Metal ink

When it comes to metal ink, whether it is a producer or an applicator, it may feel like a headache for water-based ink. In fact, it is indeed a water-based ink with a lot of problems. Some of these problems have not yet been completely resolved by chemists or producers. This article is to discuss the most common problems, and hope to share some of the research experience with readers or ink production seniors.
Metal ink, in general, only two colors, gold and silver. Are described later respectively.
(A) The golden color, whether it is green gold, gold or copper, is completely formulated with copper powder. Although some pigments are added to the colored pigments, they are still indispensable for copper powder applications. The performance of copper powder is heavier than water, and it is extremely insensitive. It is easily oxidized. The thickness of powder particles will also affect the storage properties of ink, the hiding power, color and adhesion of ink (ADHESION).
The most common problem with inks formulated with copper powder is that the ink has a short shelf life and the ink has a tendency to precipitate in the ink cartridges. The precipitates tend to form a hard mass and cannot be dissolved anymore. At the same time, the surface or upper layer will turn green when it is stored in the cocoon, and this change takes a very long time and occurs within 24 hours; some metal inks produce green compartments within a few hours. This phenomenon of turning green is that the copper powder is oxidized and begins to be light green, gradually turning into dark green or dark blue and finally turning black. At this point, the ink will not only be used again, it will even stink and need to be drained.

On the issue of "agglomerate precipitation," some people tried to use finer particles of copper powder, but this has affected the hiding power of ink. Moreover, the phenomenon of agglomeration and sedimentation has not been improved. At present, many chemists have added a small amount of anti-settling agent (Auti-Siutaing Agent) to the formula of ink. The consequence is improved, but it still can not prevent the occurrence of sedimentation, and can only make the copper powder not form a hard block and become an ointment. This ointment can still be dispersed in the ink after stirring, without affecting its viscosity (VISCOSITY).
As for the problem of copper powder being turned green by oxygen, there is still no better solution. Although ANTI-OXIDANT was tried, the effect was not significant; on the contrary, the viscosity and adhesion of the ink (ADHESION) were greatly affected. I have added 0.5 to 1% poly-sodium salt (POLYTRIAZOLE SODIUM SALT) in the formulation to extend the susceptibility of the copper powder; in other words, to extend the storage time of the ink. The test results are now listed in the above table.
(b) Silver silver ink is basically aluminum powder as a colorant. Although aluminum powder is lighter than copper powder, it is not as easily oxidized as copper powder; but it is still heavier than water, and after oxidation, it becomes aluminum oxide, which causes the ink to appear hard and precipitate, or to make the viscosity thicker. The color becomes dumb and not dazzling. This kind of phenomenon is still regarded by chemists as a problem that cannot be solved.
The author has also added 0.5% polyaluminum sodium salt and 1% anti-settling agent to the formula of silver ink and LEAVING aluminum powder. Although the problem has not been completely solved, the effect is satisfactory.
The final point to be mentioned is that the problems of metallic ink and wash still cannot be solved by the chemist. Therefore, when the printer needs to use metallic ink, it is best to ask the ink manufacturer to put metal toner and carrier ( LETDOWNVARNISH) are packaged individually, and depending on the amount required, they can be blended evenly. In this way, the metal inks used are kept fresh. It can avoid unnecessary waste due to short storage period.