Troubleshooting2026-05-25 · 7 min read
Paper Bond Failures: Starch Migration, Sizing, Surface Tension
A delamination complaint is almost always solvable in the slurry — if you know what to look for.
NT
Nordgyp Technical Desk
Editorial
Paper bond is the result of three things meeting at the right time: migratory starch arriving at the paper-core interface in the bleed water, the paper accepting that starch (a function of paper sizing), and the dihydrate crystal network growing through the resulting film.
When bond fails, isolate which of the three has shifted:
- Has migratory starch dose dropped or has its DE crept up? A higher DE migrates differently.
- Has the paper supplier reformulated their internal sizing? Ask. They will not volunteer it.
- Has foam reached the paper interface? Foam at the interface displaces starch and prevents bond.
Fiber-tear on a paper-bond test is a standard qualitative check; a bond that produces predominantly fiber tear rather than clean release is the desired result. Persistent low fiber-tear indicates a real problem, and "increase starch by 10%" without diagnosis is guessing.