Plasticizers and binders (20-50%)
Lather enhancers (0-5%)
Fillers and binders (5-30%)
Opacifying agents (0-0.3%)
Dyes and pigments (less than 1%)
Properties & Functions of Soaps
All the detergent ingredients impart different properties and functions to soaps
and detergents. There are certain other specific ingredients that are added in
specialty soaps and detergents depending on the action or characteristics desired
in the end product. For example, toilet soaps may contain antimicrobial agents to
kill or inhibit bacteria which can cause odor or disease. Some other personal
cleaning products may be made using abrasives for removing stubborn greasy dirt.
Glycerin is added as an ingredient of soap as an emollient and texture enhancer in
personal cleaning products, especially moisturizing soaps or beauty soaps. Sorbitol
is another emollient, which is used along with glycerin to help make glycerin soaps
more transparent. For making an opaque toilet soap, titanium dioxide can be
added to it.
Bleaches, detergent boosters, fillers and builders are laundry cleaning agents that
are added to enhance the effectiveness of laundry detergents and soaps and
provide special attributes and functions to these laundry cleaning products. The
laundry cleaning agents brighten and whiten fabrics and help remove the stubborn
stains. These laundry detergent ingredients also convert the soils into colorless,
soluble particles which can be removed by detergents and are carried away in the
• The fats used in soap and detergent making coming from animal or plant
sources. Each fat molecule is made up of a distinctive mixture of various
different triglycerides. In a triglyceride molecule, 3 fatty acid molecules are
attached to one molecule of glycerine. There are different types of
triglycerides; and each type consists of its own specific combination of
Components of fats and oils, which are used in making soap, fatty acids
are weak acids that are composed of two parts -A carboxylic acid group
• Hydrocarbon chain
• A carboxylic acid group consists of a hydrogen (H) atom, two oxygen (O)
atoms, and one carbon (C) atom, along with a hydrocarbon chain, which is
attached to the carboxylic acid group. Typically, fatty acids are made up of
long straight chain of carbon (C) atoms, in which each carries two
• Alkalis are soluble salts that are effective in cleaning fabrics and removing dirt without excessive
rubbing. A soluble salt of an alkali metal like potassium or sodium, alkalis are good grease
removers, as they form emulsion, a mixture where oily or solid particles are held in suspension. The
particles do not separate from the remaining liquid and hence they do not re-deposited on the
surface being cleaned.
Earlier, the alkalis used in soap manufacturing process, were obtained from the ashes of plants, but
now days, they are produced commercially. Today, the term alkali describes a substance, which is a
base (chemically) and which reacts with an acid to neutralize it. The most common alkalis used now
days in soapmaking is sodium hydroxide (NaOH), which is also known as caustic soda; and
potassium hydroxide (KOH), also known as caustic potash.
Potassium based soaps form a more water-soluble product than a sodium-based soap, and hence
they are known as "soft soaps." Soft soaps, alone or in combination with sodium-based soaps, is
generally used to make shaving creams and other water-soluble products.
When oil is mixed with an alkali, it forms glycerin and a sodium salt of fatty acid. The fatty acids that
are required to manufacture soaps are supplied by tallow, grease, fish oils, and vegetable oils. The
characteristics of soap, such as hardness, lathering qualities and transparency may vary depending
on the combinations of alkalis and fats used as ingredients. Alkaline cleaners can also be used to
remove oil from an oil-based paint, by drying it and causing it to peel or crack. Alkali products also
have a property to darken aluminum surfaces
• Alkaline substances vary in their strength. While most of the alkaline
substances are toxic, some may be corrosive and some may irritate skin
and eyes. The stronger alkalis can cause burns and, in the case swallowed,
may cause death or internal injuries. On the basis of strength, alkalis can
• Mild - An example of mild alkali is baking soda (sodium bicarbonate)
• Moderate - Common examples of mild alkalis include - household
ammonia, borax and trisodium phosphate (TSP)
• Very Strong - Washing soda (sodium carbonate) and lye (caustic soda) are
most common strong alkalis
• Where does an alkali come from?
In earlier days, rainwater was filtrated through hardwood ashes in Africa,
to produce potassium hydroxide solution. Bar soaps was made using
sodium hydroxide, which is what you get when you run electricity through
salt water. Today, potassium hydroxide is made using a similar process.
Along with its wide known use in soapmaking, additional alkalis, such as
sodium carbonate, hydroxide or trisodium phosphates are used
dishwashing products to aid in handling greasy food soils.
