brought to 69 u00b0 c within 40 minutes which corresponds to a relative pressure of 11 5 bars after polymerization for 15 minutes at 69 u00b0 c the temperature of the reaction mixture is reduced to 25 u00b0 c within ten minutes which corresponds to a relative pressure of 3 5 bars 15 kg of vinyl chloride 14 6 g of ethyl hexyl peroxydicarbonate corresponding to 0 675 g of active oxygen and 8 4 g of lauroyl peroxide corresponding to 0 338 g of active oxygen are now charged in the stirring speed is set at 75 rpm the temperature of the reaction medium is brought to 57 u00b0 c within 30 minutes which corresponds to a relative pressure of 8 2 bars and then it is brought to 71 u00b0 c within 1 75 hours which corresponds to a relative pressure of 12 bars after polymerization for 2 25 hours at a stirring speed of 75 rpm the stirring speed is reduced to 50 rpm after polymerization for 20 minutes at a stirring speed of 50 rpm and release of the nonreacted gaseous vinyl chloride 46 5 kg of polyvinyl chloride are collected after evacuation 66 kg of vinyl chloride are charged into the spherical reactor used in example 11 and the device is purged by releasing 6 kg of gaseous vinyl chloride 15 g of ethyl hexyl peroxydicarbonate corresponding to 0 717 g of active oxygen and.