Processing Machinery
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PMMA Yellowing Index Exceeds Standard
Problem Phenomenon
After outdoor use for a period, the product YI yellowing index rises and light transmittance decreases.
Cause Analysis
UV aging and accumulated heat history cause PMMA to yellow slowly; insufficient light stabilizer or a high processing degradation starting point both accelerate YI rise.; During on-site troubleshooting, verify item by item according to this mechanism to avoid blindly adjusting the machine based on experience alone.
Solution
①Select grades containing UV stabilizer; ②control processing heat history; ③compound with HALS light stabilizer; ④perform xenon lamp aging verification.; After adjustment, continuously sample to verify the effect, and resume mass production only after confirming stability.
Key Takeaway
Although PMMA has good weather resistance, it still needs stabilizer support; controlling heat history on the processing side can preserve the material's original anti-yellowing capability.; After confirming effectiveness, fix the parameters and practices into the work instruction to prevent recurrence.
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