In the world of flexible packaging, one parameter critical to product performance and production efficiency is seal temperature. Whether packaging snack foods, frozen meals, pet products, or medical supplies, creating a strong and reliable seal is essential. Furthermore, seal failure can lead to contamination, leakage, and spoilage.
What Is Seal Temperature?
Seal temperature refers to the heat required to activate the sealing layer of a flexible film. Thus, allowing two surfaces to bond under pressure. This process is typically performed using heat sealers on form-fill-seal machines, horizontal flow wrappers, or vertical baggers.
There are two key temperature benchmarks:
Seal Initiation Temperature (SIT): The lowest temperature at which a film begins to form a seal.
Optimal Seal Temperature Range: The window in which the film forms strong, consistent seals without distortion or burn-through.
Why Seal Temperature Matters
Selecting films with the right sealing properties is essential for several reasons:
Package Integrity: The seal must be robust to protect contents during transport, storage, and shelf life.
Line Efficiency: Films that seal quickly at lower temperatures can reduce dwell time, improve throughput, and lower energy consumption.
Compatibility: Some applications require sealing through contaminants like oils or powders. As such, films must be engineered to perform under those conditions.
Material Performance: Overheating can deform packaging, affect barrier properties, or damage printed designs, especially in multilayer or laminated films. In addition, overheating can cause the film structure to melt causing damage to machine tooling.
Common Film Types and Seal Temperature Ranges
Here’s a look at typical seal range temperatures for common flexible packaging materials:
Customizing for Application Needs
Some films are engineered with low-seal-temperature coatings to accommodate high-speed lines. Additionally, others are designed to seal through contamination or in cold-chain environments. This is why it’s important to work closely with your film supplier to match the film to your sealing equipment and end-use conditions.
Final Thoughts
Choosing the right flexible film isn’t just about barrier properties or appearance—it’s also about how well and how fast it seals. At PennPac, we specialize in helping our customers identify the best films for their specific sealing needs, ensuring product safety and operational efficiency.
If you’re experiencing seal issues or planning a new packaging line, let’s talk. Ask about how we can optimize your film selection for performance and peace of mind. Contact us Today!
