How to solve the fog problem in the gravure
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1. Reasons for printing the version: The technical level of domestic gravure manufacturers varies greatly. Due to the current shorter and shorter restrictions on the delivery lead time, printing companies have less time for the plate-making enterprises, in the last part of the plate making process. That is, the polishing process is easy to neglect. This negligence often leads to fogging problems in printing: in addition, the printing plate undergoes long-time printing and wear through the metal blade, and the non-image of the printing plate produces shallow dots. So the fog version of the problem has arisen.
2. Reasons for printing film: At present, there are many manufacturers of BOPP film in China. Due to the different processes, formulas and additives added by various manufacturers, some films are not flexible enough, and will be in the process of long-term printing. The wear of the printing plate causes the printing plate to produce shallow dots, which gradually produces a fog problem.
3. Reasons for the printing environment: The printing environment has a great influence on the quality of gravure printing products, especially in seasons where temperature and humidity change greatly and in harsh printing environments (such as low temperature and low humidity). Easy to produce static pollution).
4. The reason of the ink: other external reasons are easier to solve, and the fog problem caused by the ink itself is difficult to solve, which is a problem faced by the ink industry.
Second, how to solve the fog problem caused by the gravure ink itself
1. Try to design a suitable resin ratio according to the different characteristics of the raw materials:
The difference in the raw materials is very large. Even if the same pigments are treated differently, the nature of the pigments varies greatly. This requires the formulator of the composite ink to design the composite ink. Full of this difference. Since the inks of various colors have different requirements in the printing process, in designing the formula, the proportion of various synthetic resins in the ink formulation should be designed according to the characteristics of the pigment, that is, the oil absorption, the coloring power, the dispersion property, and the like. This can be determined by experimentation. In general, severe fog problems can often be solved by improving the fluidity of the ink, which is due to improved ink flow, that is, low viscosity printing. Reduce the impact of the ink on the scraper so that the scraper can clean the blank portion of the ink very cleanly.
2. Scientific application of body pigments
Adding body pigments (such as YMT ultrafine powder, YMT ultrafine barium sulfate, CC-65 powder, FH-95 powder, etc.) to the formula is not only a problem of lowering the cost of the test, but after adding the body pigment, it is filled in The resin encapsulating the pigment further enhances the body of the ink, reduces the viscosity of the ink at the same printing viscosity, and improves the squeegee performance of the blade.
3. The most current use of wax powder and OK-412 matte powder to solve the fog problem
Wax powder and matte powder OK-412 is an effective auxiliaries for reducing fog problems. The particles are easily released on the surface of the ink, which enhances the squeegee performance of the blade. However, many manufacturers add wax powder and OK-412 matte powder method, which often does not solve the problem of fog problem. It is recommended to make wax powder and OK-412 matte powder into semi-finished products, and the fineness of ink grinding is qualified. After that, it is added at a high speed and the polishing is not performed, which reduces the effect of solving the fog problem.
4. Improve the compatibility of pigments and synthetic resins with suitable wet dispersing aids
The purpose of adding a wetting and dispersing aid to the formulation is to solve the problems of the formulation system, including poor pigment dispersion, poor coating of the pigment by various synthetic resins, and poor stability of the system itself, and these problems are solved. If it is not good, it will often bring the problem of fog. It is recommended to use L-18 dispersant and GK-208 additive to disperse black, blue and red pigments.
5. Using additives to solve the problem of fog
According to the foreign experience in solving the problem of fog in high-speed printing, it is recommended to use AK-505 additive, which is to reduce the affinity of the composite ink and the chrome layer. It is not easy to adhere to the printing plate. At present, many domestic manufacturers have applied well.
6. Design a formula using a new resin system
As mentioned above, the CL-PP type composite ink is more prone to fogging problems, and it is recommended to use the BK-6380 resin system instead of the CL-PP system.