1. Brief description and classification of cosmetics
The definition of cosmetics - mainly refers to the method of smearing, spraying, etc., evenly distributed on any part of the human body surface, such as hair, face, neck, armpits, nails, lips and teeth, etc., to achieve cleaning, maintenance, beauty, modification, Chemical industrial products or fine chemical products for the purpose of changing the appearance, etc., and keeping people in good condition.
There are many types of cosmetics, which can be divided into the following categories according to the application site and effect of cosmetics:
Basic Cosmetics: Refers to products designed to protect the skin, hair and improve the health of the skin and hair.
Cosmetics: refers to the products used to modify the face, nails and other parts to increase the charm.
Special-purpose cosmetics: refers to products that are used on the face, hair and other parts with a defensive function or need to undergo some special physical and chemical treatments, and also have a certain palliative and therapeutic effect.
Second, an important raw material in cosmetics - silicone oil
Silicone has a unique silicon-oxygen bond structure Si-O-Si, endowed with large bond angle and bond length, small intermolecular force, and is not easy to crystallize unlike ordinary organic molecules, so it has good air permeability. The high bond energy makes the silicone polymer have outstanding heat resistance and excellent flexibility; the helical structure of its molecular chain and the longitudinal outer side of the methyl group make it have extremely low surface tension and good water repellency. Due to the special structure, organosiloxane polymers have a series of properties such as lubrication, softness, water repellency, defoaming, antibacterial and mildew resistance, and are used in personal care products.
The main characteristics of cosmetic products containing polysiloxane are as follows:
(1) It has good lubricating performance. After coating the skin, it can form a uniform waterproof protective film, but it does not have any sticky and greasy feeling, and the gloss is good.
(2) It has good anti-ultraviolet radiation performance, and it will not oxidize and deteriorate under ultraviolet radiation and cause irritation to the skin.
(3) Good anti-static performance. Tests show that the static electricity of the skin that has been wiped with the polysiloxane-containing skin cream is completely eliminated, and there is an obvious dust-proof effect.
(4) Good air permeability, even if a silicone film is formed on the skin, it does not affect the discharge of sweat. It has a slow release and fixed fragrance effect on flavors and fragrances, so the fragrance preservation period is longer.
(5) High stability, chemical inertness, no adverse effects on other components of cosmetics, especially active ingredients, and good compatibility.
(6) Non-toxic, odorless, tasteless, does not cause irritation and allergy to the skin, high safety, and has a certain curative effect on certain skin diseases, such as dyshidrotic eczema, neurodermatitis and occupational dermatitis.
Silicone oil is generally divided into ordinary silicone oil and modified silicone oil. So far, silicone products that have been successfully used in cosmetics include: polydimethylsiloxane, polymethylphenylsiloxane, methyl hydrogen-containing silicone oil, polyether Modified silicone oil, long-chain alkyl modified silicone oil, cyclic polysiloxane, amino-modified silicone oil, carboxyl-modified silicone oil, polymethylsiloxane emulsion, silicone wax, silicone resin, silicone-treated powder and other series.