Patent ID: 8653162

Claim:
Process for the preparation of a polymerization mixture comprising a copolymer, in which a vinyloxyalkylpolyether derivative is reacted with an acid monomer derivative with formation of the copolymer in the presence of a free radical polymerization initiator by free radical polymerization, the free radical polymerization taking place in a medium which contains less than 25% by weight of water and in totality more than 60% by weight of copolymer, vinyloxyalkylpolyether derivative and acid monomer derivative, the molar ratio of acid monomer derivative used to vinyloxyalkylpolyether derivative used being 20:1 to 1:1; the acid monomer derivative being capable of free radical polymerization having at least one carbon double bond and capable of conversion by hydrolysis or alkaline saponification into an acid monomer containing at least one acid function; and the vinyloxyalkylpolyether derivative being present according to the general formula (I) H 2 C═CH—O-(AO) a —R A (I) where R A is identical or different and is represented by —CH 2 —C(CH 3 ) 2 —OH, a linear C 1 -C 12 alkyl group or branched C 3 -C 12 alkyl group, C 5 -C 8 cycloalkyl group, phenyl group or C 7 -C 12 arylalkyl group, A is identical or different and is represented by C x H 2x where x=2, 3, 4 and/or 5 and a is identical or different and is represented by an integer from 5 to 350, the molar ratio of the vinyloxyalkylpolyether derivative used to the free radical polymerization initiator used being 2 to 100 and the vinyloxyalkylpolyether derivative used being provided in the form such that 0.1 ppm to 10 000 ppm of a stabilizer which is present as an organic compound and is suitable for inhibiting the oxidative decomposition of alkoxy groups present in polyethers is added to the vinyloxyalkylpolyether derivative used and/or the vinyloxyalkylpolyether derivative used being enriched with dissolved nitrogen with depletion of dissolved oxygen.