PET · flame-retardant grade
PET-FR
Properties of the FR condition, compared with the other PET grades.
Choose where a UL 94 V-0 rating at 0.8–1.6 mm is mandatory, e.g. electrical connectors, coil bobbins and switch bodies.
What is PET-FR?
PET-FR is PET in the FR grade — choose where a UL 94 V-0 rating at 0.8–1.6 mm is mandatory, e.g. electrical connectors, coil bobbins and switch bodies. PET-FR has a yield strength of 80 MPa (11.6 ksi) and a tensile strength of 135 MPa (19.6 ksi) — stronger than 87% of polymer grades. Elongation at break is 2% and the elastic modulus is 10.5 GPa (1.52 Msi). PET-FR has a density of 1.69 g/cm³ (0.0611 lb/in³), heavier than 94% of polymer grades. Its glass-transition temperature is 79°C (174 °F). Unfilled is the default condition FabDigit quotes; FR is available on request or by drawing note.
Advantages
- Stiff — 10.5 GPa (1.52 Msi), better than 94% of polymer grades
- Tough — resists crack growth — 4 MPa·√m (3.64 ksi·√in), better than 91% of polymer grades
- High strength — 80 MPa (11.6 ksi), better than 87% of polymer grades
- Low embodied carbon — 2.8 kg CO₂/kg, better than 87% of polymer grades
- Low, predictable mold shrinkage — 0.35%, better than 87% of polymer grades
Limitations
- Limited ductility — 2%, worse than 94% of polymer grades
- Heavy — 1.69 g/cm³ (0.0611 lb/in³), worse than 94% of polymer grades
- Difficult to machine — 40/100, worse than 81% of polymer grades
- Needs corrosion protection — 70/100, worse than 80% of polymer grades
PET-FR properties
Typical room-temperature values for PET-FR — 17 properties are specific to this condition; the rest are grade-level values shared by every PET grade. Each bar shows where the value sits among the polymer grades in FabDigit's library — further right is higher.
Physical7
PET-FR has a density of 1.69 g/cm³ (0.0611 lb/in³), heavier than 94% of polymer grades. Its glass-transition temperature is 79°C (174 °F).
Mechanical17
PET-FR has a yield strength of 80 MPa (11.6 ksi) and a tensile strength of 135 MPa (19.6 ksi) — stronger than 87% of polymer grades. Elongation at break is 2% and the elastic modulus is 10.5 GPa (1.52 Msi).
Thermal11
PET-FR is rated for continuous service to 130°C (266 °F). It conducts heat at 0.25 W/m·K (0.144 BTU/hr·ft·°F), better than 71% of polymer grades. Thermal expansion is 25 µm/m·K (13.9 µin/in·°F).
Electrical7
PET-FR is an electrical insulator with a dielectric strength of 24 kV/mm (609.6 V/mil) and a resistivity of 1×10¹⁴ Ω·m.
Chemical & Environmental3
Corrosion resistance is very good (70/100), worse than 80% of polymer grades. UV resistance is poor.
Sustainability4
Producing a kilogram of PET-FR takes about 82 MJ of energy and emits 2.8 kg of CO₂ — less than 83% of polymer grades. Typical recycled content is 25%.
Manufacturability7
PET-FR's machinability is fair (40/100, worse than 81% of polymer grades); weldability fair (45/100); formability fair (50/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other PET grades and fills
PET is also supplied in 8 other conditions. The full side-by-side table is on the PET overview.
- UnfilledDefaultDefault choice for machined precision parts, wear strips and bushings where stiffness, dimensional stability and good machinability matter.82 MPa tensile
- CF30PET compounded with 30 wt% chopped carbon fiber for very high stiffness, low creep, low mold shrinkage and static-dissipative/conductive behavior.200 MPa tensile
- GF45For maximum stiffness and creep resistance in thin-wall metal-replacement parts; brittle and abrasive to tooling.185 MPa tensile
- GF30Use for stiff, dimensionally stable structural mouldings needing 200 °C-class heat resistance (housings, connectors, under-hood brackets).160 MPa tensile
- FRChoose where a UL 94 V-0 rating at 0.8–1.6 mm is mandatory, e.g. electrical connectors, coil bobbins and switch bodies.135 MPa tensile
- IMUse when snap-fits, clips or impact-loaded housings need toughness that plain or glass-filled PET cannot supply.105 MPa tensile
- Solid Lubricant Filled (TX)Pick for unlubricated sliding: bushings, wear pads and guides where low friction and long wear life beat maximum strength.60 MPa tensile
- rPETCost- and footprint-driven choice for sheet, strapping, fiber and non-critical mouldings; IV and colour vary batch to batch.60 MPa tensile
Working with PET-FR
Is PET easy to machine?
