Quick Answer
- Seal opens at an edge: verify temperature, pressure, dwell time, and seal contamination
- Layers separate: check product chemistry and use a compatible corrosion-resistant adhesive
- Random pinhole or channel: use a vacuum leak water-bath test to locate the path
- Failure after filling or transport: review curing, material strength, and corner stress
Incorrect sealing creates a false seal
Heat-seal temperature, pressure, and dwell time work together. Excessive temperature can scorch the inner PE and make it brittle. Insufficient temperature can leave layers only partly fused, so transport pressure later opens the side seal.
Product chemistry can attack the laminate
Oily foods such as roasted coffee and pet food, as well as acidic liquids, can damage low-quality laminating adhesive and cause delamination. These applications need an adhesive selected for chemical resistance.
Skipped curing weakens the structure
A multilayer laminate needs 48-72 hours in a curing room so the adhesive can cross-link fully. Converting too early leaves the structure underdeveloped and increases the risk of delamination or weak seals.
A leak test identifies the path
A vacuum leak water-bath test submerges the pack under negative pressure so small pinholes or seal channels become visible. The result helps separate a sealing problem from a film defect.
Material quality affects durability
Softtime Packaging uses 100% virgin raw material. Avoiding recycled material reduces weak points that can appear under sealing, filling, or transport stress.
Decision Guide / Recommendation
If failure follows a seal line, first audit temperature, pressure, dwell time, and contamination. If layers peel, review the product chemistry, adhesive, and curing record. If the source is unclear, run a vacuum leak water-bath test before changing the specification.
FAQ
Can too much heat cause a bag to leak?
Yes. Excessive heat can scorch the PE sealant and make it brittle, while insufficient heat can leave a false seal.
Why do oily foods cause delamination?
Oil can attack an unsuitable laminating adhesive. The structure needs an adhesive designed for the product chemistry.
What does curing do?
Curing gives the laminating adhesive 48-72 hours to cross-link fully before the material is slit or made into bags.
How does a vacuum water-bath test find leaks?
The pack is submerged under negative pressure. Air escaping from a pinhole or seal channel reveals the leak location.
Can recycled resin create weak points?
Variable recycled content can introduce inconsistent strength. Softtime Packaging uses 100% virgin raw material to avoid these weak points.
Get a Packaging Recommendation
Send these details so our technical team can recommend a practical structure and prepare an accurate quotation.
- Product and fill weight
- Finished size, including relevant side seals or gussets
- Order quantity
- Material structure or performance needs
- Printing requirement and color count
- Destination country or port
If you have a physical sample, send it for material-structure analysis and closer matching.
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