As we know the printer with heating function which can cure 40-50% white ink before the film enter into powder machine. And then you will set up the thermostat temperature to 110~140℃,under this condition the powder will be melt as a primer, then there will be 30~40% water remaining in the white ink (between the PET film and powder primer). The inside water may produce water bubble or blister after condensation.
Some people may said that the water not always occurred, actually it depend on two points---one is the humidity if your showroom, and the other is depend on your film quality. The high quality film with strong water imbibition, which will be helpful to dry the film as far as possible. AGP can offer you high quality cold-peel film or hot-peel according to your demand. The difference you can check my previous article https://www.linkedin.com/pulse/hot-peel-cold-which-pet-film-best-iris-dong-inkjet-printer-/
How to avoid this problem?
If the powder machine manufacturer can divide the drying area into three stages, this problem can be avoided with maximum probability. In first stage we can control the temperature at 110℃,at this time the powder just begin to melt and the water will become to gas to go out. And in second stage we can set up the temperature to 120~130℃ to heating the glycerol. Then in third stage the temperature can be 140℃ to melt the powder totally to be as primer to joint with image.
Storage Tips:
1.To make sure the printed film is sealed storage as far as possible
2.Be sure to pay attention to humidity in the place where materials are stored.
