1.1 Polyurethane (PU) Glue Polyurethane adhesives are a class of versatile materials characterized by the presence of urethane linkages (-NHCOO-) in their polymer chains. These linkages are formed through the reaction of an isocyanate component (-NCO) with a polyol component (-OH). The specific properties of PU adhesives are determined by the types of isocyanates and...