06 July 2021
Sign up to our newsletterWant more news like this? Sign up to our newsletter.

New EDPM material developed for aerospace seals

Jacqueline Schwark, Chemist (left) and Dr. Paul Hochgesang, Material Research Fellow, study images of seals made from the new material for surface mould issues

Freudenberg Sealing Technologies has begun manufacturing seals made from a new ethylene propylene diene monomer material that successfully addresses a significant challenge in the aerospace industry – hydraulic seal leakage at high altitudes and low temperatures.

The new material, 80 EPDM 426288, successfully seal hydraulic systems operating at temperatures as low as -65°C, which is said to a breakthrough in EPDM formulations. Scientists at Freudenberg Sealing Technologies have used a unique polymer, rather than adding large amounts of plasticisers, to produce 80 EPDM 426288.

The material meets the rigorous requirements of the new AMS7361 specification for improved low-temperature behaviour in commercial aircraft hydraulic systems. EPDM can be crafted to resistant sunlight, ozone and chemical degradation, effectively seal phosphate-ester hydraulic fluids and other fluids and performs well at temperatures of up to 150°C.

Commercial airliners rely on standard EPDM to seal critical hydraulic systems like those found in landing gear. At such altitudes and speeds, frictional heat – generated as the plane moves through the air – maintains hydraulic system temperatures within a range that preserves the performance integrity of traditional EPDM components.

But commercial airliners are not the only aircraft plying today’s sky. Turboprop transport carriers and unmanned aerial vehicles, or drones, also fly high above the Earth. Drones, for example, have become invaluable in generating data and delivering cargo for sectors as varied as medical, environmental conservation, surveying, film and photography, law enforcement and disaster relief.

Despite their capabilities, however, drones present challenges to aerospace engineers: The speeds at which they fly – typically 100 mph (160 kph) or less – combined with flying at the same or even higher altitudes as those at which commercial airliners fly, reduce air friction and heat on aircraft’s exterior. As a result, these aircraft must endure extended periods of very cold temperatures, followed by an abrupt change in temperature when they land. The same is also true of cargo carriers and other slow traveling aircraft.

Standard EPDMs cannot tolerate prolonged exposure to very low temperatures without becoming brittle and cracking. The cracks can lead to fluid leaks in essential systems like hydraulic brake lines. Aerospace engineers were looking for a solution to such leakage issues. At the same time, ongoing development of new hydraulic fluids prompted their interest in evaluating new material formulations.

When Freudenberg Sealing Technologies learned of its aerospace customers’ needs, it launched development project to formulate a new EPDM. The project, led by Paul Hochgesang, a materials research fellow based in the company’s Plymouth, Michigan, Central Laboratories, resulted in the development of several new EPDM formulas. These formulas used more advanced monomer and polymer technology for a better balance of high- and low-temperature behaviours. While these formulas showed excellent results in meeting the material standards required in the aerospace industry, they still could not pass prolonged cold testing without losing strength and becoming brittle.

“We blended a variety of ingredients, including plasticizers, fillers and heat stabilizers, and still could not achieve the temperature gradient our customers needed. That’s when the company’s material and sourcing experts in Germany and Japan stepped in to help.” Hochgesang was introduced to a new, largely unknown industrial polymer. When added to a new EPDM formulation, the resulting material not only met, but exceeded, the cold temperature requirements needed by aerospace customers. The final development of 80 EPDM 426288 took less than six months to complete.

“This is a clear example of international collaboration among Freudenberg’s scientific community that has achieved results by pooling the knowledge and capabilities of global colleagues,” Hochgesang said. “This kind of cooperation is essential when we are working through tough customer challenges.”

Seals and components made from 80 EPDM 426288 have already been manufactured and tested in North America and Europe by several major aerospace manufacturers and system suppliers. Based on extremely positive customer feedback and reports, production of aerospace O-rings made from this new EPDM has been launched.

Author
Operations Engineer

Related Companies

Freudenberg Sealing Technologies Ltd

Similar Articles

Potting compound, packaged

From July 2021, the new IRS 3078 Polyurethane Potting Compound is available from Intertronics. The material is packaged in side-by-side cartridges, making it suitable for ...

Cable entries for enclosures

CONTA-CLIP has expanded its KES-E cable entry program for screwless mounting, adding 50 mm variants. The new KES-E-R cable entries allow for quick and secure feeding of cables ...

Preventing encapsulation voids

To help electronics manufacturers prevent voids when potting and encapsulating, adhesives specialist Intertronics has produced a white paper.

Guide to encapsulation

In readiness for the EU’s likely ban of chip encapsulation adhesives containing substances of very high concern, Delo’s chemists have produced alternatives that are not only ...

New butterfly valve seals

To ensure that process plants meet hygiene requirements, industry-specific approvals and resistance to CIP/SIP media, Freudenberg Sealing Technologies has developed a new series ...

Loctite for gasketing

For a gasket to do its job effectively, it is essential that the seal it creates remains intact over a long period of time. The gasket must also be resistant to fluids and/or ...

New Electronics Adhesives

Techsil has launched a range of new adhesives with low ion content which cure with UV, visible light or moisture. These products were specially formulated for electronics potting ...

3 LED Assembly Case Studies

Techsil’s materials provide environmental protection, extend service life and improve light performance of LED applications. The range includes LED chip packaging potting ...

Design & Automation

At the recent FAST exhibition, Design & Automation Solutions launched a range of automated application & assembly equipment for adhesives, gaskets, sealants & tapes such as this ...