Industrial pressure sensitive adhesives suitable for physicochemical microencapsulation

The main objective of this investigation is to characterize several industrial pressure sensitive adhesives (PSA) for their microencapsulation. The adhesive selected must remain stable within the variations of the microencapsulation conditions. Thanks to its encapsulation, the adhesive will be self protected into the microcapsule's shell, and its release will be then controlled applying a light pressure. First, physicochemical microencapsulation processes were selected, and three industrial water-based acrylic adhesives were consequently chosen. The adhesive main characteristics (composition, particle size distribution and peel strength) were determined. Then, particle size stability was tested under ranges of pH (from 2 to 9), temperature (from 5 to 85 °C) and electrical conductivity variations (up to 12 mS/cm), within an interval of values encountered in the physicochemical processes of microencapsulation. Finally, the compatibility with various solvents (acetone, ethanol and ethyl acetate) was also tested.