Mitsubishi Rayon Company, Limited

Akihiro Toritani

Suehiro Tayama

Yasunori Kawachi

Kouji Matsumura

Akira Nakata

Jun Nakauchi

Hideaki Makino

Masahiro Osuka

Masaki Sugihara

Koichi Shishido

Hirofumi Uno

Masaki Omote

Hiroyuki Iyota

Daisuke Shiramizu

Kaoru Matsuda

A method of manufacturing polymer particles capable of increasing the easiness of handling of powder when the powder is collected and preventing the powder from adhering to the wall surface of a dryer and the outlet of the dryer from being clogged with the powder by suppressing the occurrence of ruptured particles to reduce the produced amount of the fine powder when polymer particles are produced by spraying and drying polymer latex, characterized in that, when the polymer latex having a minimum film forming temperature of 50&#xb0; C. or higher is sprayed and dried with heating gas for drying in the dryer, the temperature of the heating gas for drying at the dryer outlet is less than the temperature obtained by adding 15&#xb0; C. to the minimum film forming temperature of the polymer latex, the wet-bulb temperature thereof at the dryer outlet is higher than the temperature obtained by deducing 30&#xb0; C. from the minimum film forming temperature of the polymer latex, and the heating gas for drying contains a vapor of 5 to 60 volume %.

Method of manufacturing polymer particles

A production method of polymer particles produces graft polymer particles by contacting a coagulant with a polymer latex (A) obtained by graft polymerizing a monomer containing methylmethacrylate to a rubber-like polymer. The method comprises a coagulation step in which polymer latex (A) is discharged into a stirring tank from an immersed nozzle provided so that the cross-sectional surface area of the discharge portion is 40 mm or more and the direction of discharge is facing in the same direction as the flow in the stirring tank and so that the linear velocity at the nozzle outlet is a velocity of 50-350 mm/s, and contacted with a coagulant to coagulate the graft polymer and obtain a slurry liquid; and a solidification step in which the resulting slurry liquid is held at a temperature of 60-100&deg; C. to solidify the coagulated graft polymer. According to the production method of the present invention, graft polymer particles having superior powder characteristics with few coarse particles and high bulk specific gravity can be obtained without requiring the use of organic solvent or special equipment. Accordingly, polymer particles having superior powder characteristics can be produced in a stable manner and at low cost.

Process for producing polymer particle

A synthetic latex is prepared by charging a portion of water and a monomer as raw materials in a reactor in a ratio of monomer/water, at which a maximum ultimate pressure in said reactor that is attained if an initial composition in said reactor before the initiation of the polymerization is polymerized from a polymerization initiation temperature in an insulated state, is within a practical proof pressure of said reactor; initiating the polymerization; adding dropwise the remainder of said water and said monomer during the polymerization, continuously or intermittently, and performing the emulsion polymerization. As a result, the emulsion polymerization can be stably performed while controlling the temperature and pressure in said reactor in a runaway reaction in all processes of the method of preparing the synthetic latex, thus making it possible to improve the productivity.

Process for producing synthetic latex

Graft polymer and thermoplastic resin composition

Acrylic multilayer polymer powders containing coagulated powders of emulsified latexes of acrylic multilayer polymers, which are suitable for drying methods using pressure dehydration extruders, etc, comprises not more than 40 wt % of a fine powder of a particle size of 212 .mu.m or less after drying, and have a volume of gaps of a pore size of 5 .mu.m or less after drying of not more than 0.7 cc per unit weight as measured by a mercurial pressure method. A desired monomer is subjected to emulsion polymerization to produce an emulsified latex of an acrylic multilayer polymer, which is then poured into a coagulating solution for coagulation.

Acrylic multilayer polymer powder

Disclosed is a methacrylic resin cast plate which is comprised of 100 parts by weight of [I] polymethyl methacrylate or a methyl methacrylate copolymer containing at least 90% by weight of methyl methacrylate units and, dispersed therein, a graft copolymer [IV] obtained by graft-polymerizing a hard resin component [III] containing at least 90% by weight of methyl methacrylate units onto a crosslinked rubbery copolymer [II] containing at least 45% by weight of butyl acrylate units and having an average particle diameter of 0.1 to 1 .mu.m, the amount of the graft copolymer [IV] being 2 to 30 parts by weight as the amount of the crosslinked rubbery copolymer. The methacrylic resin cast plate has a high transparency and impact resistance.

Methacrylic resin cast plate having transparency and impact resistance,

Disclosed is a methacrylic resin cast plate which is comprised of 100 parts by weight of [I] polymethyl methacrylate or a methyl methacrylate copolymer containing at least 90% by weight of methyl methacrylate units and, dispersed therein, a graft copolymer [IV] obtained by graft-polymerizing a hard resin component [III] containing at least 90% by weight of methyl methacrylate units onto a crosslinked rubbery copolymer [II] containing at least 45% by weight of butyl acrylate units and having an average particle diameter of 0.1 to 1 .mu.m, the amount of the graft copolymer [IV] being 2 to 30 parts by weight as the amount of the crosslinked rubbery copolymer.

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Hiroshima, Japan

Akihiro Toritani