Ethylene-propylene branched copolymers as viscosity modifiers with enhanced fuel economy
AssigneeExxonMobil Chemical Patents Inc.
InventorsJingwen Zhang, John R. Hagadorn, Jo Ann M. Canich, Peijun Jiang, Britni J. Brobey, Maksim Shivokhin
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Abstract
In some embodiments, ethylene-propylene branched copolymers are synthesized with pyridyldiamido catalysts and a chain transfer agent, and their performance as viscosity modifiers in oil are detailed. In some embodiments, the present disclosure provides for ethylene-propylene branched copolymers having a shear thinning onset of less than about 0.01 rad/s and an HTHS value of less than about 3.3. In some embodiments, the ethylene-propylene branched copolymer is used as a viscosity modifier in a lubricating composition and a fuel composition.
Claims36
A method of making a lubricating oil composition comprising:
- (a) combining a base stock oil with a branched polymer having:
- an Mw(LS)/Mn(DRI) of from about 1.0 to about 6.0;
- an Mw(LS) of from about 3,000 to about 1,000,000 g/mol;
- a g'vis of less than 0.90;
- and
- an ethylene content of about 40% to about 80% or less;
- and
- (b) recovering a lubricating oil composition.
A lubricating oil composition comprising a copolymer having:
- an Mw(LS)/Mn(DRI) is from about 2.0 to about 6.0;
- an Mw(LS) is from about 50,000 to about 1,000,000 g/mol;
- a g'vis of less than 0.90;
- an ethylene content of about 40% to about 60% or less;
- a thickening efficiency of about 1.2 or more;
- and
- a shear stability index (30 cycles) less than 40.
Dependencies are inferred from the claim text.