Blister foil is a packaging material commonly used in the pharmaceutical industry to protect and preserve medicines, pills, capsules or tablets. Aluminum packaging blister foils typically consist of multiple layers designed to perform various functions, such as providing barrier properties, ensuring stability and ease of opening.
Common structures of blister foil are as follows

1. Substrate: The substrate of blister foil is usually a thin aluminum sheet. Aluminum has several advantageous properties, such as being lightweight, a good barrier to moisture, gas, and light, and is easy to shape. The thickness of aluminum foil can vary depending on the requirements of the specific application.

2. Adhesive layer (optional): In some cases, an adhesive layer can be applied to one side of the foil. This adhesive layer helps bond the foil to other layers of packaging material, providing structural integrity and preventing delamination during the packaging process.

3. Printed layer (optional): A printed layer can be added on top of the foil to provide branding, product information, dosage instructions, or other relevant details. This layer is typically printed using inks that comply with pharmaceutical industry standards and regulations.

4. Heat seal coating: To create a seal between the blister foil and the blister pack (usually made of PVC or PVDC), a heat seal coating is applied to one side of the foil. The coating melts when exposed to heat, allowing the foil to bond securely to the blister packaging material during the packaging process.

5. Release layer: Apply a release layer to the heat seal coating to prevent premature adhesion of the blister foil to the blister packaging material. This layer ensures that the foil can be easily peeled off the blister pack without damaging the medication or compromising the integrity of the seal.

6. Optional Barrier Layers: In some cases, additional barrier layers may be incorporated into the blister foil construction to provide enhanced protection against moisture, oxygen, or other external factors that may degrade the drug. Common barrier materials include aluminum oxide or other polymer coatings.

7. Optional Lamination Layers: Depending on the specific requirements of the application, additional layers (such as polymer films) can be laminated to the aluminum foil to provide additional functionality such as enhanced barrier properties, improved puncture resistance, or enhanced Printability.