Process for the concentration of polyvinyl-chloride emulsion
US3956114A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 31, 1973 |
| Grant date | May 11, 1976 |
| Priority date | — |
| Expiry date | Aug 31, 1993 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB01D69/10
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A process of concentrating an aqueous polyvinyl-chloride emulsion employing a membrane device comprising a feed zone and a permeate zone, the zones separated by an ultrafiltration semipermeable membrane, which process comprises: introducing the polyvinyl-chloride emulsion to be concentrated into the feed zone; removing a concentrated polyvinyl-chloride emulsion from the feed zone and removing an aqueous fraction from the permeate zone; interrupting the process of concentration periodically when the flux rate of the process falls below a desired flux rate value; and contacting the semipermeable membrane with a solution containing a solvent, such as tetrahydrofurane, for the polyvinyl-chloride for a time sufficient to restore the flux value to its desired level, the semipermeable membrane employed characterized by being solvent-resistant to the solvent employed in contacting the membrane.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.