Technical Articles
What Is Open Time in Packaging Adhesives?
Technical explanation of adhesive open time for packaging buyers: definition, factors that change it, carton and corrugating use cases, and how to write open time into RFQs.
Quick answer
Open time is the working window after adhesive application during which substrates can still form a reliable bond when brought together. Too short and joints starve; too long and cartons smear, slip, or pick up dirt before cutting or stacking.
Why buyers should care
Folder-gluers, corrugators, and case sealers run at different speeds and gap times. An adhesive with the wrong open time creates open seams, weak pins, or crushed wet board even when viscosity looks “normal.”
What changes open time
Solids, temperature, coat weight, substrate porosity, ambient humidity, and adhesive chemistry all move the window. A TDS open-time note is only useful if measured under stated conditions.
How to specify it
Describe your machine type, line speed, compression or bonding time available, board/paper type, and climate. Ask suppliers for an open-time range tied to those conditions, plus a trial confirmation.
Validate on the real line
Approve glue with production blanks or board, not only lab drawdowns. Check seam integrity after compression and after a humid dwell if the lane is wet-season sensitive.
RFQ
Machine type; speed; available compression time
Substrate; coat weight target; climate notes
Open-time window requested; test method
Trial blanks; failure mode history
Related PackTrades Knowledge
How to Spec Corrugating Starch Glue for Humid-Season Production, Folding Carton and Carton Sealing Adhesives Buyer Guide, Why Carton Side Seams Open After High-Speed Gluing, What Is Alkali-Free Adhesive?
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