PCTFE HMW
Grade
ASTM D1430 · also Kel-F, Neoflon
HMW = 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.
Values for the HMW condition
Other PCTFE grades and fills
PCTFE is listed in 2 conditions; see the grade overview at PCTFE.
- HMW
- LMW-EXT
Compare all 2 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
HMWThis page 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 |
What is PCTFE HMW?
PCTFE HMW is PCTFE in the HMW grade — pick when maximum toughness, creep resistance and crack resistance are needed in thick machined stock shapes; hardest to process. PCTFE HMW has a yield strength of 33 MPa (4.79 ksi) and a tensile strength of 39 MPa (5.66 ksi) — weaker than 68% of polymer grades. Elongation at break is 140% and the elastic modulus is 1.4 GPa (0.203 Msi). PCTFE HMW 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).
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 — 140°C (284 °F), better than 76% 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 HMW properties
Typical room-temperature values for PCTFE HMW; 23 are specific to this condition. Other listed values are PCTFE reference data and may not represent this condition. Bars are the position among polymer grades.
Physical6
PCTFE HMW 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 HMW has a yield strength of 33 MPa (4.79 ksi) and a tensile strength of 39 MPa (5.66 ksi) — weaker than 68% of polymer grades. Elongation at break is 140% and the elastic modulus is 1.4 GPa (0.203 Msi).
Thermal11
PCTFE HMW is rated for continuous service to 140°C (284 °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 HMW 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 HMW 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 HMW's machinability is good (68/100, better than 71% of polymer grades); weldability poor (25/100); formability fair (40/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with PCTFE HMW
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.
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.
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 |
PCTFE HMW — frequently asked
What is PCTFE HMW used for?
PCTFE HMW 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 HMW?
PCTFE HMW has a typical yield strength of 33 MPa (4.79 ksi) and a tensile strength of 39 MPa (5.66 ksi) — weaker than 68% of polymer grades. Strength varies by condition: see the 2 listed tempers.
Is PCTFE HMW easy to machine?
Reasonably — machinability is rated good (68/100, better than 71% 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 HMW be welded?
Not readily — weldability is rated poor (25/100). 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 HMW?
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 HMW 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 HMW?
PCTFE HMW is rated for continuous use to about 140°C (284 °F), and briefly to 180°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Can FabDigit make parts in PCTFE HMW?
Yes — PCTFE HMW 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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.