| abstract |
The invention relates to a method for producing aqueous dispersions of block copolymers by a two- or multi-stage controlled radical block copolymerisation in an aqueous medium. According to said method, in a first stage: (a) at least one olefinically unsaturated monomer is copolymerised with (b) at least one olefinically unsaturated monomer, which is different from the monomer (a), of general formula (I) R1R2C=CR3R4 (I), in which the groups R1, R2, R3 and R4 independently of one another represent hydrogen atoms or organic groups, with the proviso that at least two groups represent aryl groups, whereby the aqueous medium used in stage (1) constitutes at least the entire quantity of the aqueous medium, in which the block copolymer is dispersed. In a subsequent second stage, at least additional monomer (a) is (co)polymerised in the presence of the copolymer formed in the first stage after the addition of small quantities of radical initiators, or without said addition. |