soda and Hydrogen peroxide. When it is mixed with warm water, it makes an alkaline bleaching solution that contains Hydrogen peroxide. One ounce (25 gms) of sodium perborate can be mixed in one gallon (2 liters) of water for the preparation of bleach. Sodium perborate is effective when the action is started from low temperature and then gradually the temperature is increased. It is used for the preparation of soap. The solution of sodium perborate with a little amount of water is mostly used for removal of stains.
3. Hydrogen Peroxide:
This bleach is safely used for silk wool and rayon fabrics, because it has no harmful effect on animal fibers. One part of hydrogen peroxide provides 10 or 20 parts of oxygen. It can be used in various concentrations according to the requirement of bleaching. When it is used on the white cotton and linen fabrics, 10 volume strength of hydrogen peroxide can be used without dilution.
But it should be diluted by mixing six parts of cold water to one part of hydrogen peroxide for other fabrics. In alkaline solution which is made by addition of washing soda or ammonia to water, the splitting process (conversion into water and oxygen) of hydrogen peroxide is rapid. In acidic solution it becomes slow. Hydrogen peroxide should never be allowed to dry in the fabric, because it can weaken the fabric.
4. Sodium Hypochlorite:
This is known as Javelle water which can be prepared easily and stored inside the house for laundry purposes.
For the preparation of this bleach, the following things are required:
450 gms Washing soda
225 gms Chloride of lime
2 liters Cold water
1 liter Hot water
Method of Preparation:
Mix the washing soda in boiling water. Mix chloride of lime with cold water. Keep the mixture for sometime to settle down. Then strain the clear liquid without stirring. Mix the washing soda solution with the filtered chloride of lime solution gently.
A white precipitate of calcium carbonate and sodium hypochlorite forms on mixing the two solutions which is known as Javelle water. This solution is then strained and stored in dark coloured bottles to avoid light. Sodium hypochlorite is a strong bleaching agent and can be used in white cotton and linen. The fabric may be soaked in the dilute solution of javelle water for 20 minutes or stain can be removed by sponging method.
5. Potassium Permanganate:
This has high contents of oxygen which oxidizes the stains easily. It is the most effective beaching agent for removing the perspiration and mildew stain. If can be used safely on both vegetable and animal fiber. But a brown stain due to manganese dioxide are left over the fabric which can be removed by treating it with hydrogen peroxide or oxalic acid. 20 to 30 gms of potassium permanganate are mixed with 4 liters of water for cotton and linen, but the dilution is doubled in case of wool and silk fabrics. The stained fabric is put in the potassium permanganate solution and then in hydrogen perborate or oxalic acid. The process is to be repeated until the stain is removed completely. Then rinse thoroughly.
2. Reducing Bleaches:
Reducing bleaches are opposite to oxidizing bleaches. By these bleaches, oxygen is removed from the stains and thus reducing the stain to a colourless compound.
The followings are some of the Reducing bleaches:
1. Sodium Hydrosulphite Bleach
2. Sodium Bisulphite Bleach
3. Sodium Thiosulphite Bleach
1. Sodium Hydrosulphite Bleach:
This bleach is available in the form of powder. It is a commonly used reducing bleach. This bleach can be used in all kinds of fabrics. The bleach is dissolved in hot water and readily absorbs oxygen to form sodium metabisulphite. When sodium metabisulphite is exposed to air it is broken into sodium sulphate and sulphur dioxide which is a reducing agent. For making the bleaching solution 1-4 teaspoons of sodium hydrosulphate is added to 500 ml of hot water. The fabric is soaked for a few minutes in this solution and then rinsed.
2. Sodium Bisulphite Bleach:
This is a very mild reducing bleach. The bleach is produced by neutralisation of sulphuric acid bycaustic soda. Its bleaching action is due to sulphur dioxide which takes oxygen out of the stain. The fabric can be bleached with a solution of 2 table spoon of sodium bisulphite to 500 ml of water. Then the fabric is to be rinsed thoroughly to remove the chemicals.
3. Sodium Thiosulphite Bleaches:
This is also known as Hypo. It is a bleach for cotton. This is a reducing agent. The bleaching process involves the releasing of sulphur dioxide. 30 gms of sodium thiosulphite, 15 gms of acetic acid and 8 liters of water are mixed and bleaching solution is prepared. After using this bleach, the fabric should be rinsed thoroughly.
