PROCESS FOR CONTROLLING PEARL DIMENSIONS IN THE PREPARATION OF EXPANDABLE STYRENE POLYMERS BY SUSPENSION POLYMERIZATION

A process for controlling bead size in the production of expandable styrene polymers by suspension polymerization is carried out by adding protective colloids to the aqueous phase before polymerization begins, such protective colloids being used which are homogeneously soluble in water over the enti...

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Bibliographische Detailangaben
Hauptverfasser: RIGLER, JOSEF KARL, LEITHAUSER, HORST
Format: Patent
Sprache:eng ; ger
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Zusammenfassung:A process for controlling bead size in the production of expandable styrene polymers by suspension polymerization is carried out by adding protective colloids to the aqueous phase before polymerization begins, such protective colloids being used which are homogeneously soluble in water over the entire temperature range from 25 DEG to 125 DEG C. and in which the concentration range being employed shall not lower the boundary surface tension water/styrene below 18 N/mm2. Lastly, the protective colloids are selected according to their molecular weight and the weight ratio of aqueous to organic phase lies in the range of 0.9:1 to 1:1.25, preferably in the range of 1:1. A grain spectrum is maintained predominantly greater than 0.41 to less than 2.5 mm by varying the molecular weights of the protective colloids.