Process for reducing monomer content in N-vinyl compound polymers

• Main Authors: Kuriyama, Toshiaki, Inui, Yasuko
• Format: Patent
• Language: English
• Published: 09.09.2003

The present invention relates to a method for diminishing residual monomers contained in an N-vinyl compound polymer. The invention further relates to a process for producing an N-vinyl compound polymer solution or powder having a regulated pH. A method for residual monomer diminution by which a residual monomer is speedily removed from an N-vinyl compound polymer or the like without posing a problem such as an increase in ash content; and a process for producing an N-vinyl compound polymer solution or powder which has a regulated pH and is free from a decrease in pH with time. The method comprises adding an organic acid having a boiling point of 140° C. or higher at ordinary pressure to an aqueous solution of an N-vinyl compound polymer. The process comprises adding an organic base to an aqueous N-vinyl compound polymer solution having a pH lower than 7.0 to thereby neutralize the solution and regulate the pH thereof. Those operations are conducted in a reaction vessel in which a gaseous phase is regulated so as to have an oxygen concentration of 5.0% by volume or lower.