I. Solvents play the following roles in gravure inks

1. Dissolve and disperse all solid components in the ink;

2. Wetting the surface of the printed substrate;

3. Adjust the drying speed of the ink;

4. Adjust the viscosity of the ink to meet the inking requirements of the printing plate;

5. Dissolves or swells the surface of the printed film, and improves the adhesion fastness of the ink to the film by virtue of its affinity with the solvent.

Second, the choice of solvent

1. The boiling point of the solvent is between 80-150 ° C;

2. can fully dissolve the selected ink resin;

3. Can dissolve the dry ink film remaining on the printing plate;

4. Does not corrode the printing plate roller and ink scraper;

5.non-toxic or slightly toxic, no abnormal irritating odor;

6. There is an appropriate volatilization rate. The solvent is also a binder in gravure inks. It is a true solvent that dissolves high molecular substances such as resins. It is also a diluent that acts as a diluent and a co-solvent for latent solubility. Yes, it is a true solvent for one ink system and a co-solvent for the other ink system. Even two solvents are not true solvents for an ink system, and mixed together is an excellent solvent for the ink system.

Types and properties of solvents commonly used in gravure inks

Gravure inks mainly use organic solvents. According to their chemical structure, they can be divided into aromatic hydrocarbons, alcohols, esters, ketones, or ethers. —Generally, gravure inks are required to use non-toxic or low-toxic solvents. However, many organic solvents are toxic and flammable, so pay attention to their allowable concentration values when they are used.

How to add solvents for gravure inks

The binder, pigment and other solid components in the ink can be dissolved only in solvents with good compatibility with it. When preparing the ink, do not add the single solvent directly. After mixing the solvent into a mixed solvent, slowly add it to the ink while stirring. This can prevent the agglomerated ink from being agglomerated due to the addition of a single solvent. Prevent the solvent from impacting the ink when the solvent is added suddenly, so that the pigment particles that have been originally wrapped by the resin escape and form bare pigment particles. Makes the blended ink dull and stale.