Since ink uses water as a solvent, its content in ink is usually relatively high, and can be adjusted within the range of 20-50% according to specific needs.
When the water content in the ink is relatively large, the concentration and viscosity of the ink will decrease, resulting in an increase in the ink absorption rate of the paper during the printing process, resulting in the suspension of ink leveling and the increase in the gradient of the viscosity value of the ink . In this way, in the initial stage of ink printing, the viscosity value of the ink will increase significantly, and in severe cases, it will increase suddenly, making it difficult to meet the leveling requirements, so that the leveling ends prematurely, making it difficult for the ink to form a smoother ink layer. , and the flatness of the ink surface is often the key to the success or failure of the ink gloss, so in this case the gloss will inevitably be poor.
If the water content of the ink is too low, it will inevitably lead to an increase in the solid content and a corresponding increase in its viscosity. For paper with the same absorption strength, its ink absorption rate is inversely proportional , so the greater the viscosity value, the smaller the absorption rate, and the worse the leveling property, or the leveling is not at all. It cannot be done, so that the penetration, coagulation and conjunctival effects in leveling are significantly reduced, so the flatness of the surface of the printed product obtained will inevitably be poor, and the glossiness will not be satisfactory.
Therefore, in the actual production of ink, it is necessary to strictly control the water content, neither too high nor too low . The water content can be estimated through experiments, and of course other performance requirements must be taken into account.
