| 摘要 |
PURPOSE: A method for preparing a void or hollow type emulsion polymer is provided, to form the closed void or hollow in the central part of the polymer and to allow the thickness of shell to be uniform. CONSTITUTION: The method is characterized by using 0.01-10 wt% of a multifunctional thiol-based chain transfer agent in the process forming a core polymer. Also the method comprises the steps of polymerizing a mixture of an ethylenically unsaturated acid monomer having a carboxyl group and a nonionic hydrophilic monomer in the presence of a polymerization initiator to form a seed polymer; adding a mixture of an ethylenically unsaturated acid monomer having a carboxyl group, a nonionic hydrophilic monomer, a crosslinkable multifunctional monomer and a multifunctional thiol-based chain transfer agent in the presence of a polymerization initiator to the seed polymer, to form the core capable of being swollen by an alkali; forming a shell onto the hydrophilic core to form a core/shell emulsion polymer; and swelling the core/shell polymer by using an alkali.
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