How to solve water-based case and carton sealing problems

A water-based adhesive bonds when the water leaves the glue line. On paper and board, the water goes into the fiber and into the air. Anything that slows that, or speeds it up too much, changes the bond.

Many faults come from three things: the board surface, the amount of adhesive, and the time under compression. Check those before you change grades.

This page covers cartons, glue laps, case flaps, and paper and board laminating. For corrugator washboarding, see how to solve washboarding adhesive problems making corrugated board. For hot melt case sealing, see how to solve hot melt application problems.

Why are my carton glue laps popping open?

Symptom: Side seams or glue laps open after the folder-gluer or at the packer.

Likely cause: The adhesive cannot get into a coated, varnished or UV-cured glue area. The bead is too small or compression is too short.

Fix: Keep the glue area free of varnish or coating if the design allows. Increase the bead in small steps. Lengthen the compression section or slow the line. Ask about a grade made for coated stock. Stock grade 8272 is listed for folding carton on coated stock, including UV.

Why do my case flaps spring open after compression?

Symptom: Flaps are closed at the compression exit but open a short time later.

Likely cause: The bond did not set in the compression time. Too much water, cold board, humid air or a short compression section causes this.

Fix: Lower the amount of adhesive in small steps. Lengthen compression time. Store board at plant temperature. Ask our lab about a faster-setting grade.

Why does my adhesive dry before the flap or lap closes?

Symptom: The bond shows no fiber tear. The glue line looks dry and shiny on one face.

Likely cause: Open time is too short for the line. Porous or warm board takes the water too fast. The bead is too thin or travel to compression is too long.

Fix: Increase the bead in small steps. Shorten the distance to compression. Check that the board is not hot from storage. Ask about a grade with a longer open time.

Why do my glue nozzles skin over or clog?

Symptom: Nozzles give a broken bead or spit. Dry skin forms at the tip.

Likely cause: Water leaves the adhesive at the tip during stops. The adhesive viscosity may be wrong for a fine nozzle.

Fix: Keep the adhesive moving during short stops. Cap or wet the nozzle tips at long stops. Flush with water before the adhesive dries. Use a grade made for your applicator. 8272 is offered for extrusion and for wheel application; check the TDS.

Why is my glue wheel slinging or splashing adhesive?

Symptom: Adhesive spatters off the wheel onto the board or the machine.

Likely cause: The viscosity is too low for the wheel speed, or the pan is too full. A worn scraper also adds too much adhesive.

Fix: Measure viscosity and correct to the TDS. Set the pan level. Check the scraper or doctor. See why should you control viscosity.

Why does my dry adhesive look white or chalky with a weak bond?

Symptom: The glue line is white or powdery. The bond breaks with little force.

Likely cause: The adhesive dried too cold to form a film. A cold plant, cold board or cold adhesive causes this.

Fix: Store adhesive and board at plant temperature. Warm the work area if you can. Ask our lab for the minimum use temperature of your grade.

Why does my adhesive foam in the pot or pan?

Symptom: Foam in the pot or pan. Bare spots or pinholes in the glue line.

Likely cause: Pumps, mixing or return lines pull air into the adhesive. The wrong defoamer also causes foam.

Fix: Use low-shear pumps. Put return lines below the adhesive level. Use only the defoamer we specify, at the amount we specify.

Why does the viscosity change during the shift?

Symptom: The adhesive gets thicker or thinner during the run. The bead changes size.

Likely cause: Water evaporates from an open pan. Temperature changes. Operators add water in the pan.

Fix: Cover the pan when you can. Measure viscosity at the start and during the shift. Do not add water unless the TDS allows it, and then only to the TDS range. See how to compare various viscosity measuring cups in seconds to centipoise.

Why is my laminated board warping or curling?

Symptom: Laminated sheets curl or warp after stacking.

Likely cause: The two faces have different moisture. Too much wet adhesive adds water to one face.

Fix: Lower the coat weight in small steps. Condition both sheets to the same plant conditions before laminating. Stack sheets flat with a weight. See how to add moisture back into paper. Stock grades 8252, 8275 and 8281 are listed for laminating.

Why won't my adhesive bond film, foil or poly-coated board?

Symptom: The bond peels clean from a film, foil or poly-coated face.

Likely cause: The water cannot leave between two non-porous faces. The adhesive may not wet the film surface.

Fix: Check the surface with dyne pens. Ask our lab for a grade made for film and non-porous faces. If both faces are non-porous, ask if hot melt is the better choice.

Why does my adhesive have lumps, mold or a bad smell?

Symptom: Lumps, skins, mold spots or a sour smell in the adhesive.

Likely cause: The adhesive froze, got old, or was diluted or contaminated. Dirty pans and lines also grow mold.

Fix: Protect adhesive from freezing. Use stock first in, first out. Clean pans and lines on a schedule. Do not add water unless the TDS allows it. Do not use lumpy material. Call us with the lot number.

Can I use these grades on food packaging?

Symptom: A customer asks if the carton adhesive is safe for food packaging.

Likely cause: Food packaging use depends on the grade, the structure and the conditions of use.

Fix: Some grades can be formulated to meet FDA requirements for food packaging adhesives. Confirm the grade with our lab before you run it. Ask for the regulatory statement in writing.

Stock grades

Stock water-based grades from our water-based adhesive page. Get the TDS for viscosity and solids.

What to send before you call

Tell us the board grade, the coating or varnish in the glue area, the applicator, the line speed and the compression time. Send flat blanks and failed cartons.

Related: water-based adhesive, packaging, how to select a folding carton type for packaging your product, checklist for running a trial with a new adhesive, how to solve bookbinding problems.

Still stuck on the line?

Call 800-249-0337 or contact us. Ask for a sample, an SDS, or a TDS. Our lab can test your substrate and your failed parts.

Call 800-249-0337 Request a sample Request an SDS

General plant guidance only — not a substitute for your process, SDS/TDS, or line trials. Call 800-249-0337 to match a grade.