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.
Claims14
A polymer suitable for use as a viscosity index improver for lubricating oil compositions, which polymer comprises at least one, at least partially hydrogenated 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.
A star polymer, the arms of which are a diblock copolymer having at least one first polymer block derived from monoalkenyl arene, and at least one second polymer block comprising at least partially hydrogenated 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.