Many applications rely on EPDM rubber O-rings for the benefits they offer over other types of rubber. EPDM products offer superior resistance to elements like weather, sunlight, ozone, and chemicals while also retaining their flexibility in cold temperatures.
Learn more about the composition of EPDM O-rings, their benefits, and potential applications.
What Are EPDM O-Rings and What Are Their Benefits?
Ethylene-propylene diene monomer (M-class) rubber, or EPDM, is a type of synthetic rubber that offers certain advantages over other materials, especially for use in specialized valve components such as O-rings and gaskets. It has gained wide acceptance in the seal industry.
What makes EPDM particularly appealing for use as an O-ring is its excellent resistance to weather, heat, and ozone, as well as its tensile strength. It has a hardness (Shore A) of 40-95, and withstands cold temperature environments as low as -40 °F (-40 °C) and high-temperatures up to 300 °F (150 °C). It can also act as electrical insulation in certain applications.
In addition, EPDM can withstand:
- Hot water
- Dilute acids
- Alkalis
- Ketones
- Silicone greases and oils
- Automotive brake fluids
- Automobile cooling systems
- Ultraviolet (UV) light
- Abrasion and tearing
EPDM cannot be used in association with flames or hydrocarbon fluids such as petroleum.
The Curing Process
To produce EPDM, it goes through a curing process following steps:
- Mix the base rubber materials.
- Form the materials into an O-ring shape and cure in an industrial oven using either a sulfur- or peroxide-based curing process.
- Once hardened, the material retains the desired shape and maintains consistent performance.
Sulfur Curing Produces High Resistances
The sulfur curing process is ideal for producing EPDM materials with high resistance to weather, aging, heat, oils, and chemicals. Sulfur-cured EPDM has a lower compression set and does not stain any metals or polyvinyl chloride (PVC) materials.
Peroxide Curing Produces High Tensile Strength
Meanwhile, the peroxide curing process is ideal for aerospace applications, since the EPDM produced has higher tensile strength. When machine-tested to assess how well the material bounces back when pushed or prodded, peroxide-cured EPDM O-rings easily revert to their original shape. When stretch-tested, they also exhibit high resistance to tearing.
Additionally, the peroxide curing process allows EPDM o-rings to have a higher service temperature, which can reach upwards of +350°F.
Applications of EPDM O-Rings
EPDM rubber O-rings have many valve applications across a range of industries, including automotive, aerospace, and outdoor applications.
Some specific applications for EPDM O-rings include environments exposed to:
- DOT 3, DOT 4, and DOT 5.1 glycol-based brake fluids
- Phosphate ester-based hydraulic liquids
- Alkalis and dilute acids
- Ketones
- Alcohol
- Acids and solvents (Acetone, MEK)
- Water
- Harsh outdoor weather
- Ozone exposure
- Silicone oils and greases
EPDM O-Rings from Arizona Sealing Devices, Inc.
The properties of EPDM O-rings make them popular for many potential applications. If you’re looking for reliable O-rings made from this material, turn to Arizona Sealing Devices, Inc. Founded in 1989, we have become a leading provider of EPDM O-rings and a range of other high-quality sealing products. As an ISO 9001:2015 and AS9120B certified distributor, we are committed to delivering timely, quality solutions for our customers across diverse industries.
Contact us today for more information about our products and services, or request a quote to find a solution for your application.