Material Analysis
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PE Film High Haze and Poor Transparency
Problembeschreibung
LDPE/LLDPE films have poor transparency and are hazy, failing to meet the packaging clarity requirements, and the printed patterns look dull.
Ursachenanalyse
Haze is divided into internal haze (large crystal size scattering light) and external haze (surface roughness such as melt fracture and uneven cooling); low material temperature, slow air ring cooling and surface melt fracture all increase the haze.
Lösung
①Appropriately increase the melt temperature; ②air ring rapid cooling, quickly passing through the crystallization temperature zone to refine the grains; ③eliminate surface melt fracture (increase the die temperature, add PPA); ④select high-transparency grades (such as metallocene PE); ⑤ensure melt temperature uniformity.
Wichtigste Erkenntnis
PE film haze: 'adjust crystallization internally, adjust the surface externally': rapid cooling refines the grains to reduce internal haze, and eliminating melt fracture reduces external haze; for high-transparency requirements, go directly to metallocene grades, which is more effective than forcibly adjusting the process.
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