Ultrafiltration of polyisoolefin copolymers and polyisoolefin copolymers with reduced oligomer content
US10766974B2 · kind B2 · utility
Inventor
Key dates
| Filing date | Jul 7, 2015 |
| Grant date | Sep 8, 2020 |
| Priority date | — |
| Expiry date | Jul 7, 2035 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08J2323/22
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A method of separating a polyisoolefin elastomer from non-polymeric components in an organic solvent involves ultrafiltration of a solution of the polyisoolefin elastomer and non-polymeric components in an organic solvent through a semipermeable membrane to substantially retain the polyisoolefin elastomer in a retentate and provide the non-polymeric components in a permeate. Advantageously, stabilizers for the polyisoolefin elastomer are retained in the retentate along with the polyisoolefin elastomer, permeate flux through the membrane is higher as concentration of the polyisoolefin elastomer in the solution increases up to a concentration limit, the separated polyisoolefin elastomer in the retentate has a molecular weight that can be substantially unchanged even when ultrafiltration is conducted at elevated temperature and the amount of polyisoolefin elastomer in the permeate is unmeasurable providing an oligomer-rich permeate uncontaminated by polyisoolefin elastomer. A process for curing a polyisoolefin copolymer involves reducing content of an oligomer to 900 ppm or less in a mixture of the oligomer and the polyisoolefin copolymer to produce an oligomer-depleted mixture, and a…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.