Material Drying
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Product color inconsistent with the standard color plate
Problem Phenomenon
Product color inconsistent with the standard color plate, locally or entirely yellowish and dark, transparency decreased for transparent products
Cause Analysis
Barrel temperature too high causing cellulose acetate butyrate thermal degradation and discoloration
Drying temperature too high or time too long, oxidative discoloration
Screw shear too intense, local degradation
Regrind used multiple times, degradation accumulation discoloration
Uneven dispersion of pigment or color masterbatch
Solution
Lower barrel temperature to the low range of 170-230°C
Strictly control drying conditions 75-85°C/3-4h to avoid over-drying
Reduce screw speed to reduce shear
Limit regrind ratio ≤15%
Improve color masterbatch dispersion, add mixing section
Key Takeaway
Color difference needs to be addressed from temperature, shear, drying and regrind control
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