EPDM O-rings, also known as ethylene propylene rings, are synthetic elastomers that are low-cost and exceptionally durable. They’re primarily used to seal mechanical parts in environments that have corrosive acids, solvents, and other chemicals, and are often internally lubricated to improve ease of installation or reduce friction for dynamic applications. You can find EPDM O-rings in a variety of applications, including automotive, water treatment, plumbing, pharmaceutical manufacturing, medical equipment, engineering, and more.
The following guide explains in greater detail what EPDM O-rings are and how they’re used.
EPDM O-Rings Material
EPDM-O Rings come in a variety of different formulas. The EPDM O-ring compound we supply at Allied Metric is ethylene-propylene rubber, which is a copolymer; however, we make our EPDM a terpolymer by adding a small amount of a third monomer, which allows the material to vulcanize with sulfur.
Many industries rely on EPDM O-rings for their inherent flexibility, durability, and resistance to potentially destructive environments. They are effective electrical insulators and have an extremely long shelf life. EPDMs can also be formulated with only “white list” ingredients as specified in 21.CFR 177.2600 for use in applications where the elastomer will be in contact with food or beverages.
Properties of EPDM O-Rings
EPDM O-rings are popular industrial sealants because of their resistance to water, heat, and steam. They also work well in oxygenated settings and when exposed to mild acid solvents, alkalis, ozone gases, and ultraviolet (UV) rays. They can withstand brake fluid, Skydrol™, and other hydraulic fluids. As a result, EPDM O-rings are essential in the automotive and aviation industries. However, EPDM compounds are not suitable for petroleum, gas, oil, grease, and hydrocarbon environments. The standard temperature range for EPDM O-rings is between -57°F and 257°F.
Specialty EPDM compounds offer different properties. These include:
- EPDM Sulfur-Cured: This material is inexpensive, readily available, more commercially attractive, and has a higher tensile and tear strength than standard EPDM compounds. It’s used in a wide range of filters and has a maximum operating temperature of 250°F.
- EPDM Peroxide-Cured: These O-rings are strong and will not stain PVC or metal. They can be used in systems that feature hot water, steam, ketones, alcohols, coolants, acids, and bases, whether they’re organic or inorganic. However, they’re not resistant to mineral oil, grease, or fuel, and have a maximum operating temperature of 300°F.
For use in drinking water applications, EPDMs can be submitted for approval by the National Sanitation Foundation (NSF). They are usually used in automotive air conditioning systems where R134a refrigerant gas and POE or PAG lubricant and new refrigerant for environment protection when R744 is used. In an R744 air conditioning system, it requires excellent resistance to explosive decompression in hydrogen dioxide at high pressure and high temperatures. EPDMs are also used in phosphate ester type hydraulic fluids.
Chemical Resistance of EPDM O-Rings
EPDM O-rings have additional features that make them useful, including their resistance to the following elements:
- Hot water and steam, up to 300°F (or 600°F with a specialty compound)
- Glycol-based brake fluid in an environment that’s up to 300°F
- Cleaning agents, potassium, and soda alkalis
- Organic and inorganic acids
- Phosphate-ester hydraulic fluid
- Many polar solvents
- Silicone, oil, and grease
- Exposure to weather and ozone gasses
EPDM O-Rings at Allied Metrics Seals and Fasteners
EPDM O-rings provide superior sealant capabilities and are highly resistant to a variety of conditions. At Allied Metrics, we’ve designed and manufactured high-quality oil seals, hydraulic seals, and pneumatic seals since 1989. We offer many different types of O-rings, and our team will work diligently to find the perfect material to fit your business’ needs.
Our core value at Allied Metrics is to provide inexpensive, high-quality seals and exceptional customer service. We are proud to say our seals and fasteners empower industries around the world. Visit our website to learn more about Allied Metrics and why our service is right for your business. To learn about pricing, request a quote today.