Dosage and procedure of defoamer
The dosage and efficacy of defoamer depend on the formulation system of paint or ink defoamer, especially the type of polymer, pH value, pigment dosage and the chemical structure of other additives used. Similarly, the type and dosage of defoamer are also required in the manufacturing process and construction process
The two ways of adding defoamer and defoamer concentrate are discussed. The emulsion droplets of defoamer emulsion products have been dispersed into ideal size distribution when the products are supplied. It can be added in abrasives or in the paint mixing process, and it is easy to mix evenly in paint or ink. For defoamers without hydrophobic solid particles, they can even be added in the paint
The way of adding defoamer concentrate containing 100% active substance directly affects the effect of defoamer. The particle size distribution obtained in the adding stage determines the defoamer effect. Therefore, the defoamer concentrate of water-based ink is usually added to the grinding base material. Defoamer is added to the system with high shear force, but the defoaming effect will be weakened with high shear force. The over dispersion and poor dispersion of defoamer are not conducive to the performance of defoamer. The initial defoamer effect may be good when the defoamer is added with relatively low shear force, but after the storage stage, the effect of defoamer may be reduced
General defoamers are designed to be used in the state of supply. If the shear force is not enough when adding, alcohol or coalescer can be used to pre dilute the defoamer of 100% active substance. The range of dilution ratio is 1:1 to 1:9 For defoamer, which is convenient to add and improve the reasonable distribution of defoamer particle size. In this way, the defoaming effect is improved and the tendency of shrinkage is reduced. Usually, the pre dilution of the defoamer will reduce the long-term stability of the defoamer, so pay attention to the storage stability of the defoamer after dilution