silicone oil emulsion for cosmetics can be prepared by 3 emulsion polymerization methods: ring opening polymerization, condensation polymerization and addition polymerization.
Ring opening polymerization: this method [20~27] takes two methyl cyclosiloxane, such as eight methyl ring four siloxane (D4) as raw material, as a balance reaction; in the emulsion, it usually contains 5%~10% cyclic siloxane oligomer. In storage and use, cyclic siloxane oligomers are easily volatilized from the emulsion, affecting the stability of the emulsion. When the hair cosmetics are used in the relatively centralized places such as hot air treatment, the volatile cyclic siloxane oligomers will pollute the environment and cause the contact faults of the surrounding electrical facilities. However, this method has the advantages of easy preparation and is suitable for some skin cosmetics.
Polycondensation: low viscosity a, ω – dihydroxy polydimethylsiloxane as raw materials. The most notable feature is that the product does not contain cyclic siloxane oligomers, and can produce high oil emulsion with good stability [30, 31].
Addition polymerization method: vinyl terminated low molar mass poly two methylsiloxane and low hydrogen molecular weight poly (two methyl siloxane) were used as raw materials. The products of the uncompetitive product contained no cyclic siloxane oligomers, and the dispersed diameter of the emulsion could be controlled, and the silicone oil emulsion (32, 33) could be obtained. Because of the siloxane bonds and silyl aChinayl bonds produced by addition reaction, the cosmetic products made from this emulsion have unique advantages in terms of contact, extensibility and sense of use. Moreover, the emulsion does not contain ionic surfactants, and its safety is improved when making cosmetics.