| abstract |
Pulverulent polymers of acrylic acid and methacrylic acid are prepared by polymerizing (a) from 100 to 70% by weight of acrylic acid, methacrylic acid or a mixture thereof and (b) from 0 to 30% by weight of vinylsulfonic acid or an alkali metal salt thereof in a monohydric C 1 -C 8 -alcohol, water or a mixture thereof in a pulverulent bed in the presence of a polymerization initiator and from 0.05 to 10 mol % of thiocarboxylic acid and/or a mercaptoalcohol and from 0.05 to 10 mol % of propionic acid or formic acid as regulators, each percentage being based on the monomers used in the polymerization, by maintaining the pulverulent state during the polymerization, removing the heat of polymerization by distilling off the solvent and recirculating the reaction mixture. |