Extrusion & Post
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Poor transparency of polyolefin plastomer blown films (Variant: Enhanced Measures)
Problembeschreibung
The film haze is high and the transparency does not meet the requirements.
Poor transparency affects the product appearance and display effect, and is particularly important in packaging films and optical films.
In particular, additional attention is needed on the original basis; this problem is more prominent and requires focused attention.
Ursachenanalyse
（1）The polyolefin plastomer has high crystallinity, and the crystalline regions scatter light, causing high haze
（2）The melt temperature is too low and the plasticization is insufficient
（3）The cooling rate is slow and the crystallinity is high
（4）The raw material contains impurities or gel
（5）The film surface is rough
（6）On the original basis, additional attention is needed: fluctuations in process parameters or changes in equipment status have aggravated this problem
Lösung
（1）Appropriately raise the extrusion temperature to the higher value within the range of 180-230°C for full plasticization
（2）Improve the air ring cooling efficiency, speed up cooling, and reduce crystallinity
（3）Select grades with good transparency or add a nucleating agent to refine the crystal grains
（4）Strengthen filtration, using 80-120 mesh screens to remove impurities
（5）Polish the die to improve the film surface finish
（6）And strengthen process monitoring; on the original basis, additional attention is needed to pay special attention to parameter stability
Wichtigste Erkenntnis
Poor transparency is caused by high crystallinity or impurities, and needs to be improved by raising the temperature, speeding up cooling, and selecting suitable materials.
Targeted preventive measures need to be taken in different production scenarios.
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