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US 5,648,557 AGranted
Polyether lubricants and method for their production
AssigneeMobil Oil Corporation
InventorLiwen Wei
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AssigneeMobil Oil Corporation
InventorLiwen Wei
Estimating the term…
Cyclic ethers are polymerized or copolymerized in homogeneous liquid phase using very low concentrations of heteropolyacid catalyst to produce essentially linear polyoxyalkylene polymers. The product of the polymerization contains less than 2 weight percent cyclic oligomer by-product and has a molecular weight distribution (M.sub.w /M.sub.n) between 1 and 2. Alcohols, acyl-containing compounds and alkalies can be used as end-caping groups to terminate polymerization or modify the properties of the polymer produced. The process produces novel polyoxyalkylene copolymers and block copolymers that are useful as lubricants. The copolymers have a high viscosity index and are compatible with mineral oil and synthetic hydrocarbon lubricants. Preferred comonomers are tetrahydrofuran, C.sub.2 -C.sub.20 monoepoxides and oxetan.
A polyoxyalkylene block copolymer liquid lubricant compatible with synthetic hydrocarbon lubricants and mineral oil comprising recurring blocks of recurring alkylene oxide units, said recurring alkylene oxide units comprising the polymeric residue of one or more cyclic ether monomers, said monomers selected from the group having the structures:
A polyoxyalkylene block copolymer having the structure A-B-A, wherein B comprises recurring C.sub.2 + alkylene oxide units and A comprises recurring units of substituted or unsubstituted oxyethylene, said block copolymer having a molecular weight between 250 and 10,000, molecular weight distribution (M.sub.w /M.sub.n) between 1 and 2, viscosity index of 180 to 400, at least 5 weight percent solubility in mineral oil and synthetic oil, and containing less than 2 weight percent cyclic polyoxyalkene oligomer.
Dependencies are inferred from the claim text.