Common causes of white glue spots during the dry compounding process of water-based adhesives!

Insufficient or uneven application of glue

The white glue spots caused by insufficient glue can be observed when the compound is off the machine

In addition, the uniformity of the amount of water-based adhesive is also a very critical factor.

①The assembly of the squeegee should be straight and not twisted, and the angle and pressure of the squeegee should be adjusted appropriately to ensure a uniform squeegee effect;

②During normal production, the scraper should keep moving left and right to avoid the abrasion of the glue roller at a fixed position

Poor glue leveling

Since water-based adhesives are not like solvent-based adhesives, they can achieve a better leveling effect under the action of their own gravity and surface tension after coating.

The leveling effect of water-based adhesives is also affected by the surface tension of the coating film

In addition, if the surface of the coated film is not clean, and substances with low surface tension are adhered, the leveling performance of the glue will be reduced, and a failure similar to printing "shrinkage" will occur, which is manifested in the composite film.

Clogging of rubber roller cell

In the dry compounding of solvent-based adhesives, there are generally two types of clogging of the glue roller cell.

When using water-based adhesive for dry compounding, in order to prevent clogging of the gluing roller, the scraper should be loosened when the machine is stopped, and the gluing roller should be soaked in the adhesive to keep rotating

If the cell shape of the glue roller is not suitable, it is easy to cause cell blockage, but this blockage occurs gradually

In addition, when reusing two-component water-based adhesives, it is necessary to grasp the extent of its availability and the proportion of old glue added, because this will not only directly affect the peel strength of the composite product, but also make the transferability of the water-based adhesive worse.
, Even cause the glue roller cell to be blocked, and then produce white glue spots
.