Rohm Gmbh

Hans Pilz

Franz Wenzel

Heinz Jost

Ulrich Schoedel

What is disclosed are methods for making polymer-in-oil solutions, useful for improving the viscosity-temperature relationship and low-temperature properties of lubricating oils when added thereto, which methods comprise polymerizing a methacrylic acid ester of an alcohol having 8 to 18 carbon atoms onto a polyolefin polymer of an olefinic hydrocarbon monomer having 2 to 4 carbon atoms in an oil solution of the polyolefin and ester monomers, then adding further polyolefin polymer to the solution and finally graft copolymerizing a polymerizable heterocyclic compound having a basic nitrogen atom in the ring thereof onto the resulting mixed polymers as backbone polymers or, in the alternative, separately graft copolymerizing a polymerizable heterocyclic compound having a basic nitrogen atom in the ring thereof onto a first backbone polymer which is itself a graft copolymer, in an oil solution, of a methacrylic acid ester of an alcohol having 8 to 18 carbon atoms on a polyolefin polymer of an olefinic hydrocarbon monomer having two to four carbon atoms and further graft copolymerizing a polymerizable heterocyclic compound having a basic nitrogen atom in the ring thereof onto a polyolefin polymer of the type described above and then combining the two graft copolymers thus formed to produce the desired polymer-in-oil solution.

Lubricating oil additives

A method is disclosed for making a polymer-in-oil solution, useful for improving the viscosity-temperature relationship and low-temperature properties of lubricating oils when added thereto, which method comprises a first step of polymerizing a methacrylic acid ester of an alcohol having 8 to 18 carbon atoms in a solution, in a lubricating oil, of a polyolefin polymer of an olefinic hydrocarbon monomer having 2 to 4 carbon atoms, the oil solution of said polyolefin having a viscosity of less than 15,000 centistokes at 100.degree. C., and then, in a second step, adding further polyolefin polymer of the type defined herein until the total polymer content in the oil solution is from 20 percent to 55 percent by weight of said solution and said methacrylate ester comprises from 50 percent to 80 percent of said polymer content.

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Darmstadt, Germany

Hans Pilz