Recovery Issues with Red PMMA

The red colorant will affect the material conveyance within the feed zone of the screw. Different colorants can cause many intentional and unintentional purposes including a plasticizer, lubricant, slip agent, insulator, etc.

Question: I am processing both clear and red transparent PMMA of the same grade. My question is why is the plasticizing of the red material inconsistent. Both the temperature setting is from nozzle the the feedthroat, 240, 240, 230, 190, 60 degree. The plasticizing speed is 0.1 mm/s, back pressure is 15 bar. The decompression after plasticising is ok. However, the red component isn’t stable compared to the clear one. Also I hear the screaming when in plasticising. But others for PMMA, it’s normal.
My Response: The red colorant may be affecting the material conveyance in the feed zone. In such a case, you will need to perform a rear zone temperature study (currently 190) Essentially, the red color may need a different rear zone temperature to get the desired material conveyance in the feed zone.
Related Link

When to Optimize the Rear Zone


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