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Abstract

A dispersant/antioxidant bound, Viscosity Index-improving methacrylate polymer composition having a molecular weight ranging from about 20,000 to about 2,500,000. The composition comprises a base oil and methacrylate monomers and antioxidant monomer with inherent dispersancy. The composition being prepared by: (a) mixing a antioxidant/dispersant monomer with alkyl methacrylates and an oil solvent to provide an intermediate reaction mixture; (b) stirring and purging said reaction mixture by nitrogen ebullation for about 25-35 minutes at about 200 ml/min; (c) heating said purged mixture to about 75.degree.-85.degree. C.; (d) adding both a chain transfer agent and a radical polymerization catalyst to said heated mixture and then after about 2.0 hours adding an additional amount of said catalyst to said heated mixture, and then heating said heated mixture for an additional 2.0 hours; (e) increasing the temperature of said heated mixture to about 95.degree.-105.degree. C. and maintaining said mixture at such temperature for a sufficient period of time to remove any excess of said polymerization catalyst; and (f) recovering the product methacrylate polymer.

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First Claim