PCTFE
ASTM D1430 · also Kel-F, Neoflon
PCTFE (Kel-F, Neoflon PCTFE; ASTM D1430) is a semi-crystalline polychlorotrifluoroethylene homopolymer that combines fluoropolymer chemical resistance and non-flammability with markedly better rigidity and creep resistance than PTFE, plus the lowest water-vapour permeability of any engineering plastic.
PCTFE grades and fills
PCTFE is supplied in 2 conditions, soft to hard.
Compare all 2 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
High molecular weight compression-molding grade | Pick when maximum toughness, creep resistance and crack resistance are needed in thick machined stock shapes; hardest to process. | 33 | 39 | 140 | 77 Shore D |
lower molecular weight extrusion & injection grade | Use for thin-wall extrusion, wire insulation and injection-molded small parts where flow matters more than ultimate toughness. | 35 | 34 | 80 | 80 Shore D |
Supply forms, finishes and certifications
Ways PCTFE is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
FILM | Biaxially oriented barrier film grade | Supply form |
FDA | FDA / pharma-compliant grade | Certification |
UnfilledDefault | Virgin PCTFE homopolymer | Standard supply |
What is PCTFE?
PCTFE (Kel-F, Neoflon PCTFE; ASTM D1430) is a semi-crystalline polychlorotrifluoroethylene homopolymer that combines fluoropolymer chemical resistance and non-flammability with markedly better rigidity and creep resistance than PTFE, plus the lowest water-vapour permeability of any engineering plastic. It is used for cryogenic (LOX/LH2) valve seats and seals, oxygen-system parts, high-frequency insulators and pharmaceutical barrier film (Aclar), at 37 MPa tensile and 110 % elongation. Melt viscosity is extremely high with a narrow processing window, continuous service is only about 120–150 °C, and cost is well above PTFE or PVDF. PCTFE has a density of 2.12 g/cm³ (0.0766 lb/in³), heavier than 98% of polymer grades. Its glass-transition temperature is 50°C (122 °F). PCTFE has a yield strength of 34 MPa (4.93 ksi) and a tensile strength of 37 MPa (5.37 ksi) — weaker than 67% of polymer grades. Elongation at break is 110% and the elastic modulus is 1.5 GPa (0.218 Msi).
What is PCTFE used for?
- Cryogenic valve seats
- LOX and LH2 seals and gaskets
- Oxygen-system components
- High-frequency insulators
- Pharmaceutical blister barrier film
- Chemical-resistant sight glasses and windows
- Precision back-up rings
Advantages
- Low moisture uptake — 0.01%, better than 100% of polymer grades
- Good corrosion resistance — 95/100, better than 97% of polymer grades
- Good UV / weathering resistance — 92/100, better than 93% of polymer grades
- High service temperature — 135°C (275 °F), better than 75% of polymer grades
Limitations
- Heavy — 2.12 g/cm³ (0.0766 lb/in³), worse than 98% of polymer grades
- High embodied carbon — 13 kg CO₂/kg, worse than 93% of polymer grades
PCTFE properties
Typical room-temperature values in the Unfilled condition; bars are the position among polymer grades.
Physical6
PCTFE has a density of 2.12 g/cm³ (0.0766 lb/in³), heavier than 98% of polymer grades. Its glass-transition temperature is 50°C (122 °F).
Mechanical13
PCTFE has a yield strength of 34 MPa (4.93 ksi) and a tensile strength of 37 MPa (5.37 ksi) — weaker than 67% of polymer grades. Elongation at break is 110% and the elastic modulus is 1.5 GPa (0.218 Msi).
Thermal11
PCTFE is rated for continuous service to 135°C (275 °F). It conducts heat at 0.22 W/m·K (0.127 BTU/hr·ft·°F), better than 60% of polymer grades. Thermal expansion is 65 µm/m·K (36.1 µin/in·°F).
Electrical7
PCTFE is an electrical insulator with a dielectric strength of 21 kV/mm (533.4 V/mil) and a resistivity of 1×10¹⁶ Ω·m.
Chemical & Environmental3
Corrosion resistance is excellent (95/100), better than 97% of polymer grades. UV resistance is excellent.
Sustainability4
Producing a kilogram of PCTFE takes about 240 MJ of energy and emits 13 kg of CO₂ — more than 91% of polymer grades. Typical recycled content is 0%.
Manufacturability7
PCTFE's machinability is very good (70/100, better than 74% of polymer grades); weldability poor (20/100); formability fair (45/100).
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. PCTFE is highlighted; hover a dot for its name, or open the interactive family chart.
Working with PCTFE
Is PCTFE easy to machine?
Machines cleanly with sharp positive-rake carbide tools, high speed and light feeds; more rigid and dimensionally stable than PTFE but notch-sensitive — avoid sharp internal corners and stress-relieve (anneal ~150 °C) before finish cuts.
