Hair dye is a cosmetics dyeing hair, categorized into temporary, semi-permanent and permanent hair color, which is normally semi-liquid and contained in soft tube, such as plastic tube and aluminum tube and other soft cosmetic tube.
Hair dye cosmetics have the effect of changing the color of hair, commonly known as hair dye. The Chinese belong to the yellow race, and most of them use white hair to blacken the beauty, so the hair dye is also relatively monotonous.
Europeans and Americans are used to bleaching or bleaching their hair, and then dyeing their hair into gold, yellow, linen, reddish brown, violet, etc., so their hair dyes have a wide variety of colors.
Since the reform and opening up, by the impact of international popular hair color, China has also introduced a variety of color hair dyes.
Since the reform and opening up, influenced by the international popular hair color, China has also launched color hair dyes of various colors, which has made China’s hair dye market shine.
In the 21st century, our country will enter the aging society. With the increasing number of the people in the silver-haired class, the market demand of hair dyeing products will increase day by day. Moreover, nowadays people are living fast and tense life, which causes dramatical booming of gray hair and boldness, and bring massive market.
Temporary hair dye product could be removed once washing with shampoo. These hair dye particles are too large to enter the hair shaft, they only deposit on the hair surface, forming a colored coating. In this way, the interaction between hair and dye is not strong, and it is easy to be washed off by shampoo.
Semi-permanent hair dye generally refers to the dye which can resist 6-12 shampoo washing before fading. When used, apply it on your hair, stay 20-30 minutes, rinse with water, and then you can dye your hair. Its mechanism is that the dye molecules with relatively low molecular weight penetrate into the hair epidermis and partly into the cortex, making it more shampoo resistant than temporary hair dyes. Semi-permanent hair dye is more popular in recent years because it does not damage the hair without hydrogen peroxide.
Permanent hair dyes are divided into three types: plant permanence, metal permanence, and oxidation permanence.
1. Plant permanence:
It is expensive to use the material extracted from the flower, stem, and leaf of a plant to dye, and it is seldom used in China.
2. Metal permanence:
Dyeing with metal raw materials. Its dyeing mainly deposit on the hair surface, the color has a dim metal appearance, which makes the hair brittle and lower the efficiency of perm.
3. Oxidation permanence:
The mainstream product in the market, it does not contain ordinary dyes, but contains dye intermediates and couplers. These dye intermediates and couplers permeate into the hair cortex and undergo oxidation, coupling and condensation reactions to form larger dye molecules, which are enclosed in the hair fibers. Because of the different kinds of dye intermediates and couplers and the difference of the content ratio, the reaction products of different hue are produced, and all kinds of tonal products are combined into different hues, which make the hair get different colors. Because dye macromolecules are formed in hair fibers by reaction of dye intermediates with small molecules of coupling agents, the resulting dye macromolecules are not easily flushed through the pore size of hair fibers during washing.
A week before dyeing, do not use a shampoo that combines washing and protection, and do not use protect hair oil, hair conditioner or moisturizers, which will form a protective film outside the hair and block the dye from entering. Shampoo with deep cleaning effects should be used, but try not to wash your hair 2 days before dyeing, let the hair secrete grease, form a natural protection to protect hair follicle. Local allergy tests are also performed 48 hours before dyeing.
