EN
DE
FKM
Material Type
Rubber
Material Full Name
Fluoroelastomer
Process Compatibility
Injection Molding, Compression Molding
Basic Properties
Property |
Parameter/Performance |
Remarks |
|---|---|---|
| Chemical Name | Fluorocarbon Rubber | C-C backbone with fluorine/fluoroalkyl groups (e.g., -CF₃) |
| Molecular Structure | Fully organic elastomer | Fluorine shielding effect enables extreme chemical resistance |
| Density | 1.78~1.90 g/cm³ | 60% heavier than silicone rubber (VMQ) |
| Color | Black/brown (limited color options) | Carbon black-filled; transparent grades require costly processing |
| Mechanical Properties | ||
| – Tensile Strength | 10-25 MPa (reinforced) | Superior to VMQ but brittle at low temps |
| – Elongation at Break | 100-300% | Lower elasticity than VMQ (rebound: 50-70%) |
| – Tear Strength | 20-50 kN/m | Requires carbon black/mineral fillers |
| Thermal Properties | ||
| – Service Temperature | -20℃~230℃ (short-term 260℃) | Poor low-temp performance (Tg≈0℃) but excels in steam resistance |
| – Flammability | LOI ≥95% (non-flammable) | Self-extinguishing; requires pure oxygen to burn |
| Chemical Resistance | ||
| – Oil/Solvent Resistance | Resists all mineral oils, fuels, acids (except fuming HNO₃) | <5% volume swell in jet fuel after 1000h |
| – Chemical Corrosion Resistance | Resists strong acids (HCl/H₂SO₄), weak alkalis | Vulnerable to amines (e.g., hydraulic oil additives) and ketones |
Processing Characteristics
Mooney Viscosity
- ML(1+4)121℃ 50-120 (poor flow, requires high-temp mixing)
Curing Systems:
- Bisphenol curing (170-180℃×10-30 mins)
- Peroxide curing (amine-resistant, needs post-cure)
Processing Challenges:
- Scorching risk (mixing temp must be <110℃)
- Mold corrosion (HF gas release; requires chrome plating)
Common Application Areas
-
Automotive: Crankshaft seals, turbocharger hoses (high-temperature fuel resistance)
-
Chemical: Reactor linings, acid pump diaphragms (HF resistance)
-
Energy: Oilfield blowout preventer seals (H₂S/CO₂ resistance)
FKM Modified Types
Type |
Fluorine Content |
Characteristics |
Typical Applications |
|---|---|---|---|
| Standard FKM | 66-69% | General purpose, cost-effective | Oil seals, fuel hoses |
| Low-Temp FKM | 62-65% | Tg down to -30℃ (reduced chemical resistance) | Arctic seals |
| Perfluoroelastomer (FFKM) | 72-75% | Resists strong acids/alkalis (10× standard FKM cost) | Semiconductor equipment seals |
| Peroxide-Cured FKM | – | Improved amine resistance | Automotive transmission O-rings |
Advantages & Disadvantages
Advantages |
Disadvantages |
|---|---|
| Best oil/solvent resistance | Extreme low-temperature brittleness |
| Chemical resistance (2nd only to PTFE) | Poor elasticity/abrasion resistance |
| 10+ years outdoor aging resistance | Difficult processing (special equipment needed) |
Other Elastomer & Rubber Material Selection
NR Rubber
PU Rubber
IIR Rubber
TPE Rubber
TPU Rubber
FAQ Of FKM Materials
Visit our FAQ center for more questions.
What are the core advantages of FKM rubber?
FKM (Fluorocarbon Rubber) offers the best balanced performance among fluorinated elastomers:
• Temperature resistance: -20℃~+230℃ (short-term 300℃)
• Chemical resistance: Withstands fuels, strong acids (except concentrated sulfuric acid), and organic solvents
• Low permeability: 10x lower gas/liquid penetration rate than NBR
Why must aircraft engines use FKM seals?
Complies with AMS7259/7260 aerospace standards:
- Resists JP-8 jet fuel (<10% volume swell)
- Immune to Skydrol® hydraulic fluid attack
- Maintains seal integrity at 180℃/15MPa
How to select FKM grades (Type A/B/F)?
Selection by media:
• Type A (VDF-HFP): General-purpose (most oils)
• Type B (Perfluoroether): Harsh chemicals (e.g., concentrated acids/electronic-grade chemicals)
• Type F (Low-T mod.): -40℃ dynamic seals (arctic equipment)