Soaps are mainly used as surfactants for washing, bathing, and cleaning, but they are also used in textile spinning and are important components of lubricants. Soap is a mixture of sodium salts of various naturally occurring fatty acids. Air bubbles added to a molten soap will decrease the density of the soap and thus it will float on water. If the fatty acid salt has potassium rather than sodium, a softer lather is the result. Soap is produced by a saponification or basic hydrolysis reaction of a fat or oil. Currently, sodium carbonate or sodium hydroxide is used to neutralize the fatty acid and convert it to the salt. The soaps industry is vivacious, varied, creative and tricky, and has the prospective to provide a gratifying career. Since these are basic requirements throughout the world undoubtedly the soap industry is one of the fastest growing and most profitable markets in international arena have been for the past many years. The experts based on the market analysis have predicted the soap industry to continue to grow in both the industrialized as well as developing nations. Apparently population growth, especially households with children has a proportional impact on the growth of the manufacturing sector of the industry. This means that rise in demand for soap production plants has been predicted in the clearest terms. Today the bar soap industry is thriving in much of the world, especially in the developing countries. There, toilet and laundry bar soaps are produced in large quantities, and many manufacturers exist beside the large multinational firms. In the rest of the world boutique soap manufacturers are producing elite bar soap for a select group of healthy conscious green consumers. Demand of foaming soap is increasing rapidly according to recent market research, something that is also spurning big developments in packaging solutions designed specifically for this purpose.
This book majorly deals with characteristics of soap, saponification of fats, reaction making soap, technology of soap manufacturing, saponification of distilled fatty acids, construction materials for soap making plants, various formulations of soaps, soap perfumery, plant and machinery, project estimation & its reliability etc.
Being consumable in daily life soap industry is profoundly lucrative with splendid market potential. This industry has very good future prospects. Many more new units are recommended to meet the requirement of Indians demand. The book covers formulae, processes of different type of washing and toilet soaps. It is very useful book for new entrepreneurs, technocrats and research laboratories, technical libraries and for those who wants to diversify into this field.
- Modern Technology of Soaps, Detergents & Toiletries (with Formulae & Project Profiles) 3rd Edition [NI34] by P. K. Chattopadhyay, Rs. 750.00, US$ 100.00
- Handbook on Soaps, Detergents & Acid Slurry (3rd Revised Edition) [NI38] by NIIR board, Rs. 1,575.00, US$ 150.00
- Herbal Soaps & Detergents Handbook [NI53] by H. Panda, Rs. 975.00, US$ 100.00
- The Complete Technology Book on Detergents (2nd Revised Edition) [NI92] by NIIR Board of Consultants Engineers, Rs. 1,100.00, US$ 125.00
- The Complete Technology Book on Soaps [NI110] by NIIR Board, Rs. 800.00, US$ 100.00
- Soaps, Detergents and Disinfectants Technology Handbook [NI198] by NPCS Board of Consultants & Engineers, Rs. 1,275.00, US$ 125.00
Characteristics of Soap
Saponification of Fats - The Basic Chemical
Reaction Making Soap
2. Raw Materials Oil and Fats
(The Main Raw Materials for Soaps)
Classification of Fats/Oils
Some of the Most Useful Fats and Oils
Palm Kernel Oil
Chinese Vegetable Tallow
Rice Bran Oil
Purification of Soap Fats
Bleaching By Using Oxidizing Agents
Testing Of Soap Fats
Non Fatty Raw Materials For Soap
Other Additives (Foam Producers)
Foaming Agents Used in Soap
Preparation of Colours
Soap Bases and Liquid Soaps
3. Fatty Acids
Types of fatty acids and their physical
Physical properties of fatty acids
Heat of crystallisation
Fatty acids of oils and fats
Raw materials of fatty acids
Vegetable oils and soap stocks
Manufacture of fatty acids
Pretreatment of feed stock
High pressure catalytic splitting
High pressure steam splitting
Continuous fat splitting
Refining of crude fatty acids
Distillation of fatty acids
Mazzoni fat splitting and distillation process
Distillation of crude fatty acid
Splitting plant using thermic fluid instead
Fractional distillation of fatty acids
Development trends in fatty acid distillation
Panning & pressing process
Solvent crystallisation process
Lurgi Wetting Method
Recovery of glycerine
Pre-treatment and evaporation of spent-lye
Pre-treatment and evaporation of sweet water
Distillation of crude glycerine
Synthesis of fatty acids
4. Manufacture of Soap Products
Health and safety Factors
Classification of Soap Products
Methods of Manufacture
Various Finishing Methods
Full Boiling Process (Description)
Washing Bar/Cake Soap From Neat Soap
Jet Saponification Process
Semi-Boiling Process and Cold-Made Process
Production of Washing Bar/Cake Soap
by Semi-Boiling/Cold-Made Process
Examination of Cold-Made Products
Formulations for Washing Soaps
Washing Soap Using Soap Stock as Main
Fatty Raw Material
