One of the core indicators of easy-tear sealing film is peel force. If the peel force is too high, consumers struggle to open it, leading to a poor experience. If the peel force is too low, the seal is weak, and the product risks leakage. So, how is peel force controlled? Leadtra Packaging provides a technical analysis.

1. What is peel force?

Peel force is simply the force required to tear open the sealing film, typically expressed in N/15mm (the Newtons needed per 15mm of width). The peel force for easy-tear film is generally controlled between 3-8N/15mm: too low, and it may detach spontaneously during transport; too high, and consumers need to use their fingernails or even tools to open it.

2. Key factors affecting peel force

Formulation of the heat-seal layer: The heat-seal layer is the part that fuses directly with the bottle mouth. The type and proportion of its materials determine the adhesive strength of the seal. Easy-tear formulations typically add a certain amount of modified materials to give the heat-seal layer a "controlled release" effect while maintaining seal integrity.

Heat-sealing temperature and pressure: The temperature and pressure during sealing directly affect the degree of fusion between the heat-seal layer and the bottle mouth. Too low a temperature or insufficient pressure results in a weak seal; too high a temperature or excessive pressure significantly increases peel force and may even cause the film to tear. Therefore, precise control of sealing parameters is a prerequisite for stable peel force.

Bottle mouth material and cleanliness: Different bottle mouth materials (PET, PE, PP, etc.) have different affinities for the heat-seal layer. The same film may exhibit different peel forces when sealed on a PE bottle versus a PET bottle. Additionally, oil or moisture on the bottle mouth can interfere with the heat-sealing effect, causing fluctuations in peel force.

Laminate structure of the film: Easy-tear films are typically designed as "aluminum foil + heat-seal layer" or "PET + easy-tear layer" laminates. The adhesion strength between layers and the uniformity of film thickness both affect the force curve during tearing.

3. How to precisely control peel force?

On the raw material side: Select specialized easy-tear heat-sealing resins and adjust the proportion of modifiers in the formulation to lock the peel force within the target range.

On the process side: Use high-precision coating and laminating equipment to ensure uniform heat-seal layer thickness and bubble-free adhesive layers. Monitor peel force in real time during production and make timely adjustments when fluctuations are detected.

On the application side: We recommend that customers provide actual bottle mouth samples during the sampling stage. Leadtra's technical team can then match the optimal heat-seal layer formulation based on the bottle mouth material and provide sealing parameter recommendations (temperature, power, time) to ensure stable peel force during mass production.

4. Leadtra Packaging's easy-tear solutions

Leadtra Packaging offers a range of easy-tear grades:

Gentle easy-tear: Suitable for flexible packaging and small-dose products

Standard easy-tear: Suitable for conventional food and cosmetic products

Strong seal + easy-tear: Balances long-distance transport requirements with unboxing experience

Additionally, Leadtra can assist customers in adjusting sealing machine parameters and provides peel force testing services to ensure consistent performance across every batch.

Conclusion

Easy-tear sealing film is not simply about "making it thinner." It is about finding the optimal balance between sealing and opening through the precise coordination of materials science and process control. With Leadtra Packaging, technology ensures that every tear feels just right.