Method for producing ethylene-vinyl acetate copolymer and saponified product thereof
US6683148B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Jun 5, 2001 |
| Grant date | Jan 27, 2004 |
| Priority date | — |
| Expiry date | Oct 12, 2021 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08F2800/20
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
The present invention provides methods for producing an ethylene-vinyl acetate copolymer and a saponified product thereof, in which defective appearances at the time of molding (e.g. fish eye or coloring) can be inhibited while using a recovered solvent. In the present invention, a recovered alcohol-based solvent is supplied for reuse after decreasing the concentration of an aldehyde compound contained in the solvent. The concentration of an aldehyde compound can be decreased by acetalizing it with an acid such as a cation exchange resin. For example, the concentration of an aldehyde compound in the solvent is not more than 100 ppm, and the concentration of an acetal compound in the solvent is at least 0.1 ppm but not more than 10,000 ppm.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.