Sharing of 3-year application experience of alcohol free moisturizing solution

With the continuous advancement of technology, in recent years, non-alcoholic lubricant solutions that combine environmental friendliness and economy have emerged in the industry. With the increasingly strict environmental requirements of the country, upgrading and replacing raw and auxiliary materials is imperative for printing enterprises. Promoting the use of alcohol free dampening solution is an extremely important step for printing companies to embark on the path of green printing.
Due to the uneven quality of alcohol free dampening solutions from various manufacturers, as well as differences in printing machine, equipment conditions, products and processes, and operator experience and technical differences, many manufacturers may experience various printing brush failures during testing or batch applications.
Some manufacturers, in order to facilitate operation, add 3% to 5% alcohol or isopropanol to the alcohol free dampening solution, reluctantly accepting the downgrade from "alcohol free" to "alcohol reducing" dampening solution.
Some manufacturers have encountered some problems during the testing phase, which cannot be well controlled and handled, and the advantages of alcohol free dampening solution cannot be fully utilized, resulting in uncontrolled ink balance during printing, causing operators to lose confidence and have to give up, leading to the inability to promote the use of this new material.
According to statistics, currently only a few printing companies are using fully alcohol free dampening solution. The author's unit has been successfully tested and promoted for more than 3 years. Here, we summarize the application of alcohol free dampening solution in UV offset printing for readers' reference.
The main ingredients and formula of alcohol free moisturizing solution
The alcohol free dampening solution has differences in composition and formula compared to traditional dampening solutions, and the specific formula may vary from manufacturer to manufacturer. The following are some of the main ingredients and formulas.
(1) Water based component: The main component of alcohol free dampening solution is usually water, which is the basis for replacing alcohol and is used to achieve the wetting effect of the printing plate.
(2) Softener: In order to improve the wetting performance and stability of alcohol free dampening solution, softeners are often added. Softening agents can improve the wettability of the dampening solution on the surface of the printing plate, making it better in contact with ink and water.

(3) Surfactants: In order to enhance the wetting and transfer properties of alcohol free dampening solutions, surfactants are often added. Surfactants help reduce the surface tension of liquids, allowing them to evenly cover the surface of printing plates.
(4) PH regulator: In order to maintain the appropriate pH value of the dampening solution and ensure its stability and performance, pH regulators may be added.
(5) Preservatives: In order to extend the shelf life of alcohol free dampening solution and prevent microbial contamination of water tanks and pipelines, appropriate amounts of preservatives are often added
Corrosive agent.
Water control of alcohol free dampening solution
When using alcohol free dampening solution for printing, the amount of water should be controlled to achieve the best printing effect, which is a dynamic equilibrium process. Due to the lower viscosity of alcohol free dampening solution compared to traditional alcohol dampening solution, under the same plate pattern and water roller speed conditions, the amount of water transferred to the printing plate by alcohol free dampening solution is less than that of traditional alcohol dampening solution. To prevent the printing plate from drying out, it is necessary to increase the speed of the water bucket roller. Based on experience, the water roller speed of the same product using alcohol free dampening solution is about 5 grids higher than that of traditional alcohol dampening solution. In addition, factors such as printing plates, ink, environmental temperature and humidity, paper, and machine status should also be considered, as they may all have an impact on water volume. Therefore, the offset printer should determine the correct amount of water supply based on the actual printing products and conditions during production, mainly considering the following factors.
(1) The area and distribution of the graphic and textual parts on the printing plate. The larger the area of the graphic and textual parts on the printing plate, the greater the water consumption.
(2) The thicker the printing ink layer, the greater the water consumption; The thinner the ink layer, the less water is needed.
(3) The fiber structure of paper is loose, the surface is rough, the water absorption performance of paper is strong, and the water consumption is high. Copperplate paper, cardboard, and other materials have a dense structure, smooth surface, low water absorption, and therefore require less water.
(4) Ink has good water resistance, high viscosity, low emulsification value, and requires less water. Ink has poor water resistance, low viscosity, high emulsification value, and requires more water.

