The use of the UV fluorescent ink type is very important for the anti-counterfeiting effect of the packaging. If the selection is inaccurate or poor, the anti-counterfeiting effect may not be obvious or any anti-counterfeit requirement may not be achieved at all, for example, according to the color light In terms of theory and light absorption principle, medium-long wavelength color light absorbs short wavelengths. The following is an analysis of the specific conditions of fluorescent inks in the actual product structure.
If we add a colorless fluorescent blue ink to a full-filled gold-colored coating, first the fluorescent blue ink layer will show a blue (B) color light under the illumination of a UV lamp, and then a golden (Y) color with the undercoat. Mixing, from the theoretical analysis of the color light additive method, the yellow light and the blue light are mixed and then appear as white light, that is, the yellow light and the blue light are complementary colors to each other, that is, the anti-counterfeiting effect is poor or cannot be seen at all. To any anti-counterfeiting effect. From the light absorption theory, this is because the medium-long-wavelength yellow light in the spectrum absorbs part of the blue short-wavelength light, so that the color that the fluorescent blue should present is not seen. The fluorescent red is very effective in the case of publications and the effect of exposure to standard light sources.
From this we can conclude that when choosing a UV fluorescence anti-counterfeiting ink, we must be cautious. In the general printing system, there are inks that produce complementary colors or there are inks with longer wavelengths than the selected fluorescent inks. This type of fluorescent ink is best not to use or use it can not achieve a certain degree of security. Therefore, in the production process of fluorescent anti-counterfeiting inks used in the pharmaceutical packaging industry, the selection of fluorescent inks for a variety of different printing primer materials in the printing system is particularly important. In addition, the use of fluorescent ink for the printing process requirements are also more stringent, due to the particularity of its ink system, generally in the use of the process we must pay attention to consider the following factors:
1 Since gravure printing is commonly used in drug packaging and printing processes, the choice of solvent in gravure printing is very important. Solvent is an important component of gravure ink. It has solubility and volatility. Its volatilization rate is an important factor in determining the drying speed and printing quality of volatile ink. Solvent evaporation rate is slow, and the reproducibility of the printed image is better, but if the evaporation rate is too slow, it will not completely volatilize on the printed matter, the fluorescent ink layer is prone to adhesion, resulting in blurred security image, dirty layout, Influencing the anti-counterfeiting effect and the overall appearance of the product; conversely, if the solvent in the ink volatilizes too quickly during the printing process, ink whitening, sticky rollers, etc. may occur, and hidden troubles of the ink layer stick back, resulting in the back of the packaging material. Dirty, visible in the UV light F bright spotted heavily, so that consumers have unsanitary intuition, when serious may affect the next coating and composite processes.
Due to the various manufacturers' printing equipment, the operating environment is different. For example, the speed of the printing press, the structure of the drying system, the characteristics of the printing materials, the temperature and humidity of the interior, etc. must all be considered, so the solvent for the printing process Use to take into account all factors. Generally, the dissolution parameters of the binder resin are compared. In combination with the above requirements, two or three different boiling point solvents are used in combination to achieve the expected complete anti-counterfeit effect pattern.
2 fluorescent ink in the security printing plate - the proportion of the general are very small, very few UV fluorescent ink can produce a large number of anti-counterfeit products, so in the production of fluorescent ink products, should try to follow the order task book: Calculate the amount of ink reasonably and strive for one-time use. Don't leave too much and cause unnecessary waste. General fluorescent ink products can not be repeatedly used for a long time, first, it is easy to get dirty, bring about unnecessary layout unclean problem, and second, after long-term solvent flushing ink system dilutes the fluorescent pigment, so that the fluorescent anti-counterfeiting effect is greatly reduced, even in the ultraviolet lamp The pattern or text under illumination also appears dimmed, failing to achieve the desired anti-counterfeiting effect.