Processing Machinery
2 views
Excessive gels/gel particles in random copolymer polypropylene pipe special material extruded products (Variant: strengthened measures)
Problem Phenomenon
Transparent or translucent gel particles (gel particles) are visible in the extruded film or product, affecting the appearance and transparency of the product.
Gels are resin particles that are not fully plasticized or crosslinked.
In particular, extra attention is needed on the original basis, this problem is more prominent and needs key attention.
Cause Analysis
（1）The high molecular weight components in the raw material are not fully plasticized
（2）The barrel temperature is low, and part of the resin is not completely melted
（3）The screw mixing effect is insufficient
（4）The raw material contains crosslinked or oxidized gels
（5）The filter screen mesh is not enough, and the gels are not intercepted
（6）On the original basis, extra attention is needed: process parameter fluctuations or equipment status changes have aggravated this problem
Solution
（1）Appropriately raise the barrel temperature to the higher value within the range of 200-220°C
（2）Optimize the screw design and add mixing elements
（3）Increase the filter screen mesh to 80-120 mesh
（4）Select high-quality raw materials with low gel content
（5）Check whether crosslinked materials are mixed into the regrind
（6）And strengthen process monitoring; on the original basis, extra attention is needed, with special attention to parameter stability
Key Takeaway
Gels are caused by insufficient plasticization or raw material quality problems, and need to be solved from temperature control, screw design, and raw material selection.
In different production scenarios, targeted preventive measures need to be taken.
Was this helpful?
0 people found this helpful
Thank you for your feedback!