Silicone pressure-sensitive adhesives with selective adhesion characteristics

The peel, probe tack, and loop tack adhesion characteristics of peroxide-cured silicone pressure-sensitive adhesives (PSAs) are investigated with respect to adhesive composition, peroxide concentration, and type of substrate. These adhesion properties decrease with increasing benzoyl peroxide concentration and their adhesion values vary noticeably with the substrate type. However, the loop adhesion to 'difficult-to-wet' surfaces (e.g. silicone-coated substrates) can be selectively enhanced by incorporating an organofunctional silicone into the silicone PSA mixture. The enhancement in adhesion is attributed to a wetting/adhesion improvement at the adhesive- substrate interface, and relates to the type of organosilicone modifier in the order aminosilicone > vinylsilicone > epoxysilicone > fluorosilicone.