Material Drying
3 조회수
PET over-drying oxidation
문제 현상
Over-dried preforms turn yellow, the AA value rises instead, and IV further decreases
원인 분석
Excessively long drying time or excessively high temperature triggers PET oxidative degradation, which converges with hydrolytic degradation on the same outcome: AA increases, IV decreases, and products turn yellow; over-drying is as harmful as insufficient drying
해결 방법
①Release the over-dried material and re-draw material to dry according to the standard; ②the drying temperature must not exceed the upper limit and the time is controlled at 4-6 hours; ③downgrade or scrap the oxidized yellowed material
핵심 요약
PET drying is range control, not the longer the better; both hydrolytic degradation and oxidative degradation must be guarded against, and yellowing is the alarm of over-drying; after confirming effectiveness, solidify the parameters and practices into the work instruction to prevent recurrence
이 정보가 도움이 되었나요?
0 명이 도움이 되었다고 합니다
의견 주셔서 감사합니다!