Process for suspension polymerization of styrene compositions in the presence of colophonic-resin acids or their salts, and the possibly expandable styrene polymers so obtained

摘要

The polymerization of compositions containing styrene by an aqueous suspension process in which is used a suspending agents system constituted by a mineral agent and, an extending agent which is at least a rosin acid derivative (abietic acid, neoabietic acid, dextropimaric acid) or their salts of a metal belonging to Group IIa of the Periodic Classification of elements. The use of this extending agent has the advantage to ameliorate the surface aspect of moulded articles obtained from expanded polymer pearls prepared with the above polymerization process.