PREPARATION OF POLYMER SOLUTION IMPROVING VISCOSITYYTEMPARATURE RELATION AND LOW TEMPERATURE PERFORMANCE

摘要

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 DEG 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.