Generalization of soap
Soap is an indispensable daily washing product, and the history of people using soap can be traced back to Italy before BC. Soap has been widely used in China since 1980s. A synthetic detergent appeared in Song Dynasty, which was made by mashing natural Gleditsia sinensis, adding various medicinal petal powders, and making it into a spherical shape, which was used for washing face and bathing body.
Soap is generally a solid block product, but there are also paste and liquid products. The object of soap is different from laundry soap, which is generally aimed at human skin, such as washing hands, washing face and bathing. With the improvement of people's living standards, it is required not only to have the function of cleaning skin, but also to have some new functions such as skin care, beauty, sterilization and deodorization.