Cosmetic emulsion preparations 2 of 2

  The oil mixture consists of dipropyl ether in a ratio of 3:1. The hydrophilic emulsifier is a 5:3 mixture of coco-glucoside (C8-14 APG) and sodium laureth sulfate (SLES).This highly foaming anionic surfactant mixture is the basis of many body cleaning formulations.The hydrophobic co-emulsifier is glyceryl oleate (GMO).The water content remains unchanged at 60%.

  Starting with the oil-free and co-emulsifier system, the 40% C8-14 APG/SLES mixture in water forms a hexagonal liquid crystal. The surfactant paste is highly viscous and cannot be pumped at 25℃.

  Only a small portion of the C8-14 APG/SLES mixture is replaced with a hydrophobic co-surfactant GMO to produce a layered phase with a medium viscosity of 23000 mPa·s at 1s-1. In practice, this means that the high viscosity surfactant paste becomes a pumpable surfactant concentrate.

  Despite the increased GMO content, the lamellar phase remains intact. However, the viscosity increases significantly and reaches levels for the liquid gel which are even above those of the hexagonal phase. In the GMO corner, the mixture of GMO and water forms a solid cubic gel. When oil is added, an inverse hexagonal liquid is formed with water as the internal phase. The hexagonal· liquid crystal rich in surfactants and the lamellar liquid crystal differ considerably in their reactions to the addition of oil. Whereas the hexagonal liquid crystal can only take up very small quantities of oil, the lamellar phase area extends far towards the oil corner. The capacity of the lamellar liquid crystal to take up oil clearly increases with increasing GMO content.

  Microemulsions are only formed in systems with low GMO contents. An area of low-viscosity o/w microemulsions extends from the APG/SLES corner along the surfactant/oil axis up to an oil conte of 14%. the microemulsion consists of 24% surfactants, 4 % coemulsifier and 12% oil, representing an oil-containing surfactant concentrate with a viscosity of 1600 mPa·s at 1 S-1.

  The lamellar area is followed by a second microemulsion. This microemulsion is an oil-rich gel with a viscosity of 20,000 mPa·s at 1 S^-1 (12 % surfactants, 8% coemulsifier, 20 % oils) and is suitable as a refatting foam bath. The C8-14 APG/SLES mixture helps with cleaning properties and foams, while the oily mixture acts as a skin care supplement.In order to obtain the mixing effect of the microemulsion, the oil must be released, that is, the microemulsion must be broken during use.During the rinsing process, the microemulsion with appropriate ingredients is diluted with a lot of water, which releases oil and acts as a supplement to the skin.

  To sum up, alkyl glycosides can be combined with appropriate co-emulsifiers and oil mixtures to prepare microemulsions. It is characterized by transparency, high temperature stability, high storage stability and high solubility.

  The properties of alkyl polyglycosides with relatively long alkyl chains (C16 to C22) as o/w emulsifiers are even more pronounced. In conventional emulsions with fatty alcohol or glyceryl stearate as coemulsifier and consistency regulator, long-chain alkyl polyglycosides show better stability than the medium-chain C12-14 APG described above. Technically, the direct glycosidation of C16-18 fatty alcohol leads to a mixture of C16-18 alkyl polyglycoside and cetearyl alcohol from which cetearyl alcohol cannot be completely distilled off by usual techniques to avoid color and odor deterioration. Utilizing the residual cetearyl alcohol as co-emulsifier, self-emulsifying o/w bases containing 20-60% C6/18 alkyl polyglycoside are the most suitable in practice for formulating cosmetic cremes and lotions based entirely on vegetable raw materials. Viscosity is easy to adjust through the amount of alkyl polyglycoside/ cetearyl alcohol compound and excellent stability is observed, even in the case of highly polar emollients, such as triglycerides.