Reasons and Countermeasures for Decolorization and Anti-adhesion of Flexible Package Printing Products

Defects such as decolorization and anti-adhesion often affect the quality of products. What are the reasons for this problem? What is the solution?

The decolorization phenomenon mentioned in this paper does not mean the phenomenon of poor adhesion due to the film tension problem. Decolorization and anti-adhesion are generally the phenomenon that occurs after printing with table printing inks. Decolorization and anti-adhesion are the same. the elements of. It is the anti-adhesion that occurs. Under a certain environment, the pattern of the printed surface is adhered to the unprinted film, giving a feeling of decoloration, and it should be specifically analyzed as a printing company.

At present, the plastic printing inks produced by China's ink production plants generally use polyamide resin as the linking material. The melting point of this resin is between 105°C and 115°C. That is to say: The resin is produced using this resin. After the ink is printed, the temperature of the ink layer on the surface of the printed matter is about 60°C-70°C. If the printing company finds that the decolorization phenomenon occurs in the sealed type of transportation, the decolorized printing products are all in the bottom layer.

The main reasons for this phenomenon are: the temperature resistance and formulation problems of the ink itself, which will cause the product to print under a certain pressure, with the high temperature reaching or exceeding the temperature resistance of the resin. Overprinting and decolorization may also occur in warehouses with high stacking, especially during the rainy season, with more time between March and June. During this time, the printing plant should strengthen the ventilation of transportation and warehouses to avoid high temperatures. Secondly, it can propose improvement opinions to the ink production plant. Ink manufacturers can make adjustments according to the requirements of the printing factory.

Another phenomenon occurs after printing is rolled up. When the second process is used for bag making or slitting, the rolled product is pulled open.

Anti-adhesion and discoloration were found due to:

First, the tension is too tight when winding up.

Second, the printed product is not drying enough.

Third, the mixed solvent impure, especially toluene mixed with odorous benzene and so on.

Solution:

First, adjust the appropriate winding tension.
Second, strengthen the wind and increase the drying temperature.
Third, the detection of solvent purity.

The third phenomenon has nothing to do with anti-adhesion and discoloration, but it often gives people a feeling that it is bleaching, that is, a well-made packaging bag. The color on the surface of the packaging bag that has been stacked or packaged is transferred to another. On the back of a bag (with or without printing) this phenomenon only occurs with purple or very few colors.

The main reason for this is color penetration, that is, when the ink is printed using this color, the printed product is subjected to a certain amount of time, pressure, or other special conditions, such as a PE bag for packaging clothing (using a table printing ink In India) Infiltration will soon appear. In this issue, the ink production plant is generally mentioned in the product specification or notes when selling products, such as temperature resistance, permeability, etc. Printing manufacturers should understand the characteristics of the various inks before they can avoid unnecessary losses.

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