| abstract |
(57) [Abstract] [Problem] To provide a coating with water resistance, blocking resistance, weather resistance, Provided is a novel method for producing an aqueous polymer dispersion for coatings suitable for architectural exteriors, which does not cause peeling of the coating film or generation of minute cracks even by freeze-thawing. SOLUTION: A copolymer containing at least 50% by weight of methyl methacrylate (100% by weight of a monomer mixture in the first step) in the presence of at least water, a surfactant and a polymerization initiator. A first step of emulsion-polymerizing 10 to 45 parts by weight of a monomer mixture giving a glass transition temperature of 50 to 105 ° C. (total monomer mixture is 100 parts by weight); Subsequently, the glass transition temperature of the copolymer was -2 to the reaction composition. 0 to 20 ° C., and 35 to 70% by weight of cyclohexyl (meth) acrylate and / or methyl methacrylate A method for producing an aqueous polymer dispersion for paints, comprising a second step in which 55 to 90 parts by weight of a monomer mixture containing (the monomer mixture in the second step is 100% by weight) is added dropwise to carry out emulsion polymerization. |