Abstract: The present invention relates to an aqueous polymer dispersion comprising a copolymer of anhydride monomer units and vinyl monomer units, which copolymer has been subjected to an imidization reaction. The present invention further relates to a method for the production and use of such a dispersion.

Abstract: Process for the preparation of a copolymer of maleic anhydride and an alkyl vinyl ether, comprising the steps of supplying maleic anhydride and the alkyl vinyl ether and an initiator, together forming a feed flow, through an inlet to a reactor wherein maleic anhydride and the alkyl vinyl ether react to a copolymer of maleic anhydride an alkyl vinyl ether thereby forming a reaction mixture with the maleic anhydride, the alkyl vinyl ether and the initiator characterized in that the process is a continuous process and the reactor is a loop reactor wherein the reaction mixture is internally circulated, whereby this reaction mixture arrives at the inlet before the maleic anhydride and alkyl vinyl ether have completely reacted while a remainder of initiator is still present. The invention further relates to copolymer of maleic anhydride and alkyl vinyl ether, including hydrolyzed or alcoholized copolymers, characterized in that a molecular weight distribution, expressed as Mw/Mn, is less than 2.