(5) The higher the operating speed of the offset printing press, the more water is consumed.
(6) The higher the ambient temperature, the lower the humidity, and the greater the air circulation, the more water is consumed.
(7) The better the quality of the printing plate, the better the sandblasting treatment, and the smaller the amount of water applied.
(8) The greater the printing pressure, the more water is consumed.
(9) The higher the hardness of the rubber blanket, the more water is consumed.
Precautions for using alcohol free moisturizing solution
(1) Clean the water tank and pipeline system before use, circulate the water tank and pipeline several times with clean water, and clean the residue of the original traditional dampening solution as much as possible to ensure that the new alcohol free dampening solution is clean and tidy during use. If there are too many impurities, it will directly affect the effectiveness of use.
(2) Timely remove impurities and calcified layers on the surface of the ink roller to ensure that the surfaces of the ink roller and the ink roller are clean, in order to efficiently transfer ink.
(3) When the ink balance is unstable during the printing process, it is important to promptly check the ink transfer on the surface of the ink roller of the printing seat to prevent surface ink peeling on the ink transfer roller and the ink leveling roller. Special attention should be paid to small ink volume layouts. If there is ink peeling, the machine should be stopped in time and cleaned with ink roller deep cleaning paste.
(4) When replacing the movable parts, the ink volume of each color seat should be adjusted to a lower level in a timely manner according to the size of the ink volume, so that the surface is slightly dirty. Then, gradually increase the water volume until the surface is completely absorbed, to prevent excess water from being uploaded to the ink roller (i.e. ink roller filling), causing excessive emulsification of the ink in advance, resulting in unstable ink balance and dull color.
(5) The recommended addition ratio for alcohol free dampening solution is generally 3.5% to 5.0%, with high accuracy requirements. During the testing phase, it is recommended to use manual proportioning. After the use becomes stable, gradually try using a water tank to automatically suction and add. According to the actual printing volume of each shift, mark the liquid level on the outer wall of the dampening tank to observe whether it is automatically extracted proportionally.
It should be noted that the actual addition ratio of alcohol free dampening solution should consider the influence of multiple factors, such as the condition of the printing equipment water roller, paper type, and process requirements. In practical applications, the addition ratio should not be too high, as a high ratio can easily lead to excessive emulsification of small ink level color plates, resulting in unstable colors. It is recommended to choose a suitable alcohol free moisturizing solution and its addition ratio based on the actual situation, or to use and operate it correctly according to the manufacturer's guidance and test results.

(6) Due to differences in formula and quality among different manufacturers' alcohol free dampening solutions, attention should be paid to the wear and tear of the printing plates during mass production. When using UV printing, the durability of the baked printing plate can usually reach tens of thousands of prints, while some manufacturers' alcohol free dampening solution causes significant wear on the printing plate, with a durability rate of only about 50000 prints. If a non baked printing plate is used, the durability rate is estimated to be even lower. Therefore, this is also one of the important indicators for measuring the quality of alcohol free moisturizing solution.
(7) Alcohol free dampening solution cannot effectively kill bacteria, microorganisms, etc. in water quality because it does not add alcohol components. Especially for water tanks equipped with dampening solution filtration systems, if the water tank has a long interval between water changes, it is more likely to produce impurities such as mold and microorganisms in the water tank, thereby affecting the cleanliness and stability of the water quality. Therefore, it is recommended to use alcohol free dampening solution that has good self sterilization and anti-corrosion effects.
To promote the application of alcohol free dampening solution, it is necessary for the offset printer to have comprehensive control over the equipment status, abandon some old operating habits and thinking, accumulate experience, and constantly explore and adapt. In short, the application of alcohol free dampening solution can significantly reduce VOCs emissions from Indian enterprises, improve the working environment on production sites, protect the physical and mental health of employees, improve the quality of printed products, reduce production costs, and promote the green development of Indian enterprises, thus promoting their sustainable development.