Despite substantial
research efforts, the commercial alternatives for bio-based adhesives remain
scarce. There are high requirements for adhesives used for lamination of
paper in food packaging, e.g., stable adhesion over shelf life, food safety,
water and temperature resistance to name a few. In particular, high-speed
roll-to-roll processing requires an instant tack of the adhesive to the paper
substrate, to avoid sliding of paper layers on the rollers. The coating
consolidation is fast (seconds) and occurs under pressure, followed by
drying. High initial tack implies that the adhesive can be load-bearing
during drying. There is a need to understand how physical-chemical properties
of bio-based polymers influence their initial tack performance and how to
modify it. This can be achieved by studying dewatering, bond formation and
rheological behavior. By using conventional fossil-based adhesives as
benchmark, comparisons can be made regarding chemistry and morphology. Green
chemistry principles will be used to modify selected bio-based polymers
(forest-, crop- or marine based) to provide new properties for formulations
requiring high initial tack.
