The modern consumer is often faced with a choice of which soap to buy — liquid or solid. Our great-grandmothers did not have such a choice — after all, liquid soap in its modern form appeared only thirty years ago. Every year, the volume of production of liquid soap increases, because its popularity is growing in comparison with solid soap.
Composition of liquid and solid soap
A significant difference between liquid and solid soap, in addition to consistency— is in the composition of soap.
There are two types of liquid soap. The first and most common type of liquid soap is obtained on the basis of synthetic surfactants (surfactants). As the latter, sodium laureth sulfate is most widely used. This substance has a high washing capacity in water of any temperature, gives abundant foam and is inexpensive. However, laureth sulfate negatively affects the protective lipid layer of the skin, irritating it.
The second type of liquid soap is obtained by saponification of fats and oils with potassium alkali. However, in order to obtain in this case a high-quality product with high foaming, it is necessary to use more expensive oils: olive and coconut. This type of soap has not found wide distribution due to its relative high cost.
Natural lumpy solid soap is made by saponification of vegetable oils and animal fats with caustic – sodium alkali. Palm, palm kernel and coconut oils are used as starting oils. The treatment of oils with sodium alkali gives a solid mass, which is further flavored and saturated with useful additives: extracts, vitamins, dietary supplements, etc. This is how ordinary toilet soap turns out.
Sodium and potassium salts are equally safe for the consumer, they are identical in the composition of soap and do not significantly affect the consumer properties of soap.
Differences between liquid and solid soap
As a rule, liquid soap is packed in bottles with a dispenser. There is no need to pick up a piece of soap — it is more convenient. Therefore, in public places — hospitals, offices, shopping malls, cafes, etc., liquid soap is more often used.
Despite the fact that solid soap is constantly in contact with the contaminated surface of the hands, it also does not accumulate bacteria: they are unstable to the alkaline environment of soap.
But in a dilute solution of liquid soap based on surfactants, bacteria do not die — therefore, the composition of liquid soap necessarily contains a sufficient amount of preservatives that do not allow soap to “succumb” to bacteria. Liquid soap is less than solid, suitable for allergy sufferers and people with sensitive skin. Liquid soap is also less safe than solid soap for the environment due to preservatives and synthetic surfactants.
On the other hand, the pH of liquid soap based on surfactants is close to neutral and more physiological for the skin, so liquid soap dries the skin less.
Thus, the choice between liquid soap and solid soap is a choice between convenience and naturalness, between soap that almost does not dry the skin – and soap that does not harm nature