The influence of blister varnish and printing parameters on blister peel strength

This paper focused on the influence of different blister varnishes and printing parameters, including the kind and amount of diluent, the dot area coverage, and the ink thickness, on the peel strength in blister packaging. A method was developed using Confocal Laser Scanning Microscopy to quantitatively represent the penetration depth of blister varnish. With increasing ink thickness, the penetration depth of blister varnish and hence the peel strength decreased. In addition, clear differences relating to the dot area coverage were detected, and the full point printing sample was found to produce the worst results overall. The amount of diluent also had an influence on the penetration depth of blister varnish and, therefore, the peel strength.