Polychloroprene prepn. without popcorn formation - by free radical aqueous emulsion polymerisation in specific reactor

Chloroprene is polymerised in aq. emulsion using free radical initiators and opt. polymerisation inhibitors. Polymerisation is effected in a closed vertical cylindrical reactor having a length/dia. ratio of 2-3.1, with round corners having a smooth surface and free of incorporated parts (e.g. stream breakers). The reactor is surrounded by a heating and cooling jacket and is provided with one or more propeller stirrers having 2-5, pref. 3-4, blades on their axis, the stirrers being inclined at an angle of 0-45 degrees, pref. 5-45 degrees to the vertical. The stirrers opt. rotate periodically right and left and one stirrer is located in the lower third of the reactor enclosure. During polymerisation the reactor is completely full and its contents are mixed with a recycled reaction mixt. amounting to 5-20 pref. 10-15 m3/min/m2 vol. of reactor. Process is pref. effected continuously using a series of reactors. Formation of popcorn is avoided as well as sedimentation of the emulsion. The process can thus be effected without interruption for a long time without intermediate cleaning.