Engineers at Holden, the Australian subsidiary of General Motors, needed a high-performance seal between the door and quarter window of the Holden VE Ute coupe. The seal could not have separate fixing components. This seal is highly visible and must meet strict standards relating to weather, noise and vibration.
At the engineers’ recommendation, Saint-Gobain Sekurit-the glass supplier and manufacturer of the quarter window-worked with Boss Polymer Technologies to develop the correct elastomer compounds and identify the best pressure-sensitive self-adhesive tape to meet these standards.
Boss was selected because it developed ExWeld technology for co-extruding one or more polymer compounds together with such tape. This patented technology reduces material, labor and production costs and received the Automotive Engineering Excellence Award from the Society of Automotive Engineers-Australia. Boss supplies custom-engineered ExWeld seals to specialist automotive manufacturers such as EGR and ARB, which supply international aftermarket and OEM customers.
Sekurit and Boss worked on the project for more than five months. To achieve a tight seal at high speed, Boss co-extruded two different grades of Santoprene elastomer onto the tape. “They did a good job of quickly getting the right polymer mix,” says Sekurit product development program manager Sak Suwannasri of Boss. He says this system is designed to streamline the OEM’s production line process.
“For this component, GM Holden specified a life-of-vehicle strength bond, and this required a high-quality self-adhesive tape,” says Boss director Norman Mills. “This seal is in the cabin-side air flow and must be flexible to conform to shape when the door is closed, yet firm to hold out passing air and prevent noise. The surface must also hold a very thin layer of low-friction coating.”
The VE quarter window is manufactured using the Sekurit “encapsulation” process, in which the glass and the components used to fix it to the vehicle are placed in a mold. To hold the components together and provide the required sealing edges, a reaction injection molding polyurethane compound is injected into the mold.
For more information on polymer engineering, visit www.bosspolymer.com.