In recent years, structural adhesives have slowly but steadily replaced mechanical fasteners in manufacturing applications ranging from construction and agriculture to motor vehicles and aerospace. Adhesive bonds have a number of advantages over mechanical bonds, including:
- greater flexibility
- lighter weight
- better aesthetic appearance
- faster bond speeds
A number of adhesive products – each with specific strengths – can be used in structural bonding, including:
- epoxies, which create strong bonds
- acrylics, which set the fastest and can be used on difficult substrates
- polyurethanes, which create highly flexible bonds
Innovation continues to result in stronger, more effective products. For example, new die cut adhesives – produced from two-sided and very high bond tapes – are increasingly used to bond irregular surfaces and reduce vibrations.
As a result, the ongoing switch from mechanical fasteners to adhesive bonds and the adoption of higher value formulations will bolster demand for adhesives and sealants, particularly in applications where the weight, appearance, and longevity of the bond are important. Demand in motor vehicle manufacturing and aerospace applications will chiefly benefit, expanding 3.3% and 4.6% yearly through 2022, respectively.
Motor Vehicles Are a Key Outlet for Structural Adhesives
Adhesive bonding has become particularly prevalent in motor vehicle manufacturing, where popular applications include interior assembly, windshield and window glazing, and vehicle body manufacturing.
In general, adhesives are less expensive than mechanical fasteners and also provide cosmetic advantages. Furthermore, the growing use of fiber-reinforced composites and newer plastics for automotive components has pushed the development and use of novel adhesives, as drilling holes in composite pieces can significantly weaken them.
Beyond aesthetic improvements and cost savings, using adhesives in place of mechanical bonds saves a significant amount of weight. Due in large part to the use of adhesive bonds, the average car today weighs around 130 pounds less than past models. Reducing a motor vehicle’s weight by 100 pounds has been estimated to improve fuel efficiency by about 1%.
This weight savings is particularly important because fuel efficiency standards have grown increasingly stringent while larger, heavier vehicles like SUVs and pickup trucks continue to grow more popular in America.
New Federal Policies Offer Mixed Outlook for Automotive Adhesives
The widespread use of adhesives in automotive manufacturing can be traced back to July 2011, when President Obama announced new Corporate Average Fuel Economy (CAFE) regulations for motor vehicles through model year 2025. These regulations – finalized in August 2012 – require fleet-wide average gas efficiency of 54.5 mpg (in real-life applications, around 44 mpg per automobile and 31 mpg for SUVS and pickup trucks).
Following an April 2018 review of CAFE, the Trump administration determined that the fuel efficiency standards were too harsh and announced plans to release its own revised standards for 2022-2025. Without the more stringent fuel efficiency regulations, automakers may not be under pressure to further reduce the weight of newer models. As a result, efforts to replace mechanical fasteners with adhesives in motor vehicle production may slow.
However, other moves by the Trump administration may bolster adhesive bonding use for motor vehicle applications. In June 2018, the president imposed 25% tariffs on steel and 10% tariffs on aluminum imports from the EU, Canada, and Mexico. While the permanence of these tariffs is still uncertain as the ramifications unfold, there’s no question that if they extend into the long-term, automakers will need to adapt. To do that, it’s likely that they will increasingly rely on more cost-effective composite materials and adhesives in lieu of steel components and metal fasteners, boosting demand for adhesives and sealants overall.
To Learn More
Want to learn more about the adhesives and sealants? Check out the Freedonia Group’s new study, Adhesives & Sealants in the US. This comprehensive industry report includes:
- historical data and forecasts
- demand for adhesives and sealants by product and market
- analysis of the factors affecting demand
- a breakdown of industry players
About the Author:
Christine O’Keefe, Ph.D., is an Industry Analyst at the Freedonia Group, where she focuses on chemical topics and food ingredients.