Process for obtaining mixtures of expandable styrene polymers.

Process for the production of granules of expandable thermoplastic polymers comprising the steps a) preparing a mixture of 50 to 90% by weight of polystyrene B), selected from polymerized polystyrene-radical, transparent (GPPS), or polystyrene polymerized anionically (a-PS), and 10 to 50% by weight of styrene a) selected from block copolymer of styrene-butadiene, styrene-α-methylstyrene polymers acrylonitrile-butadiene-styrene (ABS), styrene acrylonitrile (SAN), acrylonitrile-styrene-acrylate (ASA), methyl acrylate-butadiene-styrene (MBS), methyl methacrylate-acrylonitrile-butadiene-styrene (MABS), b ) mixing an organic blowing agent into the polymer melt by means of static or dynamic mixer at a temperature of at least 150 ° c, c) cooling the polymer melt comprising blowing agent to a temperature of at least 120 C, d) discharge via a die plate with holes whose diameter at the die exit is at most 1.5 mm, and e) granulating the melt comprising blowing agent directly behind the die plate under water at a pressure in the range 1 to 20 bar.