Patent ID: 6881803

Claim:
A method for producing a copolymer of an alkyl vinyl ether and maleic anhydride using a solution feeding type slurry-polymerization method which comprises the steps of: (i) feeding an organic solvent which dissolves a copolymer to be produced and maleic anhydride into a reaction vessel, and heating a homogeneous maleic anhydride solution formed; (ii) feeding an alkyl vinyl ether into the reaction vessel and copolymerizing the alkyl vinyl ether with maleic anhydride in the presence of a free radical initiator to produce a slurry in which the produced copolymer is suspended in a reaction medium; (iii) cooling the slurry once to form a homogeneous solution; (iv) heating the slurry again to precipitate a copolymer; and (v) removing the organic solvent used in the reaction under a condition in the range of a temperature capable of maintaining the slurry state.