Asked November 13th, 2012
I have invited Matt Neumann, vice president, sales and marketing at Aylward, to be our guest expert to address these questions:
Do we have to do different stabilities with a perforated and non-perforated blister? Or do we consider that the perforated blister is the worst case?
What is important to the seal integrity of the blister card/pocket is the seal area between the blister pocket and the outside edge of the blister card or between the pocket and the perforation line. The weakest point is the shortest seal area. The perforated blister configuration will be the worst case scenario as long as the seal area between blister pocket and perforation line is the “shortest” of the four sides.
Can you explain the difference between cold form blister and PVC/PVdC blister?
Both blister materials are used for moisture-sensitive products. Cold form blisters offer total moister barrier and protection from UV radiation. The cost is high, machine output rates are lower compared with PVC/PVdC, and the blister card is larger in size because cold form blister cavities need to be larger due to the forming process. Also, consumers can’t see the product inside a cold form blister, something that marketing is not really favorable.
On the other hand, PVC/PVdC offers all the advantage of a standard PVC blister with added moisture-barrier properties. For some products, this added moisture protection is sufficient. The PVdC layer is laminated to the PVC base material, and it is available in various thicknesses and qualities. There are charts available with the various material suppliers indicating the permeability of each thickness and quality combined with PVC.