Precautions in the use of Bleaches:
Some precautions are to be taken in bleaching process:
1. Over bleaching weakens the fabric so avoid this.
2. Over bleaching may lead to cracking of fabrics on handling.
3. Use a bleach of known strength.
4. Keep the temperature below 140°C For 60°C.
5. Always measure quantities of bleach accurately.
6. Bleach should be used in dilute solution.
7. Chlorine bleach should not be applied at a very high temperature. Never use these beyond 70°C.
Starch is the main stiffening agent used commonly in laundry work. Stiffening agent is given to the fabric after the washing process is completed.
Purpose of Stiffening Agents:
Stiffening agent is given to the fabric for various purposes:
1. It gives smooth glossy surface to the fabric.
2. It acts as the resistant to dirt and dust.
3. It makes the subsequent washing easier as soil stick to the starch rather than to the fabric.
4. Fabric becomes firm and pliable.
5. Ironing becomes easier.
Types of Stiffening Agents:
Starch is used for cotton and linen fabric. Gum Arabic and Gelatin are used as stiffening agent for silk and wool. Generally a thick starch solution is prepared and then it is diluted as per the requirement and is applied.
Some common starches used are:
i. Rice Starch:
Rice starch grains are very small which make a viscous solution in water. This is suitable for cold water starch. This type of starch penetrates into the fabric easily and gives stiffness and pliability to the fabric. It can be used as the stiffening agent in cotton and linen.
ii. Wheat Starch:
The starch grains make a viscous solution in water. It gives greater degree of stiffness and pliability. Both small and big size grains are available. But the method of starching is uneconomical and very much expensive for laundry work.
iii. Maize Starch:
It gives undesirable stiffness to the fabric. It is very cheap and forms a good viscous solution. But due to its extra stiffness it may be used by mixing with other soft starches.
iv. Tapioca Starch:
Tapioca is the roots of cassava plant. This starch can be provided by drying, slicing and crusting of the roots. Then a pulp is made with water. The pulp is again dried to evaporate water which become solid white mass. This provides stiffening of good quality.
v. Sago Starch:
This starch grains are easily soluble in hot water which makes a viscous solution. It penetrates into the fabric easily and gives the desired stiffness and pliability to the fabric. It can be used in all kinds of fabrics.
vi. Potato Starch:
The starch grains are very big. Generally this is not suitable for laundry work. The ground pulp is washed and dried. It is converted to powdery substance. The solution is prepared by boiling with water which give stiffness.
vii. Commercial Starch:
Different brands of commercial starches are available in the market. These are prepared by combining different kinds of starches. In Malabar and the South west coast of India polished tapioca powder and tamarind seed powder are mixed with some commercial starches.
viii. Synthetic Starch:
Now-a-days, a number of readymade starch are available in the market, which are produced by different processes. Dip Revive etc. are some of the example of synthetic starch. Some synthetic starch give good result in both cold and hot water. All starch gains form a colloidal substance by the application of heat and moisture. So care should be taken while preparing the solution.
ix. Bran Water Starch:
Bran water is used as stiffening as well as cleansing agent. Generally, this can be successfully used for stiffening of the fabric of uncertain dyes and embroidery clothes.
x. Gum Arabic Starch:
This is known as gum water. Gum Arabic is a gelatinous fluid from the tropical acacia tree which dries by exposure to air. Silk, wool, lace, expensive and delicate dress materials can be given this type of stiffening agent.
It is an expensive stiffening agent. It is easy to prepare and use. The gelatin dissolves easily in water. The quantity of gelatin depends upon the amount of stiffness.
Methods of Preparation of Starch:
There are two methods of preparation of starch used for laundry work: 1. Boiling Water Starch 2. Cold Water Starch.
1. Boiling Water Starch:
Most of the starches become perfectly fluid and gives a viscous solution in boiling water. When the starch grains are cooked they swell and starch is liberated to water which can easily penetrate into the fabric.
The ingredients necessary for boiling water starch are as follows:
Make a smooth paste of starch, borax, wax with cold water. Pour over the boiling water quickly. Stir continuously to get a viscous solution. When the starch grains burst and mix with water the liquid is changed to a transparent grey colour. This is known as standard starch jelly. This jelly is diluted immediately by adding to it an equal volume of cold water, otherwise solid lump will be formed. Borax is added to the starch as it helps to make it more resistant to atmospheric condition. Wax helps in ironing process by making the surface of the fabric smooth.
Boiling water starch is used for cotton and linen fabrics. The fabrics are dipped up and down in the starch for the penetration of starch into the fabric. Then it is dried by stretching the fabric. Before ironing damp the cloth evenly.
