Sealing Materials for O-Rings ,Oil Seals, Hydraulic Seals

Common materials include Nitrile (NBR) (for petroleum-based oils), Viton (FKM) (high heat/chemical resistance), EPDM (water-based fluids/ozone resistance), and Silicone (food/medical use). Selection depends on temperature range, chemical compatibility, and mechanical demands in applications like hydraulics, pneumatics, or harsh environments.

1. Polyurethane (P.U)

Standard Colors: Customizable (black, white, yellow, etc.) with UV-resistant pigments.

Temperature Range: -40°C to +85°C (short-term up to 120°C).

Properties:

  • Mechanical: High abrasion resistance (superior to most rubbers), tensile strength up to 3,500 PSI, and excellent load-bearing capacity.
  • Chemical: Resistant to oils, greases, and ozone but degraded by strong acids/bases.
  • Flexibility: Can be formulated as rigid foams (for insulation) or elastomers (for wheels/seals) .

Applications:

  • Automotive: Bushings, suspension components, and flexible foams for seating.
  • Industrial: Conveyor belts, rollers, and hydraulic seals due to wear resistance .
Polyurethane seals

2. Nitrile Rubber (NBR)

Standard Colors: Typically black; medical grades may be blue or white.

Temperature Range: -40°C to +120°C (short-term up to 150°C) .

Properties:

  • Oil/Fuel Resistance: Excellent resistance to petroleum-based fluids (mineral oils, fuels) but poor against ketones/esters.
  • Mechanical: Tensile strength 500–2,500 PSI, elongation up to 650%, and good compression set resistance .

Applications:

  • Automotive: Fuel hoses, O-rings, and gaskets.
  • Medical: Disposable gloves (latex-free alternative) .
Nitrile Rubber Seals

3. Hydrogenated Nitrile Rubber (HNBR)

Standard Colors: Usually black.

Temperature Range: -40°C to +150°C (short-term up to 175°C) 313.

Properties:

  • Enhanced Stability: Hydrogenation improves ozone/heat resistance and tensile strength (1,500–3,500 PSI) .
  • Chemical: Superior to NBR in resisting H₂S and amines in oil/gas applications.

Applications:

  • High-performance seals in automotive (timing belts) and aerospace (O-rings).
Hydrogenated Nitrile Rubber Seals

4. EPDM Rubber

Standard Colors: Black, white, or custom.

Temperature Range: -50°C to +150°C.

Properties:

  • Weather Resistance: Excellent UV/ozone resistance, ideal for outdoor use.
  • Chemical: Resistant to water/steam but poor against oils/fuels.

Applications:

  • Construction: Roofing membranes, window seals.
  • Automotive: Cooling system hoses.
EPDM Rubber Seals

5. Silicone Rubber

Standard Colors: Clear, white, or vibrant colors (FDA-approved for medical use).

Temperature Range: -60°C to +230°C (special grades up to 300°C).

Properties:

  • Thermal Stability: Retains flexibility at extreme temperatures.
  • Biocompatibility: Non-toxic, used in medical implants.

Applications:

  • Medical: Catheters, prosthetics.
  • Aerospace: Gaskets and insulation.
Silicone Rubber Seals

6. Polychloroprene Rubber (CR/Neoprene)

Standard Colors: Black or gray.

Temperature Range: -50°C to +120°C.

Properties:

  • Flame Resistance: Self-extinguishing; good for fire-rated applications.
  • Chemical: Moderate oil resistance, excellent weather/ozone resistance.

Applications:

  • Marine: Wetsuits, diving gear.
  • Industrial: Vibration dampers .
Polychloroprene Rubber Seals

7. Fluorinated Rubber (FKM/Viton)

Standard Colors: Black, brown, or green.

Temperature Range: -20°C to +200°C (short-term up to 260°C) .

Properties:

  • Chemical Inertness: Resists fuels, acids, and halogenated solvents.
  • Thermal: High continuous use temperature (up to 250°C).

Applications:

  • Oil/Gas: Downhole seals, valve linings.
  • Chemical Processing: Pump diaphragms .
Fluorinated Rubber Seals

8. Polyacrylic Rubber (ACM)

Standard Colors: Black.

Temperature Range: -10°C to +150°C (short-term 175°C).

Properties:

  • Heat/Oil Balance: Good resistance to hot oils but poor water resistance.
  • Mechanical: Tensile strength up to 20 MPa, elongation 450%.

Applications:

  • Automotive: Transmission seals, hoses.
  • Industrial: Textile coatings.
Polyacrylic Rubber Seals

9. PTFE (Virgin)

Standard Colors: White or translucent.

Temperature Range: -200°C to +260°C.

Properties:

  • Chemical Inertness: Resists almost all chemicals except molten alkali metals.
  • Electrical: Excellent insulator (dielectric constant: 2.1) .

Applications:

  • Electrical: High-voltage insulators.
  • Medical: Non-stick surgical tools .
PTFE Virgin Seals

10. Glass-Filled PTFE

Standard Colors: Off-white.

Temperature Range: -200°C to +260°C.

Properties:

  • Enhanced Wear: 500x better abrasion resistance than virgin PTFE.
  • Dimensional Stability: Reduced creep and thermal expansion.

Applications:

  • Valves: Seats and bushings.
  • Bearings: Self-lubricating slides .
Glass Filled PTFE Seals

11. Bronze-Filled PTFE

Standard Colors: Metallic brown.

Temperature Range: -200°C to +260°C.

Properties:

  • Thermal Conductivity: Improved heat dissipation.
  • Mechanical: Higher load-bearing capacity.

Applications:

  • Heavy Machinery: Bushings, thrust washers.
Bronze Filled PTFE Seals

12. Graphite-Filled PTFE

Standard Colors: Black.

Temperature Range: -200°C to +260°C.

Properties:

  • Self-Lubricating: Low friction without external lubricants.
  • Chemical: Retains PTFE’s inertness.

Applications:

  • Piston Rings: Chemical processing equipment.
Graphite Filled PTFE Seals