The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 18, 1993
Filed:
Oct. 28, 1991
Gary W Richie, deceased, late of Columbus, TX (US);
Raymond C Tsiang, Sugar Land, TX (US);
Ronald J Hoxmeier, Houston, TX (US);
Arthur R Bean, Houston, TX (US);
Harvey E Atwood, Kingwood, TX (US);
Shell Oil Company, Houston, TX (US);
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 pyrolidene compounds.