Factors affecting the color saturation of flexographic water-based ink

Date: Aug 12 2024 From: Star Color

The color saturation of water-based ink in flexographic printing is influenced by various factors, including the composition of the ink, operating conditions during the printing process, and environmental factors. The following is a specific analysis of these factors:

1、 Ink composition

Characteristics of pigments
Particle size, shape, and distribution: The particle size, shape, and distribution of pigments directly affect the ink's coverage and coloring power. Generally speaking, when the particle size of pigment is small, the covering power is small, but the coloring power is strong; As the particle size increases, the covering power increases, but once it exceeds a certain limit, the covering power will decrease again. In addition, needle shaped particles have a larger specific surface area than spherical particles, and their absorption and scattering abilities are stronger, so their coloring ability is also stronger.
Alkali resistance: As the resin of water-based ink is mostly alkali soluble, the selected pigment must be alkali resistant to ensure the stability and color saturation of the ink.
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Type: The binders for water-based ink are mainly divided into two types: water diluted and water dispersed. The type and properties of the binder have a significant impact on the viscosity, adhesion, gloss, dryness, and printing adaptability of the ink. For example, water-soluble acrylic resin has significant advantages in glossiness, weather resistance, heat resistance, water resistance, etc., which is beneficial for improving the color saturation of ink.
Viscosity: The viscosity of ink is an important factor affecting printing quality. Low viscosity may lead to poor transferability, insufficient ink supply, and other issues; Excessive viscosity may lead to issues such as unclear printed text and paste. Therefore, it is necessary to control the viscosity of the ink within an appropriate range to ensure the color saturation of the printed material.
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Surfactant: In order to improve the stability of pigments in water-based binders, surfactants are usually added to increase the affinity between resin and water, as well as the wettability of pigments with water-based binders. This helps to form a uniform and stable pigment slurry, improving the coloring strength and color saturation of the ink.

2、 Printing process operating conditions

Printing pressure
Appropriate printing pressure helps ink form a uniform ink layer on the substrate, thereby increasing color saturation. Insufficient pressure may lead to insufficient ink transfer; Excessive pressure may cause blurry prints or other quality issues.
Printing speed
Printing speed can also affect the drying speed and color saturation of ink. Excessive speed may cause ink to be covered by the ink of the next color group before it dries completely, affecting color saturation; If the speed is too slow, it may reduce production efficiency.

3、 Environmental factors

Temperature and humidity
The temperature and humidity of the printing environment have a significant impact on the performance of water-based inks. Excessive temperature may cause ink to dry too quickly, affecting color saturation; Excessive humidity may affect the viscosity and transfer performance of ink. Therefore, it is necessary to control the temperature and humidity of the printing environment within an appropriate range.

There are multiple factors that affect the color saturation of water-based ink in flexographic printing, including ink composition, operating conditions during the printing process, and environmental factors. In the actual printing process, adjustments and optimizations need to be made according to specific circumstances to ensure the color saturation and overall quality of the printed product.