In industrial precision protection and sealing applications, a material's chemical inertness and thermal limit directly determine the lifespan of components. When common seal materials like nitrile rubber (NBR) or standard silicone fail due to swelling upon contact with strong solvents or fuels, specialty fluoroelastomers become the only viable solution. While both Fluorocarbon (Viton/FKM) and Fluorosilicone (FVMQ) contain fluorine atoms, their physical properties and application scenarios differ significantly due to different backbone structures. Below is an in-depth comparison of these two specialty materials:
1. Fluorocarbon Rubber (Viton / FKM): The Shielding Standard for High Temperatures and Strong Corrosives
Viton (FKM) is a saturated carbon-chain elastomer copolymerized from fluorinated monomers:
- Chemical & Oil Resistance: FKM exhibits exceptional chemical stability, withstanding most hydrocarbons, diester-based lubricants, strong acids, high-concentration fuels, and organic solvents. Its chemical resistance leads all common rubber materials.
- Temperature Limits: Continuous operating temperatures range from -15°C to 220°C (with short-term peaks up to 250°C). It retains high mechanical strength and low compression set at high temperatures.
- Limitations: FKM has poor low-temperature elasticity. Below -15°C, it gradually loses flexibility and hardens (brittleness point at -20°C to -30°C), making it unsuitable for extreme cold or high-altitude aerospace applications. Additionally, it has weak resistance to ketones (such as acetone) and low-molecular-weight esters.
2. Fluorosilicone Rubber (FVMQ): The All-Weather Performer Combining Wide Temperature Range and Fuel Resistance
Fluorosilicone (FVMQ) is a copolymer modified by introducing fluorinated alkyl groups into the polysiloxane backbone, combining the advantages of both silicone and FKM:
- Chemical & Oil Resistance: Thanks to the protection of the fluorinated side chains, FVMQ offers excellent resistance to non-polar solvents, aviation fuels, lubricants, methanol fuels, and hydraulic fluids, with very low swelling.
- Outstanding Temperature Range (-60°C to 200°C): This is the core advantage of FVMQ. It maintains excellent softness and sealing flexibility at extremely low temperatures down to -60°C, while retaining continuous heat resistance up to 200°C.
- Limitations: FVMQ has high raw material costs and lower mechanical strength (tensile, tear, and abrasion resistance) compared to Viton (FKM). Thus, it is primarily used in static seals or low-dynamic precision gaskets.
3. Property Comparison Table: EPDM Foam vs. Silicone Foam
| Physical Properties / Metrics | Fluorocarbon (Viton / FKM) | Fluorosilicone (FVMQ) |
|---|---|---|
| Long-term Operating Temp Range | -15°C ~ 220°C (Short-term 250°C) | -60°C ~ 200°C (Excellent low-temp) |
| Fuel / Jet Fuel Resistance | Excellent (Low swelling) | Excellent (Low swelling) |
| Acid / Alkali Resistance | Outstanding | Moderate to Good |
| Tensile / Tear Strength | High (Great for dynamic seals) | Moderate (Not recommended for high stretching) |
| Major Applications | Fuel hoses, chemical pumps/valves, semiconductor vacuum chambers | Aerospace seals, low-temp oil lines, outdoor sensors |
4. Jun-Hsiang Enterprise — Your Custom Special Rubber and Molding Partner
Specialty rubbers like Viton and FVMQ have narrow processing windows and are significantly harder to mold than standard rubbers. Jun-Hsiang Enterprise Co., Ltd. possesses over 30 years of mold engineering and custom formulation experience, providing highly cost-effective manufacturing:
- Custom Formulations & Hardness: We support Shore A 50° to 90° hardness adjustments and can customize compounds for specific anti-static or chemical-resistant specs.
- Rubber-to-Metal Bonding: Our dedicated metal surface treatment and adhesive application line allows us to bond Viton or FVMQ to metal substrates (stainless steel, brass, aluminum alloys) during molding. The bond strength exceeds the rubber's tensile limit, preventing delamination.
Whether you require prototyping, technical evaluation, or mass production, we provide complete B2B manufacturing services. Share your STEP/IGS files or physical samples with our engineering team for in-depth consultation.