Ultraviolet-screening composite particulate and process for the production thereof
US6090373A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 19, 1998 |
| Grant date | Jul 18, 2000 |
| Priority date | — |
| Expiry date | Aug 19, 2018 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61K2800/413
- WIPO fieldPharmaceuticals
- WIPO sectorChemistry
Abstract
Ultraviolet shielding composite fine particles having transparency in a visible light region, comprising matrix particles comprising an aggregate of primary particles having an average particle size of from 0.001 to 0.3 .mu.m, the aggregate being formed while the primary particles retain their shapes; and daughter particles having an average particle size of from 0.001 to 0.1 .mu.m, the daughter particles being dispersed in and supported by the matrix particles, wherein the daughter particles have a smaller band gap energy than the particles constituting the matrix particles and are capable of absorbing ultraviolet light, and wherein the surfaces of the composite fine particles are coated with one or more silicones selected from the group consisting of modified silicones, reactive silicones, and silicone-modified copolymers, and wherein the ultraviolet shielding composite fine particles have substantially no catalytic activities. By forming composite fine particles comprising the ultrafine particles having the ultraviolet shielding ability, the composite fine particles of the present invention have substantially no catalytic activities, high transparency in the visible light region…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.