FEP
A melt-processable fluoropolymer, up to 200 °C
Typical values for the temper in the title
FEP is a melt-processable perfluoropolymer (about 260 °C), with chemical resistance almost like PTFE, but a lower service temperature: up to 200 °C. It is more transparent and cheaper than PFA.
It is used for cable insulation (especially in buildings, thanks to flame retardance), clear chemical tubing, encapsulation of O-rings with a silicone or FKM core ("encapsulated" seals), and films.
Mechanical and physical properties
| Property | Value | Note |
|---|---|---|
| Tensile strength Rm | 20–30 MPa | |
| Density ρ | 2.15 g/cm³ | |
| Max continuous service temperature | 200°C | |
| Machinability | 60% | relative rating in the site database |
Structure and family
| Feature | Value | Meaning |
|---|---|---|
| Family | perfluoropolymer | |
| Tm | about 260 °C | melt-processable |
| Service | up to 200 °C |
Typical values per producer data sheets.
Grades and versions
In fluoropolymers the choice is by service temperature, processing route (melt or sinter) and strength. All are highly chemically resistant.
| Version | Properties | When to choose it |
|---|---|---|
| Tubing and film | transparent | chemicals, lab |
| Seal encapsulation | jacket over a flexible core | encapsulated seals |
Applications
- Cable insulation
- Clear chemical tubing
- Encapsulated O-rings
- Films
- Linings
Fabrication
Machining
Use very sharp tools, a feed that does not overheat the material, and good support (the material is flexible and deforms under clamping). For precision parts, stress-relief annealing before final machining is sometimes performed.
Thermal expansion
The expansion coefficient of an unfilled polymer is several times that of a metal. In a precision part or an assembly with metal, design clearances accordingly.
Melt processing
Can be molded and extruded, and is easier than PFA.
Compared with similar materials
| Material | Rm / Rp0.2 | Welding | When it is the better choice |
|---|---|---|---|
| PFA | 25–35 MPa | Hot welding | PFA: up to 260 °C, expensive · material page |
| PTFE | 25 MPa | Sintering only | PTFE: up to 260 °C, not melt-processable · material page |
| ETFE | 38–48 MPa | Hot welding | ETFE: stronger, up to 150 °C · material page |
Common mistakes
Using it above 200 °C
For higher heat PFA or PTFE.
Applying a constant load
It creeps.
Expecting mechanical strength
It is relatively soft.
Equivalents, standards and supply
| ASTM | D2116 |
|---|---|
| Standards | ASTM D2116 |
| Forms | sheet · rod · pellets |
| Producers | Chemours (Teflon FEP) · Daikin |
Learn more
Values are typical for an unfilled grade (unless stated otherwise) and for comparison only. In polymers, properties depend on grade, filler, temperature, moisture and load duration. For design, rely on the producer data sheet for the specific grade. Sources: ASTM classification standards (D8033, D5205, D5204, D6394, D4067 and others), producer data sheets, and the METAL HUB materials database.
Updated: October 31, 2026