Optimizing Application Properties of EB Curable Laminating Adhesives for Flexible Packaging

The advantages and performance properties of Electron Beam (EB) curable laminating adhesives have been previously ° The most significant advantage is that full bonding is achieved instantly upon EB irradiation. This allows immediate slitting, shipping, heat sealing, and filling of the package. One challenge with instant bonding is that the adhesive appearance is "frozen" immediately upon cure. This is in contrast to isocyanate/polyol based adhesives where the adhesive can continue to flow-out in the rewind roll as the curing process continues. Of course the risk with isocyanate/polyol adhesives is that the flow out may not meet expectations and that a significant amount of scrap may result At least with EB curable adhesives the final optical appearance of the laminate can be evaluated immediately upon production. It is known that the most effective way to improve the optical properties of an adhesive laminated structure is to improve the lay-down of the adhesive on the primary web. Some additional improvements may also be possible by adjustment of the nip conditions. The goal of this study is to investigate the factors that affect the lay-down properties of EB laminating adhesives. The factors studied were: 1) web speed, 2) adhesive flow additives, 3) adhesive temperature, 4) coater configuration, and 5) corona treatment.