Patent ID: 6114435
Filing Date: 2000-09-05
Classification: C08F,D21H

Abstract:
A process for the preparation of an aqueous solution of a polymer containing vinylamine units, which solution has a long shelf life, by hydrolyzing a polymer containing N-vinyl-formamide units with an acid in an aqueous medium and removing formic acid eliminated from the polymer from the aqueous polymer solution, wherein a polymer containing N-vinylformamide units is used and the eliminated formic acid is esterified by adding at least a stoichiometric amount of at least one C.sub.1 -C.sub.4 -alcohol after the hydrolysis to obtain a formate ester reaction mixture and formate ester is distilled off from said reaction mixture, resulting in an aqueous polymer solution containing not more than 5% by weight of neutral salts, wherein the reaction mixture is fed continuously into a distillation column after the hydrolysis and after the addition of sad at least one alcohol, the formate ester is removed continuously at the top of the column and the aqueous polymer solution is removed continuously from the bottom column.