HMWPE FR (Flame-retardant compound)
Flame-retardant grade
Mineral- or halogen-FR filled compound for mining ducting, cable conduit and enclosure liners with fire-rating requirements.
Values for the FR condition
Other HMWPE grades and fills
HMWPE is listed in 6 conditions; see the grade overview at HMWPE.
Compare all 6 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
FRThis page Flame-retardant compound | Mineral- or halogen-FR filled compound for mining ducting, cable conduit and enclosure liners with fire-rating requirements. | 18 | 19 | 120 | 65 Shore D |
PE80 pressure-pipe grade | Lower-cost pipe grade for gas distribution and smaller-diameter water lines where PE100 design stress is not required. | 21 | 25 | 750 | 60 Shore D |
Recycled / regrind HMW-HDPE | Cost- and carbon-reduced option for non-pressure sheet, drainage pipe cores and pallets where property scatter is acceptable. | 22 | 25 | 300 | 64 Shore D |
Antistatic / conductive carbon-black filled | Use in coal/grain chutes, mining liners and fuel-handling parts where static discharge must be avoided. | 23 | 22 | 250 | 68 Shore D |
Black, carbon-black UV stabilized | Choose for any long-term outdoor exposure: pipe, geomembrane, tank and marine dock fenders. | 25 | 30 | 700 | 66 Shore D |
PE100 bimodal pressure-pipe grade | Pick for buried water/gas pressure pipe and fittings needing 50-year hydrostatic design strength and high slow-crack-growth resistance. | 25 | 34 | 700 | — |
What is HMWPE FR?
HMWPE FR is HMWPE in the FR grade — mineral- or halogen-FR filled compound for mining ducting, cable conduit and enclosure liners with fire-rating requirements. HMWPE FR has a yield strength of 18 MPa (2.61 ksi) and a tensile strength of 19 MPa (2.76 ksi) — weaker than 82% of polymer grades. Elongation at break is 120% and the elastic modulus is 1.5 GPa (0.218 Msi). HMWPE FR has a density of 1.35 g/cm³ (0.0488 lb/in³), heavier than 75% of polymer grades. Its glass-transition temperature is -120°C (-184 °F).
Advantages
- Conducts heat well — 0.55 W/m·K (0.318 BTU/hr·ft·°F), better than 99% of polymer grades
- Low moisture uptake — 0.01%, better than 97% of polymer grades
- Low embodied carbon — 2.1 kg CO₂/kg, better than 94% of polymer grades
Limitations
- Hard to polish — 25/100, worse than 90% of polymer grades
- Low strength — 18 MPa (2.61 ksi), worse than 82% of polymer grades
- Difficult to machine — 45/100, worse than 78% of polymer grades
- Degrades in UV without stabilisers — 25/100, worse than 76% of polymer grades
- Heavy — 1.35 g/cm³ (0.0488 lb/in³), worse than 75% of polymer grades
HMWPE FR properties
Typical room-temperature values for HMWPE FR; 27 are specific to this condition. Other listed values are HMWPE reference data and may not represent this condition. Bars are the position among polymer grades.
Physical6
HMWPE FR has a density of 1.35 g/cm³ (0.0488 lb/in³), heavier than 75% of polymer grades. Its glass-transition temperature is -120°C (-184 °F).
Mechanical16
HMWPE FR has a yield strength of 18 MPa (2.61 ksi) and a tensile strength of 19 MPa (2.76 ksi) — weaker than 82% of polymer grades. Elongation at break is 120% and the elastic modulus is 1.5 GPa (0.218 Msi).
Thermal11
HMWPE FR is rated for continuous service to 80°C (176 °F). It conducts heat at 0.55 W/m·K (0.318 BTU/hr·ft·°F), better than 99% of polymer grades. Thermal expansion is 160 µm/m·K (88.9 µin/in·°F).
Electrical7
HMWPE FR is an electrical insulator with a dielectric strength of 24 kV/mm (609.6 V/mil) and a resistivity of 1×10¹³ Ω·m.
Chemical & Environmental3
Corrosion resistance is excellent (87/100), better than 72% of polymer grades. UV resistance is poor.
Sustainability4
Producing a kilogram of HMWPE FR takes about 78 MJ of energy and emits 2.1 kg of CO₂ — less than 88% of polymer grades. Typical recycled content is 10%.
