CPet sealing issue ( film ) Urgent

I need some expert suggestion regarding the CPET tray Sealing.

we manufacturing frozen foods ( Process: cooking- chilling meat portion- assembling with rice warm around 75F and then blast freeze it)

Afterwards remove the product from blast freezer and transferred to film sealing (set temp for heat 375F) Seal Dwell time 3Sec.

However CPET trays is not sealing some of the area. The film is removing. (Causes: I assume in the assembly line they scoop the portioning of the components but some of the components are oily/grease which dropped on the lip of the container. Thus, its not stick properly.

Is there any food grade wipes can we use to wipe the oily/grease area before sealing. 

we have customer complain regarding the seal.  And we have to fix it by 7 days or we may breach our contract. 

Please help! 

here is my suggestion

wipe with disposable wipers dipped in a diluted PAA solution or hydrogen peroxide BEFORE blast

and/or pre chill----seal and then blast  or seal then blast

it may not be oil/grease may just be moisture because it's sooooo hot going into the blast freezer

Perhaps just blast for 20 minutes, take out seal and finish freezing?

Blast freezers will form ice crystals that are really small and if your container is a light colour you may not see them

Hi Shaik Yasmin,

Used to run an analogous process to what you describe.

And had similar problems. Assumed as Scampi due moisture.

Only eventual solution was to seal before freeze.

Good Luck !

PS - much, much later i recall a film Producer commenting that some sealing combinations are more sensitive than others. You maybe should also seek expert advice.

If you have contamination (food spillages) on the sealing rim of the tray then the film will obviously not seal properly.  You should be able to observe this on defective samples.  Does it always not seal in the same place?

Also is the heat seal head clean and cleaned regularly, if not you will have poor or uneven heat transfer.  As a first step check the tray and sealing head are clean.  Also if the sealing head is clean test it with a probe in different areas to see if heat is even. 

Good luck.

Simon

I see you have frosted products then you could consider to use ultrasonic sealing technology, which is more favourable with PET plastic. It may prevent some defects of thermal shocks.

In my company (packaging), we apply heat sealing on PE films and ultrasonic on PET. If used with heat, PET requires a higher temperature and longer time to melt, a.k.a. more energy cost and slower production rate.