Sensient Cosmetic Technologies, www.sensient-cosmetics.com, has a product called Color’N Cap Sil that encapsulates a dyestuff in a silica matrix. It results from a combination of silica sol-gel chemistry and a spray-drying process.
The sol is a colloidal suspension of silicate in a gel which is customized by changing physical parameters such as temperature and pH. When a dye such as FDC Blue 1 is added, it becomes entrapped in the silica matrix. The mixture is then spray dried to get instant solidification. This microencapsulation is a procedure devoted to entrapping solids, liquids, or sometimes gases with a coating. The particle size is micrometric. The objective of this procedure is to protect the ingredient, convert a liquid to a solid, change the surface properties, and furnish long-lasting or controlled release of the ingredient.
Color’N Cap Sil has three shades, Blue 5601 (FDC Blue 1), Red 5602 (FDC Red 40) and Yellow 5603 (FDC Yellow 5) that all consist of 99% silica and 1% dye. The primary applications of these products are in striped toothpaste where they furnish non-migrating color and to produce swirls in hair conditioners or skin cream formulas. The Blue 5601 is a blue, water insoluble powder that has good fastness to alkalis but poor fastness to acids. Its light fastness is average.
The suggested uses in various products are as follows:
It is claimed that there was no color migration when tested in water, toothpaste and in a conditioning hair care product. In bleeding comparisons with lakes in toothpaste at room temperature and 45°C after one month, more bleeding occurred with the lake formulas, even at room temperature.
Various shades of violet, orange, green, blue, or pink can be created.
When formulating, it is recommended to pre-disperse Color’N Cap Sil in a polyol or in the oil phase before adding to the emulsion. A high stirring apparatus should be used. A suspending agent may be required in a very liquid formula. All are stable from pH 4 to 9, except Blue 5601, which is not stable below pH 6.
The following formula illustrates the use of Color’N Cap Sil.
|Colored Phase Color’N Cap SIL Range||As needed|
Procedure: Disperse gum into the glycerin by mixing 5 minutes at 800rpm. Add sorbitol and water, mix for 30 minutes at 800rpm. Add phase B after dissolving in water and mix for 10 minutes. Transfer to a planetary mixer. Add phase C, mix until all particles are wet out, then mix under vacuum at maximum speed for 15 minutes. Add D and E and mix at full vacuum. Homogenize colored phase to make stripes.
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.