Does water-based ink crack?

   Yes, water-based ink can crack, but it is not inevitable. It primarily happens when the ink film is too thick, too brittle, or applied to a flexible substrate that it cannot properly adhere to.

Why Water-Based Ink Can Crack

Cracking is a failure of the ink film to remain flexible after drying. The main reasons are:

1. Ink Film Thickness: This is the most common cause. If the ink layer is applied too heavily, the surface dries and forms a skin while the underlying layers are still wet. As the entire film finally dries and contracts, it can create stress that leads to cracking, especially when the printed material is bent or folded.

2. Ink Formulation: Not all water-based inks are created equal.

   • Brittle Resins: Some resins (binders) used in the ink formulation naturally form a harder, more brittle film. This is common in inks designed for high rub resistance on paper but can be problematic on flexible materials.

   • Pigment Load: Inks with very high pigment concentration can be more prone to cracking if the resin system isn't balanced to maintain flexibility.

3. Substrate Compatibility:

   • Non-Porous Materials: Water-based inks are most prone to cracking on non-porous, flexible substrates like plastic films (PE, PP, OPP). The ink sits on the surface and forms a continuous film. If this film is more rigid than the substrate underneath, any flexing will cause the ink to crack.

   • Porous Materials: On porous substrates like paper or cardboard, the ink anchors itself mechanically by soaking into the fibers. This creates a strong bond and makes cracking much less likely, even when the box is folded.

4. Improper Drying: Excessive or improper heat during drying can "bake" the ink film, making it brittle and removing the plasticizers that allow for flexibility.

5. Lack of Flexibility Additives: Standard water-based inks may not contain plasticizers or flexible resins. For applications requiring high flexibility (e.g., printed bags, pouches), a specifically formulated flexible water-based ink must be used.

   Comparison to Other Inks

Conclusion

1. Vs. Solvent-Based Ink: Solvent-based inks for film are specifically formulated with resins (like polyurethane) that create a very strong, yet inherently flexible film that is highly resistant to cracking.

2. Vs. UV Ink: Standard UV inks can be brittle. However, UV Flexo Inks are a special category formulated with flexible oligomers and monomers designed to resist cracking on flexible packaging.

3. Will your water-based ink crack? It depends.

4. Printing on paper or corrugated cardboard? Cracking is very rare if the ink is dried properly.

5. Always consult with your ink supplier. They can recommend the exact ink formulation and press settings for your specific substrate and application to prevent cracking.

6. Printing on plastic film? Cracking is a significant risk unless you:

    

   Always consult with your ink supplier. They can recommend the exact ink formulation and press settings for your specific substrate and application to prevent cracking.

    

   

    

   1. Use a flexible formula water-based ink.

   2. Apply a thin, controlled film.

   3. Corona treat the plastic substrate.

   4. Optimize your drying process.