Inspec Foams, Inc., a part of Degussa’s Specialty Polymers division, offers a Solimide Polyimide foam that is said to be a safe and user-friendly alternative to the traditional fibrous insulations.
The polyimide foam was first created when Inspec was trying to develop a polyimide coating for solar turbine blades. In the process of curing, the polyimide coating created foam instead of a clear surface. This led to the idea of creating a non-burning, high-temperature insulation material for thermal and acoustic purposes.
Previously, the foam had a lot of cells, but they were all various sizes and the walls had various thicknesses, which is not efficient use of the material. The foam went from looking like “swiss cheese to looking more like cheddar cheese,” notes Dan Trahan, marketing director. “The cell sizes and cell walls are very uniform and consistent, and the foam just has a better appearance and a better acoustic and thermal quality.”
One feature of this foam is that it offers high-temperature insulation. Mr. Trahan says, “It continues to service temperatures up to 300°C on the high side and on the cold side, it gets down to cryogenic temperatures (-185°C).”
Typically, higher temperature products tend to require fibrous products or powdery materials, whereas the polyimide foam helps to avoid this dusty issue. According to Mr. Trahan, the polyimide foam is a solid material and does not have a chalk-like or dusty quality to it, allowing for ease of handling. Users get the exact amount of material they want by simply cutting to size. The foam does not flake or dust off.
The foam also features low off-gassing values. At regular and elevated temperatures, the foam does not release volatiles into the air, which typically create unwanted smells. “In devices that have partially or totally enclosed volumes, more of the released volatiles can collect on surfaces inside this volume,” explains Mr. Trahan. “As the volatiles accumulate on the surface of sensitive sensors, circuits, and other electronic components within the device, these sensors and circuits begin to not work properly.”
One application of this foam is in gas cooking appliances. “Inspec’s polyimide foam can be used as a higher temperature gasket to prevent air flow or air migration,” Mr. Trahan tells APPLIANCE. “Possible sealing applications are in oven doors, oven ‘ports’ or ‘wire pass-throughs,’ or in gas-fueled ovens and cooktops.”
Another application for the foam is in medical appliances such as hospital warming units. When one warming unit manufacturer switched from ceramic fibers to polyimide foam, it discovered that there were no health hazards when working with the foam. It was able to remove all of the gloves, masks, and respirators that employees had to wear every day. This reduction in health issues resulted in cost savings as well. Mr. Trahan explains, “Even though the solimide is a little more expensive, it was able to take away all [the cost] of the protective equipment that its workers had to wear when they handle the ceramic fibers.”