Water-based ink, also known as waterborne ink, is an ink that uses water as a solvent or dispersion medium. Its characteristics of "non-toxic, non-irritating, non-flammable, and non-explosive" are destined to have a broad development prospect.

Performance of water-based ink

1. Viscosity

Viscosity is a key physical parameter of water-based printing ink, which indicates the resistance of ink to flow at a certain temperature. Controlling the viscosity range can ensure smooth ink flow and print performance. Since the solvent of water-based ink is water, the water molecular weight is small and the fluidity is better, so the viscosity is usually lower than that of traditional ink.

2. Dispersibility

The dispersibility of water-based ink refers to the ability of pigments to disperse evenly in water media. Pigments are mostly solid powders, and dispersants are needed to make them evenly dispersed in water media to facilitate printing. Good dispersibility can ensure uniform color, stable printing quality, and improve printing speed and production efficiency.

3. Adhesion performance

The adhesion of water-based ink is its ability to evenly adhere to the surface of the printing material during the printing process. This performance is affected by the surface properties of the printed material, the composition of the ink and the pressure of the printing press. Good adhesion helps to ensure the clarity and color saturation of the printed pattern, while improving the printing speed and production efficiency.

4. Gloss

The gloss of water-based ink refers to the brightness of the printed surface, which is an important indicator affecting the quality of the printed product. Gloss is related to factors such as the type, particle size, dispersion of the ink pigment, the thickness of the ink film, and the surface properties of the printed material.

Generally speaking, the smaller the pigment particle size, the better the dispersion, the thinner the ink film, and the smoother the surface of the printed material, the higher the gloss of the ink.

5. Surface tension

The surface tension of water-based ink affects its coating performance and printing quality. The greater the surface tension, the better the coating performance and the higher the printing quality. The surface tension of water-based ink is affected by factors such as ink composition, dispersant, and surfactant. Excessive surface tension may cause problems such as wrinkling on the surface of the printed product and excessive viscosity, while too small surface tension may cause uneven ink coating.

6. Drying performance

The drying performance of water-based ink refers to the ability of ink to change from liquid to solid during the printing process, which directly affects the quality of printed products. Too long or too short drying time will affect production efficiency and print quality. Its performance is affected by factors such as ink composition, coating amount, printing materials, ambient temperature and humidity.

The better the performance, the shorter the drying time, the higher the production efficiency, the lower the viscosity and fluidity of the ink, and the higher the quality and stability of the printed product.

Classification of water-based inks

In the classification of water-based inks, we can divide them from different angles.

1. Classification by ingredients

Polyurethane water-based ink: Polyurethane water-based ink is a high-performance environmentally friendly ink with excellent water resistance, weather resistance and adhesion. It is widely used in packaging, labels, advertising, textiles and other fields.

Polyacrylate water-based ink: Polyacrylate water-based ink has good fluidity and adhesion, and is suitable for printing on the surface of various non-absorbent materials. Because of its low odor and low volatile organic compound (VOC) emissions, it is increasingly favored by the market.

Hydroxyacrylate water-based ink: Hydroxyacrylate water-based ink is an environmentally friendly ink with high solid content, high adhesion and fast curing, which is suitable for various printing requirements.

2. According to the purpose, water-based ink can be divided into packaging water-based ink, label water-based ink, advertising water-based ink, textile water-based ink, and electronic product water-based ink

3. According to the printing method, it can be divided into offset water-based ink, screen water-based ink, flexographic water-based ink, and gravure water-based ink.

Preparation method of water-based ink

1. Preparation of high-definition flexographic water-based ink

By adopting a series grinding process of coarse grinding and then fine grinding, nano-level color paste is ground out.

The high-definition flexographic water-based ink prepared using this series of color paste has the characteristics of rich and bright colors, which can be comparable to the printing effect of some gravure or offset printing.

2. Preparation of acrylic water-based ink

Acrylic resin is the key binder of water-based ink. Its performance has a direct impact on the quality of ink and should be focused on during the ink preparation process.

Through the results of experiments and performance tests, it is concluded that adding mixed monomers in batches to water-based ink can effectively improve the polymerization reaction rate and reaction effect; by accurately controlling the mass fraction of acrylic acid, the hydrophilicity of the ink product can be improved. At the same time, the polymerization temperature is controlled within 90°C, the polymerization time does not exceed 4 hours, the pH value is kept in the range of 8-9, and ammonia + triethylamine is used as the neutralizing liquid to prepare water-based ink with better performance.

Compared with similar products, water-based ink prepared with acrylic acid water-based resin as raw material shows better printing quality in practical applications.

As a packaging printing material, water-based ink is widely used in products closely related to people's daily life. In the context of green and sustainable development, the demand for environmentally friendly water-based inks will continue to grow. Although my country's environmentally friendly water-based ink started later than foreign countries and the import volume is relatively large, it has gradually achieved marketization and standardization. In my country, the research and development process of such products has been seeking innovative breakthroughs, showing broad development prospects and huge exploration value.