What are the reasons for the spots on the aluminum foil film?

I believe that many aluminum foil film manufacturers will encounter a problem when producing aluminum foil film, that is, there will be many spots on the surface of the composite aluminum foil film. So what is the reason? Today, Jiuzhi Plastics Network Xiaobian will bring everyone to understand:
White or gray spots sometimes appear on the surface of the aluminum foil film . This is easy to occur in the production process of a full-size ink printed and composited with an aluminized film. The main reasons are as follows.
1. The surface tension of the ink is low, resulting in poor coating effect of the adhesive and uneven coating. Therefore, the adhesion between the ink layer and the aluminized layer and the tightness between the layers will be different, thereby aluminizing The reflective effect of the surface of the layer is also strong and weak, visually forming white or gray spots.
2, the ink's hiding power is not strong or the leveling is poor, resulting in uneven coverage (especially white ink and light yellow ink). In places where the hiding effect is not good, the color of the aluminized layer will permeate through the ink.
3. The adhesive concentration is too high, the viscosity is too large, and the ink is easily adhered to the glue to change the color of the printed layer. At the same time, if the viscosity of the adhesive is too large, the fluidity is not good, and it is easy to cause uneven coating, which affects the reflective performance of the surface of the aluminized layer and causes spots.
4. The ink and the adhesive do not match, so that the adhesive has poor penetrability to the ink, and there is a phenomenon of repulsion and speckle.
5, aluminum foil film drying is not complete, the solvent volatilization is not sufficient, resulting in too much residual solvent in the adhesive, part of the ink layer is dissolved and glazed, thereby forming spots, and when mature, many tiny bubbles will form.
6. The quality of the aluminized film itself is poor, and there are many light-transmissive points. After the composite, the reflectivity of the aluminized layer is different, forming spots.
7. The temperature of the drying tunnel (especially the first drying tunnel) is too high, causing the surface glue to dry too fast and the surface conjunctiva; when the internal solvent is vaporized in the second and third drying tunnels, it will break through the surface film. The adhesive is squeezed to expose the ink, causing uneven thickness of the adhesive layer to cause spots.

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