For utility trucks, service trucks and heavy-duty trucks hard daily use is the norm, however for trucks with a dump-bed, the situation is extreme. Panels must endure almost constant impact and deformation.
One truck bed manufacturer wanted to replace welding—an expensive and time-consuming process, especially with non-ferrous or coated metals—with structural adhesives. Adhesive bonding can be accomplished with simpler equipment and requires less employee training. Flexible acrylic adhesive was a desirable solution because of its ability to provide impact resistance.
The manufacturer worked with three kinds of metal substrates—aluminum, galvanized steel and an aluminum-zinc-alloy-coated steel. Galvanized steel can be difficult to bond since many acrylic adhesives do not adhere or cure well on the coated metal. Aluminum-zinc-alloy-coated-steel is typically even more challenging to bond. Next-generation acrylic adhesives, however, showed excellent results on all three substrates during tests that included:
- Impact resistance testing: Sharp impacts hard enough to cause deformation of the substrate did not cause brittle delamination of the adhesive, and the subsequent failure mode in tear-down was 100 percent cohesive.
- Bake resistance testing: Lap shear strength and failure mode were not altered during the baking process—a milestone that had previously been a significant challenge for 10:1 acrylic adhesive systems.
- Environmental resistance: The next-generation acrylic adhesive was able to retain excellent bond strength on various metal substrates when exposed to environmental extremes.
A similar success was experienced by a manufacturer looking to use lightweight substrates for truck bodies and beds. Finding an adhesive that could handle stress loads of the truck chassis and withstand the vehicle’s high-bake finishing process were priorities for the manufacturer. Only a next generation acrylic adhesive was able to meet all the design requirements. Tests included:
- Torsional testing in which the truck bed was systematically twisted back and forth. The next-generation acrylic adhesive was strong enough not to fail; it was also flexible enough to avoid collateral damage such as stress cracks in the truck body.
- Bake resistance testing. While other adhesives fell apart during the high-temperature e-coat process, the next-generation product maintained structural integrity without any degradation.
Using next-generation acrylic adhesives saved the manufacturer time and labor costs by simplifying part assembly; it also cut costs by eliminating the steps of grinding and sanding welded spots. Next-generation acrylic adhesive use also improved the aesthetics of the finished vehicle, since using adhesives allows flat panels to maintain a smooth, unmarred appearance.
Watch for the next installment in our blog series, which will examine how wind turbines are assembled—and how next-generation acrylic adhesives are part of their structural design. If you missed part one of our series on "A Sea Change in Adhesive Chemistry," be sure to check it out.