Extrusion & Post
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PPA reduces back pressure in HDPE pipe extrusion
Problembeschreibung
During extrusion of HDPE pipes (PE100), the die head pressure is too high (30% above the normal value), the main machine current is overloaded, the extrusion output has to be reduced by 20%, and production efficiency is severely limited.
Ursachenanalyse
HDPE PE100 has a high molecular weight (MFR 0.2-0.3 g/10min) and high melt viscosity, resulting in high die head resistance; PPA is not used or the PPA molecular weight does not match HDPE; the die flow channel design is narrow (the L/D ratio is too large); the processing temperature is too low and melt flowability is limited.
Lösung
Add 0.03-0.06% PPA to the HDPE pipe formulation to reduce melt/metal wall friction; select a high molecular weight PPA grade (Mw 500,000+) to ensure coating durability; optimize the die flow channel design to reduce the L/D ratio; appropriately raise the processing temperature by 5-10°C (within the material's temperature resistance range).
Wichtigste Erkenntnis
By reducing melt/metal friction, PPA can significantly reduce the die head pressure and energy consumption of large pipe extrusion.
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