Trihydroxystearin

Description

Trihydroxystearin is a non-hygroscopic derivative of castor oil that imparts a high degree of thixotropic thickening in cosmetics mineral, vegetable and silicones oils, as well as low-polarity aliphatic solvents. Trihydroxystearin  (THS) provides thixotropy and imparts good pay-off in stick products; improves product stability when used in the oil phase of emulsions; and can be used as a binder in pressed powder formulations.  Trihydroxystearin is a mixture of glycerine and castor oil-derived fatty acid (hydroxystearic acid). It is used in amounts between 1–7% as an emollient (moisturising ingredient) and texture-improving thickening agent in cosmetics. In particular, it helps thicken the oil (lipid) part of a skin care or makeup product.

KEY PROPERTIES

• Adds thixotropic body and controls viscosity
• Reduces settling of pigments
• Improves stick pay-off
• Provides binding in pressed powders
• Improves compatibility

INCORPORATION

Trihydroxystearin should be added to the emulsion’s oil phase or, in non-emulsion-based formulations, at the beginning of the dispersion process, preferably by pre-mixing the emollient or oil for 5 minutes before other components are added. Trihydroxystearin should be subjected to as much shear as possible during processing to develop its full properties. However, when using Trihydroxy stearin, an incorporation temperature range of 55-65°C should be observed. The presence of higher polarity oils and solvents will lower this upper temperature limit. To avoid the graininess , particles forming, continuous stirring should be maintained until the formulated product has cooled to below 45°C.