Lubricant additive

摘要

A hydrogenated styrene butadiene star copolymer is incorporated in a lubricant additive package. The star copolymer can include about 3 to 25% and about 97 to 75% butadiene. The star copolymer may further be incorporated in a lubricant additive in the amount of about 12 wt % of the star copolymer as compared to the base oil.

主权项

1. A lubricant comprising a viscosity index improver wherein
a. the viscosity index improver comprises:
a hydrogenated styrene butadiene star copolymer, wherein the star copolymer is formed from styrene and butadiene monomers in a ratio of about 5 to 13% styrene to about 95 to 87% butadiene by weight, further wherein the star copolymer has greater than 50% of 1,2 polymerization of the butadiene monomer;wherein the star copolymer core comprises divinylbenzene;wherein the degree of hydrogenation of the star copolymer is at least 95%;wherein the star copolymer has 3 or more arms and the molecular weight of each arm is more than 50,000;a base oil; andwherein the star copolymer is provided in an amount to be approximately 0.5 to 1.5 wt % of the lubricant; and b. the lubricant has a mini-rotary viscometer (MRV TP-1) value improvement of at least 5000 cP over a lubricant containing a hydrogenated styrene isoprene star polymer or an olefin copolymer at generally equivalent kinematic viscosity at 100° C.