Polyurethane adhesives and sealants provide excellent flexibility, impact resistance, and durability. They are available in one-part or two-part adhesive systems. They are available in one or two-part adhesive systems. Polyurethanes (also referred to as urethanes) are formed through the reaction of an isocyanate component with amines, polyols or other active hydrogen compounds. Polyurethane adhesives bond well to plastic surfaces and make an excellent flexible potting compound. Polyurethane adhesives require a catalyst, heat or air evaporation to initiate and complete curing.  Some disadvantages of polyurethane adhesives are their short shelf life due to hydroscopic (water absorption) tendencies and their generally slower cure combined with more complicated handling and curing procedures.

There are a wide variety of polyurethane adhesives available, which offer many different application and protective features.  These include bulk flexibility, resistance to oil or chemicals, heat resistance, gap filling and leveling, retaining, sealing, and threadlocking.  Polyurethane adhesives with bulk flexibility form a layer that can bend or flex without cracking or delaminating.  They provide additional support in applications that deal with raised levels of sound, vibration or shock.  Polyurethane adhesives that are resistant to oils and chemicals are not damaged by exposure to acids, alkalis, general chemicals, oils or fuel. These polyurethanes find applications in sealing fuel or oil tanks or in chemical process vessels, piping and fittings exposed to oil and corrosive mixtures.  Similarly, heat resistant polyurethane adhesives are not damaged by prolonged exposure to raised temperatures, and many types are flame resistant, meaning that they resist ignition when exposed to high temperature and can insulate the substrate and delay damage to it.

In addition to bonding and protecting, many polyurethane adhesives are used to level, fill gaps, and seal holes.  These types vary based on the composition of the adhesive, and its style, be it a flowing liquid, viscous liquid, or compound paste.  Some of these filling applications include gap filling, which is simply closing up gaps between two bonded substrates; leveling mastics, which highly viscous polyurethane adhesives applied by trowel to give thick glue lines with gap sealing properties. Mastics are used to bond tiles to sub-flooring. Mastics fill in gaps or irregularities in a surface before tile or other materials are applied.  Retaining polyurethane adhesives reliably retain cylindrical mating parts such as bearings, pulleys, couplings, rotors and gears. They eliminate the need for press or shrink fits and provide up to twice the shear strength of these methods of assembly on slip-fit parts.  Threadlocking or threadlocker polyurethane adhesives lock all kinds of threads that are subject to transverse and axial loads against vibrational loosening. They reduce production costs and improve reliability by eliminating lock washers and other expensive locking devices. They preserve on-torque and distribute the load over the entire engagement length of the fastener, effectively eliminating premature material fatigue and fastener failure.

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FEICA - Association of European Adhesives and Sealants...

Polyurethane Adhesives, Polyurethane Adhesives Manufacturers,... of acrylic adhesives, adhesive primer, adhesives, anaerobic adhesives, engineering industry adhesives, heat resistant adhesives, hot melt adhesives,

Adhesives New ? ECHELON? Polyurethane Prepolymers offer a competitive edge to adhesives and sealants formulators by providing greater efficiency and enhanced

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