The third type of structural adhesives are known as urethane adhesives. Just like with the two previous types of structural adhesives, urethane adhesives are made up of properties that make it different and stand out from the rest.

Urethanes are normally a one component synthetic crystalline compound or ethyl which varies according to chemical structure.  Polyurethanes are a class of polymers produced through the intricate process of synthesis between Isocyanates and polyols.  Also can be a Diisocyanate.  Urethanes are a low viscosity adhesive that cures with moisture.   Moisture is typically environmental as humidity which depends on an area.  The more humid the quicker the cure.  Low humidity takes longer.  Most urethanes handing strength is within an hour but full strength is between 24 to 72 hours. 

Polyurethanes are a kind of urethane adhesive that will work on most normal materials whether they are porous or not. This can include metals, wood, cured epoxy, rubber, tile, leather, and glass as well as concretes, many plastics, and brick. It is not, however, suitable to be used on polyethylene, polypropylene, or other such substances such as silicone or Teflon.

• Cured Properties
  • They do not form very durable or environmentally resistant bonds to either unprepared or bare metals
  • They can attain an extremely high elongation (>100%) while retaining the performance of a structural adhesives
  • They will bond very well to thermoset and thermoplastic substrates
• Uncured Properties
  • There is no noticeable odor or smell
  • The liquid consistency remains at a pace that is flowable
  • They will be sensitive to contamination by any moisture
    • The moisture will give a chemical reaction from the isocyanate which will diminish the shelf life
  • It can be within a single component (a one part) or two component system
• Application Properties
  • They have a vast range of cure rates that are available by choosing the appropriate B-side
    • As with the epoxy adhesives, cure rates can be accelerated with heat
  • They are easy to distribute
    • Some of the urethane adhesives have low viscosities that could allow the use of low-cost MMD equipment
  • The cure behavior as well as the final properties can also be negatively affected by any moisture within the air or the substrate
• Two components or “parts” (One component solutions are available)
  • The A-side, which is commonly known as the resin
  • The B-side, which is commonly known as the curative

We have some great urethane adhesives in stock from LORD that we recommend checking out. Some of them are LORD 7542 Urethane Adhesive A/B, LORD 7545 A/B Urethane Adhesive (1:1), and LORD 7545 A/F Urethane Adhesive (1:1) among many other options that will help you with any project you may have!

If you have any questions about the urethane adhesives we have in stock or how they could help you, we are here to help. Please do not hesitate to reach out! Call us, toll-free, at 1-800-220-1966 or send us an email at [email protected]. Our customers stick with us, and so should your adhesives!