Manufacturability8
HMWPE FR's machinability is fair (45/100, worse than 78% of polymer grades); weldability good (65/100); formability fair (45/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with HMWPE FR
Is HMWPE easy to machine?
Very machinable but soft and gummy — use sharp high-rake single-flute tools, high speed with low feed pressure, air blast cooling; expect springback and stress relaxation, so allow generous tolerances and stress-relieve thick sheet before finish cuts.
Can HMWPE be welded?
Excellent thermoplastic weldability: butt fusion, electrofusion, hot-gas and extrusion welding give near-parent-strength joints; adhesive bonding is poor without corona, flame or plasma surface treatment.
Can HMWPE be formed, bent or molded?
Low melt index means extrusion (sheet, pipe, profile) and blow molding rather than injection molding; high melt pressures and grooved-feed extruders are typical, mold shrinkage 1.5–4% with significant post-shrinkage.
What surface finishes work on HMWPE?
Cannot be plated or painted without pretreatment; use flame/corona treatment for printing and labels, machined or embossed textures for grip, and carbon-black pigmentation instead of coatings for UV protection.
HMWPE 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 |
|---|---|---|
| 1-butene / 1-hexene comonomershort-chain branching controls density and ESCR | 0.2 – 2.5 | 1 |
| antioxidant / process stabilizer packagehindered phenol + phosphite | 0.05 – 0.5 | 0.2 |
| carbon blackblack UV-stabilized and pipe grades only (ISO 4427 / ASTM D3350) | 2 – 2.6 | 2.3 |
| ethylene (repeat unit)Ziegler-Natta or chromium-catalysed HDPE backbone, Mw ≈ 200,000–500,000 g/mol | ≥ 97.5 (balance) | — |
HMWPE FR — frequently asked
What is HMWPE FR used for?
HMWPE FR is typically used for gas and water pipe, geomembranes and liners, large blow-molded tanks, wear liners and cable jacketing. In short: stress-crack resistant HDPE; pipe and liner polyethylene; cheaper than UHMW-PE.
What is the yield strength of HMWPE FR?
HMWPE FR has a typical yield strength of 18 MPa (2.61 ksi) and a tensile strength of 19 MPa (2.76 ksi) — weaker than 82% of polymer grades. Strength varies by condition: see the 6 listed tempers.
Is HMWPE FR easy to machine?
Reasonably — machinability is rated fair (45/100, worse than 78% of polymer grades). Very machinable but soft and gummy — use sharp high-rake single-flute tools, high speed with low feed pressure, air blast cooling; expect springback and stress relaxation, so allow generous tolerances and stress-relieve thick sheet before finish cuts.
Can HMWPE FR be welded?
Yes — weldability is rated good (65/100). Excellent thermoplastic weldability: butt fusion, electrofusion, hot-gas and extrusion welding give near-parent-strength joints; adhesive bonding is poor without corona, flame or plasma surface treatment.
What surface finishes work on HMWPE FR?
Cannot be plated or painted without pretreatment; use flame/corona treatment for printing and labels, machined or embossed textures for grip, and carbon-black pigmentation instead of coatings for UV protection.
Can HMWPE FR be formed, bent or molded?
Low melt index means extrusion (sheet, pipe, profile) and blow molding rather than injection molding; high melt pressures and grooved-feed extruders are typical, mold shrinkage 1.5–4% with significant post-shrinkage.
What is the maximum service temperature of HMWPE FR?
HMWPE FR is rated for continuous use to about 80°C (176 °F), and briefly to 110°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- ASTM D3350 Standard Specification for Polyethylene Plastics Pipe and Fittings Materials — ASTM International (2021)
- ASTM D4976 Standard Specification for Polyethylene Plastics Molding and Extrusion Materials — ASTM International (2019)
- ISO 4427 Plastics piping systems — Polyethylene (PE) pipes and fittings for water supply — ISO (2019)
- Engineered Materials Handbook Vol. 2: Engineering Plastics — ASM International (1988)
- Hostalen / Lupolen HMW-HDPE pipe and sheet grade datasheets — LyondellBasell (2023)
- Continuum / DGDA bimodal HDPE pipe resin datasheets — Dow (2023)
- CAMPUS polyethylene datasets (ISO 10350 property set) — CAMPUS Plastics (2024)
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.