Ultraviolet shielding composite fine particles, method for producing the same, and cosmetics
US5827507A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 1, 1996 |
| Grant date | Oct 27, 1998 |
| Priority date | — |
| Expiry date | Apr 1, 2016 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC01P2006/60
- WIPO fieldPharmaceuticals
- WIPO sectorChemistry
Abstract
The present invention is directed to ultraviolet shielding composite fine particles having transparency in a visible light region, comprising (a) matrix particles comprising an aggregate of primary particles having an average particles diameter of from 0.001 to 0.3 .mu.m, said aggregate being formed while retaining the shapes of the primary particles; and (b) daughter particles having an average particle diameter of from 0.001 to 0.1 .mu.m, said daughter particles being dispersed in and supported by said matrix particles, wherein said daughter particles have a smaller band gap energy than that of particles constituting said matrix particles, and possess capability of absorbing ultraviolet light. The composite fine particles are produced by preparing a liquid mixture containing a mixture comprising starting materials for matrix particles and for daughter particles; forming droplets from the liquid mixture; and drying the formed droplets and/or pyrolyzing starting materials for pyrolysis therein. The cosmetics of the present invention contain the above composite fine particles.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.