A Typical Batch
Floating Toilet Soap Cake
Manufacture of Toilet Soap by Semi-Boiled/
Milled Finished Soap
A Typical Batch For Toilet Soap
Carbolic Acid Soap
Castile Soap by Boiling Process
Some Suggested Formulations for Castile Soap
Various Industrial Soaps
Laundry Washing Alds
A Fabric Cleaning Compound
Cotton Scouring Soap
Dry Cleaner's Soap
Jelly Soap/Soft Soap
Wire Drawing Soap
Preparation of Washing Soap Powder
Powdered By Pulverising Method
Washing Powder by Spray-Crystallization
Soap Beads or Granules by Spray-Drying
Brushless/Latherless Shaving Cream
Liquid Shaving Cream
Process of Manufacture
Liquid Toilet Soap Concentrates
Liquid Washing Soap Concentrate
Various Additives of Shampoos Imparting
Thickeners for Body or Viscosity
Agents for Resistance of Hard-Water
Some Typical Formulations
Shampoos Based on Synthetic Surfactants
Liquid Cream Shampoos and Paste Cream
Foamless Oil Shampoos
Medicated Dandruff Shampoos
Other Miscellaneous Shampoos
Aerosol Shampoos (Pressure Dispersed)
Method of Continuous Saponification of Fats
by Alkali Solution
Method of Continuous Splitting of fats into
fatty Acids and Glycerol with Simultaneous
Neutralization of free fatty Acids with Alkali
Continuous Neutralization Process
Description of A Process
Continuous Neutralization Process using Fatty
Acids Instead of fats
Batch Methods of Splitting fats into fatty
Acids and Glycerol
Purification of Fatty Acids
5 Technology of Soap Manufacturing
Saponification Equipments used by the
Equipment for batch soapmaking
Improved methods of saponification
Saponification of Distilled Fatty Acids
Alfa Laval Continuous Saponification
Washing of saponified soap
Counter current washes using a set of pans
Counter current washes in a single
Rotating disc contactor (RDC)
Fitting of Soap
Method of Expressing Free Alkali, Chloride
Plant for Total Soapmaking Operation
Construction Materials for Soapmaking Plants
Earth bleaching of oils
Storage of raw lye
Output of Soap and Glycerine
Analysis of oils
Ester value of oils
Glycerine Recovery Procedure
Purpose of Lye Treatment
Method of Lye Treatment
Treatment of Sweet Water
Refining of Crude Glycerine
Production of Laundry and Toilet Soaps
Frame Cooling of Soap
Production of Filled Soaps on the Mazzoni
Technology of Toilet Soaps
Production of toilet soap
Mixing of soap
Bactericides and germicides
Design of mixers
Refiners vs. Mills
Pre-treatment of Raw Materials
Fat charge control
Colour of soap base
Free alkali and chloride
Glycerol in soap
Process Controls Beyond Pan Room:
Soap Powder for Laundries
6 Various Formulations of Soaps
Toilet Soap of Inferior Quality
Toilet Soap of Lux Type
Formulae and Process Description for
Various Medicated Soaps
Shaving Soaps and Creams
Solid Shaving Preparation
Lather Shaving Cream
Liquid Soaps and Shampoos
Process of Manufacture
Washing Soap (Various Types)
Precautions regarding Manufacture of Soap
Nerol Washing Soap
Soap Removal Procedure
Formulae for Nerol Soap
7 Soap perfumery
8 Management of Soap factories
Fatty acid yield
Active detergent yield
Over/under usage of materials
Oil usage pattern
Scrap and downgrading losses
Steam, water, electricity
Source of Pollution
Detergent powder manufacture
Water treatment Section
Boiler Blow Down
Space and location
The requirements of treated effluent
Effluent treatment methodology
Treatment of Gaseous Effluents
Saponification of oils
Toilet soap mixer
Oleum handling in the sulphonation plant
Oleum still furnace
Exhaust from spray drying tower and air lift
NSD bar mixer exhaust
Chemicals for soap-making
Sampling of Raw Materials
Vendor education and rating
Bureau of Indian Standards Specifications
Conventional Approach to Quality
Recommended Approach to Quality
Implementation of Quality Assurance
Total Quality Management (TQM)
ISO 9000 Series Standards
Common Quality Problems of Soaps
Discoloration of soap
Storage and Product Assessment Tests
Assessment in laundry soaps
Assessment of toilet soaps
Feel of soap in use
Common Quality Problems of Detergents
Poor lather and detergency
Type of stains
Removal of Stains
Stains due to dyes
Physical methods of stain removal
Assessment of stain removal
9 Analytical Methods
Determination of Soap Composition
For Nature of Fatty acids in soap
For Anhydrous soap and total alkali content
Isolation of Fatty Acids and Rosin Acid
Wijs Solution (Iodine monochloride solution)
Determination of Total Anhydrous Soap and
Combined Alkali Content
Unsaponified and Unsaponifiable Matter
Testing of Fatty Oils used for Soap
Moisture and Volatile Matter
Soluble Mineral Matter
Determination of Total Fatty Acids of soap
stock and acidulated soap stock
Determination of rancidity
10 Plant and Machinery
Four Blades Chipping Machine
Other Chipping Machines
Spray Drier for making Detergent Powder
Portal Stirrer (Mechanical Agitator)
High Speed Dissolver
Ball and Pebble Mills
Automatic Liquid Filling and Weighing Machine
Automatic Paste Filling and Crimping Machine
Automatic Power Filling Machine
Marking and Printing Machine
Marking and Printing Machine
Bottle Washing Machine
11 Project Profiles
Project Estimation & its Reliability
Type of Project Estimate
Other Fixed Assets
Cost of Plant & Machinery
Government/DIC/SIDc/FI's Equity Participation
Turn Over (P.A.)
