Properties Controlling the Impact of Styrenic Block Copolymer Based Pressure-Sensitive Adhesives on Paper Recycling

A model was developed for predicting the removal of hot-melt pressure-sensitive adhesives (PSAs) from paper recycling operations via screening using standard adhesive response data. A series of hot-melt PSAs consisting of a styrene−isoprene−styrene/styrene−isoprene linear triblock, diblock copolymer blend, tackifying resin, and naphthenic process oil were blended in combinations to produce a range of properties. The PSAs were formulated with two types of tackifiers, a pentaerythritol ester of rosin and a C5 petroleum hydrocarbon, to provide variation in the formulation composition. The measured removal efficiency versus temperature curves for these PSAs possess a sigmoidal shape, with removal decreasing from 100 to 0% between transitions for the rubbery and polystyrene domains marking significant changes in the mechanical properties. An exponential-based sigmoidal function containing two fitting parameters, inflection temperature and a factor that determines the width of the sigmoid, provided an excellent...