Polyurethane adhesives vary significantly in their composition and are used in many different applications in a broad range of market segments. Polyurethanes make good adhesives for several reasons:
* Chemical bonding with water and hydroxyls on the substrate surface (e.g., hydrogen bonding)
* Physical bonding through van der Waals forces and low surface energy (effective wetting of most substrates)
* Mechanical bonding through low viscosity and diffusion into porous substrates.
Through broad latitude in formulation composition, the adhesive stiffness, elasticity and crosslinking properties can be tailored to suit specific needs.
Major applications for polyurethane adhesive include footwear, construction, and packaging and assembly.Excellent adhesion to wood substrates and water resistant bonds have encouraged the use of polyurethane adhesives in constructing aircraft, boats, lawn furniture, and other laminated materials for outdoor use as well as more general purpose woodworking applications.