Dispersant-viscosity improvers for lubricating oil compositions

A nitrogen containing copolymer prepared by a process comprising reacting, in the presence of a free radical initiator,

• (A) from about 55% to about 99.9% by weight of one or more alkyl acrylate ester monomers containing from 1 to about 24 carbon atoms in the ester alkyl group, wherein at least about 50 mole % of the esters contain at least 6 carbon atoms in the ester alkyl group, and
• (B) from about 0.1% to about 45% by weight of at least one nitrogen containing monomer selected from the group consisting of vinyl substituted nitrogen heterocyclic monomers and vinyl substituted amines provided that the total of (A) and (B) equals 100%, and optionally, in the presence of a chain transfer agent, wherein monomer (A), the free radical initiator, and if used, the chain transfer agent, are first combined to form a mixture, whereupon from about 10% to about 80% of said mixture is mixed with monomer (B);
• from about 20% to about 100% of the mixture of monomers (A) and (B) is heated until an exotherm is noted, then while maintaining reaction temperature, first adding the balance, if any, of the mixture of monomers (A) and (B) over about 0.25 hour to about 5 hours followed by addition over 0.25 to about 5 hours of the remaining mixture of monomer (A) and initiator, optionally adding additional initiator, whereupon the reaction is continued to completion.