Shampoo History and Science
The History of Shampoo
Soap has been around from as early as 600bc and was made from various animal fats and wood or plant ashes containing potassium carbonate.
Soap production spread slowly throughout the middle ages. Although on the increase, the benefits of soap was slow to be realised by general societies at that time.
In 1831 Sulphonated olive oil (turkey-red oil) was one of the first soapless detergents (surfactants) to be made in a laboratory.
In the 1930's, fatty alcohols were used in the production of synthetic detergents. The first fatty alcohols used were derived from body oil of the sperm or bottle-nosed whale. Efforts soon followed to derive these materials from the less expensive Tryglycerides found in coconut oil, palm kernal oil and tallow. This was all to change because soon after World War 2, another raw material, Alkylbenzene, became available in huge quantities.
The Soap Tax
In the 13th and 14th Centuries, soap-makers had to pay tax on the soap they produced. After the Napoleonic Wars, this soap tax rose as high as three pence per pound. Tax collectors would lock the soap-boiling pans at night to prevent soap makers evading the duty on soap production. In 1853, the soap tax was abolished at a loss to the state of over one million pounds. By the 19th Century, soap became commonly used by most households.
"Soap consumed by a nation is an accurate measure of it's wealth and civilisation."
Justus Von Liebig, a German Chemist at that time.
Soapless Shampoo for Hair
The majority of liquid shampoos in use today, are generaly termed as soapless shampoo, are based on the alkyl sulphates, and the most widely used of which is triethanolamine lauryl sulphate. When properly prepared, this substance is particularly suitable for washing hair for two reasons.
1. It does not leave dully deposits on the hair when used in hard water.
This is because, when the shampoo reacts with the calcium salts found in hard water, it forms calcium lauryl sulphate. This is a soluble salt which rinses freely from the hair.
2. The finished product occupies a position on the acid to alkali scale equal to about P.H. 7.
P.H.7 is chemically neutral. This means that it will not normaly interfere with any chemical hairdressing processes which follow shampooing. More importantly, being non alkaline, it will not normaly cause damage to the hair structure.
The Manufacturing of Shampoo
Soapless shampoo or synthetic detergents are usually made from one of three things...
1. Triethanolamine Lauryl Sulphate
2. Sodium Lauryl Sulphate
3. Ammonium Lauryl Sulphate
...together with light oils and perfume.
A soapless shampoo or detergent is produced by boiling oils and fats with sodium or potassium hydroxide, this makes a hard soluble soap and glycerine as a by-product.
A solvent detergent is made from petrol or Carbon Tetrachloride.
A dry powder detergent is made from simply talc and chalk.
Alkylbenzene is a liquid hydrocarbon petroleum by-product and is treated with concentrated Sulphuric acid and made into acidic Alkyl Sulphonates or Hydrogen Sulphates. This is followed by neutralisation with various bases. Today, Alkylbenzene is the most important raw material for synthetic detergent production; About 50% of all synthetic detergents produced in the United States and Western Europe are based on it.
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