Extrusion & Post
7 visualizações
Poor transparency of linear low-density polyethylene blown film (variant: strengthened measures)
Fenómeno do problema
The film has high haze and transparency does not meet requirements.
Poor transparency affects product appearance and display effect, which is especially important in packaging film and optical film.
Especially, additional attention is needed on top of the original basis; this problem is more prominent and requires focused attention.
Análise das causas
(1) Linear low-density polyethylene has high crystallinity; crystalline regions scatter light, resulting in high haze
(2) Melt temperature is on the low side and plasticization is insufficient
(3) Slow cooling rate results in high crystallinity
(4) The raw material contains impurities or gel
(5) The film surface is rough
(6) On top of the original basis, additional attention is needed as process parameter fluctuations or equipment condition changes aggravate this problem
Solução
(1) Appropriately increase extrusion temperature to the higher value within the 190-250°C range for full plasticization
(2) Improve air ring cooling efficiency, accelerate cooling and reduce crystallinity
(3) Select grades with good transparency or add nucleating agents to refine crystal grains
(4) Strengthen filtration, using 80-120 mesh screens to remove impurities
(5) Polish the die to improve film surface finish
(6) And strengthen process monitoring; on top of the original basis, additional attention is needed to pay special attention to parameter stability
Conclusão principal
Poor transparency is caused by high crystallinity or impurities and needs to be improved by increasing temperature, accelerating cooling and selecting suitable materials.
In different production scenarios, targeted preventive measures need to be taken.
Isto foi útil?
0 pessoas acharam isto útil
Obrigado pelo seu comentário!