In the flexographic plate making process, we need to get a plate with stable surface tension. Only when the surface tension of the plate is stable, we can establish a reliable platform to work with the surface tension of the ink. So, how to ensure that the plate making process for flexo printing process to provide stable surface tension of the plate? In fact, in the flexo plate making process, there should be a way to stabilize the surface tension of the plate.

       Follow the requirements of the flexo plate supplier

       Strictly follow the procedures provided by the flexo plate supplier for the distillation, measurement and compensation of environmentally friendly solvents. Do not take a shortcut and take a shortcut for granted, instead, you will take a detour and take the wrong path. The question is how to use the right solvent under the premise of protecting commercial interests. The approach provided by the supplier is indeed somewhat cloudy, but doing it first is the only feasible way. Need to strengthen the monitoring of the surface tension of the plate after it is made, a simple and practical way is to test with a corona pen, supplemented by a high magnification of the plate depression area of the gloss.

       Stable solubility of plate washing solvent

       Tetrachloroethylene - n-butanol traditional plate washing solvent is unique in solubility stability, but the toxicity of tetrachloroethylene is too large, from the "flexo printing is recognized as environmentally friendly printing method" this standard, tetrachloroethylene plate washing really should not be. But in addition to the cost of solvents, is there a reason why the stability of plate quality is really higher with this method of plate washing? This is like the gravure industry always feel that toluene ink than non-benzene ketone-free ink printing suitability is better. We should get from the method is a mixture of solvents must be measured and directional complementary ideas, abandoned is the solvent is not environmentally friendly.

       Plate washing with water-soluble solution

       Water-soluble solution contains organic solvents, the boiling point is very high, not easy to volatilize, and because it is mixed with the latent heat of evaporation of water, the comprehensive balance of solvents is covered up, the contradiction is not prominent. But the water-soluble plate wash is, after all, to dissolve the uncured resin in it, so with the increase in solids, its concentration will also decline, and solubility decline will be more dependent on the role of brushing, thus enhancing the plate surface tension, plate surface tension will also fluctuate, this is something that must be noted. After the water-washed version made, it is said that the contact with ethanol is safe, the printing plate does not swell, but in practice found after the swelling, the supplier is recommended not to use ethanol, and instead use isopropyl alcohol and methanol 1:1 solvent mixture. The case shows that we still have the need for in-depth research on water-washed plates, not to mention that the toxicity index of water-based additives is not optimistic. 

       Thermal plate making technology

       Can really get rid of the plate washing solution (including organic solvents and aqueous solvents) plate washing on the surface tension of the plate interference is the thermal plate technology. This plate making process is characterized by heating the uncured photopolymer from a solid to a liquid, and then applying pressure to its surface with a pressurized cylinder, similar to the way a gravure transfer unit sucks out the ink from the cavities of the printing plate by means of an impression cylinder, the non-woven fabric wrapped around the pressurized cylinder sucks out the liquefied resin from the printing plate, completing the separation of the cured and uncured photopolymer. The surface tension of the thermal plate completely reflects the characteristics of the solid itself, avoiding the impact caused by the dissolution and desorption of the solid material by the plate washing solution and other processes, and avoiding the fluctuation of the surface tension of the printing plate during the plate making process.

       The thermal plate is able to withstand criticism in terms of environmental protection, but the operating data provided by the thermal plate supplier now, the fineness of the plate produced is much less. At the same time, the pressure level is also a problem. Too much pressure can collapse the edges of the dot and affect the accuracy of the dot. In addition, the surface properties of nonwovens are not simply a matter of long and short fibers; we are more concerned with their ability to absorb liquid resins. In general, the thermal plate making technology is further refined and improved, so that we can get fine printing plates and at the same time ensure stable surface tension of the plates.

       Once the plate making process can provide a plate with stable surface tension for the flexographic process, the next issue is the ink. Our goal is to need inks that work effectively with the surface tension of the printing plate, whether solvent-based inks, water-based inks, or UV inks. This stick should and can be handed over to the ink community.

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