Solvent free UV curable coating for paper protection

In this study, a new type of paper protective self-healing coating is reported. Thus, the coating systems are based on a 2K system a polyether polyol and aliphatic acrylic isocyanate and designed to react with the surface of different papers. The coating was designed to react with the surface atoms or oxidized products by two different mechanisms thus forming chemical bonds between the paper surface and the coating. By this and the adjustment of the coating system to extremely low water uptake or water vapour penetration and oxygen penetration the paper surface is protected from the most aggressive environmental species. Further, the coatings are produced without the use of solvents so that a very smooth surface is formed with high hardness (Shore D hardness of >30) but as well elastic (elongation at break >4%) and high thermal stability. In addition, the production process combines surface coating and UV curing process following each other within a few seconds. Such type of coating could have many applications such as in the finishing processes printing and packaging industry. Additionally plasma pre-treatment was used to improve the adhesion between the paper and the coating material.

Automated summary

This study introduces a new type of paper protective self-healing coating based on a 2K system. The coating is designed to react with different paper surfaces, forming chemical bonds and providing high hardness, elasticity, and thermal stability. The coating process combines surface coating and UV curing within seconds, with potential applications in the printing and packaging industry.