Polymeric particles and their preparation
US4920160A · kind A · utility
87Cited by
17References
14Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jul 10, 1989 |
| Grant date | Apr 24, 1990 |
| Priority date | — |
| Expiry date | Jul 10, 2009 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S525/902
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
Swollen core/sheath polymeric particles are disclosed having one or more voids in the core formed by reaction with a base such as sodium hydroxide. The sheath contains styrene or similar monomer polymerized in an amount greater than 25 mole percent and the polymer is free of acid groups. The core contains acid groups. Swelling is effected at an elevated temperature and in the absence of an organic solvent. The swollen particles on drying in a paint or other composition have air in the voids and act then as opacifying agents.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.