Material Drying
2 views
Silver Streaks Caused by Moisture in EVOH Processing
Problem Phenomenon
EVOH injection molded product surfaces show white silver streak marks
Cause Analysis
Raw material moisture content >0.05% vaporizes during high-temperature processing forming bubbles that are stretched into silver streaks; insufficient drying or moisture condensation in the hopper
Solution
1) Dry raw material at 80°C for 3-4h to moisture <0.02%; 2) Increase back pressure 0.5-1MPa for venting; 3) Reduce injection speed to avoid air entrapment; 4) Heat hopper to prevent moisture condensation
Key Takeaway
Silver streaks are caused by moisture vaporization and stretching; drying and venting are the main countermeasures
Was this helpful?
0 people found this helpful
Thank you for your feedback!