What should I do if the hot melt adhesive particles are not firmly attached to the corrugated cardboard box? Don’t blame the glue yet, avoid these 5 pitfalls

First, correct a common misconception: corrugated cardboard boxes cannot be tightly sealed, and most of the time it is not a problem with the quality of the glue particles, but rather due to insufficient pressing time, moisture in the cardboard box, improper glue amount or temperature, or the cardboard box being covered with film or dust. By checking each of these five pits one by one, the bonding strength usually increases immediately.

The Five Most Common Pits

• Insufficient pressing time for pit oneHot melt adhesive forms a film by cooling, and after spraying, it must be compressed for 3-5 seconds. The number one reason for adhesive failure is that the compression section of the conveyor belt is too short and the manual release of the adhesive is required;
• Pit 2 cardboard box is dampMoisture blocking adhesive liquid on the surface of damp cardboard boxes greatly reduces adhesion, especially during the rainy season;
• Inappropriate temperature in Pit ThreeIf the temperature is too low, the adhesive solution will become sticky and uneven, and if it is too high, it will oxidize and lose, which will weaken the bonding;
• Pit four covered with film or dustFilm coated cardboard boxes, printed ink surfaces, and surface dust can all make it difficult for the adhesive to bite, so it is necessary to choose a high initial adhesion formula or perform surface treatment;
• Pit Five Glue Quantity and Glue Point LocationThe adhesive point falls on the support of the corrugated edge or the amount of adhesive is too small, and it will open as soon as the force is applied.

Correct troubleshooting sequence

First, look at the pressing process – extend the pressing time or slow down the production line to test one box; Check the cardboard box again – confirm it is dry and free of film covering; Then check the process – calibrate the temperature according to the recommended range, glue amount, and glue point position. In the technical follow-up data of Guangzhou Sunlife Trading, 80% of the “adhesion failure” complaints can be resolved by pressing and moisture. When it is really necessary to change the adhesive, consider using high initial adhesion or special formula for film coating.

When do we really need to change the glue

If the cardboard box is coated, laminated, or has a high wax content surface, ordinary sealing glue particles cannot bite it, then it is necessary to replace it with Sunlife hot melt adhesive specifically for high initial adhesion and adhesive film, and provide sufficient pressing time.

Frequently Asked Questions

Q: Is it because the amount of sealing and opening glue increases in winter that the glue has deteriorated?
No. Low temperature causes the glue to cool too quickly and shortens the initial adhesion window. You can increase the pot temperature by 5-10 ℃ or change the low-temperature resistant formula, and ensure that the pressure is in place.

Q: How to quickly determine whether it is a pressing or adhesive problem?
Compare manually pressing several boxes: if they are firmly pressed once, it indicates that it is a matter of pressing time, and only consider glue or surface treatment after pressing and opening.

Remember: When sealing corrugated cardboard boxes, check the process first and then change the glue. Most of the “not sticking firmly” issues are caused by the process pit, not the glue pot.