| 摘要 |
Thermoplastic foam sheet material is formed using an apparatus comprising an extruder, means for feeding polymer into said extruder, means for introducing an expanding agent into the extruder, a low-shear mixing and cooling chamber, a substantially non-shear cooling chamber, and a sheet forming die disposed to receive the output of said substantially non-shear cooling chamber. The polymer may be polystyrene and the expanding agent may be pentane, hexane or heptane. The sheet is stretched. |
