Encapsulated hydrophilic polymers and their preparation
US5545695A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 6, 1995 |
| Grant date | Aug 13, 1996 |
| Priority date | — |
| Expiry date | Jun 6, 2015 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08F265/04
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
A multistaged polymer containing a hydrophilic core fully encapsulated with a hydrophobic shell without a tiecoat layer is disclosed. A method is also disclosed for encapsulating hydrophilic polymers including the steps of: PA1 (1) emulsion polymerizing a hydrophilic core polymer from about 5% by weight to about 100% by weight, based on the total weight of the core polymer, of a hydrophilic monoethylenically unsaturated monomer and from 0% by weight to about 95% by weight, based on the total weight of the core polymer, of at least one nonionic monoethylenically unsaturated monomer; PA1 (2) emulsion polymerizing, in the presence of the core polymer, at least one shell polymer from about 90% by weight to about 99.9% by weight, based on the total weight of shell polymer, of at least one nonionic monoethylenically unsaturated monomer and from about 0.1% by weight to about 10% by weight, based on the total weight of the shell polymer, of an acid-functional monoethylenically unsaturated monomer, PA2 wherein the acid-functional monoethylenically unsaturated monomer is added to the polymerization of the shell polymer over 100% of the total shell monomer feed when the particle size of the c…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.