| abstract |
The invention relates to a process for preparing a (meth) acrylate copolymer containing tertiary amino groups by free-radical polymerization in solution from a monomer mixture selected from a) 30 to 70 % by weight of a C 1 -C 4 -alkyl ester of acrylic acid or methacrylic acid and b) 70 to 30 % by weight of an alkyl ester of acrylic acid or methacrylic acid with a tertiary amino group in the alkyl radical and c) 0 to 10 % of further copolymerizable vinyl monomers, whereby one or more polymerization initiators, optionally one or more molecular weight regulators and one or more solvents or of a solvent mixture are added to the monomer mixture to give a polymerization mixture, which is polymerized at temperatures from 30 to 120 °C over a period of 2 to 24 hours,, where the polymerization mixture is finally polymerized to give a polymerization syrup with a conversion of the monomers to the copolymer of at least 99 % by weight, where the polymerization syrup is subsequently degassed by distillation or by extrusion and the degassed polymerization syrup is further comminuted to a copolymer preparation in the form of a granulate or powder, where the copolymer preparation is characterized by a molecular weight (M w ) of 25.000 to 75.000 g/mol a polydispersity index of 2.1 to 2.9 and a residual solvent concentration of less than 1.000 ppm by weight. |