"Water-redispersible powders of film-forming polymers with a ""core/shell"" structure"
US5872189A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 8, 1997 |
| Grant date | Feb 16, 1999 |
| Priority date | — |
| Expiry date | Sep 8, 2017 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S977/70
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
The present invention relates to a water-redispersible powder based on film-forming polymers which are substantially water-insoluble and which are prepared by aqueous emulsion polymerization of monomers containing ethylenic unsaturation with a "core/shell" structure comprising a hydrophobic core based on a polymer exhibiting a Tg (glass transition temperature) of between -30.degree. and +25.degree. C., preferably between -10.degree. and +20.degree. C., and a hydrophilic shell based on a polymer exhibiting a Tg higher than +55.degree. C., preferably higher than +90.degree. C., characterized in that the shell is bonded to the core by covalent bonds resulting from the reaction of an agent for grafting the shell onto the ethylenic unsaturations remaining in the core, and is substantially insoluble in an alkaline medium.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.