Break Even Point (B.E.P.)
Neem Soap (Medicated Soap)
Nerol Washing Soap
(Following is an extract of the content from the book)
VARIOUS FORMULATIONS OF SOAPS
Toilet Soap of Inferior Quality (Cold Process)
|1.||Coconut Oil||12 Kg.1||2 Part|
|Soap Stone||4-6 kg.||4-6 Part |
|Water||1.5 kg.||1.5 Part|
|Soda Lye (35Â° Be)||6.5 kg.||6.5 Part|
|Colures||1.5-3 gms.||0.0015-0.003 Part|
|Perfumes||5 gms.||0.005 Part |
|Castor Oil ||1|
|Soda Lye (35Â° Be)||11|
|Soap Stone Powder No. 1||5|
|Soda Lye (39Â° Be)||5|
Soapstone is dissolved in the oil and is made homogeneous. Then, water is added in the lye and the mixture is poured in the soap kettle and stirring is done in well manner. After sometime when the whole mixture becomes homogenous, it is left for 10 minutes. After 10 minutes perfumery material is added and the slurry is filled in the frames and is covered by blankets. After 24 hours soap is taken out of the frame and is cut into tablets.
|Toilet Soap of Lux Type||Part|
|Soda Lye (35Â° Be)||10.5|
|Perfumes of Rose or Nargis ||0.057|
Ground zinc oxide is dissolved in coconut oil and the solution is filtered. Now soda lime (lye) is added continuously. When soda lye in finish the solution is left for few minutes. Now perfumes are added as well as musk powder is also added. Now the slurry is filled in the frames and after setting, the soap is taken out of the frame and is cut according to requirement in the form of bars and tablets.
|Soda Lye NÂ° (35Â° Be)||5.325|
|Perfume Khas, Soap Perfumes||0.057|
|Amla Soap ||Part|
|Soda Lye NÂ° 35Â°||5.325|
|Amla Soap Perfumes||0.057|
|Soda Lye (35Â° Be)||5.325|
|Pink Co lour||0.00005|
|Soda Lye NÂ°(35Â°)||5.3125|
|Yellow Co lour||0.0001|
|Rogan (Oil) Sandal||0.057|
|or Sandal Soap Perfumes||0.085|
|Soda Lye NÂ°(39Â° Be)||5|
|Musk Powder (Artificial Musk)||0.085-0.114 |
|Benzaldehyde or Almond Perfume||0.029|
|Soda Lye (35Â° Be)||5.325|
Besides these above-mentioned formulae numerous formulae can be prepared. Perfumes formulae described previously may guide to change the toilet soap variety.
Transparent soaps may be prepared in several ways. One of the oldest methods is to dissolve a good quality soap in alcohol by the aid of gentle heat and then distill off about 80 per cent of the alcohol and run the transparent liquid soap into moulds. This method is expensive but good. Ways of economising have been found by making addition of sugar, castor oil and glycerine during the process for ordinary good quality millings. In the former methods of manufacture,s a necessary prerequisite for success is a first class milling base. Such a raw material is more easily and satisfactorily converted from crystalline to the colloidal state which is really the essence of the process. There is of course no necessity to use duty paid ethyl alcohol, a good quality industrial spirit, pure methyl alcohol or even iso-propyl alcohol to yield good results. The moisture content of the milling chips is important for the higher this, is the less transparent and brilliant is the finished tablet. Drying should be conducted at a fairly low temperature so that a good colour preserves. The moisture content should at the completion of this process not exceed 5 per cent. For such hundred weight of soap, a 20 gallon jacketed still having stirring apparatus and bottom and side exits is necessary. It is preferable two, employ to one for solution of the soap in the alcohol and the other for recovery of the latter. The recovery kettle should be shallow to allow a large evaporating surface. The temperature is usually about 75Â°C. The quality of alcohol necessary for solution varies according to the soap used and to the skill of the operator. One hundred weights of chips will in one case require 19 to 23 litres of spirit while in another as much as 38 litres will be necessary. Settling or the dissolved soap demand careful attention and may require upto six hours. The clear supernatant solution is run off in the recovery kettle from the side exit and the residues withdrawn from the bottom for further treatment. The addition of glycerine at this stage in the process is general. The quantity should be kept low owing to its hygroscopic nature. I or 2 percent is sufficient and will aid transparency, more than this will produce tackiness and a dull finish. The temperature is now maintained at 75Â°C and sometimes slightly increased until 75 or 80 percent of the added alcohol has been recovered. This depend upon how firm the soap will set and experimental tests are made from time to time ensure success. The kettle is allowed to cool and then the perfume and any co lour in clear solution are added. The liquid soap is now run out into narrow frames or bar moulds and subsequently cut to the size necessary for stamping. Shrinkage will of course occur as the past traces of alcohol evaporate, but this is generally allowed before cutting. A skilled operator will have adjusted this process so that brilliant transparency and hardness are secured within few days of manipulations.
