| abstract |
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 DEG to 240 DEG C. by a heater, wherein an internal pressure the heater is maintained at 8 to 35 kg/cm2G; (b) discharging the heated polymer composition into a tank in which pressure is maintained at -0.7 to 1.0 kg/cm2G, 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 DEG to 280 DEG 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. |