Viscoelastic materials such as pressure sensitive adhesives are used as constrained damping layers in a variety of applications. Historically, materials such as foams and acrylic and rubber adhesives have been popular choices. However, in the aerospace and defense markets, innovation is occurring at a rapid pace. For example, rockets are being launched into orbit at record numbers and metal and carbon fiber parts are exposed to high temperatures. Aircraft and spacecraft, containing the same types of materials, are exposed to subzero temperatures. With new technological advances in aerospace and defense, there are new challenges. Is it time for a new noise and vibration solution as well?
Momentive's NVH PSA kit, is a brand-new & commercially available product that allows an end user to custom formulate in order to meet the damping requirements of a specific application. The NVH PSA kit is novel due to 4 specific reasons.
The first reason the NVH PSA kit is novel is because by mixing the components of the kit in different ratios, you can customize the peak composite loss factor in extreme low and high temperatures. Specifically, the NVH PSA kit will work in cold temperatures from -54°C (-65F) and also in high temperatures from 204°C (400° F). These extremes prevalent in the aerospace and defense markets.
Second, the NVH PSA kit has a composite loss factor that remains high over a wide temperature range as compared to common alternatives such as acrylic and rubber products. This could lead to an improved damping product or the reduction of damping layers or multiple part numbers.
Third, the NVH PSA kit has unique performance characteristics unrelated to damping. It can be used as a contact adhesive and applied in under 20 minutes or as a transfer film or tape and be used immediately. The NVH PSA kit, with its silicone backbone, also shows resistance to UV and moisture and has good insulation properties.
Fourth, the NVH PSA kit can be customized by the end user to meet a specific application. In aerospace and defense, a lot of applications are secretive. There can be a reluctance to share information. Also, noise and vibration requirements can change as a product is being developed and tested. Momentive understands these requirements, so the NVH Kit is completed with a mixing guide that allows the end user to formulate on their own.
In order to study these performance characteristics of the NVH PSA kit, the product was mixed at different component ratios and the modulus was recorded at a sweeping temperature range using DMA (dynamic mechanical analysis.) The resulting data validated the reasons to consider using the NVH PSA kit for constrained layer damping for the most demanding aerospace and defense applications.