| 摘要 |
PROBLEM TO BE SOLVED: To obtain the subject polymer so as not to solidify the system during polymerization by introducing a second monomer aqueous solution at polymerization temperature in a specific range of a volume ratio of an aqueous solution phase to a hydrocarbon phase. SOLUTION: An aqueous solution of a hydrophilic unsaturated monomer (mixture) such as (meth)acrylic acid is introduced into a hydrocarbon solution of a surfactant (e.g. sorbitan monolaurate) having 8-12HLB at a polymerization temperature of 75±10 deg.C while stirring the aqueous solution and the hydrocarbon solution, and the monomer (mixture) is subjected to reverse phase suspension polymerization under combined action of a radical polymerization initiator and a temperature, and when the monomer is polymerized, an aqueous solution of a second hydrophilic saturated monomer (mixture) such as (meth)acrylic acid is introduced into a reaction medium at 75±10 deg.C polymerization temperature in a volume ratio of the aqueous solution phase to the hydrocarbon phase of 0.6-1.2 and, when the second monomer is polymerized, the hydrocarbon phase and water are extracted by distillation and drying to provide the objective polymer having straight chain or branched chain and, as necessary, crosslinked.
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