Viscosity index improvers for lubricating oil compositions
AssigneeInfineum International Limited
InventorsStuart Briggs, Chin Chu
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Abstract
A polymer suitable for use as a viscosity index improver for lubricating oil compositions, which is at least one, at least partially hydrogenated linear or star-shaped random copolymer of isoprene and butadiene, in which at least 70 wt. % of the butadiene is incorporated into the polymer as 1,4 units and the weight ratio of isoprene addition product to butadiene addition product in the copolymer is in a range of from about 90:10 to about 70:30.
Claims19
A polymer suitable for use as a viscosity index improver for lubricating oil compositions, which polymer comprises at least one, at least partially hydrogenated linear or star-shaped random copolymer of isoprene and butadiene, wherein at least 70 wt. % of the butadiene is incorporated into the polymer as 1,4 units and the weight ratio of isoprene addition product to butadiene addition product in said copolymer is in a range of from about 90:10 to about 70:30.
Dependencies are inferred from the claim text.