Aluminized bond failure to polyester film

I use various suppliers to provide Aluminized ¡ mil. Polyester film for use in manufacturing of fire retardant materials. Lately the bond between the aluminum and the polyester film is breaking down where the aluminum is no longer attached to the film. My questions are

1. Is there a test I could use to check for proper bonding of the aluminum to the film prior to my use.
2. What factors in the manufacturing process could affect such a bond.

The most basic test is a tape test. In this case you stick a piece of scotch tape to the aluminum coating and pull the tape off. If the aluminum sticks to the tape then the adhesion of the aluminum to polymer probably isn't good enough to do what you want.

There are many possible reasons why you are getting low adhesion. The biggest is probably the substrate isn't clean enough. It is good to remove water, small polymer molecules and grease from finger prints from the polymer prior to metallizing. Many people do this by plasma cleaning the polymer prior to depositing metal. Another reason for low adhesion could be a leak in the vacuum system. This could be contaminating the interface as the coating is going down.