Some years ago a percent was taken out by S.P. Villain for the preparation of transparent soap having a high perfume content by the use of a soluble form or derivative of cellulose. This is alleged to form a film coating on the surface of the soap which prevents deterioration of the perfume.
When buying soap chips, it is usually advisable to send the contract samples to competent analyst for report. The following physical characteristics should also be noticed-co lour, dampness, odors and taste. The first quality chips are generally white, the second slightly creamy, the third darker, and the fourth and fifth brownish. For an average good sample of toilet soap, a mixture fourth and fifth brownish. For an average good sample of toilet soap a mixture of equal parts of Nos. 1 and 2 are excellent. Many firms however rely entirely on No. 2 for first quality toilet soap and a mixture in equal parts of 2 and 3 for lower grades. A damp has is more difficult to mill than a normal sample. It is better to buy on the dry side and add the necessary quantity of water during mixing and prior to milling. The first quality chips are practically odorless; the second and third grades have a slight odors reminiscent of traces of paracresol methyl ether. The lower grades have sometimes quite a strong smell. They can only be used in colored soaps, but owing to the larger quantity of perfume necessary to cover the odors, it generally pays in the long run to buy a better grade base and less perfume. It is soap tastes salty, it should be discarded since it will crack after plodding and soon become unsaleable. When an analyst's report is obtained, the fatty acid content and percentage of free alkali or free fat should be noted. Absolute neutrality is very seldom found, but it is better to have traces of free fat. The latter soon jurn the soap rancid and the quantity of perfume used becomes prohibitive. Free alkali is prone to effect the perfume by the decomposition of estes, etc. This may be counteracted to some extent by the addition of lanoline (about 1 percent) and the use in the perfume of gum resin such as storox. A dark coloured base can be much improves by the addition of 0.5 to 1 percent of Zinc or Titanium dioxide. The two formulae are described hereunder.
|1. ||Stearic Acid||50|
|Caustic soda lye (No. 20) ||100|
Melt the first three constituents and stir in caustic soda. Allow to stand for few days. Now add spirit to dissolve the soap and heat to 130Â° to 160Â°F, till a transparent liquid is obtained. Saponification is complete by this time. To recover the alcohol distillation of alcohol may be conducted in stills provided with suitable condensors. Finally add the sugar dissolved in 30.3 litres of water and glycerine. Add the colour and perfumes if necessary and crutch well. Put into frames, slab bar and place for some time in cool dark room. The alcohol then evaporates gradually. The soap hardens and becomes perfectly transparent.
|Soda lye (No. 35) ||12|
For the manufacture of transparent soap, the economic consideration will be of the same type as in the case of toilet soaps given in previous chapter.
The process of manufacturing medicated soaps is very simple. First of all, an ordinary soap-stock is prepared in the usual way and into this is worked by means of crutcher, or by the milling process the substance which imparts the special properties to the soap. To prepare stock soap of good quality, proceed is follows:
Coconut Oil[ ][ ][ ][ ][ ][ ][ ] [ ]900 Part
Caustic soda lye (10Â° Be)[ ][ ][ ][ ][ ] [ ][ ][ ]600 Part
Boil the soda lye in a porcelain vessel gradually and the oil without stopping the heat. When the mixture becomes smooth, add 375 part of caustic soda lye No. (20Â° Be). The mass becomes thicker after few minutes, the heating is stopped when a small sample solidifies on cooling. About 1/3 part of water is then added when the soap will separate and rise to the surface. The mixture is then cooled, the water poured off, the mass mixed twice with a 20 percent salt solution and finally with cold water. The water is allowed to drain off in a hair sieve and the mass pressed to remove the excess of water.
