METHOD FOR MANUFACTURING HYDROPHILIC POLYMER PARTICLE

摘要

In a method for producing hydrophilic polymer particles, a dispersion in which an aqueous-phase component including hydrophilic monomers and a polymerization initiator is dispersed in an oil-phase component including a hydrophobic solvent is prepared. Thereafter, the hydrophilic monomers are polymerized in the aqueous phase by supplying oxygen to a reaction vessel and, while oxygen is being supplied, heating the dispersion having a reduced dissolved oxygen concentration in the reaction vessel so that the temperature of the dispersion is increases. The time from the start of reduction of the dissolved oxygen concentration of the dispersion to the start of the heating is 0.1 hour or more and 3.5 hours or less. The amount of oxygen supplied to the reaction vessel is greater than or equal to 0.02 volume %/h and less than or equal to 0.9 volume %/h with respect to the volume of the dispersion under standard conditions.

主权项

1. A method for producing hydrophilic polymer particles, the method comprising:
step 1: preparing a dispersion in which an aqueous-phase component including hydrophilic monomers and a polymerization initiator is dispersed in an oil-phase component including a hydrophobic solvent having a solubility of 1 mass % or less in water at 25° C.; step 2: reducing a dissolved oxygen concentration of the dispersion prepared in step 1; and step 3: polymerizing the hydrophilic monomers in the aqueous phase by supplying oxygen to a reaction vessel and, while oxygen is being supplied, heating the dispersion whose dissolved oxygen concentration was reduced in step 2 in the reaction vessel so that a temperature of the dispersion increases, wherein a time from a start of reduction of the dissolved oxygen concentration of the dispersion in step 2 to a start of heating of the dispersion in step 3 is greater than or equal to 0.1 hour and less than or equal to 3.5 hours, and an amount of oxygen supplied to the reaction vessel in step 3 is greater than or equal to 0.02 volume % per hour and less than or equal to 0.9 volume % per hour with respect to a volume of the dispersion, under standard conditions of a temperature of 25° C. and an absolute pressure of 101.3 kPa.