| 摘要 |
Process for manufacturing expanded polystyrene meat trays comprising the following steps: plasticizing a mixture comprising polystyrene, cellulation regulator materials, and a masterbatch containing sodium alkyl-(C10-C18)-sulphonate in an extruder at a temperature exceeding 200 DEG C; injecting an expanding agent into an extruder zone in which homogenization of the various ingredients has already occurred; cooling the material to a constant temperature of between 150 DEG C and 180 DEG C; extracting the material (8) through a die; applying a first rigid film (9) to one side of the material; applying a second rigid film (9') to the other side of the material; winding the extrusion-obtained composite sheet comprising the two applied rigid films into reels; maintaining the reels at ambient temperature for a period of between 1 and 30 days; heating the sheet to a temperature of between 140 DEG C and 160 DEG C; thermoforming the sheet by drawing within a mould, the cavity of which is put under vacuum both from the female side and from the male side. |
