Expired Materials

[holar09]

Can expired Materials cause preform to be whitish? How long can a Pet Resin material stay before its expiration?

[MTUHusky]

"Expired" is probably a bad term to use. Plastic sitting over long periods of time can become oxidized. This is a form of degradation and it can cause all sorts of issues from discoloration, to processing issues, to failure in the field. Have a MFI done on the material and if your within 5% of what it should be then you should be ok from a structural/functional perspective. If the oxidation is causing the discoloration, there is nothing you can do about it that I am aware of so if the color is an issue then scrap it.

Discoloration can also be caused by too hot of temps on your dryer (speeds up oxidization and degridation).

Husky