Influence Of Pigment Stability On Ink
Pigment yellow 83 manufacturer reminds that when the ink manufacturer produces the ink, firstly, the pigment needs to be dispersed in the connecting material, and then the pigment will be crushed into fine pigment particles through mechanical mixing and grinding, so that the pigment particles are evenly dispersed in the connecting material. Secondly, the stability of the pigment in the dispersion system must be maintained, or the pigment particles will be easy to flocculated, agglomerated, returned to the roughness, or the ink will be gelatinized in the dispersion system.
This is due to the different structure of different pigment particles and different pigment surface properties of different pigments, so that the surface of the pigment particles in different linker also has a great difference in affinity, and this difference will make the pigment particles that have been uniformly dispersed to regroup into clusters or circles. At this time, the precipitation ability of pigment particles in the ink will become higher, the distribution uniformity will be reduced, and the fluidity of the ink will become poor, we call this phenomenon flocculation phenomenon, and at the same time this phenomenon of flocculation structure is very loose, and it is easy to be mechanically broken by mixing, and then become uniformly dispersed system again. Generally speaking, if the pigment particles in the connecting material undergo very serious flocculation, then the pigment particles in the connecting material will merge to form large pigment particles, which we call this phenomenon as agglomeration. At this time, the distribution of the pigment is very uneven, and the settling ability is greatly increased, this phenomenon is one of the cases of the ink returning to the coarse.
In order to prevent the pigment from aggregating on the coloring matter, we can add surfactant into the ink to keep the stability of the ink, such as ionic surfactant or non-ionic surfactant can be used to keep the stability of the ink in dispersed system. Generally we use ionic surfactants, which can make the active agent in the form of positive or negative ions to be adsorbed on the surface of the pigment, so that its corresponding charge can be diffused with the pigment particles together with the connecting material medium to produce charge repulsion. These diffused charged ions surround the pigment particles and repel the equally charged particles around them, forming a double electric layer around the pigment particles, preventing the particles from approaching and reducing the occurrence of flocculation phenomenon. However, it is also necessary to pay attention to avoid using surfactant in excess, if surfactant is used in excess, it is easy to make the ion concentration decrease and the repulsion property of pigment particles occur.
The different dielectric constants between the pigment particles and the connecting material can cause the attractive van der Waals force, and the attractive van der Waals force can keep the stability of the dispersive system. However, any use of attractive van der Waals forces to maintain the stability of the dispersive system needs to be determined by theoretical guidance and experimentation.