Viscosity Index Improvers for Lubricating Oil Compositions

• Main Authors: OBEROI SONIA, BRIGGS STUART
• Format: Patent
• Language: English
• Published: 27.06.2013
• Subjects: ADDING MATERIALS TO FUELS OR FIRES TO REDUCE SMOKE ORUNDESIRABLE DEPOSITS OR TO FACILITATE SOOT REMOVAL; CHEMISTRY; COMPOSITIONS BASED THEREON; FIRELIGHTERS; FUELS; FUELS NOT OTHERWISE PROVIDED FOR; LIQUEFIED PETROLEUM GAS; LUBRICANTS; MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVINGCARBON-TO-CARBON UNSATURATED BONDS; METALLURGY; NATURAL GAS; ORGANIC MACROMOLECULAR COMPOUNDS; PEAT; PETROLEUM, GAS OR COKE INDUSTRIES; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BYSUBCLASSES C10G, C10K; TECHNICAL GASES CONTAINING CARBON MONOXIDE; THEIR PREPARATION OR CHEMICAL WORKING-UP

Polymers suitable for use as a viscosity index improver for lubricating oil compositions including linear polymers characterized by the formula: D'-PA-D''; and star polymers characterized by the formula: (D'-PA-D'')n-X; wherein D' represents an "outer" block derived from diene having a number average molecular weight of from about 10,000 to about 120,000 daltons; PA represents a block derived from monoalkenyl arene having a number average molecular weight of from about 10,000 to about 50,000 daltons; D'' represents an inner random derived from diene having a number average molecular weight of from about 5,000 to about 60,000 daltons; n represents the average number of arms per star polymer formed by the reaction of 2 or more moles of a polyalkenyl coupling agent per mole of arms; and X represents a nucleus of a polyalkenyl coupling agent.