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. 07, 2002
Filed:
Apr. 25, 2001
Jean-Luc Cabioch, Chateaugay, FR;
Nicole Dajoux, Ceyrat, FR;
Michelin Recherche et Technique S.A., Granges-Paccot, CH;
Abstract
The present invention provides a process for preparing a branched diene elastomer having a high proporation of starred chains comprising anionically polymerizing at least one conjugated diene monomer having 4 to 12 carbons in a polymerization medium comprising a hydrocarbon solvent, such as cyclohexane, and an organometallic initiator, such as n-butyllithium, wherein tris-(2,4-di-tert-butylphenyl)phosphite is added to the polymerization medium as a starring agent during or at the end of polymerization in an amount such that the molar ratio of the starring agent to the initiator is between 0.1 and 1.5, preferably between 0.2 and 0.5. The process produces a branched diene elastomer having a high proportion of starred chains. The elastomer can be a homopolymer, such as polybutadiene or polyisoprene or a copolymer, such as polystyrene/polybutadiene.