Method for preparing asymmetric radial polymers
US5212249A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 28, 1991 |
| Grant date | May 18, 1993 |
| Priority date | — |
| Expiry date | Oct 28, 2011 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08G81/022
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
A method for preparing asymmetric radial polymers wherein the different polymeric arms are contacted sequentially with a nonpolymerizable coupling agent. Contacting of the final step in the process, which frequently but not necessarily always will be the second step in the process, will be carried out in the presence of a polar compound suitable for increasing the amount of vinyl content in a conjugated diolefin polymer during polymerization thereof. The method used narrows the relative arm distribution of the several asymmetric radial polymers produced and significantly increases the amount of total product having the desired ratio of polymeric arms and accomplishes this objective in relatively short reaction time. Any nonpolymerizable coupling agent known in the prior art to be useful in the production of asymmetric radial polymers may be used in the method of this invention but nonpolymerizable coupling agents having from 3 to about 12 functional groups are most effective and nonpolymerizable coupling agents having 2 or 3 functional groups are most preferred. Useful polar compounds are, generally, selected from the group consisting of ethers, tertiary amines, pyridine and pyroli…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.