Extrusion & Post
11 조회수
PET Blowing Milky White Whitening (Overheated Crystallization)
문제 현상
Porcelain-white turbid areas appear on the bottle body, mostly at the bottom or thick-wall areas; the whitened areas have increased brittleness and decreased strength.
원인 분석
The preform is locally overheated, and PET has thermally crystallized before stretching; the crystallized zone cannot be normally oriented and stretched, and appears milky white after blowing with deteriorated mechanical properties.
해결 방법
①Reduce the temperature of the corresponding heating zone and shorten heating time; ②strengthen preform temperature measurement and thermal image monitoring; ③check lamp aging and reflector condition; ④reject crystallized preforms.
핵심 요약
Milky white whitening is caused by overheated crystallization, and its machine adjustment direction is opposite to that of pearlescent whitening, so they must be accurately distinguished first; thermal imager monitoring of heating uniformity is an effective preventive means.
이 정보가 도움이 되었나요?
0 명이 도움이 되었다고 합니다
의견 주셔서 감사합니다!