Zeon Corporation

Nippon Zeon Company, Ltd.

Takeo Fujino

Kazuhiro Sato

Seiji Funakura

A stripping process is provided which continuously strips volatile substances from a dispersion containing a polymer particles through stripping the volatile substances from a dispersion by blowing an inert gas into the dispersion to draw the volatile substances into the inert gas, removing the volatile substances from the gas mixture of the inert gas and the stripped volatile substances and circulating the purified inert gas obtained by removing the volatile substances from the gas mixture, and blowing the purified inert gas into the dispersion. Also provided is a production process for a toner which uses this stripping process.

Process for stripping volatile substances from dispersion comprising polymer particles and process for producing toner

A toner for development of electrostatic images which has a residual polymerizable monomer content lower than 70 ppm and is substantially spherical as demonstrated by the flowability of at least 55%, and a process for producing a toner reduced in residual polymerizable monomer content by subjecting a slurry containing polymer particles obtained by polymerization to a stripping treatment under reduced pressure.

Toner for development of electrostatic image and production process thereof

The invention relates to a process for producing a polymerized toner, including the step of polymerizing a polymerizable monomer composition containing at least a polymerizable monomer and a colorant in an aqueous medium. After polymerization, an aqueous dispersion containing polymer particles formed is subjected to stripping under reduced pressure in an evaporator after polymerization. At this time, the aqueous dispersion within the evaporator is continuously taken out of the evaporator and heated in an external heat exchanger, and the heated aqueous dispersion is returned to a liquid phase within the evaporator and subjected to stripping under reduced pressure within the evaporator while circulating the aqueous dispersion, thereby distilling off volatile organic compounds. By the production process, a polymerized toner markedly reduced in the content of a residual polymerizable monomer and having excellent properties is provided.

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Kanagawa, Japan

Takeo Fujino