There are many reasons for the occurrence of white spots on aluminized composite films, mainly due to the following three reasons: 1, The ink particle size is large or the particle size distribution is too wide, generally the particle size of white ink has a greater impact. Ethyl ester in the binder is a good solvent for ink. The infiltration results of ink particles of different particle sizes are different. The chromaticity change after drying in the oven will be different.”White dot”. Generally in this case, it is obvious when the machine is off, and the white spot phenomenon will be alleviated after curing, and may disappear. 2, The surface tension of the adhesive is high, and the effect of wetting and spreading on the aluminized composite film is poor. This is the current aluminized composite film”white spot phenomenon”one of the main reasons. The coating effect of the adhesive is not good. After the printing layer is covered, the color and luster on different parts will change, producing the same effect as the previous one, and sometimes producing large spots. 3The problems of equipment drying, coating and the system itself cannot guarantee the sufficient and uniform coating of the adhesive and the sufficient volatilization of the ethyl ester.Other reasons for the white spot phenomenon of the aluminized composite film, such as the full-bottom printing screen roller anilox is too shallow, reducing the ink covering power and so on.
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