Polyurethane O-Rings & Gaskets | Seal & Design Inc.

Polyurethane (AU/EU)

Polyurethane MaterialOne must differentiate between polyester urethane (AU) and polyether urethane (EU). AU type urethanes exhibit better resistance to hydraulic fluids. Polyurethane elastomers, as a class, have excellent wear resistance, high tensile strength and high elasticity in comparison with any other elastomers. Permeability is good and comparable with butyl rubber.

Both o-rings and gaskets can be made from EPDM materials.

Names: Polyurethane, Millable Polyurethane, AU, EU

Compound Info
ASTM D1418 Designation AU, EU
ASTM D2000/SAE J200 Type, Class BG
Hardness (Shore A) 40-90
Color black
Thermal Properties
Standard Min Temp. -30°F (-34°C)
Max Temp. 175°F (79°C)


Chemical Resistance
Chemical Resistance
  • Pure aliphatic hydrocarbons (propane, butane, fuel)
  • Mineral oil and grease
  • Silicone oil and grease
  • Water up to 125°F(50°C) (EU type)
  • Ozone and aging resistance
Not compatible
NOT compatible
  • Ketones, esters, ethers, alcohols, glycols
  • Hot water, steam, alkalis, amines, acids

Disclaimer: These are general guidelines only. All materials should be tested in your application.