Soap
soap (of Latin saponem) is a solid substance used for washing, washing or cleaning.
Synopsis |
History
The soap was invented in approximately 3000 years ago, witholive oil and of weld vegetable. This soap was particularly famous for its disinfecting properties, due mainly to the use of ashes of bay-tree in its manufacture.
Product of cleaning known in since the time , it was then manufactured starting from ashes (alkaline) and of tallow, but was used only as shampoo.
From XVE century, the area of becomes an important center of production, using the oil ofolive local. weld (at the time the word "soda" indicated it sodium carbonate) comes initially from the ashes obtained by of like salicorne. In , Nicolas Leblanc invent one process allowing to obtain soda starting from sea water.
In , it Eugene Chevreul explain reaction of and shows that them greasy substance are made of a combination between glycerol and of fatty acids. With XIXE century, of oils of and of palm coming from overseas are employed in the soaps.
Since XXE century, the soap is competed with by surface-active synthetic which is used in detergents, the gel showers and "soaps without soap".
Saponification
The soap results from one chemical known as of , chemical conversion during which greasy substances (greases or oils) are hydrolized in alkaline medium by a base, generally of (KOH) or of weld (NacOh)), with one ranging between 80 and 100 . of the greasy substances produces glycerol and a mixture of carboxylate (of sodium or potassium) which constitutes the soap. Soaps manufactured from weld are hard. Soaps manufactured from is soft.
of saponification:
CH2(OOC-R) - CH(OOC-R) - CH2(OOC-R) + 3 NacOh -- > CH2OH - CHOH - CH2OH + 3 R-CO2- Na
that is to say: greasy substance + NacOh (or KOH) -- > glycerol + soap
where R is a chain of carbon atoms and hydrogen. One can have for example R=(CH2)14 - CH3
detailed article:
Properties
The soap is surface-active. Detergent properties of of carboxylate R-CO2- Na are due to their amphiphilie: they are appeared as a long chain whose end, negatively polarized, is absorbent while the other end is lipophilic. The latter is thus fixed easily on greases, the other remaining in contact with the flushing water.
At the time of the toilet, the soap dissolves grease constituting it film hydrolipidic who covers the skin. Grease is involved in water with dirtinesses which it contains. The disadvantage is that the film hydrolipidic is used to protect skin and to retain its water. Soaping - or any washing using products comprising of surface-active, for example gel for the shower or detergents - thus weakens the skin, until the film hydrolipidic reconstitutes, at the end of several hours.
The soap is basic. Its is close to 10. At the time of the toilet, it disturbs it of skin (to which the pH is close to 5).
In a water last, the molecules of the soap react with and forms calcium salt deposits. Moreover, one needs a greater quantity of soap to clean. To avoid these disadvantages, one adds today to the soaps of the agents antiliming like the EDTA.
Composition
Basic composition
The raw materials to manufacture soap are the fat content and soda (or mugs it up). But after the reaction of saponification, the finished soap does not contain any more soda nor of oil. It is made up mainly the carboxylate ones of sodium (which is the soap molecules) and contains also water.
Glycerin (or glycerol) is a by-product of the saponification which one can eliminate. But one leaves sometimes glycerin because it brings its properties hydrating to the soap.
Principal fat content used
The following table lists the fat content which is generally used at the time of the manufacture of the soaps.
| fat content (oil or lubricate) | name INCI fat content | name INCI soap molecules obtained (1) |
| tallow (grease of b?uf) | ? | Tallowate Sodium |
| lard (grease of pig) | ? | Lardate Sodium |
| groundnut oil | Arachis hypogaea | Peanutate Sodium |
| olive oil | Olea europea | Olivate Sodium |
| oil copra () | Coconuts will nucifera | Sodium cocoate |
| palm oil | Elaeis guineensis | Palmate Sodium |
| oil cabbage tree | Elaeis guineensis | Sodium Palm Kernelate |
(1) if the soap is a liquid soap manufactured containing , it is necessary to replace "sodium" by "potassium" in the names INCI.
Additives
To the basic receipt, one can add different additives according to the required effect:
- antiliming agents
- conservatives
- dyes
- perfumes
- agents surgraissants (oils) to manufacture a soap will surgras
- hydrating agents like honey
- abrasives to manufacture a soap exfoliant
- essential oils extracted from plants
- ingredients disinfectants to manufacture a soap antibactérien
In its simplest form, the soap is a product detergent completely biodegradable. But the additives, them, are often polluting.
Types of soap
The soap is presented in the form of block (bread), of powder, spangles (detergents) and can be sold in solution (soap says liquid).
soap of Alep, oldest soap , is based on oil ofolive and of oil of bay-tree.
household soap traditional is prepared with oil ofolive and of weld.
Soap is often prepared with tallow of b?uf.
A cake of soap is a small soap cake, of more elaborate composition - presence of dye, perfume, bactericide or another additive - intended for the toilet (hygiene body).
A soap will surgras is enriched in agents surgraissants, for example of vegetable oils. The presence of oils limits drying due to the soap which removes fatty film (film hydrolipidic) covering the skin naturally.
The soft soap or soft soap is obtained starting from vegetable oil and from potash. It was recommended for the cleaning of the tilings. There is also soft soap for the body.
A soap without soap, as its name indicates it, does not contain soap molecules. Also called dermatological bread or syndet (for synthetic detergent), it is containing surface-active synthetic. Its is close to the pH of the skin.
The industry of lubricants use, for the manufacture of greases, the soaps of , of , of or of.
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