The purpose of this paper is to outline the current state of polyurethane bonding technology in the transportation industry. The paper focuses on the strengths and limitations of this technology and the reasons for its long-term success in the market place.
Significant advances have been made in the range of end use applications for polyurethane structural adhesives. The introduction of the new General Motor's Lumina, Silhouette, and Transport mini vans has created the largest assembly line use of structural adhesive to bond SMC body panels to date. Molders and manufacturers of more traditional SMC assemblies have made noteworthy improvements in productivity with fast cure bonding cycles and simplified production processes using polyurethane technology.
Auto makers have continued to capitalize on the cost and performance benefits of bonded composite body vehicles for specialty niche markets. This is following the successful tradition established by the General Motors Chevrolet Corvette.
These advances will be explained by examining specific bonding applications. High volume assembly will be described through the GM APV program. Rapid cure and simplified assembly will be covered with GM W-car spoilers and Corvette subassemblies, and new specialty niche vehicles through Chrysler's Viper program.
The recent market expansion of polyurethane structural adhesives has occurred, in part, because of their unique combination of bonding performance and manufacturing processability. The ability to custom design polyurethane adhesives to achieve specific physical and chemical performance will be reviewed. Waste minimization and environmental safety are key manufacturing concerns. These issues will also be addressed through material handling and dispensing techniques.