Producing expandable polymer particles useful e.g. for producing foams, comprises e.g. heating polymer component, introducing physical blowing agent component into obtained polymer melt, extruding polymer melt, and granulating polymer melt

摘要

Producing expandable polymer particles, comprises (a) providing a polymer component comprising polymerized styrene and polymerized acrylonitrile, (b) heating the polymer component for forming a polymer melt, (c) introducing a physical blowing agent component into the polymer melt for forming a foamable melt, (d) homogenizing the mixture, (e) optionally adding additives to the polymer component in at least one of the steps (a), (b), (c) and/or (d), (f) extruding the blowing agent-containing polymer melt, and (g) granulating the blowing agent-containing polymer melt to obtain a granulate. Producing expandable polymer particles which are suitable for processing into foams having a density of 50-120 g/liter, comprises (a) providing a polymer component comprising (P1) 60-85 wt.% polymerized styrene and (P2) 15-40 wt.% polymerized acrylonitrile, (b) heating the polymer component for forming a polymer melt, (c) introducing 3.11-3.91 wt.% a physical blowing agent component comprising 80-100 wt.% at least one hydrocarbon having 2-7 carbon atoms, into the polymer melt for forming a foamable melt, (d) homogenizing the mixture, (e) optionally adding additives to the polymer component in at least one of the steps (a), (b), (c) and/or (d), (f) extruding the blowing agent-containing polymer melt using a nozzle plate, and (g) granulating the blowing agent-containing polymer melt in a liquid filled chamber at a pressure of 1-20 bars, preferably 6-14 bars, to obtain a granulate having an average particle size of 0.81-1.11 mm, preferably 0.92-1.09 mm. Independent claims are also included for: (1) the expandable polymer particles obtainable by the above method; (2) producing a foam molded part, comprising the steps (a)-(g), (h) optionally coating the expandable polymer particles with a coating agent comprising glycerol monostearate, glycerol tristearate, glycerol tribenzoate, filling silicic acid, alkyl esters compounds of cyclohexanecarboxylic acid, of formula (I) or phenyl ester compounds of 10-21C alkyl-sulfonic acid, of formula (II), (i) pre-foaming the granulate to obtain foam particles, and (j) fusing the foam particles in a closed mold; (3) the foam molded part obtainable by the above method; and (4) a composite molded part comprising at least one core layer which is the above foam molded part, and a cover layer. R1 : 1-10C alkyl or 3-8C cycloalkyl; m : 0-3; n : 1-4; R : 1-30C alkyl; and R2 : 10-21C alkyl. [Image].