What should I do if the hot melt adhesive particles are not firmly attached to the coated paper? The solution is to first look at the film surface and then adjust the adhesive

What should I do if the hot melt adhesive particles are not firmly attached to the coated paper?

Direct answer: The root cause of the poor adhesion of laminated paper is mostly due toLow membrane surface energy, glue not eating paper fibers, poor coordination between opening time and compressionThese three points. The surface of laminated film (especially optical film) is smooth and has low polarity. Ordinary book and magazine adhesive particles only “stick” to the film without real anchoring, and can be easily peeled off. Guangzhou Sunlife Trading has dealt with a large number of such problems on site for graphic and text fast printing and color box customers. The idea is to first distinguish between “sticking film or paper”.

Three step positioning and countermeasures

• First distinguish the fracture surfaceIf the adhesive layer remains intact on one side and the film surface is clean after tearing, it indicates insufficient adhesion of the film surface; If the glue is stretched thin by wire drawing, it is a problem with the amount of glue or temperature.
• Membrane surface treatmentIt is recommended to use high polarity and high tolerance for low-energy surface sealing special adhesive particles for the optical film; When conditions permit, perform local corona discharge or roughening at the bonding site to achieve immediate adhesion.
• Glue adjustment and pressingProperly increase the glue application temperature by 5-10 ℃ to facilitate better spreading of the glue, shorten the distance from glue application to compression, and hold the compression for 2-3 seconds to anchor the glue before it dries on the surface.

Quick Checklist

Frequently Asked Questions

Q: Is sub film more adhesive than light film?
Yes, the surface of the sub film is slightly thicker and has higher energy, and its adhesion is usually better than that of the light film; But it is still recommended to use laminated adhesive particles instead of ordinary sealing glue.

Q: Can changing the glue solve the problem or must we change the process?
In most cases, choosing the appropriate film coating model for Sunlife hot melt adhesive can solve the problem; If the material is extremely difficult to stick, such as high gloss cold film, it needs to be treated with roughening or corona discharge.

Summary: First, judge whether it is a problem with the film or the adhesive by looking at the fracture surface, and then select the adhesive or treat the film surface accordingly. If the laminated paper is not firmly adhered, it can be basically improved on the same day.