METHOD OF SUSPENSION POLYMERIZATION

PURPOSE:To make it possible to produce a polymer which forms less fish eyes and has a high bulk density, by increasing the number of revolutions of an agitator at a specified time after initiating the polymerization in the suspension polymerization of a radical-polymerizable water-insoluble monomer. CONSTITUTION:Suspension polymerization of a radical-polymerizable water- insoluble monomer such as vinyl chloride is carried out in such a manner that the number of revolutions of an agitator of a polymerization tank is increased during an arbitrary period from the time at which the conversion is 5%, preferably 10%, to the time at which the conversion is 50%, preferably 30%. Also, after the increase of the number of revolutions, it is preferred that the agitation is carried out with the number of revolutions further increased during the period wherein the conversion is further increased by at least 10%, and that this is maintained till the conversion is increased by 20%. The range of the increase of the number of revolutions of the agitator is 101-150%, preferably 110-120% of the average number of revolutions per unit time during the period from the time when the monomer is supplied to a polymerization tank to immediately before the time when the conversion reaches 5%.