Why does the composite bag produce spots?

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 hiding power of the ink is not strong or the leveling property is poor, resulting in uneven covering. 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. The composite bag is not completely dried, and the solvent is not sufficiently volatilized, resulting in too much residual solvent in the adhesive. Some of the ink layer is dissolved and glazed to form spots, and when it is mature, many tiny bubbles are formed.

6. The aluminized film itself has poor quality and has many light-transmissive points. After the composite, the reflectivity of the aluminized layer is different, thereby forming spots.

7. The temperature of the drying tunnel is too high, causing the surface glue to dry too fast and the surface is conjunctiva; when the internal solvent is vaporized in the second and third drying tunnels, it will break through the surface film and squeeze the adhesive to expose The ink causes uneven thickness of the glue layer to cause spots.