Quality control of hair coloring cosmetics

On the hair dye, dye composition is a key. Dye intermediates selected the pros and cons, good or bad effects directly related to the stain. Dye intermediates are not a pure substance, but a compound, it should be the color of dye intermediates and the oxidation reaction may to choose. In addition, a small number of different locations for dye intermediates containing biotin substituents isomers, namely, the oxidation product of, generate a different color, affect the staining results, so that the requirements of the quality of dye intermediates to be guaranteed, that is to do to the more pure the better, as far as possible the raw materials meet the quality requirements.

The oxidant is the other major component of hair dye, the concentration of the active substance in the oxidizer, a direct impact on the full extent of the oxidation reaction of dye intermediates in hair dye process. Oxidants in the active matter content is low, then the oxidation reaction has not been completely may generate color than the original mining develop lighter, due to the completion of reaction had to entirely under the influence of other media, as well as possible reaction proceed , but the hair after the color instability, less than the original results. Conversely, if the high active substance content in the oxidant, the oxidation reaction may be carried out completely, but the oxidant itself have bleached hair both oxidation may occur simultaneous bleaching and oxidation, and oxidant high levels of the active material, will greatly enhance the destructive power of hair keratin, exacerbated by the extent of damage to the hair. Also reach the desired effect.

In addition, the cream hair dye or hair shampoo to use more of the active material of the hydrogen peroxide as oxidant, peroxide of hydrogen itself is a rather unstable substance, easily decomposed to loss of oxygen, only the relatively stable under acidic conditions, so in preparation hydrogen peroxide solution when the pH value of the proper control of oxidant. If the acidity of minoxidil oxidant is low, too unstable hydrogen peroxide is easily decomposed; acidity high, slow down the hydrogen peroxide decomposition rate, and reduce the free alkali content mixed with the dye matrix part, the same affect staining results . Adjust the pH value of the oxidant in the preparation to 3.0-4.0, but alone is not enough to control the pH value to stabilize the oxidant, then add some stabilizer to block oxidant decomposition rate.

The free alkali content of the hair dye is the key to affecting the quality. If the pH is too high, under alkaline conditions the scalp and easy expansion, dye intermediates penetrate the hair dye in alkaline easily oxidized color, and accelerate the dyeing speed; in the hair dye process, however, a strong alkaline dyes which easily lead to skin irritation, while storage will accelerate dye intermediates oxidation rate, shorten the shelf life. If the PH is low, the oxidation reaction has not been completely the same bow I played dyeing effect weakened. Generally dye part of the pH value is about 9-11.

The hair dye‘s viscosity should be controlled to a certain target when it is in preparation and operation. Because viscosity of the dye is also involved in the effect of dyed hairs. If the tretinoin viscosity is low, in the process of hair, it could easily lead to contaminate scalp, clothes. And the hair dye paste is easy to stick on surface of the hair, making hair uneven and impact the dyed effect. The viscosity of the hair dye should be increased thus making the hair dye cream not only adhere to the hair surface but also does not drip on your clothes. In the packaging, it is easily installed irrigation. Generally viscometer is used to measure viscosity, including dye composition, oxidant, and viscosity of the dye. According to different formulations, people can select a variety to desired viscosity.Source:http://www.cosprm.com