Patent ID: 9714311
Date: 2017-07-25
CPC Classifications: B01J,C08F

Claim:
1. A method for producing a hollow polymer particle, the method comprising: a core polymer formation step of forming a core polymer by copolymerizing a monomer mixture (a) consisting of 20 to 60% by weight of an acid group-containing monomer and 80 to 40% by weight of another monomer that is copolymerizable with the acid group-containing monomer; and subsequently a shell polymer formation step of forming a shell polymer by copolymerizing a monomer mixture (b) consisting of 0 to 15% by weight of an acid group-containing monomer and 100 to 85% by weight of another monomer that is copolymerizable with the acid group-containing monomer so that the shell polymer covers the core polymer wherein, the method further comprises a step of adding a preservative to an aqueous dispersion including the core polymer, the step of adding a preservative being conducted during a time period after the core polymer formation step and before the shell polymer formation step, and a step of forming a void by neutralization of at least one portion of an acid group provided by the acid group-containing monomer used for the formation of the core polymer, the neutralization comprising addition of a base to an aqueous dispersion including a polymer covered with the shell polymer, the step of forming a void being conducted after the shell polymer formation step.