Use in Soapmaking
Acidic oils and alkaline solutions are prime ingredients in soapmaking. To
produce a perfect bar of soap, oil and alkalis should be in perfect balance.
The unsaponified oils are known as "Free fatty acids", which add to the
moisturizing characteristics of high quality soaps. However if these oils are
used in excess, the soap will not lather and will have a shortened shelf life.
The use of excess alkali in a soap make it harsh and drying to the skin.
Alkali Vs Acid
• Acid V/s Alkali & SoapmakingAcidAlkaliNormal pH is 7.0
Water should be 7.0Acids are chemicals that have a pH lower than
"neutral". An acid can be mild or extremely caustic.Alkaline
substances have a pH more than 7.0. They can be mild or
corrosive.The type of acid, which is used to make soap is a fatty
acid, obtained either from animal fat or vegetable oil.The alkali,
which is used to cause the chemical reaction with the fatty acids, is
either made from potash (lye water) or sodium
hydroxide.SaponificationWhen a base reacts with oil or fat, fatty
acids get separated from the glycerin and the potassium of sodium
component of the alkali bonds with fatty acids. The product, which
is formed by the sodium or potassium and the fatty acid, is a salt. In
technical terms, soap is a salt. Glycerin (also called glycerol) is a by-
product, which has its own cleansing properties. It is hydroscopic,
i.e. it moisturizes as it attracts water from the air.
• Glycerin is a natural by-product of the soap manufacturing process. It is a humectant that means it
attracts moisture to your skin. While commercial manufacturers remove the glycerin for its uses in
more profitable expensive lotions and creams, handcrafted soap generally retains glycerin in them.
Glycerin is also highly hygroscopic that means it absorbs water from air. Because of this hygroscopic
property, pure, 100 % glycerin when placed on the tongue may raise a blister, as it is dehydrating.
However when it is diluted with water, it soften your skin.
Highly glycerinated clear soaps generally contain about 15 to 20 percent pure glycerin. Known as
"melt and pour soaps", these soaps melt at about 160 degrees Fahrenheit, and solidify fairly
quickly. Due to their high glycerin content, these soaps are very moisturizing to the skin. However
the high glycerin content also means that these soaps will dissolve more quickly in water than
soaps with less glycerin content.
Where does glycerin come from?
Until 1889, people did not know how to recover glycerin from the soap manufacturing process and
so glycerin required for other applications was commercially produced from the candle making
industry. In 1889, a feasible method to separate glycerin from the soap was discovered. As the
prime use of glycerin was to make nitroglycerin that was used to make dynamite, soap making
business became a more profitable one.
• The technique of separating glycerin from the soap is fairly complicated process. In the simplest terms, soap is made using fat and lye. The fats
already contain glycerin, which is due to their chemical makeup. When the fats and lye react, soap is produced, and the glycerin is left out as a
byproduct. However, while it is chemically separated, it is still blended into the soap mix.
While a cold process soap manufacturer would usually pour into the molds at this stage, a commercial soap manufacturer will add salt. The salt
makes the soap to curdle and float to the top. After creaming off the soap, glycerin is left off. Then the pure glycerin is separated out by distillation.
Finally, in the end, glycerin is de-colorized by filtering it through alcohol, or by using some other bleaching techniques.
A colorless, odorless and viscous liquid, glycerin is a chemical compound with formula HOCH2CH(OH)CH2OH. This colorless, odorless, viscous liquid is
widely used in pharmaceutical formulations. Sweet in taste, glycerin is low of toxicity and has 3 hydrophilic alcoholic hydroxyl groups, which are
responsible for its solubility in water and its hygroscopic characteristic. The chemical has a surface tension of 64.00 N/m at 20 °C and has a
temperature coefficient of -0.0598 mN/(m K).
An important thing to know about glycerin is that it should be placed in a slotted soap dish to ensure proper drainage. In the case, there is too much
water on the soap it will start to gel.
Besides making nitroglycerin, glycerin is also used in various other processes, including -Soap making
• Conserving preserved fruit
• As a base for lotions
• To prevent freezing in hydraulic jacks
• To lubricate molds
• In some printing inks, in cake and candy making (because of its antiseptic quality)
• Sometimes used to preserve scientific specimens in jars in biology labs
• Used as a solvent in the manufacture of alkyd resins and ester gum type inks
• Benefits of Glycerin in Skincare
Glycerin is a humectant, which means it promotes the retention of moisture. It has no drying characteristics and hence leaves the skin smooth and
silky. It has found to be really effective and god for elbows, heels, tender skin and children's skin.