The soap so obtained is in the form of paste, which is brought to a suitable consistency by a very moderate heat in a drying oven, in order to leanable the selected medicament to be incorporated, after which, the soap is pressed into tablets and dried at a temperature from 30Â° to 35Â°C.
Formulae and Process Description for Various Medicated Soaps
|Soda Lye No. 35||6.375|
Sulphur flower is dissolved in the spirit. Now it is mixed with oil. Colour is dissolved in water and mixed with caustic lye. Now soda lye is added to oil mixture. Continuous but slow stream provided with the agitator to the mixture. After the addition of whole lye, the whole mixture is left for few minutes and then run into frames which becomes solid after about 24 hours. Sulphur may be added directly to the soap slurry in fine powdered form.
|Soda Lye No. 35||5.312|
|Colour (Red or Pink)||0.0015|
(Life Buoy Type)
|Soda Lye No. 35||26|
|1. ||Coconut Oil||24|
|Soda Lye No.36||21|
Colour is dissolved in water and then add soda lye which in turn is added to the oil slowly and stirring of the mixture is carried out continuously. After adding the whole lye to the oil, it is kept as it is for some time. Now carbolic acid is added and the slurry is filled in the frames for setting. Process remains the cold process.
|Soda Lye No.35||5.75|
Stock soap is melted over slow fire. Camphor is dissolved in the spirit and added to the molten soap stock with vigorous stirring. When the mixture becomes homogeneous it is filled into moulds.
5. Chaulmogra Soap
This soap is made especially for controlling and avoiding the skin diseases.
|Casutic Soda Lye No.36 Be.||15|
|Green Soap Colour||q.s.|
If oil is in solid or lumpy form, it is put on furnace in soap kettle for melting. Now as in the cold process, lye is added in a thin stream. Now ichthyol is added with stirring. As the mass becomes concentrated it is filled into frames for setting.
For the manufacture of medicated soap of any variety's everything is same as in manufacture of toilet soaps, except the addition of disease relieving compounds. So far establishing a factory of medicated soap, capital investment will be the same as in the case of toilet soap.
SHAVING SOAPS AND CREAMS
Shaving soap differs from toilet soap essentially in that saponification is generally effected with potash as well as soda lye, and further that absolute neutrality must be obtained in the finished article to prevent irritation. A creamy and lasting lather is very important. The raw material must be of the finest and consist principally of tallow and coconut oil together with small quantity of lard oil, castor oil and lanolin.
There are many forms in which shaving preparations are available.
These are available in the form of solid, liquid, powdered, stick, free flowing liquid leather cream and aerosol.
From the viewpoint of technology, solid shaving soaps and leather creams are somewhat similar products in the method of their functioning as well as in their composition.
A shaving product in any form that it is to be used must conform to certain specification in order to aid the shaver. It must be non-irritating to the face and must retain its moisture during the time that it remains as the face even of a slow shaver. It must soften the beard sufficiently so that the razor cuts readily or must retain the softening effect of soap and water.
The shaving preparation should provide lubricity so that the razor can glide easily along the face, and it should be of sufficient viscosity to hold the individual hair erect. In addition, the product should remain stable over a wide temperature range.
SOLID SHAVING PREPARATION
A bar shaving soap resembles an ordinary bar toilet soap. But there is a vital difference between the two. The chief difference between the two products is found in materials used.
In shaving soap, potassium hydroxide replaces all or part of the sodium hydroxide.
A bar or cake shaving soap can be made according to formula 1. In the manufacture of any solid shaving soap, the perfume is best incorporated during milling process.
1.Bar or cake shaving soap.
|Toilet soap from Cattle||50.00%|
|Coconut Oil Manila||5.00|
|Caustic potash, Specific gravity 15||10.00 |
The solid shaving soap or cake may be manufactured in one of the several ways. It usually consist of a mixture of tallow and coconut oil soaps, to which a certain amount of potash soap is added. It can be made entirely in a soap crutcher using a mixture of sodium and potassium hydroxide.
LATHER SHAVING CREAM
A lather shaving cream may be defined as solution of soap in glycerol and water in which excess solid soap may be dispersed. The cream should be low in potassium chloride. Borax is a valuable additive but the amount of borax must be very closely controlled.
The most desirable shaving cream is one which will not change its viscosity over a wide range of temperature.
Potassium hydroxide is used in the manufacture of lather creams. The ratio of potassium hydroxide to sodium hydroxide is one of many critical factors that affect the physical form and stability of the cream. One of the most important raw materials for lather cream is stearic acid. For the preservation of cream, it is usually advisable to add a small percentage of oil antioxidant although there are formulations in which an ontidant is unnecessary.
Phenolic compounds with long side chains have proved very successful as an antioxidants.
Italics. After the saponification of the stearic acid and the coconut oil add the remainder of the strearic acid and also add such special ingredients as lanolin and the antioxidant. Heat the glycerol, boric acid and half of the total water required to 65Â°C, mix and run slowly into the crutcher, stirring until the creamy paste is uniform. Heat the remaining water to 44Â°C and add as fast as the cream will absorb it.
