PET-C (Ertalyte®) – semi-crystalline polyester, natural and PTFE-filled
The engineering plastic with the highest dimensional stability and low wear in humid environments
Semi-crystalline PET is the most dimensionally stable engineering plastic: it absorbs very little water, has low thermal expansion and excellent wear resistance. It outperforms POM and nylon in precision parts that run wet. The PTFE-filled grade (Ertalyte TX, TECAPET TF) lowers friction for bushings and guides without lubrication.
Designations and equivalents
| System | Designation |
|---|---|
| Abbreviation (ISO 1043) | PET-C / PET + PTFE |
| Trade names | Ertalyte (MCAM); TECAPET (Ensinger); Ertalyte TX (MCAM); TECAPET TF grey (Ensinger) |
Standards by product form
| Form | Standard |
|---|---|
| Rod, sheet and tube | Manufacturer's specification (MCAM Ertalyte, Ensinger TECAPET) |
| Food contact | FDA 21 CFR 177.1630; EU 10/2011 |
| Machined part to drawing | ISO 2768 tolerance or as per drawing |
Composition and filler
Nominal composition
| Component | Content |
|---|---|
| Semi-crystalline PET | 100% (natural) or with PTFE |
| PTFE-filled grade | PTFE incorporated as a solid lubricant |
Mechanical properties
Typical values from the stock-shape manufacturer's catalog, 23 °C (PET-C, PET + PTFE); ISO/ASTM methods as per the source
| Property | Value |
|---|---|
| Tensile strength | PET-C: 90 MPa · PET + PTFE: 76 MPa |
| Modulus of elasticity (tensile) | PET-C: 3,500 MPa · PET + PTFE: 3,300 MPa |
| Elongation at break | PET-C: 15% · PET + PTFE: 5% |
| Compressive strength | PET-C: 103 MPa · PET + PTFE: 102 MPa |
| Hardness | PET-C: Rockwell M 96 · PET + PTFE: Rockwell M 94 |
| Notched impact | PET-C: 2 kJ/m² · PET + PTFE: 2.5 kJ/m² |
Typical physical and thermal properties
| Property | Value |
|---|---|
| Density | PET-C: 1.39 g/cm³ · PET + PTFE: 1.44 g/cm³ |
| Maximum continuous service temperature | 115 / 100 °C |
| Maximum short-term temperature | 160 °C |
| Minimum service temperature | -20 °C |
| HDT (1.8 MPa) | PET-C: 80 °C · PET + PTFE: 75 °C |
| Melting point or glass transition | 245 °C |
| Linear thermal expansion | PET-C: 80 µm/m·K · PET + PTFE: 85 µm/m·K |
| Thermal conductivity | 0.29 W/m·K |
| Water absorption (24 h) | PET-C: 0.07 / 0.16% · PET + PTFE: 0.06 / 0.13% |
| Water absorption (saturation) | PET-C: 0.5% · PET + PTFE: 0.47% |
| Dielectric strength | PET-C: 22 kV/mm · PET + PTFE: 21 kV/mm |
| Flammability (UL 94) | HB |
Friction, wear and PV limit
| Property | Value |
|---|---|
| Dynamic coefficient of friction against steel | PET-C: 0.2 (dynamic, dry against steel (MCAM QTM 55007)) · PET + PTFE: 0.19 (dynamic, dry against steel (MCAM QTM 55007)) |
| PV limit (pressure × velocity) | PET-C: 0.098 MPa·m/s (MCAM QTM 55007, dry against steel, safety factor 4:1 already applied; original 2,800 psi·ft/min) · PET + PTFE: 0.21 MPa·m/s (MCAM QTM 55007, dry against steel, safety factor 4:1 already applied; original 6,000 psi·ft/min) |
PV and friction depend on the test method, the mating surface (steel, stainless, roughness), lubrication and each manufacturer's safety factor: compare values from the same source and confirm by testing in critical applications.
Chemical resistance
| Medium | Resistance |
|---|---|
| Acids | Limited in strong acids; good in weak acids |
| Bases (alkalis) | Limited: bases and hot water above 60 °C hydrolyze PET |
| Solvents | Good (ketones/esters acceptable); chlorinated solvents unacceptable |
| Hydrocarbons and oils | Very good |
| Steam and hot water | Limited (hydrolysis above ~60 °C) |
Stock forms and sizes
- Rod (round bar)
- Sheet (plate)
- Tube and bushing
- Raw material: rod (round bar), sheet (plate) and tube, cut to size
- Machined part to drawing or sample, in the same order as the metal parts
- Lot certificate of conformity; FDA/EU 10/2011 declaration when the grade allows
Service temperature, machining and assembly
| Item | Usual practice |
|---|---|
| Service temperature | Continuous service up to 115 / 100 °C, short peaks up to 160 °C; minimum -20 °C (unloaded; under load, limited by HDT and creep). |
| Annealing (stress relief) | Stress-relief annealing before precision machining. |
| Bonding and welding | Bonding is possible after surface preparation. |
| Machining | Machines very well, with excellent stability and surface finish. |
Typical applications
- Precision parts for food and packaging machinery
- Bushings, guides and wear strips
- Pistons and valves
- Instrument and fixture parts
Alternatives: POM for lower cost; PEEK for higher temperature and steam.
Frequently asked questions
Which standards cover PET-C (Ertalyte®)?
Rod, sheet and tube: Manufacturer's specification (MCAM Ertalyte, Ensinger TECAPET). Food contact: FDA 21 CFR 177.1630; EU 10/2011. Machined part to drawing: ISO 2768 tolerance or as per drawing.
Up to what temperature can PET-C (Ertalyte®) be used?
Continuous service up to 115 / 100 °C, short peaks up to 160 °C; minimum -20 °C (unloaded; under load, limited by HDT and creep).
Which materials can replace PET-C (Ertalyte®)?
POM for lower cost; PEEK for higher temperature and steam.
PET or POM?
PET is more dimensionally stable and wears less; POM is tougher and cheaper. In precision parts running wet, PET usually wins.
