Ethylene Propylene, frequently abbreviated as EPR/EPDM, is a copolymer or terpolymer rubber compound used in applications like cold and hot water, food and beverage, and medical devices. 

EPR O-rings, or EPDM O-rings, have good temperature performance, weather resistance, compression set, and electrical properties, making these O-rings an excellent choice for many applications.

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Benefits of Ethylene Propylene O-rings

Due to their mechanical properties, EPDM O-rings and EPR O-rings can be great sealing options for many applications. 

These mechanical properties include: 

  • Low compression set
  • Great temperature resistance
  • Excellent flexibility
  • Resistance to aging and sunlight
  • Good chemical resistance
  • Excellent tensile strength and tear resistance
  • Great resistance to water and steam
  • Good weather and ozone resistance

Ethylene Propylene O-rings are resistant to:

  • Acids
  • Grease
  • Sunlight 
  • Ketones 
  • Brake fluids 
  • Cleaning agents
  • Silicone oils 

This means EPDM O-rings can be used with several lubricants and in outdoor environments.


The standard durometer range is range from 40 Shore A to 90 Shore A. However, most Ethylene Propylene O-rings have a hardness of 70-80 Shore A. 

Temperature Range

EPDM O-ring temperature ranges are standard from - 70ºF to 250ºF. These temperatures are based on dry air; the actual temperature range depends on end-use application and will vary. Contact us for more details.

Dimensions & Sizes

Dimensions of EPR O-rings can vary significantly based on application. Whether metric or imperial sizes are required, many sizes can be produced. See our O-ring size chart for some of the most common sizes that we offer, or contact us to discuss a size not shown.

Common Uses and Applications

Ethylene Propylene O-rings are used in a variety of applications. Ethylene Propylene O-rings are a widely used seal, especially in the food and beverage industry and with water and steam applications. Some of the most common uses are:

Are EPDM O-rings right for your application? Spend less time searching for answers and contact Wyatt Seal; order confidently, knowing that you’re getting the right sealing solution that will arrive on time, perform well, and last.

EPDM O-ring Colors

For many applications, the standard black Ethylene Propylene O-ring will suffice. However, the O-rings can be made in different colors in other applications. These can include high-visibility colors. For more information on what colors are available, contact us.

Ethylene Propylene O-Ring Material Information

Ethylene Propylene (EPR) is a rubber copolymer made from ethylene and propylene. However, it could also be a terpolymer by adding a third monomer called diene, which could also be called Ethylene Propylene Diene Terpolymer. 

While all Ethylene Propylene O-rings have an extensive temperature range, the exact amount depends on the curing the O-ring will have. There are two types of curing the EPDM O-ring can have: Sulphur cured and Peroxide cured. 

The Sulphur cured EPDM will generally be more cost-effective, but the Peroxide cured will have a larger temperature range. Sulphur-cured O-rings are more apt to harden and have low compression set at high temperatures than their Peroxide cured counterparts which are harder to produce. 

There can be specially formulated Ethylene Propylene O-rings for special applications. For instance, the food and beverage industry will require an FDA-Approved food grade EPR O-ring or EPDM O-ring. This means the materials used must meet strict standards. Other specialty formulations could also be used for medical and pharmaceutical applications.

Ethylene Propylene O-rings can be produced by injection molding, compression molding, or extrusion. Although a round O-ring is standard, EPDM O-rings can be made into other cross-sections. These cross-sections are dependent on application. 

All EPDM O-rings must be lubricated to work correctly. The lubrication depends on the application, but it is generally a form of grease.

You tell us your specifications, and we’ll find you the perfect O-ring or seal for the job — guaranteed. Contact us to learn more.