| 摘要 |
PROBLEM TO BE SOLVED: To obtain the subject polymer branched into a star shape, capable of manifesting a narrow polydispersity index, having improved shear stability and useful as a lubricating oil composition by polymerizing an acrylic monomer, or the like, in a tubular reactor according to an anionic polymerization. SOLUTION: (A) At least one kind of acrylic monomer and, as necessary, at least one kind of solvent, a nonacrylic vinyl monomer and/or a monomer for improving performances (B) an anionic polymerization initiator system, a monomer for forming a core and, as necessary, a solvent in a mixture containing the components A and B are brought into contact therewith for a time sufficient to react both the components A and B to a desired conversion rate in a tubular reactor according to a continuous method. In the process, the temperature of the tubular reactor is maintained within the range of 30 to -78 deg.C. Furthermore, (C) at least one kind of monomer selected from the group consisting of the acrylic monomer, the nonacrylic vinyl monomer and/or the monomer for improving the performances and the solvent are preferably further contained. |
