| 摘要 |
<p>1. A process for the preparation of copolymers which contain monoethylenically unsaturated monocarboxylic acids and dicarboxylic acids as copolymerized units, by copolymerizing the monocarboxylic acids with the dicarboxylic acids or, if desired, their inner anhydrides, in an aqueous medium in the presence of a water-soluble initiator, wherein (a) from 10 to 60 % by weight, based on the sum of the monomers, of maleic acid, itaconic acid, mesaconic acid, fumaric acid, methylenemalonic acid or citraconic acid, an alkali metal salt thereof or, if desired, an anhydride thereof, (b) from 90 to 40 % by weight of a monoethylenically unsaturated monocarboxylic acid of 3 to 10 carbon atoms or an alkali metal salt thereof, and (c) from 0 to 20 % by weight of another monoethylenically unsaturated monomer which is free from carboxyl groups and is copolymerizable with (a) and (b), are copolymerized in an aqueous medium having a total monomer content of from 20 to 70 % by weight, in the presence of from 0.5 to 5 % by weight, in the presence of from 0.5 to 5 % by weight, based on monomers, of the water-soluble initiator, by introducing the dicarboxylic acid, its salt or its anhydride into the aqueous medium, adding the monocarboxylic acid together with the initiator in the course of from 3 to 10 hours, completing the reaction at 60 to 150 degrees C, monomers (a) and (b) being used in a form in which they are 20-80 % neutralized during the reaction, and, where appropriate, hydrolyzing the anhydride groups.</p> |
