3 Cutting-Edge Sealing Technology Innovations
This year’s Paris Air Show showcased two of today’s most innovative sealing technologies, Kalrez and Vespel, as part of an exhibition themed on “Flying High With Innovation.” The exhibit used Kalrez and Vespel to demonstrate how advanced technologies can create parts and shapes that solve the toughest problems involving sealing, friction and wear in aerospace applications. The demonstration focused on how innovative materials such as Kalrez, a synthetic rubber, and Vespel, an advanced plastic, can improve the performance of jet engines and wind turbine covers by extending life, reducing weight and supporting operations under extreme temperatures.
Kalrez and Vespel illustrate how sealing technology innovations underlie improvements in other technological fields. Here’s a look at three of today’s cutting-edge materials that are helping industries such as aerospace, automobile manufacturing and healthcare make important strides forward.
Kalrez, the latest in a long line of synthetic rubbers developed by DuPont over the last century, is the brand name for FFKM, a type of perfluoroelastomeric compound similar to Teflon. With a composition built on a fully fluorinated backbone with multiple carbon-fluorine bonds, FFKM combines elasticity with superior chemical tolerance and excellent temperature resistance, as well as low gas permeability and resistance to steam, weathering, and ozone. Standard Kalrez sealing compounds resist degradation by nearly all chemicals and can handle a temperature range from 13 degrees below 0 to over 600 degrees Fahrenheit.
These properties make Kalrez a popular solution for o-rings and gaskets intended for use in applications with harsh chemical environments or high temperatures. Kalrez is widely used in the chemical and petroleum industries, for chemical analysis and process instruments, for semiconductors, and for paints and coatings that need to withstand high temperatures. Significantly more expensive than other solutions, FFKM is typically reserved for applications that other materials cannot handle.
Another critical rubber sealing material that is the subject of constant innovation is silicone. Silicone rubber o-rings join flexibility with the ability to resume their original shape even after being subjected to pressure. Standard silicone can withstand a wide temperature range between 80 degrees below 0 and 400 degrees Fahrenheit and can handle stress during temperature changes. Silicone resists damage by ultraviolet light, and it keeps its insulating properties after exposure to electricity. Silicone is also biocompatible thanks to properties such as chemical inertness and non-toxicity.
These properties make silicone ideal for many applications. For instance, in aerospace applications, silicone is used to join parts that would come apart under temperature changes if not held together. Current innovation aims to develop silicone elastomers with enhanced resistance to fuel and solvents. Silicone is also ideal for medical applications such as sealing medical devices.
An important non-rubber sealing innovation is polyimide-based plastics, with Vespel being a popular example in this category. Polyimides have high heat resistance with a low coefficient of thermal expansion, allowing superior performance under high temperatures. They also exhibit high mechanical toughness, low deformation under stress, chemical resistance to solvents and oils, and low electrical conductivity.
These properties make Vespel popular for sealing applications such as piston rings, valve discs, seal rings, and washers. It is particularly useful for maintaining seals at high temperatures and pressures or where low friction is required, handling heat changes better than other plastics, and handling wear and tear better than metal-to-metal seals. Vespel is widely used in manufacturing and electronics, in everything from jet engines to tractors.
More Advances in Sealing Technology to Come
Advances in sealing technology help other industries where seals are needed in applications involving high temperatures, high pressure, harsh chemical conditions, or other tough environments. Kalrez with its high chemical resistance, silicone with its wide temperature range, and Vespel with its thermal durability illustrate the specialized materials that have been developed to support diverse sealing applications. These are just a few of the many innovative substances that manufacturers have developed to meet the huge demand for sealing, and new materials will continue to emerge as technology continues to advance.