The invention relates to a polymer product obtained by polymerization ofi) at least one monomer selected from N-vinylformamide and vinyl acetate, andii) maleic anhydrideto give a copolymer comprising N-vinylformamide and/or vinyl acetate and maleic anhydride followed by hydrolyzing formamide groups originating from N-vinylformamide to amino groups and/or acetate groups originating from vinyl acetate to hydroxyl groups and acid anhydride to dicarboxylic acid groups to give a water-soluble copolymer comprising amine and/or hydroxyl and carboxyl groups, wherein the molar ratio of the N-vinylformamide and/or vinyl acetate monomer to the maleic anhydride monomer is from 70:30 to 30:70. The polymer product can be used as a dispersing agent or as a scale inhibiting agent.