LOCTITE® UR 7221 is a solvent-free, polyurethane (PU) adhesive ideal for general assembly applications. It’s typically used for manufacturing sandwich elements with porous substrates, e.g. wood, which contain humidity. The substrates can be bonded to one another or to metals, laminated panels, various plastics, rigid foams made of polystyrene, polyurethane and others. When applied, LOCTITE UR 7221 hardens by humidity or spraying with a fine water mist. At room temperature and with the required humidity in the joint, sufficient strength will be obtained after approximately 2 to 4 h. Faster curing can be achieved using a heated press with a maximum temperature of 70°C (158°F).