The surface tension of the ink is an important indicator in the various performance indicators of digital printing production, because in order to obtain high-quality printed fabrics, it is necessary to have the appropriate surface tension to make the inkjet printer eject standard ink droplets. The surface tension of the ink is affected by the alcohol additives and surfactants in the ink composition. In the process of digital inkjet printing, the formation of ink droplets is mainly controlled by the surface tension, as long as the surface tension is appropriate. The ink flow is broken at the nozzle to form small droplets of approximately spherical shape.
The surface tension of digital printing ink is a key factor, which determines the permeability of the ink color and the clarity of the pattern. The surface tension of digital printing ink is extremely obvious for the formation of ink droplets and the printing quality of patterns.
If the surface tension of the ink is too high, the ink flow is difficult to break, the ink is not easy to form small droplets, and the nozzle surface is not easily wetted, which will cause the ink droplets to not print smoothly and cause intermittent interruptions. The surrounding ink buildup will affect the linear movement of the fine droplets and the reproducibility of the digital printing effect, as well as the wetting and penetration of the droplets on the fabric.
The lower the surface tension of the ink, the smaller the contact angle between the substrate and the ink drop, which is beneficial to increase the coverage rate and improve the quality of the printed pattern. However, if the surface tension of the ink is too low, it is difficult to form tiny and uniform ink droplets. Form a “satellite shape” to generate sputtering points, affecting the effect of digital printing patterns.
Proper surface tension must ensure that a satisfactory quality of digital printing patterns can be obtained, so that the ink can easily penetrate into the interior of the fabric without causing permeation on the surface of the fabric. Therefore, the surface tension of general ink should be controlled between 30~50mN/m.
