Improvements in and relating to process for continuous mass polymerization of styrene and methyl methacrylate

摘要

Styrene and methyl methacrylate are continuously bulk copolymerized by passage between two diathermic walls for 15 minutes-3 hours at a reaction temperature constant at a value between 130 DEG and 200 DEG C. and corresponding to a Fikentscher K value of 50-80 in the copolymer formed, the ratio between the heat exchange surface of the two diathermic walls and the thickness of the mixture of monomers passing therebetween being at least 0.1 cm.-2 per unit volume of the mixture (in c.g.s. units), and copolymer is separated from the mixture collecting at the outlet of the diathermic walls and which contains 60-80% of styrene/methyl methacrylate copolymer. The polymerization apparatus (see Fig. 3) may comprise an annular space between two concentric cylinders (1 and 2) both of which are subjected to the action of a heat regulating fluid (in jacket 7 and pipe 8), the annular space being fed (at 4) with the monomers (in the proportions 1:9 to 9:1) and having a radial width of 0.2-4.5 cm; a screw pump (6) may be provided to extract the mixture of copolymer and unconverted monomers which are fed to a devolatilizer.