CPET BLK
Additive grade
BLK = 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.
Values for the BLK condition
Other CPET grades and fills
CPET is listed in 8 conditions; see the grade overview at CPET.
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 |
BLKThis page 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 |
What is CPET BLK?
CPET BLK is CPET in the BLK grade — classic black ready-meal tray colour; carbon black also improves UV stability but blocks NIR sorting unless detectable pigment is used. CPET BLK has a yield strength of 56 MPa (8.12 ksi) and a tensile strength of 60 MPa (8.7 ksi) — stronger than 63% of polymer grades. Elongation at break is 30% and the elastic modulus is 2.8 GPa (0.406 Msi). CPET BLK 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).
Advantages
- Tough — resists crack growth — 4.3 MPa·√m (3.91 ksi·√in), better than 95% of polymer grades
- Good UV / weathering resistance — 70/100, better than 83% 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
- High mold shrinkage — 2%, worse than 81% of polymer grades
- Needs corrosion protection — 70/100, worse than 78% of polymer grades
- Heavy — 1.38 g/cm³ (0.0499 lb/in³), worse than 77% of polymer grades
CPET BLK properties
Typical room-temperature values for CPET BLK; 28 are specific to this condition. Other listed values are CPET reference data and may not represent this condition. Bars are the position among polymer grades.
Physical6
CPET BLK 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 BLK has a yield strength of 56 MPa (8.12 ksi) and a tensile strength of 60 MPa (8.7 ksi) — stronger than 63% of polymer grades. Elongation at break is 30% and the elastic modulus is 2.8 GPa (0.406 Msi).
Thermal11
CPET BLK is rated for continuous service to 115°C (239 °F). It conducts heat at 0.25 W/m·K (0.144 BTU/hr·ft·°F), better than 72% of polymer grades. Thermal expansion is 62 µm/m·K (34.4 µin/in·°F).
Electrical7
CPET BLK is an electrical insulator with a dielectric strength of 20 kV/mm (508 V/mil) and a resistivity of 1×10¹² Ω·m.
Chemical & Environmental3
Corrosion resistance is very good (70/100), worse than 78% of polymer grades. UV resistance is very good.
Sustainability4
Producing a kilogram of CPET BLK 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 BLK's machinability is good (58/100, worse than 55% of polymer grades); weldability poor (25/100); formability good (60/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with CPET BLK
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.
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.
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) | — |
CPET BLK — frequently asked
What is CPET BLK used for?
CPET BLK 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 BLK?
CPET BLK has a typical yield strength of 56 MPa (8.12 ksi) and a tensile strength of 60 MPa (8.7 ksi) — stronger than 63% of polymer grades. Strength varies by condition: see the 8 listed tempers.
Is CPET BLK easy to machine?
Reasonably — machinability is rated good (58/100, worse than 55% 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 BLK be welded?
Not readily — weldability is rated poor (25/100). 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 BLK?
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 BLK 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 BLK?
CPET BLK 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.
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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.