The first patented pressures sensitive adhesives (PSA) were derived from natural rubber for bandages back in 1850. Recent developments in the use of polyurethane dispersions (PUDs) to replace natural rubber in non-allergenic examination gloves have sparked interest in their evaluation in PSAs. New continuous PU dispersion technology has allowed the creation of novel PUDs based upon polyether polyols and methylenediphenyl-diisocyanate (MDI). These PU dispersions are solvent free, high solids (50-60 wt %), and have submicron sized particles and excellent stability. The PUDs from this process have been found useful for designing PSAs with properties ranging from removable to high shear strength. In this presentation, the versatility of these new dispersions formulated with waterborne tackifiers and other PSA additives will be demonstrated. Physical property and rheological data from the evaluation of a variety of PUD formulations will be discussed with focus on the material science of the design and formulation of pressure sensitive adhesives.
展开▼
