Seals: Materials of Construction

Sun Hydraulics' cartridge valve seals (and manifold/body gaskets when present) are offered in the following customer-specified material choices:

Buna N o-rings

Buna N (Nitrile) O-rings (10-year shelf life)

  • 70-durometer, B46-70 (31.5% Nitrile) or N470 (30-31% Nitrile) or equivalent
  • 90-durometer, C-90-90 (39% Nitrile or equivalent)
  • Manufacturer's temperature range rating: -22° to 230° F (-30° to 110° C)
  • O-rings are black in color
  • Cartridges configured with Buna N seals will also contain one or more of the following seal materials:
    • Hytrel Polyester Elastomer back-up rings
    • PTFE back-up rings and/or Glyd® Ring.
    • Polyurethane 
Fluorocarbon rubber (Viton) o-rings

Fluorocarbon Rubber FKM (Viton®, product of E.I. DuPont) O-rings (20-year shelf life)

  • 75-durometer, V14-75 Fluorocarbon or equivalent
  • 90-durometer, V23-90 Fluorocarbon or equivalent
  • Manufacturer's temperature range rating: -10° to 250° F (-20° to 120° C)
  • O-rings are brown in color
  • Cartridges configured with Viton® seals will also contain one or more of the following internal seal materials:
    • Viton® back-up rings
    • PTFE back-up rings and/or Glyd® Ring.
EPDM o-rings

EPDM O-rings (No limited shelf life) Ethylene Propylene Diene Monomer*

  • 80-durometer EPDM rubber o-rings
  • Manufacturer's temperature range rating: -70 to 250° F (-60 to 120°C)
  • O-rings are purple in color
  • Cartridges configured with EPDM seals will also contain the following seal material:
    • PTFE back-up rings and/or Glyd® Ring.

See our EPDM seals page for more information.
image of polyurethane seal kit

Polyurethane O-rings (10-year shelf life)

  • Available for high cycle/higher pressure applications, providing more abrasion resistance for longer seal life.
  • 90-durometer hydrolytically stabilized for water compatibility 
  • Manufacturer's temperature range rating: -22 to 260° F (-30 to 125°C)
  • O-rings are teal in color
  • Hytrel Polyester Elastomer back-up rings off white in color (Ref: Simrit-Freudenberg-NOK)

Note: Seal kits include only the external seals of the cartridge.  To order seal kits, see our Cartridge Seal Kits listings page.

Specifying a Material at Time of Order

When a material choice is available for a given product, instructions for specifying the choice are shown in the "Configuration" section of the product details page.

For additional details on other Sun products' materials, see our "Cartridges: Materials of Construction" and "Manifolds: Materials of Construction."

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