O-Ring Elastomers

Nitrile (Buna-N)
The most widely used O-Ring elastomer.  Excellent resistance to petroleum products.  Excellent compression, set, tear and abrasion resistance.  Does not have good resistance to ozone, sunlight, or weather (unless specifically compounded).  Should not be stored in direct sunlight or near motors or other electrical equipment which may generate ozone.  Temperature range:  - 40° to +250°F.

Fluoroelastomer [Viton® (E.I. duPont)]
Excellent mechanical and physical properties.  Good resistance to petroleum products, low compression set, and high temperature resistance.  Wide spectrum of chemical compatibility.  Good for vacuum service and low gas permeability.  APG stocks the Type "A" Grade Fluoroelastomer.  Other grades are available - please inquire.
Chloroprene (Neoprene)
Moderately resistant to petroleum products.  Good ozone and weather resistance.  Good compression set.  Excellent for sealing refrigeration fluids such as Freon®.  Temperature range:  -65° to +250°F.

Recommended for applications requiring a wide temperature range and good dry heat resistance.  Good weather and ozone resistance.  Limited oil resistance.  Not normally recommended for dynamic sealing applications due to relatively poor tensile and tear strength and relatively low abrasion resistance.  Temperature range:  -80° to +450°F.

Highly Saturated Nitrile (HSN, HNBR)
Better resistance to high temperatures, superior physical properties, and improved chemical resistance over traditional nitrile compounds.  It also has better resistance to ozone, sunlight, and other atmospheric conditions.  Excellent resistance to compression set.  Green HSN is used in refrigerant R134a applications.  Temperature range:  -40° to +325°F.

Ethylene Propylene (EPR, EPDM, EPM)
Excellent resistance to Skydrol® fluids used in commercial aircraft hydraulic systems.  Also recommended for hot water, steam, and phosphate ester type hydraulic fluids.  Resistant to some acids, alkalies, and ozone.  Not recommended for petroleum fluids or diester lubricants.  Temperature range:  -65° to +300°F.

PTFE [TFE, Teflon® (E.I. duPont)]
White thermoplastic fluoroethylene resin offers a combination of qualities not found in any other material - chemical inertness, heat resistance, low friction, dialectric strength, weatherability, zero water absorption, toughness, and flexibility.  Temperature range:  -65° to +500°F.

Aflas® (Asahi Glass Co., Ltd.)
Advantageous combination of high temperature, chemical, and electrical resistance properties.  Recommended for oils and lubricants, hydraulic and brake fluids, transmission and power steering fluids, sour oil and gas (H2S), amine corrosion inhibitors, ozone, steam, acids, bases, alcohols, and a variety of other chemicals.  Temperature range:  -25° to +450°F (+500°F short term).

Urethane (Polyurethane)
Resistant to petroleum oils, hydrocarbon fuels, oxygen, ozone, and weathering.  Particularly recommended for hydraulic systems where high pressures, shock loads, wide metal tolerances, or abrasive contamination is anticipated.  Not recommenced for acids, ketones, and chlorinatied hydrocarbons.  Some urethanes are also sensitive to water and humidity.  Temperature range:  -65° to +200°F.

Teflon® Encapsulated
Seamless and uniform Teflon® FEP encapsulation which completely encloses a core material of either silicone or Viton® elastomer.  Matches the chemical and temperature resistance of solid PTFE O-Rings and possesses the elasticity and recovery properties of the core elastomer which are crucial in many sealing applications.

Fluorosilicone (FVMQ)
Good low/high temperature resistance.  Excellent resistance to petroleum oils and fuels.  Used in aerospace applications for fuel systems and systems requiring resistance to diester base lubricants to +325°F.  Due to limited strength and abrasion resistance, this material is generally recommended for static applications only.  Temperature range:  -80° to +350°F (+400°F short term).


"APG Can Supply Virtually Any O-Ring Made - Standard or Non-Standard"