Dow Helps Honda Turn to Weld Bonding with an Epoxy-Based Structural Adhesive

Asthe industry knows, the use of structural adhesives to bond vehicle components together is becoming an increasingly popular solution for automakers, and Honda is no exception. Often, they combine adhesives with a traditional joining method to improve strength, and this is just what Honda has done with its fifth-generation Odyssey. The car will be made with twice as much adhesive bonding as its predecessor.

Materials are not only becoming lighter but also thinner, particularly when steel is used. This can mean that regular welds just aren’t strong enough on their own. The new Honda’s Body in White (BIW) consists of various grades of steel and just 1 percent aluminum, but it will use about 44 meters of adhesives. This not only reduced the need for additional reinforcing components, a move which shed 5kg from the overall weight of the car but also improved torsional rigidity by 10%.

However, the change could mean that extra caution must be exercised when spray treating body and closure panels after their arrival at the assembly plant. If the adhesives have not cured sufficiently, the treatment will remove some of the adhesive from the bond line resulting in reduced bond strength. The uncured adhesive could also be redeposited on body panels necessitating repair work before paint application.

The problem has been resolved with Toughened Betamate, a structural adhesive with higher viscosity developed by Dow. While it has higher viscosity, the epoxy-based structural adhesive will still be compatible with existing production line applicators but has improved wash-off resistance. It also exhibits greater tensile modulus which will make it an appropriate choice for high-strength, downgauged steel components. Lap shear strength remains consistent across a wide range of curing temperatures, and the adhesive can cure at low temperatures.