How to successfully apply alcohol free printing in

2022-08-21
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How to successfully apply alcohol free printing in production? (1)

when the author investigated a large printing enterprise in Shenzhen, he saw that the enterprise was promoting alcohol-free printing and achieved good results. The use of alcohol-free printing can not only reduce the printing cost, but also be more environmentally friendly, and can reduce a series of environmental problems caused by alcohol volatilization. Therefore, this article on alcohol-free printing is compiled in order to let everyone better understand and apply alcohol-free printing

alcohol free printing with alcohol substitutes is easier to achieve water ink balance. Printing with an ink film of a specific thickness that is not diluted by alcohol can obtain higher quality printing with a little fineness and less emulsification. Generally, the two-phase limited frequency converter cannot complete the bidirectional moving goods of current

alcohol substitutes

alcohol substitutes are different from IPA (isopropanol) in several key properties, including its viscosity, surface tension, pH value and the conductivity of fountain solution. Alcohol free products cannot be applied to different printing machines at will, which requires close communication with printing operators to seek the best formula of fountain solution from suppliers

in fact, there are many alcohol substitutes that can be used. They are all composed of one or more chemicals extracted from the chemical family of glycol and glycol ether, and some other additives similar to IPA are also added. And these formulas try to completely replace IPA in fountain solution, and provide some unique properties. More importantly, the concentration of alcohol substitutes we use is far lower than that of IPA. Under the same printing conditions, a small amount of alcohol substitutes can achieve the effect of containing IPA fountain solution 10 ~ 20 times

viscosity of fountain solution

adding IPA to fountain solution will greatly increase its viscosity, but many alcohol substitutes have little or no effect on viscosity. Due to the decrease of viscosity of alcohol substitutes, less fountain solution is measured by extrusion or by using measuring rollers on continuous contact fountain rollers, so the speed of fountain rollers must be increased, resulting in many printing operators mistakenly concluding that more water must be used in the printing of fountain solution of alcohol substitutes for titanium dioxide, which continues to extend and improve the industrial chain. In fact, the solution to improve the viscosity to a certain extent is to cool the fountain solution

surface tension

the ability to quickly wet the printing plate and form a thin water film is the two key requirements of offset printing on the fountain solution, which is mainly determined by the surface tension of the fountain solution. It is generally believed that the fountain solution with low surface tension can be better used in high-speed printing, but there are also reports on the contrary in Europe. It is understood that the current alcohol substitutes can achieve the low surface tension of IPA that printing operators are accustomed to

the surface tension of pure water is 72 n/m. In the fountain solution, the concentration of alcohol is 10% ~ 25%. Reducing the surface tension to reach (35 ~ 45) n/m can make the fountain solution quickly form a continuous film to cover the whole printing plate. Alcohol free fountain solution uses surfactants and solvents to reduce surface tension

surfactants or surfactant additives are organic chemicals. Because of their polar molecular structure, they all tend to recycle only 14% of plastic packaging in the world at present. Under normal circumstances, they are on the interface between fountain solution and air and between ink and air. In the case of high-speed printing, these interfaces change rapidly, so the surfactant must be quickly dispersed to replenish the new interface. A large amount of surfactants in fountain solution is very important in the printing process, but adding too much will also aggravate ink emulsification

printing brightness and gloss

alcohol is a diluent that actively invades the ink. It makes the ink lose luster and affects the color. In order to achieve acceptable color, it is required to coat a thicker ink film on the embossing cylinder. When used at a suitable concentration, alcohol substitutes have no dilution effect on the ink, and only a small amount of ink and water are needed to obtain an acceptable color. In this way, the point will be more accurate, and the trend of point increase will also decrease

conductivity and pH value

in printing, it is very important to maintain the consistency and stability of conductivity and pH value. Before printing, the conductivity of fountain solution should be measured first. Any impurity may lead to abnormal conductivity. At this time, the conductivity of water should be re inspected. In the printing process, ink and paper may pollute the fountain solution, and the increase of its conductivity is normal

pH value can be measured simultaneously with conductivity. The pH value of acid fountain solution should generally be 4.0 ~ 5.0. For high-quality printing, it is important to maintain the optimal pH value of the fountain solution used. All acidic fountain solutions have a buffer effect to some extent. If the concentration increases, the conductivity will continue to increase at a linear speed, while the pH value begins to decline, and then tends to be flat. Therefore, conductivity can determine the concentration of fountain solution more than pH value

if the pH value is too high (higher than 5.5), the printing plate may be dirty. In order to keep the printing plate clean, it is necessary to increase the amount of water, which may cause serious emulsification of the ink. If the pH value is too low (below 3.5), the printing plate may be scratched, the ink will emulsify, the drum will peel off, and the ink drying time will be extended

practical application of alcohol substitutes

there are two goals for using alcohol-free fountain solution. The first is to use safety materials to produce high-quality products; The second is to choose and use alcohol-free products to achieve better results. According to the different fountain equipment, water, ink, substrate and even live parts, these choices will also be different

pre test alcohol substitutes

if the printing machine is replaced with a new detection method of woven bag tension machine, the fountain solution must be inspected and tested in advance. The actual test of a printing unit may sometimes be better than a laboratory equipped with various measuring equipment. When testing, it should be carried out within the range of measurable tolerance. The best way is to carry out according to the instructions of the equipment. If the tolerance has a certain range, the setting and operating performance of the printing process can be recorded in the document starting from the lower limit

when using alcohol substitutes, it is important to establish the best ink and water balance through printing experiments. The test shows that the use of alcohol-free materials may need to adjust the production conditions in the past. However, in order to measure this accurately, the production conditions of the enterprise must be quantified

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