Adhesive Control in Thin Filmy Pressure-Sensitive Adhesives Prepared from Polyurethane and/or Acrylic Copolymers

Abstract

Pressure-sensitive adhesive (PSA) sheets having a thin filmy PSA layer (1 µm thickness) were prepared from polyurethane or acrylic copolymer and their adhesive properties were investigated. In the polyurethane-based adhesive sheets, an increase of probe tack energy and peel strength was attributed to the improvement of the wettability to the uneven adherend surface as well as the cohesive strength of the adhesives. On the other hand, the peel strength in the acrylic adhesive sheets increased as interactions between the adhesive surface and the adherend surface increased. Furthermore, the adhesive properties of the adhesive sheet laminates which were prepared using the polyurethane-based adhesive and the acrylic adhesives were also examined. The highest peel strength in these sheet laminates was 5.1N/25mm, which was significantly higher than that of single layer PSA sheets. This result is probably owing to the synergistic effects of the improvement of the wettability to the uneven adherend surface and the surface interaction among the sheet laminates.