The use of polymers as viscosity modifiers (or viscosity index improvers) or dispersant viscosity modifiers in oils of lubricating viscosity is known. Typical polymer backbones include polymethacrylates, polyolefins or hydrogenated styrene-butadienes, and functional derivatives thereof. For dispersant viscosity modifiers, the backbone may be functionalized with a grafted nitrogen-containing compound.
USPTO Backgrounds
USPTO Backgrounds