Patent ID: 8536285
Filing Date: 2013-09-17
Classification: C08F,C08L

Abstract:
1. A process for preparing a copolymer in a semicontinuous mode of operation in a polymerization apparatus containing a polymerization reactor connected to a metering device, the process comprising: (a) initially introducing an acid monomer into the metering device and initially introducing polyether macromonomer and water into the polymerization reactor, (b) metering the acid monomer from the metering device via an acid monomer metering line into the polymerization reactor, (c) passing free radical polymerization initiator into the polymerization reactor before and/or during the metering of the acid monomer into the polymerization reactor, thereby forming an aqueous medium in the polymerization reactor, and reacting the acid monomer and the polyether macromonomer in the aqueous medium by free radical polymerization and forming the copolymer, wherein the molar ratio of all the acid monomer used to all the polyether macromonomer used is 20:1 to 1:1, the molar ratio of the acid monomer initially metered into the polymerization reactor to the acid monomer metered into the polymerization reactor after initially passing the initiator being 3:1 to 1:10, and passing a discharged portion of the copolymer-containing aqueous medium continuously during the free radical polymerization from the polymerization reactor to the acid monomer metering line via a reaction mixture line which is connected via a mixing device to the acid monomer metering line, the discharged copolymer-containing aqueous medium being mixed with the acid monomer in the mixing device during the metering of the acid monomer and being recycled to the polymerization reactor after the mixing via the acid monomer metering line.