We are manufacture solvent bais holography film.
After holography tape test is 95% pass but we are facing the continuous delamination problem
Answer
The tape adhesion test does not measure adhesion it only measures lack of adhesion. If a coating comes off with the tape test it has very bad adhesion.
If the tape does not bring off the coating all it proves is the adhesion is anything from just a little better than the tape adhesive all the way through to adhesion such that the failure plane will be a cohesive failure within one of the layers and not at the interface.
I would check your deposition process to see if there has been any type of pre-treatment to the polymer film before metallization. If there is no pre-treatment then using a pre-treatment could improve the adhesion. If you are using a pre-treatment then there are two possibilities. One is that the treatment is not enough to maximise the adhesion and the second is that the treatment is too much and the surface has been damaged such that you have gone past the peak adhesion to a lower level off adhesion.
If you have a pre-treatment then review how the level of treatment was optimised. If it wasn't optimised then start from a low level and increase the treatment to see where the optimum level is. This will probably require using the lamination to test the adhesion level as the tape test does not have the range of adhesion to give any meaningful answers.
Solvents are often a problem in causing delamination but it often only happens where the adhesion is already not as good as it could be. The better the coating is bonded to the substrate the more difficult it is for the solvent to migrate into gaps in the interface. If the adhesion is poor the solvent can migrate into the interface and any swelling will put a force on the interface encouraging delamination. Defects in the substrate surface or coating can often be traced back as the source of delamination. The defects have poor adhesion associated with them which allows in the solvent and the delamination spreads from there.
The same can be true of pinholes where after lamination the air in the pinhole can expand and the pressure of the volume change can start a delamination if the adhesion is not good enough.
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