Pre-drying is not necessary if a vented cylinder is used but if a normal cylinder is used then PMMA must be processed dry and it is advisable to pre- dry the granules for up to 8 hours at 70-100°C. Surface defects and blisters will form if damp granules are processed.
ARKEMA
PMMA – POLYMETHYLMETHACRYLATE (ACRYLIC)
Injection Molding
- Melt temperature : 200- 250°C
- Mold temperature : 40 – 80°C
High injection pressures are needed because of poor flow properties and it may be necessary to inject slowly to get the correct flow.
Extrusion
- Extrusion temperature : 180 – 250°C
A degassing screw with an L/D ratio of 20 –30 is recommended.