Preparation of SIS/SBS-based UV-cross-linkable pressure-sensitive adhesives using the thiol-ene reaction

Hot-melt pressure-sensitive adhesives (HMPSAs) usually contain styrene-isoprenestyrene (SIS) or styrene-butadiene-styrene (SBS) block copolymers, tackifier, plasticizer and other additives. However, these PSAs cannot be used in high-temperature applications or where solvent and chemical resistance properties are required. We, therefore, developed UV-cross-linkable HMPSAs by the thiol-ene reaction with the aim to increase adhesion properties at elevated temperature. For effective UV cross-linking, the selection of photoinitiator and photo-cross-linker is very important for thermal stability and fast curing. Adhesion properties, such as probe tack, peel strength and shear adhesion failure temperature (SAFT), were evaluated to measure PSA performance as a function of photoinitiator type.