Polymerization process for methacrylic acid esters

摘要

A process for the continuous polymerization of a methacrylic acid ester having the formula wherein R is an alkyl radical having 1 to 6 carbon atoms comprises (1) continuously charging to a first polymerization zone, at a temperature of from 70-107 DEG C., a solution containing 10-40%, by weight, of an inert organic solvent of boiling point from 100-140 DEG C., and, based on the weight of the ester, 0.01-5.0% of a polymerization initiator and 0.2-1.0% of a chain length regulator, continuing the polymerization until the reaction media contains 10-35% polymer solids, (2) transferring the reaction media to a second polymerization zone wherein a temperature gradient of from about the boiling point of the volatiles at the top, to a temperature sufficient to maintain the final polymeric solution flowable at the bottom is maintained, allowing the reaction media to flow slowly downwardly through this second polymerization zone in the substantial absence of externally applied agitation until the ester is at least 90% converted, (3) continuously removing the highly converted ester polymer to a third heated zone at a temperature of 110-245 DEG C. to remove substantially all of the voltaile components in the polymer and recovering the polymer. Of the many suitable ingredients listed the following are exemplified: comonomers:-acrylonitrile and styrene; solvents:-xylene and toluene; polymerization initiators:-dicumyl peroxide and 2, 5-dimethyl 2, 5-di-(tertiary butyl peroxy)hexane; chain length regulator:-dodecyl mercaptan. Other suitable alkyl-acrylates are also specified. Various additives may be incorporated after polymerization. The final product is discharged as viscous strands into cooling water and cut into short lengths. The polymers may be used for fabricating motor car light lenses, dials, instrument panels, control knobs, handles, pen and pencil barrels, hair brush backs, jukebox panels, sheets for partitions, and dentures, and for the embedment of normal and pathological tissues. U.S.A. Specification 2,601,572 is referred to.