1.0 PRE-EXPANSION PROCESS (FOR EPS AND HIPS ONLY)
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The raw material (in solid spherical bead form) is expanded in the pre-expansion
chamber to the specified expansion times or density. Steam is used for the
expansion process. MPC uses 2 batch-type pre-expanders for this process. |
2.0 EXPANDED MATERIAL AGING PROCESS (FOR EPS AND HIPS ONLY)
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Since there is partial vacuum inside the beads, these are easily deformed. An
aging process is required where-in the beads are placed in air-permeable
silos to allow air in entering the internal portion of the beads until pressure
equilibrium is achieved between outside pressure and internal bead pressure.
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