| abstract |
Composition of matter useful as multifunctional viscosity index improver for lubricating oil comprising reaction product of: n (i) n (a) degraded ethylene-alpha-olein copolymer obtained by degrading copolymer of ethylene and at least one other alpha-olefin monomer, said copolymer comprising intramolecularly heterogeneous copolymer chains containing at least one crystallizable segment of methylene units and at least one low crystallinity ethylene-alpha-olefin copolymer segment, wherein said at least one crystallizable segment comprises at least about 10 weight percent of said copolymer chain and contains at least about 57 weight percent ethylene, wherein said low crystallinity segment contains not greater than about 53 weight percent ethylene, and wherein said copolymer has a molecular weight distribution characterized by at least one of a ratio of M w /M n of less than 2 and a ratio of M z /M w of less than 1.8, and wherein at least two portions of an individual intramolecularly heterogeneous chain, each portion comprising at least 5 weight percent of said chain, differ in composition from one another by at least 7 weight percent ethylene; said degraded ethylene-alpha-olefin copolymer grafted with (b) ethylenically monounsaturated carboxylic acid material having 1 to 2 carboxylic acid groups of anhydride group to form grafted ethylene copolymer; and n (ii) amido-amine or thioamido-amine comprising reaction product of (a) polyamine, and (b) alpha, beta-unsaturated compound represented by the formula ##STR1## wherein X is oxygen or sulfur, Y is OR 4 , --SR 4 , or ##STR2## and R 1 , R 2 , R 3 , R 4 and R 5 are independently selected from hydrogen, hydrocarbyl, and substituted hydrocarbyl. |