Mitsubishi Gas Chemical Company, Inc.

Shinichi Hieda

Masahiro Kurokawa

Yasushi Higuchi

Shojiro Kuwahara

Takafumi Abe

Shojiro Kawahara

A high quality copolymer of styrene and methyl methacrylate is economically produced by polymerizing styrene and methyl methacrylate in a homogeneous solution of raw materials comprising methyl methacrylate, styrene, and an antioxidant, while the solution of raw materials is continuously supplied to a polymerization reactor including at least one complete-mixing type reaction tank, continuously removing the polymerization product from the polymerization reactor, supplying the polymerization product removed from the polymerization reactor directly to an extruder having a plurality of vents, and extruding a copolymer from the extruder, while volatile matter are removed through the plurality of vents.

Process for producing a copolymer

A process for continuously preparing a high quality methacrylic polymer with a high productivity is provided. The process comprises continuously polymerizing methyl methacrylate alone or a monomer mixture of methyl methacrylate and an alkyl acrylate by a solution polymerization using methanol as a solvent, directly feeding the resulting polymerization reaction product to an extruder having a plurality of vents, and extruding the polymer, while volatiles are removed through the vents.

Process for preparing polymer

A process is provided for preparing a high-quality methyl methacrylate polymer by polymerizing a monomer comprising methyl methacrylate as a main component in the presence of a radical polymerization initiator, a chain transfer agent, and 5 to less than 10 wt. % methanol. The polymerization is carried out in a uniform solution. According to this process, a methyl methacrylate polymer is obtained which reduces the generation of silver streaks, voids, coloring, odor and the like at the time of thermal molding.

Process for preparing methyl methacrylate polymer

A process for purifying a polymer by separating and removing volatile components from a polymer composition containing the volatile components, which comprises: (a) heating the polymer composition containing a methanol solvent to a temperature of 120.degree. to 240.degree. C. by a heater, wherein an internal pressure the heater is maintained at 8 to 35 kg/cm.sup.2 G; (b) discharging the heated polymer composition into a tank in which pressure is maintained at -0.7 to 1.0 kg/cm.sup.2 G, and then separating and collecting most of the volatile components to lower the concentration of the solvent in the remaining volatile components in the polymer composition to 0.5% by weight or less; and (c) feeding the resultant polymer composition to a vent extruder maintained such that a barrel temperature at an inner side thereof is 160.degree. to 280.degree. C. and pressure in a vent portion is 5 to 400 Torr, and then extruding the polymer composition to lower the content of the remaining volatile components in the composition to 1% by weight or less. Alternatively, between the above-mentioned steps (b) and (c), there can be interposed a step (b') of introducing an inert gas into the polymer composition before heating or during heating, or in the vicinity of the polymer composition which is being discharged into the tank. By using this process, a polymer can easily be separated and purified, so that a high-quality polymer, particularly a methyl methacrylate polymer, can be efficiently manufactured, without polymer discoloration.

Process for purifying polymer

A process is provided for preparing a high-quality methyl methacrylate polymer by polymerizing a monomer comprising methyl methacrylate as a main component in the presence of a radical polymerization initiator, a chain transfer agent, and a small amount of methanol as a solvent. The polymerization is carried out in a uniform solution at a temperature of 90.degree. to 180.degree. C. so that a monomer conversion of 40 to 90 mol % is attained. According to this process, a methyl methacrylate polymer is obtained which reduces the generation of silver streaks, voids, coloring, odor and the like at the time of thermal molding.

A process for preparing an .alpha., .beta.-unsaturated carboxylic acid and/or an .alpha., .beta.-unsaturated carboxylic acid ester from at least one ester selected from .alpha.-hydroxycarboxylic acid ester, .alpha.-alkoxycarboxylic acid ester and .beta.-alkoxycarboxylic acid ester as a starting material by a vapor-phase catalytic reaction in the presence of a crystalline aluminosilicate as a catalyst. According to the process, .alpha., .beta.-unstaturated carboxylic acid and/or an ester thereof can be produced in a mild condition and a high yield.

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Hiratsuka, Japan

Shinichi Hieda