PUR glue, otherwise known as polyurethane hot melt adhesive, is a reactive hot melt adhesive that is heated before application. Unlike traditional hot melts, however, the PUR adhesive reacts with moisture in the air as it cures and changes chemically to create a powerful bond.
Because of the chemical changes that occur during the curing process, PUR adhesive is incredibly strong. Whereas traditional hot melts are similar to a wax bond that can come apart if reheated, PUR adhesives do no such thing and can offer great strength in minutes — continuing to get stronger as it cures over 24-48 hours.
Due to the nature of the product and how it cures, the typical shelf life of unopened polyurethane hot melt adhesives is 12 months. But proper storage will prevent premature activation.
PUR hot melt adhesives are moisture-curing products. To prevent it from curing prematurely, keep it dry from water or any other moisture at all times.
Recap and store the PUR correctly to minimize waste and extend the shelf life of the opened product. To do this, extrude a one-inch bead of adhesive to remove all air from the tube and any product that has already come into contact with moisture in the air. Then, securely attach the cap and store it in a cool, dry place. If recapped and stored properly, the shelf life of an opened Infinity Bond 50-gram cartridge can be extended up to 12 months.