White Paper: Fast-Curing Structural Polyurethane Adhesive Increases Manufacturing Throughput
Manufacturers have benefited from replacing mechanical fasteners with structural adhesives when bonding composites, plastics and painted metal. Additional benefits—such as lower exotherm, lower odor and higher elongation-accrue when structural polyurethane adhesives replace acrylic and methyl methacrylate adhesives (MMA). A historic barrier to urethane adoption, however, has been its slower cure rate of cure.
Specifically, most urethanes have a linear relationship of open time to cure time, so adhesives that offer reduced handling time also present a very short open time, leaving inadequate time for product assembly. Conversely, adequate open times are associated with slow cure times for polyurethanes. In this way, polyurethanes have traditionally been at a disadvantage compared to the fast rate of cure which allows for quicker
production rates when using MMAs. Adding heat to cure urethanes has been a common solution, but this adds the cost of heated tooling to the manufacturing costs as well as creating potential quality issues with ‘cold spots’ in heated tooling. (Cold spots are complex shapes and thicknesses of the component that are sheltered from the heat applied for curing or in the tooling itself.) Polyurethanes requiring heat to fully cure can experience incomplete cure. Learn more.
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