Ink Composite with Solvent-Free Generates Bubbles
The solvent-free ink is based on the polyether castor oil system. In theory, there should be no compatibility issue between the ink and adhesive. If adjustments are to be made from the resin perspective, reducing the resin's viscosity could potentially resolve the problem of composite bubbles.
Polyether adhesives generally have a better odor compatibility with the ink compared to polyester adhesives. The compatibility between the polyester adhesive and ink varies. There are numerous factors that contribute to bubble formation. These factors include material structure, material barrier properties, air humidity, ink drying characteristics, solvent residues, adhesive application levels, pressure from the laminating rolls, and various other factors.
The ink's fineness is crucial as it contributes to the leveling of the adhesive on top. Improved leveling on the top surface and adjusted adhesive application levels can reduce the chances of bubble formation and white spots.