Aspherical hollow silica particles as spf boosters
AssigneesDow Global Technologies LLC, Rohm and Haas Company
InventorsJie XIONG, Fanwen ZENG, Wenjun XU, Dean M. MILLAR
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Abstract
Described herein are aspherical hollow silica particles, processes for making aspherical hollow silica particles, and uses of aspherical hollow silica particles in sun care compositions. To form the aspherical hollow silica particles, deposition of a silica shell on a calcium carbonate template using a sol-gel chemistry is employed. Subsequent dissolution of the calcium carbonate template forms voids (e.g., a hollow interior) in the aspherical hollow silica particles.
Claims21
A sun care composition, comprising:
- aspherical hollow silica particles having a long axis and a short axis, wherein the average short axis is greater than 400 nm;
- and
- at least one sunscreen active.
A process for making aspherical hollow silica particles having a long axis and a short axis, wherein the average short axis is greater than 400 nm, and wherein the aspherical hollow silica particles contain less than about 2 wt. % organic substances without further purification, the process comprising:
- dispersing calcium carbonate templates in ethanol,
- adding ammonium solution,
- then adding tetraethyl orthosilicate (TEOS), and
- adding acid to dissolve the calcium carbonate templates.
(canceled)
A sun care composition, comprising:
- aspherical hollow silica particles having a long axis and a short axis, wherein the average short axis is greater than 400 nm, and the long axis is at least 1.25 times greater than the short axis;
- and
- at least one sunscreen active.
Dependencies are inferred from the claim text.