Can anyone tell me if ThermoFlex Plus has a shlef life. I purchased a few rolls of this product and they are about 5 years old now. They have been in normal house temp over the years and now it will not release when peeled. I have tried the same design three times on a cotton canvas tote bag. I am using a Hotronic at 350 for 20 seconds. When the product was new I had no problems.
Thanks for any information.