| 摘要 |
<p>PROBLEM TO BE SOLVED: To obtain an emulsion polymer with low-density voids, and to provide a method for producing the emulsion polymer. SOLUTION: The emulsion polymer particles are obtained by the following procedure: (a) an aqueous emulsion containing (1) a multi-tiered emulsion polymer comprising core-tiered polymer and shell-tiered polymer, wherein the core- tiered polymer is composed of 5-100 wt.% of hydrophilic monoethylenic unsaturated monomer as a polymerization unit and 0-95 wt.% of at least one kind of nonionic monoethylenic unsaturated monomer as the other polymerization unit and the shell-tiered polymer contains >=50 wt.% of a nonionic monoethylenic unsaturated monomer as a polymeriztrtion unit, (2) >=0.5 wt.% of a monomer based on the component (1), and (3) a swelling agent, is put under such a condition as not to cause substantial polymerization of the monomer followed by (b) decreasing the amount of the monomer by >=50 wt.%.</p> |
