Patent ID: 7838606

Claim:
A process of producing a copolymer in which a polymerizable monomer comprising at least recurring units of substituted (meth)acrylate, is subjected to radical polymerization with a polymerization initiator dissolved in an organic polymerization solvent, thereby obtaining a polymerization reaction mixture that comprises a product copolymer; and recovery of said product copolymer is carried out with a single hermetically-closed vessel divided by a filter medium into a first section into which the polymerization reaction mixture is introduced and agitated and a second section from which a filtrate is discharged from the vessel, said process comprising: (1) introducing said polymerization reaction mixture into said first section which comprises a poor solvent for said copolymer, and precipitating solid copolymer from said polymerization reaction mixture; (2) filtering the contents in said first section, which comprises the polymerization reaction mixture, the poor solvent, and the precipitated solid copolymer through said filter medium, thereby removing the filtrate from said precipitated solid copolymer, and recovering the precipitated solid copolymer on the filter medium; wherein said copolymer possesses a chemical structure which causes its solubility in alkaline water to vary by the action of an acid.