2. Cold Water Starch:
This starch gives more stiffness. So it is used for thin muslin fabrics, collars, cuffs, shirt, frills, caps etc.
Dissolve the borax and wax in boiling water. Mix the starch with cold water. Add the borax and wax mixture into the starch. Add turpentine and stir the mixture continuously till a viscous solution is formed. Strain through a fine muslin cloth. Allow it to stand for half an hour by covering it. This helps in softening of starch grains, stir thoroughly before use.
Usually, the fabrics are to be given this cold water starch in dry condition. The dry garments are immersed in this solution. Squeeze out the fabric. Then rub off the surface starch grains with a muslin cloth. This gives a very stiff finish. Borax and wax are added to laundry starch because borax gives whiteness and wax gives glossiness to the fabric.
Methods of Preparation of Bran Water Starch:
One part of wheat bran (out kernel) is boiled in four parts of water. After it begins to boil, the heat lowered down. It should be boiled in low heat for half an hour. When the solution becomes cool, it should be filtered in a muslin cloth. The solution may be diluted as per requirement. It forms non-alkaline solution with water.
Methods of Preparation of Gum Water:
Granulated gum comprising of aerobic acid, lime, magnesium and potassium salt is dissolved in boiling water. It is stirred continuously to give a smooth solution which is strained and kept in the bottle. Formalin may be added to prevent microbial spoilage.
For the preparation of gum-water the following ingredients are required:
Gum Arabic: 100 gms
Boiling water: 500 ml
Soak the gum in water overnight in ajar. The jar should be put in hot water to dissolve the gum. Stir occasionally, strain through a muslin and keep them in a bottle.
Methods of Preparation of Gelatin:
Gelatin: 15 gms Water: 500 ml
When the gelatin is completely mixed with water, a solution is prepared. This is diluted with hot water. The dry fabrics are immersed in this solution when it becomes cool. Then it is dried. The actual dilution depends on the kind of material and stiffness required.
White fabrics when continuously washed give a yellow colour mark on the fabric. In order to remove this tint, blueing process is necessary. Blue is used in the last rinse for bleached cotton and linen. Whiteness of the fabric can be restored by the application of blue. Blue is available in the market in the form of powder, liquid, balls and cubes.
Purpose of Application:
1. Helps to remove the yellow tint that appears on clothes due to repeated washing.
2. Brightens the white fabrics.
3. Restores the whiteness of the fabric.
Classification of Blue:
Blues are both soluble and insoluble. There are so many types of blue like Ultramarine, Prussian, Indigo, Coltar dyes or Aniline Blue, Methyl violet, methyl blue etc.
1. Ultramarine Blue:
This blue is commonly used in laundry work. It is very cheap and has no harmful effect on fabrics. This blue is produced from Soda ash, Sodium sulphate, Charcoal, Sulphur and clay. All these materials are heated and then ground which becomes a powdery substance. This blue dissolves easily in water. It gives a violet blue colour.
2. Prussian Blue:
This blue is prepared from a mixture of iron sulphate and potassium Ferro cyanide. It is not widely used as a laundry blue because it leaves rust marks on the fabric after ironing.
3. Aniline Blue:
Aniline Blue is prepared from coalter dyes. It is easy to prepare and use. This blue is commonly used in laundry work. This is available in the form of solution of powders. The colour is purplish blue. This dye is highly soluble in water. So by continuous rinsing, this is totally removed from the fabric. Therefore it is applied on the last rinse.
This is prepared from the leaves of the group of plant named as Indigo era family. The colour is dull blue. This blue is available in two forms, alkaline indigo and acid indigo. Alkaline indigo is more soluble in water. So it is suitable for laundry work.
5. Soluble Blue:
All soluble blues are a type of chemical dyes. They produce an even colour and leave no sediment. Aniline Blue is a type of soluble Blue.
Method of Use of Blue:
Blue is generally applied at the last rinse, when the fabric is free from soap. Some soluble blues or liquid blue can be directly introduced in water and is mixed properly in it. Insoluble blue and the powder form of blue are applied in a separate manner. The blue is tied in a piece of muslin cloth and squeezed in cold water till the desired colour is obtained. Then the fiber is to be immersed completely in blue water.
The fabric is then removed from blue water and dried in open air and sunlight. Sometimes blueing and starching process are combined. Every time stir the blue water, when the fabric is to be put inside it. The fabric must be opened before being put in otherwise patches of blue colour will form on the surface of the fabric. If the fabric is becoming deeper in colour, it may be rinsed in another bucket of water. Blue plays an important role in laundry work in almost all houses for washing white fabrics.