LIQUID SOAPS AND SHAMPOOS
Sometimes these are also called soap-essence. For public room, liquid soaps are more economical than cake-soap. These provide better rinsing than the cake or powdered soap.
The main difference between liquid soap and hard soap is that the former is saponified with caustic potash and the latter with caustic soda. When suitable oils are used, caustic potash produces a soap that will give a rich lather in low concentrations.
Due to its chemical and physical properties, coconut oil is used extensively in making liquid soaps, especially if a rich lathering soap is desired. However, it is suggested that the coconut oil is not be used alone, but in combination with other oils, since it tends to produce soaps which are too fluid and somewhat irritating to the skin. Linseed oil and palm-kernel oil are not recommended for liquid soaps, since they tend to produce disagreeable odors, which cannot be masked readily with perfume. Groundnut oil in small percentages has been used to make coconut oil soap softer and reduces the lather. Corn oil upto 30 percent is common. Castor oil upto 20 percent of the fat mixture can be used safely.
Process of Manufacture
Coconut oil is heated upto 50Â°C in the boiling pan, and then caustic potash lye of 50Â°Be and then water is added with stirring. Saponification may start in ten or fifteen minutes, and it is necessary to note that the pan does not boil over. It may be necessary to sprinkle cold water over the surface of the mass to keep it from forming over the top of the pan. After saponification, the soap should be tested for free alkali, which if present is neutralised with correct amount of fatty acid. If there is insufficient potassium hydroxide present, the soap is adjusted with lye. The finished product may be alkaline to the extent of about 0.05 percent free alkali.
A 50-55 percent soap product results by this method and it is diluted with hot, softened water to the desired concentration.
When making a 40 percent total solid liquid soap, 0.03 to 0.05 percent free caustic potash will help the soap say, clear in cold weather, and will also allow a finished product of slightly higher concentration which will not jell readily, as would be the case if this grade of soap is absolutely neutral.
After liquid soap has been made up, it is transferred to storage tanks. When the soap has become thoroughly clear, it may be siphoned from the top, off through a fancet six to twelve inches above the bottom. Sediments should be flushed out of the tanks periodically. If the mass remain cloudy, one or two percent kieselguhr or talcum may be added. The clear soap may also be separated by filtering. Finally, it is packed into suitable containers.
When a shampoo is based upon soap, it is frequently a potassium salt of the fatty acid. If it is based on a synthetic, it is often a triethanol-amine salt. Liquid shampoos are generally prepared from sulphonated oil and are promoted as oil shampoos. In these formulations, mineral oil may be added to the shampoos, as it does not rinse out readily, remaining as a dressing on the hair. Liquid shampoos are very popular as they are easy to apply. When well formulated, they give excellent foaming and are easy to rinse.
While originally, egg shampoos were composed only of egg. There has been a recent promotion of a number of shampoos which are bases either upon soap or upon a synthetic detergent to which some egg powder had been added. Soap shampoos have been marketed that contains some 20-30% of whole egg. However, there has been no evidence to show that this large proportion of egg improves the quality of the shampoo or the appearance of the hair. In any event, there is little doubt that the cleansing action of these shampoos with egg added is due primarily to the soap or the synthetic detergent present in the formulations. It is also certain that the addition of egg has an excellent sales promotion value for use on dry type of hair.
These products have a very limited demand although formerly they had a market in hard water area. Quillaja saponaria is one of whole class of saponins widely distributed in nature. Commercially, saponin is usually extracted with water and alcohol from the Quillaja bark or from soap root.
WASHING SOAP (VARIOUS TYPES)
Although the basic principal of soap manufacture is the same that any alkali reacting with an oil or fat yields soap, yet, with different raw materials and processes (cold process, semi-boiled and full-boiled process) several types of washing soap may be manufactured.
As now-a-days fats and oils are dearer, the soap industry requires other non-conventional raw materials and at least they require raw material composition at the optimum cost with better quality.
Generally for the manufacture of washing soap, fat-oil mixture is melted in the pan or soap-kettle. To it, correctly weighted quantity of caustic soda lye is added gradually. The temperature is kept generally at 35Â°C. The whole mass is continuously stirred, with small wooden rod if it is small scale process and with metal stirrer attached to the soap kettle. The stirring is continues till all the lyes are in and until the mixture thickens to the consistency of trade. This condition would be attained generally in the course of quarter to half and hour. If the temperature of the oils is not above 90Â°C, it will take much longer for the contents to thicken and in may cases, the constituent, may not combine at all, but separate into two distinct layers of oil and caustic lye.
