Polyvinyl alcohol and method for producing same
US10766978B2 · kind B2 · utility
Assignees
Inventors
Key dates
| Filing date | Mar 30, 2017 |
| Grant date | Sep 8, 2020 |
| Priority date | — |
| Expiry date | Jun 1, 2037 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08K5/235
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
A polyvinyl alcohol is produced in a method comprising: a polymerization step comprising polymerizing vinyl ester monomers by controlled radical polymerization in the presence of a radical initiator and an organic cobalt complex to obtain a polymer solution containing a polyvinyl ester; an extraction step comprising extracting a cobalt complex from the polymer solution by contacting an aqueous solution containing a water-soluble ligand with the polymer solution; and a saponification step comprising saponifying the polyvinyl ester after the extraction step to obtain a polyvinyl alcohol. A method for producing a polyvinyl alcohol is thus provided that has a narrow molecular weight distribution and a high number-average molecular weight with good hue and further good solubility in water.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.