Preparation of PHEMA by precipitation/suspension polymerization
US4904749A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 16, 1988 |
| Grant date | Feb 27, 1990 |
| Priority date | — |
| Expiry date | Dec 16, 2008 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08F20/28
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
Disclosed is a method for preparing poly(2-hydroxyethyl methacrylate) polymers (PHEMA) by a precipitation/suspension polymerization technique wherein a reaction mixture comprising hydroxyethyl methacrylate monomer (HEMA), solvent, and a free-radical initiator is subjected to heating for a time adequate for said PHEMA to be formed. The improvement in process of the present invention comprises restricting said HEMA to contain less than about 0.5 wt-% polyfunctional acrylate content, incorporating a suspending agent in said reaction mixture, agitating said reaction mixture during said heating, and restricting said solvent to one having a solubility parameter of between about 7.5 and 9, to produce PHEMA polymer particles ranging in size from about 30 to 1,000 microns and having a molecular weight ranging from about 500,000 to 2,000,000.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.