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US 8,999,905 B2Granted
Lubricant additive
AssigneeAfton Chemical Corporation
InventorAkhilesh Duggal
Life of this patent
Estimating the term…
Abstract
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.
Claims15
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;
- and
- wherein 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.
7 more elements
A method of improving the mini-rotary viscometer value (MRV TP-1) of a lubricant comprising the step of:
- mixing a lubricant with a viscosity index improver,
- wherein the viscosity index improver comprises:
- a. a hydrogenerated 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, and still further wherein the star copolymer core comprises divinylbenzene;
- b. wherein the degree of hydrogenation of the star copolymer is at least 95% and further wherein the star copolymer has 3 or more arms and the molecular weight of each arm is more than 50,000;
- c. a base oil;
- and
- wherein the star copolymer is provided in an amount to be approximately 0.5 to 1.5 wt % of the lubricant.
4 more elements
Dependencies are inferred from the claim text.