If the fatty materials are rancid and contain free fatty acids, there is the risk of the caustic soda lye seizing upon the free acids in preference to the neutral oil and forming hard lumps of soap. Side by side with these will be neutral oil and the free caustic entangled in these lumps thereby preventing a thorough and satisfactory combination of all the materials and the resultant product will be irregular and imperfect. Excessive stirring is also to be avoided as it tends to break up the emulsion and the mixture will not set in the frames.
When the mixture of oil and caustic lye thickens it should be ladled out into the frames where saponification proceed vigorously, the temperature of the mixture rising to about value saponification should be complete within 24 hours (and in some cases less than 6 hours). Saponified mixture is kept in cool and dark place in the frames covered by bags or old blanket in order to encourage saponification. The soap will be quite hard and ready for cutting on the third day after it is made, if taken out early it will be hot and soft.
Some Formulae for Washing Soap
|Coconut Oil||2||Common Salt||1.25
||Soda Lye NÂ° 35Â°||10
Process: (Full-boiled Process) Oil or fats are run into the soap kettle and are warmed. Now flour-fine is added and stirred well so that there would be no grainy substance in the pan. Salt is dissolved in water and is added to the soda grainy substance in the pan. Salt is dissolved in water and is added to the soda lye and this soda-lye salts solution is added to the warmed up oil at once and stirring is carried out vigorously. The mixture is left for boiling and is stirred sometimes in between. After about one or one and half an hour, the mixture becomes concentrated and it is again agitated well so that any oil left is consumed. Now the mixture is fed to the frames which is kept in cool and dark places usually. After setting, the soap is taken out of the frames and is slashed into piece as required.
2. Bar Soap
|Soda Lye NÂ° 35Â°||4.25|
|3. ||GroundNut Oil ||3.5|
|Soda Lye NÂ° 35Â°||4.5|
|4.||Palm Oil or Tallow||10|
|Soap Stone ||5|
|Soda Lye NÂ° 35Â°||11.5|
5.Bar Soap of Cheaper Class
|Palm Oil or Tallow ||6|
|Soda Lye NÂ° 35Â°||8|
|Perfume & colour||q.s|
|6. ||GroundNut or Seasame Oil||13|
|Mahua, Tallow or Palm Oil||13|
|Soda Lye NÂ° 36Â°||16|
|7.||Mahua, Palm Oil or Tallow||1|
|GroundNut or Sesamum Oil||10|
|Soap Stone Fine Quality||8|
|Soda Lye NÂ°-36Â°||17|
|8.||Mahua, Oil or Tallow||7|
|GroundNut or Cottonseed Oil||12|
|Soda Lye NÂ°-36Â°||14|
|9.||Mahua, Palm Oil or Tallow||8|
|Cotton Seed Oil or Linseed Oil or GroundNut Oil ||4|
|Soap Stone NÂ°-1||9|
|Common Salt or Washing Soda||0.75 |
|Soda Lye NÂ°-36Â°||9|
|10.||Mahua Oil or Tallow||8|
|Soda Lye NÂ°-36Â°||8.5|
|Salt or Washing Soda||1|
|11.||Cotton Seed or Linseed Oil||8 |
|Tallow or Mahua Oil||8|
|Soda Lye NÂ°-36Â°||11|
|12.||Mahua Oil or Tallow||9|
|Soda Lye NÂ°-35Â°||6|
|Mahua Oil or Tallow or Palm Oil||9 |
|Soda Lye 36Â°||11|
|14.||Mahua Oil or Tallow||7.5|
|Soda Lye NÂ°-36Â°||6.75|
|15.||Mahua Oil or Tallow||7|
|Soda Lye NÂ°-36Â°||6|
|16.||GroundNut Oil or Cotton Seed Oil or Linseed Oil||20|
|Mahua Oil or Tallow||10|
|Soda Lye NÂ°-36Â°||20|
|17.||Cotton Seed or GroundNut Oil||7 |
|Mahua Oil or Tallow||3|
|Soda Lye NÂ°-36Â°||6|
|18.||Cotton Seed Oil or GroundNut Oil||4 |
|Mahua Oil or Tallow||6|
|Soda Lye NÂ°-36Â°||6|
|19.||GroundNut or Cotton Seed Oil||6 |
|Mahua Oil or Tallow||4|
|Soda Lye NÂ°-36Â°||6.5|
|20.||Cotton Seed or GroundNut Oil||5 |
|Mahua Oil or Tallow||4|
|Soda Lye NÂ°-36Â°||7|
|21.||Washing Soap for Washing Silken, Woolen or Cotton Clothes Sajji||5|
|Soap Stone Powder||1|
22. Washing Soap specially for Silken Clothes
Precautions regarding Manufacture of Soap
Raw materials such as oils, fats, alkalis and other auxiliary materials whichever be undergoing use must be pure individually.
Goggles should be used during the soap preparation because soda lye may harm the eyes.
Every constituent should be used in its exact proportion.
Soap concentrate should run into frames only after complete saponification.
