Synthesis and cross-linking of acrylic PSA systems

Since their introduction half a century ago, pressure-sensitive acrylic adhesives have been successfully applied in many fields. They are used in self-adhesive tapes, labels and protective films, as well as in dermal dosage systems for pharmaceutical applications, in biomedical electrodes, and in the assembly of automotive parts, toys, electronic circuits and keyboards. Three properties which are useful in characterizing the nature of pressure-sensitive adhesives (PSAs) are tack, adhesion and cohesion. They are determined, to a large degree, by the kind of monomers, solvent nature, initiator type and amount, molecular weight of acrylic co-polymer, polymerization method, and especially by the type and quantity of the cross-linking agent added to the PSA. There are internal and external cross-linking agents. UV technology is well established in the market and allows the production of a wide range of UV-cross-linkable pressure-sensitive adhesives with interesting features.