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Patent Pick: DIY Particle Dispersion

February 18, 2016 | Contact Author | By: Rachel Grabenhofer, Cosmetics & Toiletries
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  • Keywords/Abstract
Suspended beads 850

Keywords: pigment | milling | coating | metal oxide | self-dispersing | polyhydroxy stearic acid

Abstract: Are you "back at the grind," milling metal oxides for color cosmetics or sunscreens? These inventors are enabling the work do itself, with a self-dispersing particle coating.

Are you "back at the grind," milling metal oxides for color cosmetics or sunscreens? These inventors are enabling the work do itself, with a self-dispersing particle coating.

Self-dispersible coated metal oxide powder
U.S. Patent 9254398
Publication date: Feb. 9, 2016
Inventors: D. Schlossman, Y. Shao and C. Orr

Described in this patent is a composition consisting of metal oxide particles that are coated with an organic dispersant in an amount that renders the particles self-dispersible. Also disclosed are cosmetic compositions that include said composition.

While the dispersion of micro metal oxides has been disclosed in literature, they typically require milling, which involves equipment not often available to formulators; in many cases, only mechanical mixers or homogenizers are available. Even when a milling process is available, variations from milling can make proper dispersion in formulas difficult.

Therefore, the present solution sought to improve the dispersibility of pigments, e.g., metal oxides, to provide the desired performance even in the absence of milling. This invention removes the need to separately add a dispersing agent, and improves the dispersibility of the pigment.

Specifically disclosed is a particulate metal oxide having a coating that includes a polyhydroxy stearic acid in an amount that makes the particulate metal oxide self-dispersible. The particulate metal oxide may be titanium dioxide, zinc oxide, aluminum oxide or an iron oxide. It is suggested for liquid or dry make-up such as a sunscreen, foundation or pressed powder, lipstick, blush, eye-shadow or mascara. The cosmetic composition may be anhydrous or an emulsion.