CPET
CPET is a semi-crystalline, nucleated polyethylene terephthalate sheet and moulding grade, with 62 MPa tensile strength, 40% elongation and a continuous service temperature of 115 °C, with heat resistance up to about 220 °C for oven use.
Reference datasheet — CPET is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
CPET grades and fills
CPET is supplied in 8 conditions, soft to hard.
Compare all 8 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
Foamed CPET | Physically foamed CPET core for lightweight, thermally insulating ovenable trays; lower strength but 30–50% material saving. | 22 | 25 | 12 | 62 Shore D |
Impact-modified CPET | Choose when trays must survive frozen drop and de-nesting; 2–8% olefinic elastomer raises notched impact at the cost of stiffness and heat resistance. | 50 | 90 | ||
Flame-retardant crystalline PET | Halogenated or phosphorus FR package for electrical housings and connectors requiring V-0 at 0.75–1.5 mm. | 55 | 55 | 8 | 86 Shore D |
Recycled-content CPET sheet | Cost- and footprint-reduced tray sheet with 30–80% post-consumer rPET in the core and virgin food-contact skins. | 55 | 58 | 25 | 84 Shore D |
Carbon-black / pigmented CPET tray sheet | Classic black ready-meal tray colour; carbon black also improves UV stability but blocks NIR sorting unless detectable pigment is used. | 56 | 60 | 30 | 85 Shore D |
Mineral/talc filled and nucleated CPET | Higher filler loading for faster crystallization, better rigidity and dimensional stability in high-speed thermoforming lines. | 58 | 12 | ||
Heat-stabilized / high-IV extrusion grade | High-IV (0.80–0.95 dl/g) chain-extended resin with antioxidant/hydrolysis stabilizers for repeated ovening and sheet re-extrusion. | 58 | 62 | 60 | 85 Shore D |
30% glass-fiber reinforced crystalline PET | For injection-molded structural or electrical parts needing 200 °C+ HDT and high stiffness rather than food trays. | 150 | 2.5 | 100 HRM |
Supply forms, finishes and certifications
Ways CPET is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
FDA | Food-contact / dual-ovenable certified grade | Certification |
STDDefault | Nucleated crystallizable PET sheet, unfilled/natural | Standard supply |
What is CPET?
CPET is a semi-crystalline, nucleated polyethylene terephthalate sheet and moulding grade, with 62 MPa tensile strength, 40% elongation and a continuous service temperature of 115 °C, with heat resistance up to about 220 °C for oven use. It is specified for dual-ovenable ready-meal trays because crystallization locks in dimensional stability at oven temperatures; forms include extruded and foamed sheet plus injection, talc-filled, GF30, FR, FDA, rPET and black conditions. The trade-offs are an opaque matte surface, notch sensitivity, hot tooling with a crystallization dwell, and no solvent bonding. Use APET where clarity matters more than heat resistance. CPET has a density of 1.38 g/cm³ (0.0499 lb/in³), heavier than 77% of polymer grades. Its glass-transition temperature is 78°C (172 °F). CPET has a yield strength of 58 MPa (8.41 ksi) and a tensile strength of 62 MPa (8.99 ksi) — stronger than 66% of polymer grades. Elongation at break is 40% and the elastic modulus is 2.8 GPa (0.406 Msi).
What is CPET used for?
- oven-safe food trays
- ready-meal packaging
- dual-ovenable containers
Advantages
- Tough — resists crack growth — 4.5 MPa·√m (4.1 ksi·√in), better than 96% of polymer grades
- Low embodied carbon — 3 kg CO₂/kg, better than 83% of polymer grades
- Low moisture uptake — 0.1%, better than 77% of polymer grades
Limitations
- Heavy — 1.38 g/cm³ (0.0499 lb/in³), worse than 77% of polymer grades
CPET properties
Typical room-temperature values; bars are the position among polymer grades.
Physical6
CPET has a density of 1.38 g/cm³ (0.0499 lb/in³), heavier than 77% of polymer grades. Its glass-transition temperature is 78°C (172 °F).
Mechanical17
CPET has a yield strength of 58 MPa (8.41 ksi) and a tensile strength of 62 MPa (8.99 ksi) — stronger than 66% of polymer grades. Elongation at break is 40% and the elastic modulus is 2.8 GPa (0.406 Msi).
Thermal11
CPET is rated for continuous service to 115°C (239 °F). It conducts heat at 0.24 W/m·K (0.139 BTU/hr·ft·°F), better than 67% of polymer grades. Thermal expansion is 62 µm/m·K (34.4 µin/in·°F).
