Water-based ink is an environmentally friendly printing ink that uses water as the solvent. It is widely used in food packaging, paper printing and other fields. However, during its production, transportation or printing process, a large number of bubbles are often generated due to stirring, pumping or high-speed printing. These bubbles not only affect the uniformity and leveling of the ink, but also may cause defects such as pinholes, spots and even ink breaks on the printed products, seriously affecting the printing quality.
At this time, defoamers play the role of "behind-the-scenes heroes". Defoamers are a type of additive that can effectively inhibit or eliminate foam. They are usually composed of hydrophobic particles (such as silica) and low surface tension carriers (such as mineral oil or organic silicon). When added to water-based ink, defoamers can quickly spread to the surface of the bubbles, destroying the stability of the bubble membrane, causing the bubbles to burst and preventing the formation of new bubbles.
In practical applications, the selection of defoamers is very crucial. Common types include mineral oil-based, organic silicon-based and polyether-based. Among them, organic silicon defoamers have high efficiency and low dosage, but may affect the re-saturation property of the ink; mineral oil-based has good compatibility and low cost, but the defoaming speed is slower. Therefore, formulation engineers need to make precise adjustments according to the ink system, printing process and final application.
It is worth noting that defoamers are not "the more, the better". Excessive addition may cause surface shrinkage, loss of gloss and even affect adhesion. Generally, the recommended addition amount is 0.1% to 0.5% of the total weight of the ink, and the optimal dosage should be determined through small-scale tests.
With increasingly strict environmental regulations, the application prospects of water-based ink are broad. Efficient and stable defoamers will become an indispensable part to ensure its performance. The seemingly insignificant few drops of defoamers actually silently safeguard every clear and beautiful printed picture.