ePTFE CB-COND
Additive grade
also Gore-Tex
CB-COND = carbon-filled / antistatic expanded PTFE
Carbon-black or carbon-fiber loaded ePTFE for static dissipation in solvent/fuel service and for fuel-cell gas-diffusion or electrode substrates.
Values for the CB-COND condition
Other ePTFE grades and fills
ePTFE is listed in 5 conditions; see the grade overview at ePTFE.
Compare all 5 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
CB-CONDThis page Carbon-filled / antistatic expanded PTFE | Carbon-black or carbon-fiber loaded ePTFE for static dissipation in solvent/fuel service and for fuel-cell gas-diffusion or electrode substrates. | 5 | 10 | 80 | 50 Shore D |
uniaxially expanded ePTFE cord / tape form-in-place sealant | Pick for large, warped, glass-lined or FRP flanges and manway covers where a cut gasket cannot conform — the cord is laid in place and crushed to shape. | 6 | 25 | 120 | 42 Shore D |
mineral-filled (barium sulfate / silica) expanded PTFE sheet | Use where cold flow / creep relaxation of pure ePTFE is unacceptable: mineral filler raises density and stress-retention at the cost of some conformability. | — | 12 | 100 | 50 Shore D |
ePTFE membrane laminated to PET/PPS/glass scrim (filter media) | Choose for surface-filtration baghouse and HEPA/ULPA media: the ePTFE layer gives >99.99% capture and easy dust release, backing carries the mechanical load. | 12 | 30 | 60 | — |
microporous ePTFE membrane / breathable film (Gore-Tex type) | Choose for waterproof-breathable laminates, vents, sterile barrier and 0.02–5 µm liquid/gas microfiltration; very thin (5–100 µm) with strong machine-direction orientation. | — | 40 | 120 | — |
What is ePTFE CB-COND?
ePTFE CB-COND is ePTFE in the CB-COND grade — carbon-black or carbon-fiber loaded ePTFE for static dissipation in solvent/fuel service and for fuel-cell gas-diffusion or electrode substrates. ePTFE CB-COND has a tensile strength of 10 MPa (1.45 ksi), weaker than 79% of polymer grades. Elongation at break is 80% and the elastic modulus is 0.3 GPa (0.0435 Msi). ePTFE CB-COND has a density of 0.9 g/cm³ (0.0325 lb/in³), lighter than 82% of polymer grades. Its glass-transition temperature is 126°C (259 °F).
Advantages
- High service temperature — 260°C (500 °F), better than 97% of polymer grades
- Good corrosion resistance — 95/100, better than 97% of polymer grades
- Low moisture uptake — 0.01%, better than 97% of polymer grades
- Good UV / weathering resistance — 92/100, better than 93% of polymer grades
- Lightweight — 0.9 g/cm³ (0.0325 lb/in³), better than 82% of polymer grades
Limitations
- High embodied carbon — 13 kg CO₂/kg, worse than 93% of polymer grades
- Poor heat conductor — 0.15 W/m·K (0.0867 BTU/hr·ft·°F), worse than 80% of polymer grades
- Difficult to weld — 15/100, worse than 78% of polymer grades
ePTFE CB-COND properties
Typical room-temperature values for ePTFE CB-COND; 20 are specific to this condition. Other listed values are ePTFE reference data and may not represent this condition. Bars are the position among polymer grades.
Physical4
ePTFE CB-COND has a density of 0.9 g/cm³ (0.0325 lb/in³), lighter than 82% of polymer grades. Its glass-transition temperature is 126°C (259 °F).
Mechanical7
ePTFE CB-COND has a tensile strength of 10 MPa (1.45 ksi), weaker than 79% of polymer grades. Elongation at break is 80% and the elastic modulus is 0.3 GPa (0.0435 Msi).
Thermal8
ePTFE CB-COND is rated for continuous service to 260°C (500 °F). It conducts heat at 0.15 W/m·K (0.0867 BTU/hr·ft·°F), worse than 80% of polymer grades. Thermal expansion is 110 µm/m·K (61.1 µin/in·°F).
Electrical6
ePTFE CB-COND is an electrical insulator with a dielectric strength of 20 kV/mm (508 V/mil) and a resistivity of 100 Ω·m.
Chemical & Environmental3
Corrosion resistance is excellent (95/100), better than 97% of polymer grades. UV resistance is excellent.