Electrical7
CPET is an electrical insulator with a dielectric strength of 20 kV/mm (508 V/mil) and a resistivity of 1×10¹³ Ω·m.
Chemical & Environmental3
Corrosion resistance is very good (75/100), worse than 66% of polymer grades. UV resistance is fair.
Sustainability4
Producing a kilogram of CPET takes about 84 MJ of energy and emits 3 kg of CO₂ — less than 81% of polymer grades. Typical recycled content is 40%.
Manufacturability8
CPET's machinability is good (60/100, better than 51% of polymer grades); weldability good (65/100); formability very good (75/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the polymer family
Yield strength against density for every polymer grade FabDigit runs. CPET is highlighted; hover a dot for its name, or open the interactive family chart.
Working with CPET
Is CPET easy to machine?
Trims and die-cuts cleanly when cold; for milled parts use sharp, high-rake tools, high speed and air cooling — crystalline PET is notch-sensitive and can craze with coolant.
Can CPET be welded?
Joined mainly by heat sealing or impulse sealing to APET/PE lidding film; hot-plate and ultrasonic welding work, solvent bonding does not.
Can CPET be formed, bent or molded?
Dry to <50 ppm (dew point ≤ -40 °C, 4 h @ 160 °C) then thermoform or injection mold into a 130–150 °C tool with 8–20 s dwell so the part crystallizes before demolding.
CPET 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 |
|---|---|---|
| talc (nucleating agent)controls crystallization rate in hot mold | 0.3 – 5 | 1.5 |
| impact modifier (olefinic/acrylic elastoprevents brittleness of the crystallized matrix | 0 – 8 | 4 |
| chain extender / stabilizer packageantioxidant + hydrolysis stabilizer, food-contact compliant | 0.1 – 1 | 0.4 |
| pigment (carbon black or TiO2) | 0 – 3 | 1 |
| poly(ethylene terephthalate)IV typically 0.72–0.85 dl/g for sheet extrusion | ≥ 88 (balance) |
What surface finishes work on CPET?
Surface is matte and opaque after crystallization; decorate by flexo/offset printing, in-mold labelling or corona-treated laminate — no plating or anodizing.
How much does CPET cost?
CPET is a standard-cost polymer ($$), cheaper than about 71% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
CPET — frequently asked
What is CPET used for?
CPET is typically used for oven-safe food trays, ready-meal packaging and dual-ovenable containers. In short: ovenable PET sheet; crystallized, opaque, heat-stable; highest-temperature PET packaging.
What is the yield strength of CPET?
CPET has a typical yield strength of 58 MPa (8.41 ksi) and a tensile strength of 62 MPa (8.99 ksi) — stronger than 66% of polymer grades. Strength varies by condition: see the 8 listed tempers.
Is CPET easy to machine?
Reasonably — machinability is rated good (60/100, better than 51% of polymer grades). Trims and die-cuts cleanly when cold; for milled parts use sharp, high-rake tools, high speed and air cooling — crystalline PET is notch-sensitive and can craze with coolant.
Can CPET be welded?
Yes — weldability is rated good (65/100). Joined mainly by heat sealing or impulse sealing to APET/PE lidding film; hot-plate and ultrasonic welding work, solvent bonding does not.
What surface finishes work on CPET?
Surface is matte and opaque after crystallization; decorate by flexo/offset printing, in-mold labelling or corona-treated laminate — no plating or anodizing.
Can CPET be formed, bent or molded?
Dry to <50 ppm (dew point ≤ -40 °C, 4 h @ 160 °C) then thermoform or injection mold into a 130–150 °C tool with 8–20 s dwell so the part crystallizes before demolding.
What is the maximum service temperature of CPET?
CPET is rated for continuous use to about 115°C (239 °F), and briefly to 220°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does CPET cost?
CPET is a standard-cost polymer ($$), cheaper than about 71% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- ISO 527 / ISO 178 / ISO 75 polymer test methods — ISO (2019)
- 21 CFR 177.1630 — Poly(ethylene phthalate) polymers — US FDA (2023)
- Engineered Materials Handbook Vol. 2: Engineering Plastics — ASM International (1988)
- CAMPUS polymer datasheets — PET (semi-crystalline, nucleated) — CWFG / material producers (2024)
- CPET dual-ovenable tray sheet processing guides — PET sheet extruders / resin producers (2023)
- PET PET (2026)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.