Technical Articles
Why Paper Cans Leak at Bottom Seals
Troubleshoot paper can bottom leaks: liner breaks, seal heat, dust, and fill process. Fix the seal system before reprinting China lots.
Quick answer
Paper cans leak at bottom seals when liner integrity, seal heat/pressure, or contamination prevents a continuous bond. Changing only outer artwork will not fix a seal-system mismatch.
How do you diagnose the leak path?
Dye or water tests show corner channeling, center seal voids, or liner pinholes. Photograph seals before and after squeeze or vacuum checks.
Which process variables to lock?
Seal temperature/dwell, dust on flanges, liner wrinkles, and fill temperature all matter. Cold powder fills can hide seal weakness until transit vibration.
RFQ
Failure photos; product fill; seal method
Liner structure; proposed process change
Trial quantity; acceptance leak test
Retention samples; substitution ban
When should you change structure?
If process controls are already tight and leaks remain, trial a different liner or end construction—then freeze the new BOM before reprint.
Related PackTrades Knowledge
Food-Grade Paper Can Spec Checklist, How to Spec Composite Paper Cans, Why Stand-Up Pouches Leak at the Bottom Seal, How to Freeze Packaging Specs Before Mass Production in China.
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