SILICONE PRESSURE-SENSITIVE ADHESIVES WITH SELECTIVE ADHESION CHARACTERISTICS

The peel, probe tack, and loop tack adhesion characteristics of peroxi de-cured silicone pressure-sensitive adhesives (PSAs) are investigated with respect to adhesive composition, peroxide concentration, and typ e of substrate. These adhesion properties decrease with increasing ben zoyl peroxide concentration and their adhesion values vary noticeably with the substrate type. However, the loop adhesion to 'difficult-to-w et' surfaces (e.g. silicone-coated substrates) can be selectively enha nced by incorporating an organofunctional silicone into the silicone P SA mixture. The enhancement in adhesion is attributed to a wetting/adh esion improvement at the adhesive-substrate interface, acid relates to the type of organosil-icone modifier in the order aminosilicone > vin ylsilicone > epoxysilicone > fluorosilicone.