How to Specify Pharmaceutical Blister Foil (PTP): Thickness, Lacquer and Testing

Pharmaceutical blister foil is unforgiving: a thickness drift of two microns or a lacquer weight variance can stop a packaging line or, worse, pass qualification and then fail in the field. This is the specification checklist we work through with every blister foil enquiry.

1. Alloy and temper

PTP foil is almost always 8011 or 8021 in hard temper. 8021 is used where higher strength or better barrier after forming is needed. Soft temper is not suitable: the foil must stay flat and push through cleanly.

2. Thickness

Typical range is 0.02 to 0.025 mm, with tolerances tighter than general purpose foil. Thickness is not only a barrier question; it determines whether the lidding pushes through consistently on the blister line and whether the pocket keeps its shape.

3. Heat seal lacquer

If the foil is to be sealed to a blister film, you must specify the lacquer system. It has to match the film:

• PVC — the most common, standard vinyl lacquer
• PVDC — where moisture barrier matters more
• PP / COC — for higher temperature sealing or specific chemical resistance

Lacquer weight is specified in grams per square metre and must be matched to your sealing temperature, pressure and dwell time.

4. Testing and documentation

Ask for batch test reports covering thickness, pinholes, surface cleanliness, tensile strength, elongation and lacquer weight. For regulated markets, DMF documentation may also be required.

5. Packing

Lacquer is moisture sensitive. Rolls should ship sealed in barrier bags inside wooden cases and be used within the shelf life stated by the supplier. Foil that has absorbed moisture will seal inconsistently.

We produce PTP foil in 8011 and 8021 with plain or lacquered finish, from 1 MT per size. Full details are on the pharmaceutical aluminium foil page, or see the wider packaging and container foil range.