Abstract: There is disclosed a process for the continuous polymerization of methyl methacrylate with a lesser cost, thermally polymerizable comonomer such as styrene, in the presence of a large quantity of solvent by introducing the monomers into a continuos loop of recycled solvent and removing the polymerized product therefrom. The polymerization is practiced in a plurality of stages, preferably two stages wherein the bulk of the polymerization is performed in the first stage and the final stage is operated to deplete the initiator and any thermally polymerizable comonomer, and polymerization modifiers from the crude polymerizate, thereby forming a crude polymerizate suitable for devolatilization. The crude polymerizate is preheated and devolatilized in a flash zone. Sufficient pressure is maintained on the crude polymerizate in the devolatilizer preheater to avoid the formation of foam encrustations on the heat exchange surfaces of the devolatilizer preheater and on the surfaces of the transfer lines.

Abstract: The continuous solution polymerization of an acrylate, particularly methyl methacrylate, is practiced in the presence of a large quantity of solvent by introducing the monomer feed into a continuous loop of recycled solvent and removing the polymerized product therefrom. The polymerization is practiced in a plurality of stages, preferably two stages wherein the bulk of the polymerization is performed in the first stage and the final stage is operated to deplete the initiator and any other polymerization modifiers, thereby forming a crude polymerizate for devolatilization. A product of superior thermal stability and optimum heat distortion temperature is achieved by the addition of some of the comonomer such as methyl acrylate, or ethyl acrylate, etc., to the final stage or stages of the polymerization. Additionally, the product quality is enhanced by addition of a portion of the chain transfer agent, such as n-dodecyl mercaptan, to the final stage or stages of polymerization.

Abstract: Disclosed is a multiple-stage flash devolatilization process, and apparatus for use therein, for recovering volatiles from mass processable polymers, which enables optimally low pressures to be employed without the necessity for refrigeration to condense the volatiles recovered thereby, comprising separating the volatiles from the polymeric material by flashing in a first flash devolatilization zone to remove the majority of the volatiles and then flashing in at least one additional flash devolatilization zone maintained at a lower pressure, preferably as low as practically possible, to remove residual volatiles, and then recovering the volatiles for further use by feeding the volatiles recovered from the additional flash zones back into the stream of volatiles leaving the first flash zone, the higher pressure of which allows the combined free volatiles present therein to then be condensed in a conventional non-refrigeration cooling process.

Abstract: Disclosed is a multiple-stage flash devolatilization process, and apparatus for use therein, for recovering volatiles from mass processable polymers, which enables optimally low pressures to be employed without the necessity for refrigeration to condense the volatiles recovered thereby, comprising separating the volatiles from the polymeric material by flashing in a first flash devolatilization zone to remove the majority of the volatiles and then flashing in at least one additional flash devolatilization zone maintained at a lower pressure, preferably as low as practically possible, to remove residual volatiles, and then recovering the volatiles for further use by feeding the volatiles recovered from the additional flash zones back into the first flash zone, the higher pressure of which allows the combined free volatiles present therein to then be condensed in a conventional non-refrigeration cooling process.