Experts Explain Why Something So Simple Is So Important
By Abby Bowman
Adhesives are, literally, the glue that holds the entire auto glass industry together. Unless a windshield is bonded to the vehicle body properly, there’s no guarantee it will hold the glass in place. For decades, using an adhesive has been the only legal way to affix the windshield. There’s no sign of that changing anytime soon.
AGRR magazine spoke with some of the industry’s adhesives experts to learn why they are so important and what innovations the future might hold.
Jeff Olive
Director of Quality and Training, Auto Glass Safety Council
Jeff Olive says adhesives are and will continue to be a critical safety element, especially during a collision.
“The airbag uses the windshield as a backboard when an accident takes place, therefore pushing a passenger against the airbag,” he says. “If the windshield isn’t bonded properly along that section, the windshield could pop up, allowing the airbag to escape underneath the bottom of the windshield and not provide any protection between the dashboard and the passenger.”
One of the most notable advancements Olive has recently seen in this critical component is the improvement in minimum drive-away time. He notes that most major adhesive manufacturers now have products with a minimum drive-away time of 30 minutes.
That 30 minutes is just about the exact amount of time a technician needs to reassemble everything before performing any necessary Advanced Driver Assistance Systems (ADAS) calibration.
“The level that we’ve reached with 30-minute drive-away time—by the time you’re done assembling the car, you’ve almost reached that time where the customer can safely take the car back on the road, or you can perform a dynamic ADAS calibration,” he says.
For this reason, Olive doesn’t think the minimum drive-away time needs to be any shorter.
“I don’t think there’s the need for something instant,” he says. “Instant may be a little difficult because … you want a little bit of time to put those mouldings back on or adjust the windshield.”
Mike Rea
Senior Products Engineer, Sika Corporation
Properly bonded windshields are critical for modern vehicles, Mike Rea says.
“To have a ‘properly bonded’ windshield, the entire system—all of the links in the chain—have to be correct and in place,” he says. “As adhesive manufacturers, we must provide our technicians with the tools and information they need to ensure the entire system is accounted for and functioning properly.”
Rea adds, “The adhesive system supports, in every way, the intended purpose of the vehicle’s design and performance. Most importantly, it ensures the safety and protection of everyone on the road.”
Rea, who has been in the industry for almost 25 years, says there have been so many adhesive innovations he’s lost track of them all. The developments that stand out to him include shorter minimum drive-away times, higher viscosity, primerless-to-glass adhesive innovations, the elimination of hazardous ingredients, and the widespread use of unipicks over cartridges.”
Rea says that although adhesives with an almost immediate minimum drive-away time are certainly possible, the concept presents some challenges.
“Sika could offer a product today that meets the FMVSS 212 standard immediately after installation,” he says. “The hurdles are doing this with a product that can be used with standard industry equipment and still be sold at a price that glass companies are willing to accept.”
Rea says it’s difficult to predict where auto glass adhesives will go next.
“While discussions with our OEM partners indicate that technology will continue to broaden and advance, we really do not know how our vehicles will be changing in the next five to ten years with respect to e-mobility, ride share, ADAS, autonomous driving, and more,” he says. “This can make it difficult to predict what advancements will be needed.”
He says the industry should remain curious about new technology and seize opportunities for development as they arise.
Steve Allison
Research Investigator, DuPont
Steve Allison says that in both original equipment manufacturer (OEM) and aftermarket environments, adhesives are simply easier to use than mechanical fasteners.
“Adhesives help with parts consolidation, lightweighting, ease of assembly or repair, and creating a continuous bond line that supports improved structural integrity,” he says.
Allison says DuPont works with OEMs to ensure that adhesives contribute to the structural integrity and safety of an entire vehicle.
“Adhesives help make the windshield a structural component of the vehicle and stand up to global requirements for rollover and roof crush,” he says.
In addition to shorter minimum drive-away times, Allison notes primerless adhesives and adhesives that hold the glass in place better for ADAS calibrations as notable developments over the past few years.
According to Allison, adhesive technology must also continue to adapt alongside the rise of electric vehicles (EVs) and hybrid vehicles (HEVs).
“By design, these vehicles have a quieter ride, and wind and road noise will become more noticeable and bothersome,” he says. “Customers will judge a windshield replacement by the quietness of the ride. Quality urethane adhesives can play an important role in improving acoustics and delivering an enjoyable ride.”
Allison doesn’t see adhesives with an immediate minimum drive-away time on the horizon either. “An immediate-drive material is certainly possible, but we don’t see a demand for it [at DuPont],” he says.
The current shortest drive-away time of 30 minutes is enough time for the technician to finish their work and prepare the car to return to the customer. Any less than that, and the technician may not have enough time to adjust before the adhesive has cured.
According to Allison, DuPont was one of the first companies to market primerless-to-glass (P2G) adhesives over 25 years ago. He says there is a continued push for P2G adhesives with other technology incorporated.
“The expectation is that new-generation P2G adhesives will have advanced benefits like 30-minute drive-away time, high modulus, and non-conductive formulations,” he says.
Allison adds that using P2G adhesives can be better for the environment because of the lack of primer.
Zuhair Madanat
Owner, Auto Glass Experts
Zuhair Madanat says adhesives have helped lay the foundation for many automotive technologies.
“The crash zones, the aerodynamics of the vehicle, safety features such as airbags—all of that, the adhesive plays a major role in,” he says. “If we didn’t have the adhesive technology and the ability to do certain things with the adhesive, we wouldn’t be able to have the vehicles we have today or the safety features we have today.”
Madanat says he’s grateful that adhesive manufacturers have developed one primer per product, rather than the multi-part primer systems or specific-use primers that used to be common in the industry.
“When you have that, there are more and more variables and things that can go wrong,” he says. “Now, you just have this one primer, and there’s less risk of things going wrong.”
Mandanat says that the now-common 30-minute drive-away time also increases safety during mobile jobs and dynamic calibrations.
“Otherwise, you’d have to wait two to four hours to safely drive the vehicle on the road [for a dynamic calibration],” he says. “The calibration technician’s life is just as valuable. Otherwise, it’s not safe to drive it even just for a calibration.”
While Madanat thinks shorter or nonexistent minimum safe drive-away times would be possible, he’s not sure it would be practical.
“I think there’s always a risk and reward factor in everything you do,” he says.
He says a shorter minimum drive-away time risks not giving technicians enough time to make necessary adjustments, while 30 minutes allows technicians enough time to finish their work.
Madanat would like to see innovations in primer storage and application.
“It kind of seems like a little bit of a dated technology,” he says.
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