UV-photopolymerized acrylic pressure-sensitive adhesives with semi-interpenetration structure: Effect of plasticizer structures on adhesion properties

Acrylic pressure-sensitive adhesives (PSAs) were synthesized using a solvent-free ultraviolet-induced polymerization method. The monomers n-(isobutoxymethyl) acrylamide, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, and methyl methacrylate and an initiator, hydroxy dimethyl acetophenone, were used to prepare acrylic copolymers as prepolymers. A multifunctional monomer, trimethylolpropane triacrylate, was added to form a semi-interpenetrating network, leading to an increase in the modulus and elasticity of the prepolymer. This decreased the peel strength, which is suitable for temporary protective films. Rheological data from small-amplitude oscillatory shear measurements also revealed consistent results suitable for removable PSAs. The plasticizers, such as dioctyl phthalate and dioctyl terephthalate, possessing favorable interactions with the main resins were found to exhibit transparency, clear debonding, and ultralow release, which are essential features for temporary protective films.