Patent ID: 10246604

Abstract:
To provide a method for producing an aqueous liquid containing a vinyl polymer, of which the production efficiency is high, without lowering the yield of the vinyl polymer. When removing a hydrophilic organic solvent from a mixed liquid comprising a vinyl polymer, the hydrophilic organic solvent and water to produce an aqueous liquid containing the vinyl polymer, a liquid phase and a gas phase are formed in a closed container, a part of the liquid of the liquid phase is formed into small droplets and brought into contact with the gas phase to vaporize the hydrophilic organic solvent, and the vaporized hydrophilic organic solvent is removed from the closed container. Specifically, for example, a closed container 10 having a liquid inlet 22, a gas outlet 30, a liquid outlet 21, a liquid inlet 22 and a liquid outlet 21 which are connected and having an external circulating system provided with means to control the temperature and the pressure of liquid, is filled with a mixed liquid 40 to form a liquid phase 50 and a gas phase 51, the mixed liquid 40 of the liquid phase 50 is circulated from the liquid outlet 21 to the external circulating system 20, and the temperature and the pressure of the mixed liquid 41 in the external circulating system 20 are controlled to conditions such that the hydrophilic organic solvent is easily vaporized in liquid droplets in the gas phase 51, followed by discharging the mixed liquid 41 in the form of the small droplets from the liquid inlet 22 to the gas phase 51 and draining the gas in the gas phase 51 from the gas outlet 30.