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Thread: Expired Materials

  1. #1
    Join Date
    Aug 2018
    Posts
    11

    Expired Materials

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

  2. #2
    Join Date
    Aug 2014
    Location
    Michigan
    Posts
    71

    Re: Expired Materials

    "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

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