The sealing principle of an aluminum cap can be explained
Sealing Principle of an Aluminum Cap:
The aluminum cap achieves an effective seal primarily through a combination of **compression and deformation**. The key components involved are:
1. Aluminum Shell – Provides structural rigidity and maintains the shape of the cap.
2. Liner (Sealing Material) – Typically made of materials like PVC, foam, or induction seal foil, which forms a tight barrier when compressed.
3. Tamper-Evident Band (if applicable) – Ensures integrity by breaking upon first opening.
Mechanism:
- When the cap is crimped or screwed onto the container (e.g., a glass bottle), the **liner is compressed** against the rim of the opening, creating a hermetic seal.
- For induction sealing (common in pharmaceuticals/food), an **induction heat-seal liner** bonds to the container mouth when exposed to electromagnetic induction, enhancing leak-proofness.
- The aluminum’s malleability allows it to conform tightly to container threads or grooves, preventing air/liquid ingress.
Applications:
Widely used in **beverage, pharmaceutical, and food packaging** due to its excellent seal integrity, corrosion resistance, and tamper-evident features.