Solvents are the most important auxiliary materials in the gravure printing of plastic packaging films. Intaglio printing inks use the lowest viscosity and the fastest drying speed in all kinds of printing, which is mainly determined by the properties of solvents. Solvents use it as a liquid to suit printing needs. The main component of gravure printing ink is solid, which accounts for 50%-70% of the ink composition and cannot be directly used for printing. The solvent not only adjusts the viscosity of the ink, so that it can meet the printable requirements of the printed substrate, and has a great influence on the quality of the plastic packaging printing product. Therefore, it should attract the attention of printing companies.
The role of solvent
The substance that can dissolve other substances is called a solvent. The substance is dissolved in a solvent to form a solution of the substance, and the solvent is dispersed and dissolved by the dissolved substance and is called a solvency. The stronger the dissolving power, the faster the dissolving speed and the lower the dissolving viscosity. Since the solvent is a low viscosity liquid, it can be added to the ink with the purpose of reducing the viscosity of the oil black. As there are many types of printing inks, there are common printing inks (also known as polyamide printing inks), plastic printing inks (also known as chlorinated polypropylene inks), printing inks of polyurethane systems, etc. With the increasing awareness of environmental protection, water-based inks without solvents are also on the market, so to obtain them, high-quality prints must use matching solvents.The role of solvents includes:
1. Solvents can dissolve materials such as additives, additives, and additives to make them fluid and evenly disperse pigments. This helps the transfer of ink on printing presses, and makes them adhere to printing materials.
2. Solvents are very low viscosity liquids and are added to higher viscosity printing inks to reduce the viscosity of the ink. The operator can adjust the viscosity of the ink according to the depth of the printing plate roller, the number of lines, the printing speed and other conditions to obtain the best printing effect.
3. The printer can also use the solvent to adjust the ink according to the conditions such as the printing speed of the gravure printing machine, drying capability of the drying device, weather conditions, and the size of the pattern: {: drying speed. In general printing conditions—F, the drying speed should be adjusted with the use of a fast 'F' solvent or a slow-drying solvent final as the conditions change. Different solvents have different volatilization rates. The use of a mixed solvent is a combination of the characteristics of multiple single solvents to meet the requirements of printing conditions. Gravure printing often uses a mixed solvent to dissolve the ink. The function of adjusting the drying speed by the diluent and the function of dissolving the resin are the most important properties of the solvent
4. The organic solvent generally has a low surface tension and a small contact with the surface of the printing material plastic film, which can improve the absorbability of the printed film. The solvent in the ink will dissolve or swell the printed film to increase the affinity of the ink and the film.
5. The solvent is diluted with ink using a mixed solvent to meet the needs of printed products. The remaining printing ink is easy to save and can be used next time.
