Vinyl alcohol copolymers for use in aqueous dispersions and melt extruded articles
US7994265B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Aug 13, 2010 |
| Grant date | Aug 9, 2011 |
| Priority date | — |
| Expiry date | Aug 13, 2030 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08F2800/20
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
In a method of preparing an aqueous dispersion selected from drilling fluids, hydraulic cement compositions, mineral pigment containing coatings, and papermaking furnishes or in a method of preparing a melt extrudate, the improvement comprising: a) producing a copolymer of vinyl alcohol (VOH) and 2-acrylamido-2-methyl propane sulfonic acid or a salt of such acid (AMPS) by steps including continuously feeding with agitation, vinyl acetate (VAM) and AMPS as comonomers, a free radical yielding polymerization initiator, and a solvent for said comonomers, initiator, and copolymer resulting from the copolymerization of said comonomers, maintaining the resulting reaction mass in said first reaction zone under polymerization conditions for a residence time sufficient for a major proportion of AMPS fed to said first reaction zone to polymerize, continuously feeding reaction mass from said first reaction zone with an additional supply of AMPS to a second reaction zone, maintaining the reaction mass in the second reaction zone for a residence time sufficient to polymerize a major proportion of the AMPS added to the second reaction zone, continuously withdrawing reaction mass from the second r…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.