The decolorization phenomenon mentioned in this paper does not refer to the phenomenon of poor adhesion due to film tension. Decolorization and anti adhesion are generally a phenomenon that occurs only after printing with surface printing ink, and decolorization and anti adhesion have the same factors. Decolorization And Anti Adhesion Of Flexible Packaging Prints
It is precisely the emergence of anti sticking. In a certain environment, sticking the pattern of the printing surface to the film without printing gives people the feeling of decolorization. As a printing enterprise, it should be analyzed in detail.Decolorization And Anti Adhesion Of Flexible Packaging Prints
At present, the plastic surface printing ink produced by China’s ink manufacturers generally uses polyamide resin as binder, and the melting point of this resin is between 105 ℃ – 115 ℃, that is, after printing with the ink produced by this resin, the temperature resistance of the ink layer on the surface of the printed matter is about 60 ℃ – 70 ℃. If the printing enterprise finds that the decolorization phenomenon occurs during the sealed transportation, And the decolorized prints are in the bottom part.
The main reason for this phenomenon is: the temperature resistance and formula of the resin of the ink itself, which will occur when the printing products reach or exceed the temperature resistance of the resin under a certain pressure and the high temperature. Decolorization And Anti Adhesion Of Flexible Packaging Prints
The phenomenon of anti adhesion and color removal will also occur when the printing products are stacked too high in the warehouse, especially in the plum rain season, which often occurs from March to June. Decolorization And Anti Adhesion Of Flexible Packaging Prints
During this period, the printing factory should strengthen the ventilation of transportation and warehouse to avoid high temperature as far as possible. Secondly, improvement suggestions can be put forward to the ink manufacturer. The ink manufacturer can adjust according to the requirements of the printing factory.
Another phenomenon occurs after printing and winding. When the second process of bag making or slitting is carried out, the rolled prints are opened and found to have anti adhesion and decolorization. The reasons are as follows:Decolorization And Anti Adhesion Of Flexible Packaging Prints
1、 Tension is too tight during winding.
2、 The printing is not dry enough.
3、 The mixed solvent is impure, especially toluene mixed with odorous benzene, etc.Decolorization And Anti Adhesion Of Flexible Packaging Prints
1、 Adjust the proper winding tension.
2、 Strengthen the wind force and increase the drying temperature.
3、 Test the purity of the solvent.
In fact, the third phenomenon has nothing to do with anti stick decolorization, but it often gives people a feeling that it is decolorization, that is, the color on the surface of the prepared packaging bag is transferred to the back of another bag (with or without printing) after stacking or packaged goods. This phenomenon occurs only in purple or very few colors.Decolorization And Anti Adhesion Of Flexible Packaging Prints
Its main reason is color penetration, that is, after printing with ink of this color, the printed matter will soon penetrate under certain time, pressure or other special circumstances, such as PE bags for packaging clothes (printed inside with surface printing ink). Decolorization And Anti Adhesion Of Flexible Packaging Prints
On this issue, when selling products, ink manufacturers generally mention it in the product manual or precautions, such as temperature resistance, permeability, etc. Printing manufacturers should understand the characteristics of various inks in order to avoid unnecessary losses.Decolorization And Anti Adhesion Of Flexible Packaging Prints