Liquid Vehicle
Environmentally compliant formulation of adhesives and coatings for paperboard packaging avoids organic solvents by using aqueous carrier systems to deliver polymer particles to the substrate. The utilization of a water-based acrylic dispersion allows for the safe and efficient application of protective coatings and adhesives. It consists of acrylic polymer micro-particles suspended in water, which serves as the continuous phase.
This formulation eliminates emissions of volatile organic compounds during the drying process. It provides a non-flammable and low-odor alternative to solvent-based systems on the converting line.
Film Formation
Evaporation of the water carrier causes the suspended polymer particles to pack closely together and eventually coalesce. This coalescence process creates a continuous, flexible plastic film over the paperboard fibers. The speed of this film formation depends on the temperature of the drying ovens and the relative humidity of the surrounding air.
It determines the line speed of the converting machinery.
Adhesion Build
Developing a strong bond with the paperboard requires the acrylic polymer to wet the fiber surface before coalescence is complete. This wetting enables the polymer chains to interpenetrate the porous structure of the paper. It leads to a high-strength bond once the water has been fully removed.