Machines like a free-cutting engineering plastic: sharp positive-rake carbide, high speed, light finishing passes and air/mist cooling give excellent surface finish and tight tolerances; watch for stress relief in thick stock (anneal before finish cuts).
Can PET be welded?
No solvent bonding — join by ultrasonic, hot-plate, IR or laser welding, or use cyanoacrylate/epoxy after abrasion/plasma treatment; mechanical fastening and self-tapping screws work well.
Can PET be formed, bent or molded?
Dry pellets to <0.02 % moisture (150 °C, 4 h desiccant) to avoid hydrolytic IV loss; melt 265–295 °C with hot mold 100–145 °C for full crystallization, or chilled mold/copolyester for clear amorphous APET sheet that thermoforms readily.
What surface finishes work on PET?
Takes machining, printing, hot stamping and vacuum metallizing well after corona/flame or plasma pre-treatment; can be laser-marked, but paint adhesion needs a primer and no plating/anodizing applies.
PET chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| isophthalic acid / CHDM comonomerin bottle/APET copolyester grades to suppress crystallization | 0 – 3 | 1.5 |
| glass fiber0 in default unfilled grade; 15–45 % in GF variants | 0 – 45 | 0 |
| solid lubricant (PTFE/other)TX bearing grades | 0 – 20 | 0 |
| flame retardant + synergistFR V-0 grades | 0 – 20 | 0 |
| nucleant / heat stabilizer / mold releasstandard additive package | 0 – 3 | 0.5 |
| ethylene terephthalate repeat unit (–C10polycondensate of purified terephthalic acid (PTA) or DMT with mono-ethylene glycol; Sb/Ti/Ge catalyst residues at ppm level | balance | — |
PET-FR — frequently asked
What is PET-FR used for?
PET-FR is typically used for precision machined mechanical components, slide bearings and wear strips, pump and valve parts, electronic structural parts, beverage bottles and food packaging film. In short: durable industrial PET.
What is the yield strength of PET-FR?
PET-FR has a typical yield strength of 80 MPa (11.6 ksi) and a tensile strength of 135 MPa (19.6 ksi) — stronger than 87% of polymer grades. Strength varies by condition: see the 9 listed tempers.
Is PET-FR easy to machine?
Not especially — machinability is rated fair (40/100, worse than 81% of polymer grades). Machines like a free-cutting engineering plastic: sharp positive-rake carbide, high speed, light finishing passes and air/mist cooling give excellent surface finish and tight tolerances; watch for stress relief in thick stock (anneal before finish cuts).
Can PET-FR be welded?
With care — weldability is rated fair (45/100). No solvent bonding — join by ultrasonic, hot-plate, IR or laser welding, or use cyanoacrylate/epoxy after abrasion/plasma treatment; mechanical fastening and self-tapping screws work well.
What surface finishes work on PET-FR?
Takes machining, printing, hot stamping and vacuum metallizing well after corona/flame or plasma pre-treatment; can be laser-marked, but paint adhesion needs a primer and no plating/anodizing applies.
Can PET-FR be formed, bent or molded?
Dry pellets to <0.02 % moisture (150 °C, 4 h desiccant) to avoid hydrolytic IV loss; melt 265–295 °C with hot mold 100–145 °C for full crystallization, or chilled mold/copolyester for clear amorphous APET sheet that thermoforms readily.
What is the maximum service temperature of PET-FR?
PET-FR is rated for continuous use to about 130°C (266 °F), and briefly to 150°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Can FabDigit make parts in PET-FR?
Yes — PET-FR is available for CNC machining, sheet metal and injection molding with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- Ertalyte / Ertalyte TX PET-P stock shapes datasheet — Mitsubishi Chemical Advanced Materials (Quadrant) (2022)
- Rynite PET thermoplastic polyester resin product & molding guide — DuPont / Celanese (2021)
- Arnite A (PET) grade datasheets — Envalior / DSM Engineering Materials (2023)
- CAMPUS plastics database — PET unfilled and GF grades — CWFG / CAMPUS consortium (2024)
- Engineered Materials Handbook Vol. 2: Engineering Plastics — ASM International (1988)
- ASTM D5927 — Standard Specification for Thermoplastic Polyester (TPES) Molding and Extrusion Materials — ASTM (2021)
- ISO 7792-1/-2 — Plastics, thermoplastic polyester (TP) moulding and extrusion materials — ISO (2012)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.