Effect of silanized polyurethane content on adhesion properties of a polyurethane-acrylic hybrid adhesive

Polyurethane (PU)-acrylic hybrid adhesives have recently attracted much attention. However, the need to use acrylic monomers with a specific functional group able to react with PU has limited the design of these adhesives. To solve this problem, in this research, the polyol used for the synthesis of PU was modified by a silane coupling agent containing a carbon-carbon double bond. The free radical polymerization of the acrylic comonomers was performed afterwards in the presence of 10 to 20 wt. % salinized PU. The presence of PU in the hybrid pressure-sensitive adhesive (PSA) improved and then reduced the peel force and tack, while increased the shear strength. Due to a suitable balance in its viscoelastic properties, the PSA containing 15 wt. % silanized PU exhibited better adhesion properties, including peel force, shear strength, and tack, which were 1.3, 2.4, and 2.4 times those of the pure acrylic PSA, respectively.