Using this method, Croda established a large set of data for many simple emulsions, which enabled a statistical analysis of the relative contributions of emollients and emulsifiers to the sensory feelings of these emulsions. They determined that the fundamental feel of an emulsion is determined by the choice of the emulsifier (or emulsion stabilizer system). It had been thought that the emollient was the primary factor in the feel of a product.
But Croda researchers discovered that emulsifiers are primarily responsible for initial feel, and the emollient is felt once the emulsion has broken after rub out as part of the product’s after feel. A Sensification kit was developed that contains formulation prototypes to demonstrate sensorial properties that Croda’s different emulsifiers exhibit. Samples can be ranked as light to heavy or fluid to viscous for comparative purposes.
One of Croda’s newest emulsifiers, Natragem E145NP (INCI: Polyglyceryl-4 laurate/succinate (and) water), I assume, was tested as above. Croda is promoting it as having the following benefits:
- Approved natural by Ecocert;
- Hot and cold processable;
- High HLB, oil in water emulsifier;
- Electrolyte, pH and temperature tolerant;
- Creates emulsions from sprayable lotions to thick creams;
- Can be used with high and low polarity oils; and
- Is non-preserved.
Some other water phase thickeners suggested are xanthan gum (0.1-0.5%), carbomer (0.05-0.1%) and xanthan gum (and) Veegum Ultra (0.1-0.3%). When it is added to the oil phase, a small amount of water phase thickener (0.1-0.2) is useful, as are soft, waxy materials. Recommended co-emulsifiers are glyceryl stearate and sorbitan stearate, both at 1.5 to 3%. Useful waxes for the oil phase at 2-4% are cetearyl alcohol, behenic acid and stearic acid that create soft to medium viscosity creams. These co-emulsifiers and waxes are necessary to create firmer creams. The viscosity will build up over one to two days.
A cold process lotion can be achieved as follows:
Procedure: Disperse ingredients of the water phase in the main tank. In separate container, combine oil phase and add to water phase with stirring. Finally, homogenize for one minute.
Recommended applications for Natragem are for skin, hair and baby care, color cosmetics, natural creams and
lotions and deodorants.
Harvey M. Fishman
Harvey Fishman has a consulting firm in Wanaque, NJ, specializing in cosmetic formulations and new product ideas, offering tested finished products. He has more than 30 years of experience and has been director of research at Bonat, Nestlé LeMur and Turner Hall. He welcomes descriptive literature from suppliers and bench chemists and others in the field.