[russell745]

My company is a manufacturer of amorphous polyethylene terephthalate sheets otherwise known as A-PET or polyester.
The sheets are transparent are are used in printing applications for clear boxes and cologne and perfume gift set dust covers.
We have just received a lab report that said that a major defect occurred as a result of our sheets being...

"The surface was deemed to be contaminated with low molecular weight aliphatic oil with a slight amount of an Aldehyde/Ketone character.  This will prevent adhesion and complete curing of the UV coating, both of which caused the failure on the job."


UV coating is a clear coating applied on a printing press that in this case would act as a surface barrier that adds moderate to significant abrasion resistance. The report states that this aliphatic oil compromised the UV coating which led to the sheets scratching.

This statement is somewhat vague and /or broad, and quite frankly we do not fully understand what this substance could be.
Can someone possibly explain the nature of this substance and some possible substances in layman's terms?

Thanks

[camptzak]

My company is a manufacturer of amorphous polyethylene terephthalate sheets otherwise known as A-PET or polyester.
The sheets are transparent are are used in printing applications for clear boxes and cologne and perfume gift set dust covers.
We have just received a lab report that said that a major defect occurred as a result of our sheets being...

"The surface was deemed to be contaminated with low molecular weight aliphatic oil with a slight amount of an Aldehyde/Ketone character.  This will prevent adhesion and complete curing of the UV coating, both of which caused the failure on the job."


UV coating is a clear coating applied on a printing press that in this case would act as a surface barrier that adds moderate to significant abrasion resistance. The report states that this aliphatic oil compromised the UV coating which led to the sheets scratching.

This statement is somewhat vague and /or broad, and quite frankly we do not fully understand what this substance could be.
Can someone possibly explain the nature of this substance and some possible substances in layman's terms?

Thanks

I would need to see the synthesis plan for the polyethylene terephthalate.
but basically it means you have some fat in your polymer that will prevent it from adhereing properly to surfaces and this contaminant will cause issues with your photostabilizer ( the compound that stops radical reactions caused by ultraviolet light )
It could be from contamination of the reaction mixture, improper handling at any time during the reaction, some error in synthesis planning or something overlooked in setting up the reaction conditions.

whoever is doing your lab work screwed up. try using a different lab. I can give you some good references if you're in the north east.

[fledarmus]

It might also be a lubricant or cleaning agent on your forming equipment that is being transferred to the sheets. Swabbing any surfaces that touch the plastic and sending the samples to the same lab that found the contaminant might let them match the sample and help you identify the source of the contaminant.

[curiouscat]

Did you grease / lubricate any equipment lately?