Sustainability3
Producing a kilogram of ePTFE CB-COND takes about 250 MJ of energy and emits 13 kg of CO₂ — more than 92% of polymer grades. Typical recycled content is 0%.
Manufacturability4
ePTFE CB-COND's machinability is good (55/100, worse than 64% of polymer grades); weldability poor (15/100); formability very good (75/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with ePTFE CB-COND
Is ePTFE easy to machine?
Do not turn or mill porous sheet — die-cut, water-jet, slit or ultrasonically cut; use sharp steel-rule dies and back the material to avoid crushing and edge densification.
Can ePTFE be welded?
Not melt-weldable in the usual sense; joints are made by lap-and-sinter above 340 °C, PFA/FEP film bonding, adhesive-backed overlaps or skiving-and-clamping.
Can ePTFE be formed, bent or molded?
Made by paste extrusion/calendering of fine-powder PTFE plus lubricant, lubricant removal, then uniaxial or biaxial stretching at 200–330 °C and optional amorphous locking (sinter) above 340 °C; final parts are cut or laminated rather than molded.
What surface finishes work on ePTFE?
No paint or plating adheres without corona/plasma or sodium-etch pretreatment; typical finishing is adhesive backing (PSA strip), PFA edge sealing, scrim lamination, or hydrophobic/oleophobic surface treatment for vents.
ePTFE 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 |
|---|---|---|
| processing lubricant (isoparaffin naphth16–25% added for paste extrusion, volatilized before/during expansion | 0 – 0.1 | 0 |
| barium sulfate / silica filleronly in filled (FILLED-MIN) gasket grades | 0 – 40 | 0 |
| carbon black / carbon fiberonly in conductive/antistatic grades | 0 – 20 | 0 |
| PTFE (tetrafluoroethylene homopolymer)fine-powder (paste-extrusion) PTFE resin per ASTM D4895; ePTFE contains no plasticizer after lubricant removal | ≥ 95 (balance) | — |
ePTFE CB-COND — frequently asked
What is ePTFE CB-COND used for?
ePTFE CB-COND is typically used for gasketing sheet/tape for flanges, membrane filters and vents, vascular grafts and medical implants and sealant cord for irregular flanges. In short: most conformable PTFE gasket; lowest-density PTFE form; cut, not machined.
What is the tensile strength of ePTFE CB-COND?
ePTFE CB-COND has a typical tensile strength of 10 MPa (1.45 ksi) — weaker than 79% of polymer grades. Strength varies by condition: see the 5 listed tempers.
Is ePTFE CB-COND easy to machine?
Reasonably — machinability is rated good (55/100, worse than 64% of polymer grades). Do not turn or mill porous sheet — die-cut, water-jet, slit or ultrasonically cut; use sharp steel-rule dies and back the material to avoid crushing and edge densification.
Can ePTFE CB-COND be welded?
Not readily — weldability is rated poor (15/100). Not melt-weldable in the usual sense; joints are made by lap-and-sinter above 340 °C, PFA/FEP film bonding, adhesive-backed overlaps or skiving-and-clamping.
What surface finishes work on ePTFE CB-COND?
No paint or plating adheres without corona/plasma or sodium-etch pretreatment; typical finishing is adhesive backing (PSA strip), PFA edge sealing, scrim lamination, or hydrophobic/oleophobic surface treatment for vents.
Can ePTFE CB-COND be formed, bent or molded?
Made by paste extrusion/calendering of fine-powder PTFE plus lubricant, lubricant removal, then uniaxial or biaxial stretching at 200–330 °C and optional amorphous locking (sinter) above 340 °C; final parts are cut or laminated rather than molded.
What is the maximum service temperature of ePTFE CB-COND?
ePTFE CB-COND is rated for continuous use to about 260°C (500 °F), and briefly to 300°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- ASTM D4895 — PTFE Resin Produced from Dispersion (fine powder) — ASTM International (2018)
- ASTM F36 / F38 — Compressibility & Creep Relaxation of Gasket Materials — ASTM International (2020)
- ASTM F104 — Classification System for Nonmetallic Gasket Materials — ASTM International (2019)
- ASTM D882 / D1708 — Tensile Properties of Thin Plastic Sheeting — ASTM International (2018)
- Expanded PTFE gasket sheet, joint sealant and membrane datasheets — W. L. Gore & Associates / Donaldson / Sumitomo Electric (Poreflon) (2023)
- Engineered Materials Handbook, Vol. 2: Engineering Plastics (PTFE section) — ASM International (1988)
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.