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Choosing hard aluminium vs soft aluminum for blister packaging

2026-06-03

The hardness of aluminium foil used for blister lids has a direct impact on how a tablet is accessed and how the pack behaves when pressure is applied. The main distinction between hard and soft aluminium comes down to how the material reacts under force, and that difference shapes the user experience as well as the level of protection built into the packaging.

Hard aluminium

Hard aluminium foil in push-through blisters is the version most commonly associated with traditional applications. It is usually produced at around 25 micrometres in thickness and has relatively low elongation. When pressure is applied from the back of the blister, the foil gives way quickly and breaks cleanly, allowing the tablet or capsule to pass through with limited effort. That controlled break is what makes it suitable for straightforward dispensing, where access needs to be simple and predictable.

Soft aluminium

Soft aluminium foil and controlled access behaviour work differently. It has higher elongation and greater flexibility, so it does not break as easily under pressure. Instead, it resists deformation for longer, which means more force is required to push a tablet through the pack. This added resistance is often used when packaging needs a higher level of protection against unintended opening, including situations where child access is a concern. Child-resistant features in soft aluminium packaging are often achieved through this natural resistance to perforation. The material itself makes access more difficult.

Final thoughts

Sealing process and material compatibility in blister packs is the foundation for both hard and soft aluminium applications. Both rely on the same principle, where the inner coating system has to bond correctly with the blister film. That depends on the interaction between primer, lacquer, and aluminium surface, as well as the sealing conditions themselves. The process relies on a controlled balance of pressure, temperature, and time. If any of these elements are off, the bond can become inconsistent and affect the performance of the packaging.

Choosing between hard and soft aluminium in practice usually comes down to how the blister is expected to behave when opened. Hard aluminium supports easy, direct push-through access, which is why it is widely used in standard pharmaceutical blister formats. Soft aluminium shifts that behaviour toward higher resistance and greater control over opening. Both materials are available in our offer, including our standard hard aluminium of 20 µm as well as softer aluminium grades of 25 µm and 20 µm designed for increased elongation and child-resistant applications. In many cases, the final choice is about how much opening resistance is required for the specific product and user context.

If you are considering which aluminium structure would fit your application, it is worth discussing the details early in the process. Our team can help match the foil type and specification to the packaging requirements and end-use expectations. Contact us and we will advise on the most suitable solution.