Technical Articles
Why Stand-Up Pouches Leak at the Bottom Seal
Troubleshooting guide to stand-up pouch bottom-seal leaks: seal window, contamination, gusset geometry, laminate curl, fill splash, and corrective buyer actions.
Quick answer
Stand-up pouches leak at the bottom seal when seal temperature/pressure/dwell, contamination, or gusset geometry prevent a continuous sealant bond. Changing print artwork will not fix a seal-window or fill-splash problem.
Inspect the leak path
Dye or water tests should show whether failure is at gusset corners, center bottom, or channeling near wrinkles. Photograph seals before and after squeeze tests.
Check the seal window
Confirm sealant grade, jaw temperature, pressure, and dwell against the approved trial card. Aged laminate or substituted PE layers can shift the window.
Look for contamination
Powder, oil, or splash in the seal area is a common field cause. Review filler nozzles, vacuum, and pouch opening controls—not only the pouch maker.
Review gusset design
Aggressive gusset geometry or uneven web tension creates corner voids. Validate on production pouching equipment at target speed.
Apply one change set
Adjust seal settings, filler splash control, or laminate sealant together in a controlled trial. Retain failed and passing pouches from the same lot.
RFQ
Failed pouch photos; dye-test results; lot IDs
Laminate stack; seal settings; filler notes
Proposed correction; trial quantity
Acceptance leak method; retention samples
Related PackTrades Knowledge
How to Spec Stand-Up Pouch Barriers for Food Export, Zipper and Tear-Notch Spec Checklist for Retail Pouches, Laminated Film Structures for Food Flexible Packaging, How to Verify Flexible Film Laminators in China.
Buyer Checklist
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