At present, with the widespread adoption of water-based inks, the market share is getting higher and higher. Due to the continuous improvement of people's awareness of environmental protection, the goal of environmental protection printing has been promoted, and the environmental protection characteristics of water-based inks are safe, non-toxic, non-volatile organic gases, non-combustible, and non-explosive. "Green printing, safety printing, and healthy printing" are becoming more and more popular. Nowadays, water-based inks will be more widely used and have a wider market share. Water-based ink is commonly known as water-based ink. Water-based ink is mainly suitable for packaging and printing products with very strict sanitary conditions such as common in daily life: beverages, food, medicines, children's toys, tobacco and alcohol, etc. The flexographic water-based ink is also called liquid ink, which is mainly composed of soluble resin, organic pigment, solvent and related additives through compound grinding process 1. Water-based ink raw materials Pigments give the ink color characteristics and meet the color requirements of printing. General organic pigments and inorganic pigments can be used for water-based inks. Since the resins of water-based inks are mostly alkali-soluble, when choosing pigments, it is necessary to use alkali-resistant pigments. However, the distribution density of pigments in water ink is much greater than that of solvent-based inks, and the surface tension and polarity of water are greatly different from solvents, making pigment dispersion more difficult, which directly affects the stability, viscosity and pH of inks. Adding surfactant can increase the affinity of resin and water and the affinity of pigment and water-soluble binder, so as to solve the problem of ink stability. The viscosity and pH of the ink need precise control. When the pH value is higher than 9.5, the alkalinity is too strong, the viscosity of the ink will decrease, the drying speed will slow down, and the water resistance will be poor; when the pH value is below 8, the alkalinity is too weak, the viscosity of the ink will increase, drying Speeding up will cause defects such as dirty, pasted, and blistering. When choosing pigments in the printing process, high-grade pigments with bright color, low viscosity and stable system among domestic pigments should be selected to make water-based inks. 2. Water-based ink formulation The excellent basic formula of water-based ink obtained through practice Water-soluble acrylic resin 25% ～ 35% Water 15% ～ 25% Ethanol 5% ～ 15% Triethylamine 5% ～ 10% Pigment 10% ～ 30% Auxiliary 1% ～ 3% 3. Auxiliaries used in water-based inks In order to improve the performance of water-based inks, various additives need to be added, and the additives used in water-based inks are more important than solvent-based inks. Commonly used water-based ink additives are the following: ①Defoaming agent: used to eliminate foam in water-based ink, the dosage is generally 1% to 2%. ②Stabilizer: Mainly prevent the ink from coalescing and mildew during storage and transportation, reduce the viscosity of the ink and adjust the pH of the ink. Generally, ammonia water or ethanolamine and other additives are used. ③Other additives: dispersant, preservative, leveling agent, slip agent and cross-linking agent. By using these additives scientifically to improve the weaknesses of water-based inks, the stability of water-based inks can be improved. Ningbo Smile tools Co.,ltd , https://www.nbsmiletools.com