Production of pre-expanded polystyrene for use in production of polystyrene foam, e.g. for insulation, involves pre-expanding expandable polystyrene and then coating the particles with water-absorbent polymer

摘要

A method (M1) for the production of pre-expanded polystyrene particles (I) coated with water-absorbent polymer(s) (W), involves (a) pre-expanding particles of expandable polystyrene to give particles with a bulk density (DIN ISO EN 60) of 5-50 g/l and then (b) coating the particles with polymer (W). Independent claims are included for (1) polymer-coated, pre-expanded polystyrene particles (I) obtained by this method (2) molded parts (II) made from polystyrene foam obtained from (I) (3) a method (M2) for the production of (II) by filling (I) into a gas-permeable mold, reducing the volume by pressing the particles in the closed mold, hardening at 20-100[deg]C and then demolding the product (4) a method (M3) for the production of (II) by filling (I) into a mold, expanding the particles and welding them together in the closed mold at 60-120[deg]C, and then demolding the product .