During the production process, there are two common problems, white spots and bubbles. The following are frequently occurring problems and corresponding solutions.
1. White spots
After compounding, you can see white spots of different sizes and distributions on the product, which is the phenomenon of white spots. This kind of white spot phenomenon is easy to appear on the full-page white or light background printing pattern, because the white or light background color has poor covering power and it is easy to see the white spots.
Cause
（1）Due to the high viscosity of the adhesive, the spreading effect on the ink layer is poor.
（2）Insufficient hiding power of the ink leads to more obvious white spots.
（3）Insufficient pressure affects the effectiveness of the ripening process, and white spots exist in areas of insufficient pressure.
Solution
（1）Choose low-viscosity solvent-free compounding, or reduce the viscosity of the glue through process conditions.
（2）Improve ink opacity performance.
（3）Adjust the process conditions so that the product will not appear white spots after the curing process
2.Bubble
Cause
（1）There are too many residual solvents in the printing film itself, and bubbles will be generated when it volatilizes.
（2）Due to insufficient surface tension, the glue is applied unevenly and bubbles are generated in places where the glue is not applied.
（3）The amount of gluing is insufficient, resulting in uneven gluing and large surface air bubbles.
Solution
（1）Control the solvent of the printing film within a certain range.
（2）Control surface tension to maintain within a certain range.
（3）Appropriately increase the amount of glue.
It is not surprising that flexible packaging appears around our lives, so it is even more important to use environmentally friendly adhesives. The solvent-free flexible packaging adhesive used by Xintongda Plastic Products Co., Ltd. has the advantages of high initial adhesion, softness and good transparency. It can provide customers with a perfect and strong flexible packaging, and at the same time jointly protect the earth’s environment. For more product information, please contact us.
