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-021 U90 EU Polyether Urethane 90 Duro O-Ring


Quantity Discount Prices
Min:  2
  • Model: U90021
  • 3801 in Stock
  • 15/16"ID X 1-1/16"OD X 1/16"CS
  • Actual: 0.926"ID X 0.070"CS
  • Metric: 23.52mm ID X 1.78mm CS
  • PDF Data Sheets

O-ring Size: 15/16"ID X 1 1/16"OD X 1/16"CS


Description: Polyurethane

Polyurethane rubber is notable for its combination of hardness with elasticity, outstanding abrasion resistance and tear strength. Elastomeric urethane rubber, not to be confused with thermoplastic polyurethane, may be either ether (EU) or ester (AU) base, with the latter being the far more common of the two. It is often referred to as the "millable gum" urethane. The ester based polymer is superior in resistance to abrasion and heat, while the ether based polymer has better flexibility at low temperatures. Polyurethane is a moderately expensive material whose use is usually limited to applications that require its outstanding physical properties. Common end use applications are industrial seals, industrial rolls, O-Rings, caster wheels, gaskets, shoe soles and conveyor belts. Peroxide is the most commonly employed cure system, but sulfur curing is also possible in the extremely complex vulcanization chemistry involved in polyurethanes.



Physical Properties*

Abrasion resistance
Compression Set
Flame resistance
Gas permeability
Low temperature flexibility
Tear resistance
Tensile strength

Chemical Resistance*

Concentrated acids
Concentrated Bases
LP Gas
Mineral oil
Silicone Fluids

Operating Temperature

-40 to 180 °F
*Excellent, good, fair and poor are intended to serve as general guidelines only. Actual testing in the application environment is always recommended.

The O-ring Store is a distributor of O-rings, Seals, Seal Kits, Hydraulic Seals, and Pneumatic seals for many applications. We provide seal products to a variety of industries and customers such as: Automotive, Pool, Spa, Pump, Restaurant, Washer, Hydraulic, Coatings, construction equipment, material handling, industrial plant applications, farming, and logging equipment. We do not imply that these kits are original replacement parts.

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Stock O-Rings in over 20 different compounds and durometers the following six are the standard rubber materials in a range of durometers (Shore A) hardness to satisfy practically any service condition:

Viton® O-Rings / FKM: Fluorocarbon (Viton®) exhibits exceptional resistance to chemicals, oils, temperature extremes (-13°F to +446°F), low compression set, low gas permeability and excellent aging characteristics. Applications include: aircraft engines, automotive fuel handling systems, and chemical processing industries. FKM is also suitable for high vacuum applications. It is not recommended for exposure to ketones, alkalis, and Skydrol® fluids. Custom compounds are available with improved chemical and low temperature resistance.
AS-568 Viton® O-Rings | Metric Viton® O-Rings

Buna-N O-Rings / Nitrile O-Rings / NBR: Nitrile (Buna-N) is the most widely used elastomer due to its excellent resistance to petroleum products, operating temperature range (-40°F to +257°F) and one of the best performance-to-cost values. It's an ideal material for aerospace, automotive, propane and natural gas applications. Special Hydrogenated Nitrile (HNBR) compounds can improve resistance to direct ozone, sunlight, and weather exposure while increasing temperature range to +300°F.
AS-568 Buna-N O-Rings | Metric Buna-N O-Rings

Ethylene-Propylene / EPDM O-Rings: EPDM has outstanding resistance to heat, water and steam, alkali, mild acidic and oxygenated solvents, ozone, and sunlight (-40ºF to +275ºF); but it is not recommended for gasoline, petroleum oil and grease, and hydrocarbon environments. This popular rubber compound is usually the first choice for low torque drive belt applications.
AS-568 EPDM O-Rings | Metric EPDM O-Rings

Fluorosilicone O-Rings / FVMQ: Fluorosilicone (-75º to +400ºF) combines the good high and low temperature stability of silicones with the fuel, oil, and solvent resistance of fluorocarbons. FVMQ is unparalleled for aerospace fuel systems, auto fuel emission control systems and to meet or exceed government, military, aerospace, automotive, industrial and commercial specifications. However, due to relatively low tear strength, high friction and limited abrasion resistance of these materials, they are generally not used in dynamic applications. They are also not recommended for exposure to brake fluids, hydrazine, or ketones.
AS-568 Fluorosilicone O-Rings | Metric Fluorosilicone O-Rings

Silicone O-Rings / VMQ: In the Silicone family, you will find compounds which are superior as static seals in extreme temperature conditions. Standard compounds handle operating temperatures -85º to +400ºF. Silicone compounds are popular in food and medical applications because they are very clean and do not impart odor or taste. Special Phenyl silicones can be used down to -148°F.
AS-568 Silicone O-Rings | Metric Silicone O-Rings

Neoprene® O-Rings / CR: Neoprene (-40º to +250ºF) is reasonably priced and features good resistance to petroleum oils, ozone, sunlight and oxygen aging, relatively low compression set, good resilience and outstanding physical toughness. It is the preferred sealing material for the refrigeration industry because of its resistance to ammonia and Freon®.
AS-568 Neoprene® O-Rings