Ultraviolet shielding composite fine particles, method for producing the same, and cosmetics
US5902569A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 27, 1997 |
| Grant date | May 11, 1999 |
| Priority date | — |
| Expiry date | Aug 27, 2017 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC01P2006/90
- WIPO fieldPharmaceuticals
- WIPO sectorChemistry
Abstract
The present invention is directed to ultraviolet shielding composite fine particles having transparency in a visible light region include (a) matrix particles comprising an aggregate of primary particles having an average particle diameter of from 0.001 to 0.3 .mu.m, the aggregate being formed while the primary particles retain their shapes; and (b) daughter particles having an average particle diameter of from 0.001 to 0.1 .mu.m, the daughter particles being dispersed in and supported by the matrix particles. In the composite fine particles, the daughter particles have a smaller band gap energy than the particles constituting the matrix particles and are capable of absorbing ultraviolet light, and the resulting ultraviolet shielding composite fine particles have substantially no catalytic activity.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.