| 摘要 |
PROBLEM TO BE SOLVED: To provide a manufacturing method for a water dispersion of an alkali soluble polymer of a high solid content stably, solving the problems of generation of a large quantity of an aggregate and solidification of all polymer system in case of an emulsion polymerization of a highly hydrophilic polymerizable monomer component. SOLUTION: In this manufacturing method, a water dispersion of an alkali soluble polymer with more than 30 mass % solid content is obtained with much improved stability during emulsion polymerization, even if the quantity of an emulsifier used is decreased to not more than 2.0 pts.mass to 100 pts.mass total polymerizable monomer, by intensively compounding the polymerizable monomer containing a strong acid group and a chain transfer agent at an initial polymerization process and keeping the concentration of the polymerizable monomer in an initial polymerization reaction solution to 5-45 wt.%, and in a dropping process during the emulsion polymerization, increasing the water quantity when preemulsion is prepared, and dropping while keeping the polymerizable monomer concentration of the preemulsion not higher than 50 mass %.
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