Hair dye is a cosmetic that dyes hair. Divided into temporary, semi-permanent and permanent hair dyes. In the dye base, in order to achieve a certain consistency for easy use, the dye base is generally made into a paste.
It is better to use O/W emulsification system to improve the stability of the dye matrix
As a paste, it generally comes in two forms, one is to add a thickener to increase the consistency, and the other is to make an emulsion to achieve the purpose of thickening. There are also a few that use a combination of the two. Since the dye matrix generally contains most of the dye, water-soluble thickeners are generally chosen as thickeners. In the dye matrix formula of water-soluble thickener, its stability is often not good. During the storage process, the paste will slowly be oxidized from the surface to the inside, and the color will become darker, resulting in a decrease in hair dyeing effect, and ultimately it cannot be used. The reason may be that in such a matrix formula, all substances are uniformly dissolved in the aqueous solution. When exposed to air, an oxidation reaction occurs and gradually penetrates into the interior, causing the entire paste to deteriorate. Therefore, it is generally not recommended to use additives. Thickener method to increase the consistency.
The use of emulsification systems to provide stability to dye matrices has been reported. After experiments, it was concluded that it is better to use the O/W emulsification system to improve the stability of the dye matrix. This is because the process and equipment are relatively simple, the preparation conditions are not harsh, the repeatability is good, the paste itself is stable and is not easy to break the emulsion, and the prepared The obtained paste is not easily oxidized. Even after the surface is oxidized, it can form a relatively stable barrier layer to prevent air from further penetrating into the paste, thereby achieving the purpose of improving the stability of the dye matrix.
To prepare a good O/W emulsion system in the dye matrix, cetyl alcohol, stearyl alcohol and their mixed alcohols are generally used, and it is recommended to use oleyl alcohol with double bonds, and these Ethylene oxide adducts of long-chain fatty alcohols. These long-chain fatty alcohols are oil-soluble polar compounds that form a stable composite layer together with surfactants, which is beneficial to improving the stability of the dye matrix.
The following is a brief introduction to cetyl alcohol, octadecanol and cetadecanol:
Cetyl alcohol: white crystal with rose aroma. Soluble in ethanol, ether, benzene, chloroform, acetone, insoluble in water. It is suitable for use in various cosmetics as a base, especially suitable for creams and lotions; in medicine, it can be directly used in W/O emulsifier pastes, ointment bases, etc. The raw materials of Pingpingjia can also be used as defoaming agents, soil and water moisturizers, gas chromatography fixatives (color-forming agents); they can also be used as raw materials for the production of alcohols, amides and sulfonated products for detergents; and as heat preservation agents for rice fields.
Stearyl alcohol: white flakes or granules. Soluble in alcohol, benzene and chloroform, insoluble in water. It is widely used in daily chemicals, textiles, printing and dyeing and other industries, and is a raw material for manufacturing surfactants, emulsifiers and various additives. Used as a base (emulsifier) for creams and lotions in cosmetics. Stearyl alcohol has stronger emulsion thickening properties than cetyl alcohol.
Cetearyl-octadecanol: Cetearyl-octadecanol, also known as cetearyl alcohol, is a mixture of solid fatty alcohols containing octadecanol and cetyl alcohol, in the form of white solid, flake or Granular. Grease chemical raw materials are mainly composed of cetyl alcohol and carbon stearyl alcohol. For use in cosmetics, plastics, leather, textiles, synthetic detergents and other industries. As a base in cosmetics, it is especially suitable for creams and lotions; in medicine, it can be directly used in W/O emulsifier pastes, ointment bases, etc.; in hair care and skin care.
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