The sealing film of coffee capsules is a seemingly simple yet technically precise composite film. It is not only the "sealing cover" of coffee capsules, but also the core component that safeguards the fresh soul of coffee and assumes critical functions during extraction. 

Unlike ordinary food packaging film, coffee capsule sealing film needs to achieve a perfect balance between the conflicting needs of "long-term sealing and preservation" and "instant high-pressure penetration extraction". Its performance characteristics are specifically reflected in: 

1. Excellent barrier protection 

This is its primary function. The sealing film adopts a multi-layer composite structure, usually including: 

Aluminum foil layer: As the core barrier layer, it can almost 100% isolate oxygen, water vapor, and light. This is the key to ensuring that the volatile aroma compounds (flavor oils) of ground coffee powder are not oxidized, the moisture content is stable, and the flavor is not lost for several months or even longer. 

Outer layer (printing/protective layer): Provides mechanical strength and can be used for brand identification printing. 

Inner layer (heat seal layer): It is firmly heat sealed with the polypropylene (PP) or aluminum edge of the capsule cup body, forming an airtight seal to ensure foolproof performance. 

2. Precision designed puncturability 

This is the most distinctive technological core. After putting the capsule into the coffee machine: 

Adaptability: The sealing film must have specific mechanical strength and toughness. It needs to be tough enough to maintain a seal, while also being able to be precisely and cleanly punctured under the specific pressure of the coffee machine's water injection needle (or puncture needle) without tearing or producing large irregular areas of debris. 

Extraction channel: The hole formed by puncture is the only channel for high-pressure hot water (usually up to 9-19 bar) to uniformly enter the capsule powder compartment, and its puncture effect directly affects the water flow distribution and extraction efficiency. 

3. Food safety and temperature resistance 

All materials must comply with strict food contact safety standards and will not migrate harmful substances into coffee under high temperature and pressure. 

It must be able to withstand the impact of short-term high-temperature hot water (above 90 ° C) without deformation or functional failure. 

Leadtra Packaging is a wholesale and customized manufacturer of aluminum foil sealing film, specializing in the research and development and production of various high barrier packaging materials and easy to tear sealing packaging materials. They are widely used in food, medicine, cosmetics, and daily necessities packaging, and have many advantages such as green environmental protection, high safety, strict testing, and stable quality. If you are interested in or have any questions about us, please feel free to call us for consultation.