Patent ID: 7144951

Claim:
A process comprising: (A) dissolving a hydrocarbon polymer in one or more solvents selected from the group consisting of aromatic ester oils of the formula wherein R 1 , R 2 , R 3 , R 4 , R 5 , and R 6 are independently selected from the group consisting of hydrogen, —COOR 7 , —COOR 8 , —COOR 9 , —COOR 10 , —COOR 11 , and —COOR 12 , provided that no more than 5 of R 1 , R 2 , R 3 , R 4 , R 5 , and R 6 are hydrogen, and R 7 , R 8 , R 9 , R 10 , R 11 , and R 12 are independently selected from the group consisting of alkyl and alkylesters to form a solution of said hydrocarbon polymer in said solvent(s); and (B) adding an ethylenically unsaturated C 3 to C 10 carboxylic acid material and a free radical initiator to said solution over about 0.1 to about 12 hours at a temperature of from about 25° C. to about 250° C., whereby said ethylenically unsaturated C 3 to C 10 carboxylic acid material is grafted onto said hydrocarbon polymer; wherein said hydrocarbon polymer has previously been prepared from at least one C 2 to C 28 polymerizable hydrocarbon and has a number average molecular weight in the range of from about 5,000 to about 500,000.