Perm is a kind of hairdressing method, which can be divided into physical perm and chemical perm, of which chemical perm is the most commonly used one. Perm can make hair richer (with curling effect); Change the shape and direction of hair (curling is not very effective).
The basic process of perm is divided into two steps. The first step is to break the sulfur bond and hydrogen bond in hair through chemical reaction. Step 2, arrange the stable hair core structure.
Development history
In daily life, hair is regarded as an ornament. Throughout history, people have been looking for ways to curl their hair. Perm is closely related to the development of perm tools, which can be said to be the promotion of perm tools.
In 1990s, North Korea invented ceramic ironing, and then it spread to Japan, Taiwan Province Province from Japan, and finally to Chinese mainland. This is a long process, and ceramic ironing has been popular until the beginning of the 20th century.