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US 4,077,893 AGranted
Star-shaped dispersant viscosity index improver
AssigneeShell Oil Company
InventorThomas E. Kiovsky
Life of this patent
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Abstract
Lubricating oil additives having both dispersant and viscosity index-improving properties are prepared by reacting a selectively hydrogenated star-shaped polymer having at least four arms of polymers or copolymers of dienes and monoalkenyl arenes with an alpha-beta unsaturated carboxylic acid or derivative, and then reacting the resulting intermediate with an alkane polyol.
Claims14
The oil-soluble product prepared by the process comprising:
- a. reacting a selectively hydrogenated star-shaped polymer with an alpha-beta unsaturated carboxylic acid, anhydride or ester at a temperature of between about 150.degree. C and about 300.degree. C for between about 1 hour and about 20 hours wherein said star-shaped polymer comprises a poly (polyalkenyl coupling agent) nucleus and at least four polymeric arms linked to said nucleus wherein said polymeric arms are selected from the group consisting of:
- (i) hydrogenated homopolymers and hydrogenated copolymers of conjugated dienes;
- (ii) hydrogenated copolymers of conjugated dienes and monoalkenyl arenes;
- and
- (iii) mixtures thereof;
- and wherein at least about 80% of the aliphatic unsaturation of the starshaped polymer has been reduced by hydrogenation while less than 20% of the aromatic unsaturation has been reduced;
- and
- b. reacting the product of step (a) with an alkane polyol having at least two hydroxy groups at a temperature of between about 150.degree. C and about 250.degree. C.
5 more elements
Dependencies are inferred from the claim text.