Solution to the technical problem of biting and co

Solution to the technical problems of biting and cross color in printing

major technical problems in packaging and printing have plagued people for a long time, mainly focusing on ① ink migration; ② The ink film turns yellow; ③ Printing white dots; ④ The growth rate fell by 1.4 percentage points, and the stickiness and adhesion; ⑤ Discolored rigid polyurethane foam is thinner than other materials: it can be used as a contrast and fade; ⑥ White ink film; ⑦ Pinhole and shrinkage; ⑧ Transfer without inking; ⑨ Biting color (commonly known as cross color) and fading; ⑩ Poor gloss (whitening). These printing technology problems have become a common consensus of production failures

1. Bite color (commonly known as cross color). In the process of packaging and printing, when the temperature rises after the first or second chromatic printing, it will be found that the printing ink film on the surface of the previous printing ink film is too soft and even wrinkled. This phenomenon is called the prelude to color biting. When there is a strong solvent in the ink system during the next printing (overprint), it may completely penetrate the previous ink film and be bitten up, so as to be miscible into the next color ink film. In serious cases, it can make the later packaging and printing ink film mixed into mottled (dyeing). The main reason is that there are soluble components (resins or solvents) in printing inks

when printing this kind of ink, we must use diluting solvent. Never use strong solvent to adjust the viscosity of the ink or speed up the printing speed, so as to shorten the time of secondary use for high-precision or tertiary overprint. Before printing, we should use mixed solvent to adjust the re solubility (re solubility) effect of the ink, so as to determine the proportion of diluting solvent

2. Poor gloss (whitening). This fault mostly occurs in volatile dry printing ink printing. After high-speed printing, an opaque white ink film will appear during the rapid evaporation of solvent. This phenomenon is sometimes temporary, but mostly persistent. This is because the cooling device near the drying printing ink film blows or the air is frozen to the dew point, that is, the absorbed water (steam) returns to the ink film and condenses. If the solvent or pigment in the ink system contains water, it will also cause poor gloss of the printing image and text ink film. In other words, the higher the volatility of the solvent, the greater the tendency of the poor gloss of the graphic ink film (whitening) of the packaging and printing ink

the preventive measures are: adjust the solvent used for packaging and printing ink; Appropriately increase high boiling point solvents (such as cyclohexanone, glycol, propylene glycol ether, butanol, etc.), reduce the amount of solvents that volatilize quickly, and control the relative temperature in the workshop environment (air) below 65% during the packaging and printing process, especially in the rainy season in coastal areas and rainy days in the north