| 摘要 |
<p>This invention relates to novel polymer blends used as additives and which improve the viscosity index of lubricating oils. Specifically, the polymer additive compositions comprise partially crystalline olefin copolymers (OCP) such as EPM (ethylene-propylene cpolymer) or EPDM (ethylene-propylene diene terpolymer) and star styrene isoprene polymers or amorphous OCPs such as EPM or EPDM and star styrene/isoprene based polymers or crystalline and amorphous olefin copolymers with star styrene/isoprene based polymers. The additive compositions disclosed are particularly useful for preparing solid polymers with excellent dimensional stability. These polymer blends when dissolved in mineral oils comprise lubricant additives which improve the viscosity index and low temperature properties of lubricating oil compositions. Blends of crystalline and amorphous EPM or EPDM with attached polar functional groups and star polymers are also useful as additives. These materials have multifunctional performance properties and are referred to as dispersant or dispersant/antioxidant olefin copolymers.</p> |
