Abstract: There is provided an apparatus for suspension polymerization to produce polymer particles having uniform size. The apparatus has a droplet forming device with at least one orifice and a recycle line which recycles the aqueous dispersion medium through the droplet forming device, a first reactor and a second reactor. The apparatus can produce polymer particles having uniform particle size.

Abstract: There is provided a suspension polymerization process for production of polymer particles having a substantially uniform size, which process comprises the steps of: (a) applying regular vibration to a flow of a monomer liquid which has a specific gravity smaller than that of an aqueous dispersion medium, (b) introducing the aqueous dispersion medium containing the droplets in a first reactor comprising a recycling means which discharges the aqueous dispersion medium from the bottom of the reactor and recycles it to the top of the reactor, (c) partially polymerizing the monomer liquid in the first reactor so that the specific gravity of the droplets does not exceed that of the aqueous dispersion medium while maintaining the suspended condition of the droplets, and (d) discharging the partially polymerized droplets together with the aqueous dispersion medium from a lower portion of the first reactor and introducing them in a second reactor, and (e) further polymerizing the partially polymerized droplets in the

Abstract: The present invention provides a method for producing expandable thermoplastic polymer particles which comprises conducting polymerization by adding a polymerizable monomer either continuously or intermittently to thermoplastic polymer particles having a uniform particle size suspended in water, the improvement wherein an amide compound is added when the added amount of the polymerizable monomer is not more than one half of the total amount to be added in the course of polymerization and resulting polymer particles are impregnated with an easily volatile blowing agent after completion of addition of the amide compound and the polymerizable monomer. According to the present invention, expandable thermoplastic particles which are capable of giving cells, fine and uniform in size, are obtainable even by expanding immediately after production without any aging period.

Abstract: By a process for suspension polymerization, which comprises steps of:supplying a slurry comprising droplets of a monomer liquid having a substantially uniform size dispersed in an aqueous dispersion medium to a tower type reactor in which said medium forms a downflow, andsuspension polymerizing the monomer with avoiding merging or splitting of the droplets in a fluidized bed which is formed by the downflow of said medium and buoyancy of the monomer liquid droplets, whereinthe specific gravity of said medium is made larger than that of a polymer particle to be produced by the addition of a water soluble inorganic salt to said medium, anda polycarboxylic acid type anionic polymeric surfactant is used as a suspension stabilizer for the monomer liquid droplets,polymer particles having a substantially uniform size are produced with high polymerization conversion.