Bonding Beyond the Basics: Adhesives for Coated & High-Porosity Liners
As the demands of the packaging market evolve, so do the materials used to create corrugated board. The industry is seeing a rapid increase in the use of specialized linerboards, from high-gloss, coated papers for premium retail displays to lightweight, high-porosity recycled liners for e-commerce. While these new substrates offer benefits in terms of print quality, sustainability, or cost, they also present significant challenges for the bonding process. A standard starch adhesive that works perfectly on traditional kraftliner may fail completely on these more demanding surfaces. A successful corrugator operation in the modern era requires an adhesive strategy that is as versatile as its product mix.
Coated and high-holdout liners are particularly challenging. These papers are treated to have a sealed, non-porous surface to improve printability and create a premium look. However, this very property makes them difficult to bond with a traditional water-based adhesive. Because the surface is non-porous, the water in the adhesive has nowhere to go. It cannot be absorbed by the liner, so the adhesive cannot set and build its initial bond strength. This results in a weak, 'wet' bond line, slow machine speeds, and a high risk of delamination. To overcome this, a specialized adhesive is required. These formulations often have a much higher solids content and are designed to build tack with minimal water loss, effectively 'sticking' to the surface rather than relying on absorption to set.
On the other end of the spectrum are high-porosity or highly absorbent recycled liners. Driven by sustainability goals, these liners are becoming increasingly common. However, they present the opposite problem. These papers are so absorbent that they can 'drink' the water from a standard adhesive too quickly. This 'dries out' the adhesive before it has a chance to properly gel and form a strong bond, resulting in a brittle, starved bond line that is prone to failure. The solution here is an adhesive with high water-retention properties. These advanced formulations are designed to hold onto their moisture longer, ensuring that there is enough water present at the flute tip to allow for proper gelatinization and the creation of a deep, penetrating, and durable bond.
Successfully navigating this complex substrate landscape requires a partnership with a knowledgeable adhesive supplier. At Kubron Chemicals, our technical team thrives on these challenges. We don't believe in a one-size-fits-all approach. We work with our customers to analyze their specific linerboards, running trials and adjusting formulations to create the perfect adhesive for their unique needs. Whether it's developing a high-solids adhesive for a difficult coated board or a water-retentive formula for a new recycled liner, our goal is to provide a customized solution that allows our clients to run any substrate with confidence, speed, and quality. We provide the chemical expertise that turns bonding challenges into competitive advantages.