Analysis of the Reasons of Ink-ink Stacking and Ink Agglomeration

Ink and water printing are directly linked to the agglomeration of the ink, which can cause the gelation of the ink and the vitrification of the printed ink film. Properly increasing the pH value or using inexpensive inorganic salts will allow the ink to regain its original printability, both to improve flow and washability, and to reduce foaming or gelation. In this regard, the author analyzes the following main reasons from the above phenomena.

1. Disperse excessively.

2. Due to improper storage, the ink absorbs moisture and causes flocculation.

3. The pigments or fillers in the ink system are not neutralized by the alkaline binder and are neutralized, and a chemical reaction occurs and builds up.

4. Ink is mixed with paper scraps or rags.

5. Misuse of solvent. For example, some amphoteric solvents or active solvent molecules associate to form size-sized aggregates.

6. The ink yield value is too high, the ink head is too short, and the pigment content is too high, especially if the filler is not resistant to the alkaline linking material causing it to swell. If it is treated with an acidic solvent, it is reduced to a solid state and then redissolved with a solvent.

7. The solvent volatilization gradient in the ink body is unbalanced. In particular, the ratio of the true solvent to the co-solvent is not balanced, and the neutralization agent is not balanced with the neutralizer releasing (exothermic) or volatilizing.

8. When the addition of ammonia brings in the absorbing carbon dioxide, the charging of the particles is blocked, the oxidation is accelerated, and the merging of the oxygen molecules in the water is promoted. At the same time, the excessive addition may also affect the glossiness.

9. After the ink is exposed to air, there is an oxide film mixed in the ink, and the ink may have precipitated particles or the ink is short and dispersed unevenly.

10. Resin monomer composition, especially acrylic resin, disappears when acrylic monomer is increased to 30%.

11. Ink absorption is too strong, Baotuan, uneven dispersion will cause poor ink delivery.

12. Although the addition of white carbon black can overcome the ink delamination and prevent the precipitation of the ink, excessive addition will result in the non-flow of the ink and the decrease of the gloss of the printed ink film.

13. Although the relative density of the pigment or filler is the same, but the particle core size is not equal, it will be in the flocculation state.

14. Ink flocculation or gelation occurs after acid invasion.