Patent ID: 6946524

Claim:
A process for producing it polyester amide, said process comprising reacting a polyisobutylene having an isobutylene monomer content of at least 50% with: (a) a first reagent comprising an anhydride of a monounsaturated carboxylic acid having from 3 to 21 carbon atoms in the presence of a radical initiator selected from the group consisting of azo-bis-isobutyronitrile, dibenzoyl peroxide and derivatives thereof, at a temperature of from 65 to 100° C.; and (b) a second reagent comprising monoethanolamine; wherein the polyisobutylene and the first reagent are used in a ratio by weight of from 5:1 to 20:1, wherein the polyisobutylene and the second reagent are used in a ratio by weight of from 100:1 to 10:1, and wherein the reaction with the first reagent and the reaction with the second reagent are carried out in separate stages.