Can PCTFE be welded?
No practical solvent or adhesive bonding without surface etching; joining is limited to hot-plate/fusion welding of thin sections, so parts are normally one-piece machined or mechanically sealed.
Can PCTFE be formed, bent or molded?
Very high melt viscosity and narrow window between melting (~212 °C) and thermal degradation (>300 °C); compression molding with slow controlled cooling is standard, injection/extrusion needs corrosion-resistant screws and tight temperature control.
Manufacturability
The process limits FabDigit applies to PCTFE. Every PCTFE part is priced by an engineer; design inside these and the quote comes back without a redesign loop.
CNC machining
| Machinability | Better70 / 100 |
|---|---|
| ISO material group | N.8 |
| Cutting speed (rough / finish) | 400 / 500 m/min |
| Minimum wall | 0.5 mm |
| Minimum internal radius | 1 mm |
| Drill depth limit | 10× diameter |
| Best surface (machined / polished) | Ra 0.8 / — |
| Hardenable after machining | No |
Sheet metal
| Formability | Fair45 / 100 |
|---|---|
| Weldability | Fair20 / 100 |
Injection molding
| Mold shrinkage | — |
|---|---|
| Wall thickness | — – — |
| Recommended draft | — |
| Pre-drying | — |
PCTFE 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.
| Element | Spec limit (wt %) |
|---|---|
| chlorotrifluoroethylene (CTFE) monomer u-(CF2-CFCl)n-; nominal 39% F, 30% Cl, 31% C by weight; no fillers or stabilizers in virgin grades | balance |
What surface finishes work on PCTFE?
Not paintable or platable without plasma/chemical surface activation; typical finishing is precision machining and lapping of sealing faces plus annealing to relieve residual stress.
Surface treatments FabDigit runs on polymer parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Injection Molding Coating
Organic Coating
Metallization / Functional
Equivalent designations
Standards and trade names that resolve to PCTFE in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- ASTM
- D1430
- Trade names
- Kel-FNeoflonNeoflon PCTFE
- Also called
- PolychlorotrifluoroethyleneF3
How much does PCTFE cost?
PCTFE is a specialty-cost polymer ($$$$$), pricier than about 99% 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.
PCTFE — frequently asked
What is PCTFE used for?
PCTFE is typically used for cryogenic valve seats, LOX and LH2 seals and gaskets, oxygen-system components, high-frequency insulators, pharmaceutical blister barrier film and chemical-resistant sight glasses and windows. In short: cryogenic chemical expert.
What is the yield strength of PCTFE?
PCTFE has a typical yield strength of 34 MPa (4.93 ksi) and a tensile strength of 37 MPa (5.37 ksi) — weaker than 67% of polymer grades. Strength varies by condition: see the 2 listed tempers.
Is PCTFE easy to machine?
Yes — machinability is rated very good (70/100, better than 74% of polymer grades). Machines cleanly with sharp positive-rake carbide tools, high speed and light feeds; more rigid and dimensionally stable than PTFE but notch-sensitive — avoid sharp internal corners and stress-relieve (anneal ~150 °C) before finish cuts.
Can PCTFE be welded?
Not readily — weldability is rated poor (20/100). No practical solvent or adhesive bonding without surface etching; joining is limited to hot-plate/fusion welding of thin sections, so parts are normally one-piece machined or mechanically sealed.
What surface finishes work on PCTFE?
Not paintable or platable without plasma/chemical surface activation; typical finishing is precision machining and lapping of sealing faces plus annealing to relieve residual stress.
Can PCTFE be formed, bent or molded?
Very high melt viscosity and narrow window between melting (~212 °C) and thermal degradation (>300 °C); compression molding with slow controlled cooling is standard, injection/extrusion needs corrosion-resistant screws and tight temperature control.
What is the maximum service temperature of PCTFE?
PCTFE is rated for continuous use to about 135°C (275 °F), and briefly to 180°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does PCTFE cost?
PCTFE is a specialty-cost polymer ($$$$$), pricier than about 99% 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.
Can FabDigit make parts in PCTFE?
Yes — PCTFE is available for CNC machining, sheet metal and injection molding; every part is priced by an engineer rather than instantly. Upload a STEP file to get a price and a DFM check.
Sources
- Neoflon CTFE (PCTFE) resin data — M-300P / M-400H — Daikin Industries (2021)
- Kel-F 81 / PCTFE stock shape properties — Arkema / 3M legacy data (2015)
- Engineered Materials Handbook Vol.2: Engineering Plastics — ASM International (1988)
- Aclar PCTFE barrier film technical data — Honeywell (2020)
- ASTM D1430 — Standard Classification System for Polychlorotrifluoroethylene (PCTFE) Plastics — ASTM (2019)
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.