REGENERATION METHOD FOR REACTION SOLVENT, REACTION SOLVENT, AND AQUEOUS URETHANE RESIN DISPERSION

摘要

PROBLEM TO BE SOLVED: To provide a regeneration method for a reaction solvent whereby the reaction solvent is recovered from an aqueous urethane resin dispersion and regenerated into a high-purity reaction solvent hardly containing a basic reaction initiator and water. SOLUTION: The method recovers and regenerates the reaction solvent from the aqueous urethane resin dispersion prepared by dispersing, in water, a urethane resin formed by polymerization in the presence of a basic reaction initiator in the reaction solvent. The method comprises the following: a recovery step wherein the reaction solvent is evaporated and recovered from the aqueous dispersion; a neutralization step wherein the basic reaction initiator contained in the recovered reaction solvent is neutralized and fixed by adding an acid to the recovered reaction solvent; a distillation step wherein the reaction solvent after the neutralization step is distilled out, and water contained in the reaction solvent is taken out of a vessel; and a membrane separation step wherein water contained in the reaction solvent distilled out is separated and removed by a gas separation membrane. COPYRIGHT: (C)2005,JPO&NCIPI