Patent ID: 6403731
Filing Date: 2002-06-11
Classification: C08F

Abstract:
A process for preparing a polymer solution comprising radically polymerizing a monomer mixture comprising at least one unsaturated monomer in a solvent for the unsaturated monomer(s) and the polymer in the presence of a radical polymerization initiator, said at least one unsaturated monomer having a lower boiling point than that of the solvent, wherein (a) the weight ratio of the total amount of the unsaturated monomers to the solvent is in a range of from 1/9 to 7/3, (b) the polymerization is carried out until the conversion of the unsaturated monomer having the lowest conversion of all the other unsaturated monomers whose boiling point is lower than that of the solvent reaches at least 85%, (c) after completion of the polymerization, the reaction mixture is distilled under rectification conditions to remove the unreacted unsaturated monomer or monomers, (d) the rectification conditions are a number of theoretical plates of 3 or more and a reflux ratio of 0.5 or higher, and (e) the amount of the solvent removed after the distillation is 20% by weight or less based on the amount of the charged solvent.