Reasons for easy discoloration of prints

Discoloration of printed ink film is a failure of the printing process or the finished product in the outdoor aging stage. The printing ink film undergoes aging in the atmosphere. Under very severe conditions, premature discoloration or even discoloration occurs. The ink film is exposed in the atmosphere. Due to the effect of ultraviolet rays, the degree of color change depends on the temperature, temperature, and light of the atmosphere. The strength and the properties of the printed ink film, the saturation of the color and the color tinting power, and the pH of the ink film, the impurities in the atmosphere, or the length of the continuous exposure time in the atmosphere vary.

Therefore, before printing, we should try our best not to use easily discolored lake ink, and use rutile to extract white ink produced from titanium dioxide; add it in packaging printing ink to improve its anti-tarnish property. At the same time adding brighteners is one of the common methods.

2. Ink film whitening white ink, blue ink systems after the printing process, wet ink film surface exhibits irregular white spots white pigment (also known as floating color, which is different from black, blue white color floating point), in particular It is more apparent when compounded or after aluminum plating. If it is a blue ink, different sizes of pinhole-like blank spots tend to appear after printing, which seriously affects the appearance quality of the packaging print. The main cause of the failure is related to the type of pigment selected in the ink system, and the flocculation or separation of the pigment due to the incorporation of another ink, which causes the pigment in the ink system to float.

The countermeasures for this fault are: First, it is better to use pigments with the same particle size and the same specific gravity as raw materials for the production of inks; secondly, to extend the dispersion time or subtract the additives that contain the activity.