FKM (Fluoroelastomer/Viton): Premium High-Performance Elastomer
Fluoroelastomer (FKM), commonly known by the trade name Viton®, is a premium synthetic rubber engineered for extreme chemical resistance, high-temperature performance, and long-term durability in the most demanding industrial environments. Specified across aerospace, automotive, chemical processing, and oil & gas applications, FKM delivers unmatched sealing reliability where standard elastomers cannot survive.
Key Properties of FKM Rubber
-
Exceptional Chemical Resistance: Superior resistance to acids, fuels, oils, solvents, and aggressive chemicals
-
High Temperature Performance: Continuous operation from -20°F to 400°F (-29°C to 204°C), with specialty grades to 500°F
-
Fuel & Oil Resistance: Outstanding resistance to petroleum fuels, synthetic oils, and aromatic hydrocarbons
-
Low Permeability: Minimal gas and fluid permeation—ideal for critical sealing applications
-
Oxidation & Aging Resistance: Excellent long-term stability in high-temperature oxidative environments
-
Compression Set Resistance: Superior resistance to permanent deformation at elevated temperatures
-
Flame Resistance: Self-extinguishing with excellent flame and smoke resistance
Common Applications & Uses
-
Aerospace: Fuel system seals, O-rings, gaskets for jet fuel and hydraulic systems
-
Automotive: Engine seals, fuel injector O-rings, transmission seals, turbocharger gaskets
-
Chemical Processing: Pump seals, valve seats, gaskets for aggressive chemical environments
-
Oil & Gas: Downhole seals, wellhead equipment, high-temperature/high-pressure applications
-
Semiconductor: Plasma-resistant seals, vacuum chamber gaskets, chemical delivery systems
-
Industrial: High-temperature hoses, expansion joints, chemical-resistant coatings
-
Pharmaceutical: Sterile seals, autoclave gaskets, chemical-resistant components
Advantages of FKM
- Industry-leading chemical resistance—compatible with acids, fuels, oils, and aggressive solvents
- Highest continuous temperature rating among common elastomers (up to 400°F standard, 500°F specialty)
- Exceptional resistance to aromatic and chlorinated hydrocarbons (benzene, toluene, TCE)
- Superior compression set resistance at elevated temperatures
- Extremely low permeability to gases and fluids for critical sealing
- Excellent oxidation and weathering resistance for long service life
- Flame-resistant and self-extinguishing properties
- Multiple grades available for specific chemical and temperature requirements
Limitations & Disadvantages
-
High Cost: Significantly more expensive than NBR, neoprene, EPDM, and other standard elastomers
-
Poor Low-Temperature Flexibility: Limited flexibility below -20°F; specialty low-temp grades required for cold environments
-
Steam & Hot Water Incompatibility: Not suitable for steam or hot water applications—EPDM is superior
-
Polar Solvent Sensitivity: Poor resistance to ketones, esters, and some amines
-
Processing Complexity: Requires specialized compounding and curing processes
-
Adhesion Challenges: Difficult to bond without specialized primers or surface treatments
FKM vs. Other Rubber Materials
FKM vs. NBR (Nitrile): FKM offers superior chemical resistance, higher temperature capability (400°F vs. 250°F), and better aromatic hydrocarbon resistance. NBR is more cost-effective with better low-temperature flexibility for standard petroleum applications. Use FKM for extreme conditions; NBR for cost-sensitive oil/fuel contact.
FKM vs. EPDM: FKM excels in fuel, oil, and chemical resistance with high-temperature performance, while EPDM is superior for weather, steam, and hot water applications. FKM is the choice for chemical/fuel systems; EPDM for outdoor sealing and water contact.
FKM vs. Silicone: Both offer high-temperature performance, but FKM provides superior fuel and oil resistance while silicone offers better low-temperature flexibility (-65°F) and broader temperature range. FKM is preferred for fuel/chemical contact; silicone for extreme temperature cycling without chemical exposure.
FKM vs. Neoprene: FKM significantly outperforms neoprene in chemical resistance, temperature capability, and compression set resistance. Neoprene is more economical for moderate-exposure applications. FKM is specified for severe chemical and high-temperature environments.
FKM vs. FFKM (Perfluoroelastomer): FFKM offers even broader chemical resistance and higher temperature capability (up to 600°F), but at significantly higher cost. FKM is the cost-effective choice for most demanding applications; FFKM for the most extreme chemical and thermal conditions.
FKM Grades & Types
-
Type A (Dipolymer): Standard grade with excellent fuel and oil resistance—most common general-purpose FKM
-
Type B (Terpolymer): Enhanced chemical resistance, particularly to acids and steam—broader compatibility
-
Type F (Tetrapolymer): Superior low-temperature flexibility with maintained chemical resistance
-
GLT/GFLT: Specialty low-temperature grades for cold-environment applications
-
Extreme grades: High-temperature formulations for continuous service to 500°F
Technical Specifications
-
Hardness Range: 55–90 Shore A (customizable by formulation)
-
Specific Gravity: 1.80–1.95
-
Tensile Strength: 1,000–2,500 psi (varies by grade)
-
Elongation at Break: 150–300% (varies by formulation)
-
Compression Set: Excellent at elevated temperatures (typically <25% at 200°C/392°F for 70 hours)
-
Temperature Range: -20°F to 400°F continuous (-29°C to 204°C), specialty grades to 500°F
Why Choose FKM from Rubber Mexico?
Our FKM compounds are formulated for maximum chemical resistance, thermal stability, and sealing performance across aerospace, automotive, chemical processing, and oil & gas applications. With in-house molding, precision machining, and custom compounding capabilities, we deliver mission-critical FKM components engineered to your exact specifications and operating conditions.
Need a custom FKM solution? Contact us for material selection guidance, grade optimization, compound development, prototyping, and production support for your most demanding sealing challenges.