Besides Mahua oil, tallow, Castor oil, Neem oil, Rosin and Palm also make the soap concentrate denser and hard. Diluting oils are coconut oil, groundnut oil, cotton seed oil, mustard oil, linseed oil and seasame oil. The ratio of hard and soft oil should be 60:40 during use, although it may not be true for the soaps using salt, flour-fine and water.
Silicate soap concentrate should fill in the frames only when it is fully saponified and is dense otherwise, silicate may be filtered out of the soap.
If soap concentrate be harder, it should not be filled into the frames, but is boiled with additional water so that the concentrate would be homogenous enough for forming.
Coconut oil gives good and creamy lather to the soap. So one-tenth to one-fifth part of the oil should be coconut oil in the manufacture of soap.
Castor oil yields brightness to the soap so it should be used in the ratio of 1/8 to 1/10 of the total oil content.
Aluminium or zinc should not be used as the metal of construction because soap or alkali easily corrode these metals.
Silicates must not be dissolved in either the salt water or washing soda water.
NEROL WASHING SOAP
"Nerol soaps" are used mostly for washing clothes. This soap is manufactured by full-boiled process. This process is better than cold process and it is in practice in most of the soap factories.
Pour water in the soap-boiling pan. Then pour mahua oil and acid oil in it and heat the mixture. When oil and water boil thoroughly, weights the required amount of lye and add it in small amount to the soap making pan and stir well. Boil it for about half an hour. In this way, add half of the lye in the mixture into the pan. The remaining half of the lye should be added four times at intervals of half an hour.
Every time when the lye is added, it should be mixed with a wooden ladle into the oil mixture. Boil it thoroughly till the oil mixture bursts and a layer of water and soap is seen separately. Now, take out a small sample of soap mass with the iron spade and make a cake by this sample to know its preparation. We can see the drops of water floating separately over the soap layer. This soap layer is taken out with an iron spade and the nerol soap is ready. Put off the fire in the furnace and transfer the soap mixture into a waterpro of storage tank. The lye that is visible below the surface of the soap layer should also be poured into the tank along with the soap. When the saponification process begins, stir it with a wooden ladle so that that there may be adhesion into the soap.
Now there are three separate layers of the mixture. The upper layer is lighter. The soap in the second layer is heavy and adhesive. The lye mixed in third layer is of middle quality. It contains a mixture of lye, water etc, in which the percentage of caustic soda lye is in greater proportion. The lighter or swollen soap of the upper layer into it. After three days, observe the state of the soap in the tank. It will solidify during this time. Then it should be taken out from the tank, otherwise it should be washed thoroughly.
Generally, in small soap factories about 2-quintal nerol soap is prepared in one batch. The reason being that the tank used is generally of this capacity. The nerol solidifies in this tank. The size of the tank is generally 11.5 Ã— 17.5 Ã— 45.0 cm. This has 2-quintal capacity.
Soap Removal Procedure
To remove the soap layer from the above tank, a knife of about 22.5 cm length is generally used. Three equal marks are made in breadth-wise over the layer of soap by the above knife. Then these marks are sub-marked with a long wooden footrule. These sub-marks are drawn to gain the previous marks. Now the width of the soap layer has been divided into three equal parts. Now a long smooth stick is placed over these lines and in this way the slabs are separated from each other.
Formulae for Nerol Soap
|Caustic Soda lye 50Â°Be||24|
Nerol Washing Soap (White)
|Caustic Soda lye 40Â°be'||20|
|Caustic Soda lye 39Â°be'||20|
|Rice Bran Oil||15|
|Neem Oil Panner (grained soap made from neem oil)||15|
|Caustic Soda Lye 40Â°Be'||20|
For all the formulae, the procedure of manufacture is the same as described in the beginning.
|Soda Lye NÂ°-35'||20|
|6. ||Coconut Oil||12|
|Soda Lye NÂ°-35'||14.5|
|7. ||Coconut Oil||8|
|Mahua Oil ||8|
|Soda Lye NÂ°-35'||10|
|Soda Lye NÂ°-35'||18|
|9.||Mahua Oil or Tallow or Palm Oil||24 |
|Soda Lye NÂ°-35'||12|
|10.||Mahua Oil or Tallow or Palm Oil||17 |
|Soda Lye NÂ°-35'||10|
|11.||Mahua Oil or Tallow||30|
|Groundnut or Seasame Oil||1|
|Soda Lye NÂ°-35'||20|
|12.||Mahua Oil or Tallow||10|
|Seasame or Groundnut Oil||8|
|Soda Lye NÂ°-35'||10|
|13.||Mahua Oil or Palm Oil||40|
|or Tallow (or in Mixture) Soda Lye NÂ°-35' ||26|
|Cotton Seed Oil||16|
|Soda Lye NÂ°-35'||26|
|Soda Lye NÂ°-35'||24.7|
|16.||Mahua Oil or Tallow||24|
|Soda Lye NÂ°||26|