Patent ID: 6242538
Filing Date: 2001-06-05
Classification: C08F

Abstract:
A process for making gel-free hydrogenated functionalized anionic polymers using multi-lithiuim initiators which comprises:(a) anionically polymerizing at least one monomer with a multi-lithium initiator in a hydrocarbon solvent,(b) functionalizing the polymer by adding to the polymer a capping agent that reacts with the ends of the polymer chains such that strongly-associating chain ends are formed resulting in a polymer gel,(c) adding a trialkyl aluminum compound to the polymer gel whereby the gel dissipates,(d) adding a sufficient amount of a proton source to provide at least 1 mole of protons per mole of lithium ions and at least 2 moles of protons per mole of aluminum wherein the proton source is an organic acid with a pK.sub.a of 11 or less or a mixture of the organic acid and an alkanol, provided that sufficient organic acid is added to provide at least 0.4 moles of protons per mole of lithium ions,(e) hydrogenating the polymer with a hydrogenation catalyst, and(f) optionally washing the terminated polymer with aqueous mineral acid.