Solutions for Water Marks, Blotches, and Pinholes in Gravure Printing

Is the Leveling Agent Effective?

When issues like water marks, blotches, or pinholes arise, many ink customers find themselves puzzled, questioning whether the leveling agent they are using is suitable. However, based on Shunfeng Ink's years of experience, the leveling problems of inks often cannot be solved solely by the leveling agents. Below are other potential causes of ink defects and their corresponding solutions.

1. Printing Conditions
   Solution: Increase printing viscosity, enhance printing speed, and optimize the plate line speed, etc.

2. Viscosity and Flow Properties of the Ink
   Solution:

• Choose appropriate resins and pigments. The leveling properties of the ink largely depend on the resin's ability to wet and stabilize the pigments. Poor flow properties of the ink are often due to the intermolecular forces between pigments affecting its flow, which is why glossy varnish generally does not experience leveling issues. The more pigment powder present in the ink system, the harder it is to achieve good leveling. For instance, nitrocellulose disperses well in surface printing inks, while chlorinated polyvinyl or polyether resins are better suited for reverse printing.
• Add appropriate dispersants to improve the wetting and encapsulation of the pigments, reducing intermolecular forces between pigment powders to enhance the ink's flow properties and leveling ability.

3. Spreading Ability on Substrates
   For water-based gravure inks, adding substrate wetting agents can reduce the surface tension of the ink, improving its spreading ability on substrates. Based on our application experience, we recommend the following wetting agents to address wetting issues on different substrates.
   Solution:

• For absorbent substrates (e.g., regular paper), use standard substrate wetting agents.
• For non-absorbent substrates, when standard wetting agents are insufficient, high-performance substrate wetting agents can be employed.
• For particularly difficult-to-wet substrates (e.g., poorly treated PP), we recommend using silicone-based substrate wetting agents.