HDPE · reinforced grade
HDPE-GF20
Properties of the GF20 condition, compared with the other HDPE grades.
HDPE compound with 20% coupled short glass fiber — roughly triples stiffness and doubles heat-deflection temperature versus unfilled HDPE, at the cost of ductility.
What is HDPE-GF20?
HDPE-GF20 is HDPE in the GF20 grade — hDPE compound with 20% coupled short glass fiber — roughly triples stiffness and doubles heat-deflection temperature versus unfilled HDPE, at the cost of ductility. HDPE-GF20 has a yield strength of 50 MPa (7.25 ksi) and a tensile strength of 55 MPa (7.98 ksi) — weaker than 52% of polymer grades. Elongation at break is 3% and the elastic modulus is 4.2 GPa (0.609 Msi). HDPE-GF20 has a density of 1.08 g/cm³ (0.039 lb/in³), lighter than 66% of polymer grades. Its glass-transition temperature is -110°C (-166 °F). FDA Compliant is the default condition FabDigit quotes; GF20 is available on request or by drawing note.
Advantages
- Low embodied carbon — 2 kg CO₂/kg, better than 96% of polymer grades
- Low moisture uptake — 0.02%, better than 92% of polymer grades
- Conducts heat well — 0.35 W/m·K (0.202 BTU/hr·ft·°F), better than 91% of polymer grades
- Stiff — 4.2 GPa (0.609 Msi), better than 86% of polymer grades
- Low, predictable mold shrinkage — 0.45%, better than 78% of polymer grades
Limitations
- Limited ductility — 3%, worse than 83% of polymer grades
- Hard to polish — 30/100, worse than 80% of polymer grades
HDPE-GF20 properties
Typical room-temperature values for HDPE-GF20 — 44 properties are specific to this condition; the rest are grade-level values shared by every HDPE grade. Each bar shows where the value sits among the polymer grades in FabDigit's library — further right is higher.
Physical6
HDPE-GF20 has a density of 1.08 g/cm³ (0.039 lb/in³), lighter than 66% of polymer grades. Its glass-transition temperature is -110°C (-166 °F).
Mechanical16
HDPE-GF20 has a yield strength of 50 MPa (7.25 ksi) and a tensile strength of 55 MPa (7.98 ksi) — weaker than 52% of polymer grades. Elongation at break is 3% and the elastic modulus is 4.2 GPa (0.609 Msi).
Thermal11
HDPE-GF20 is rated for continuous service to 100°C (212 °F). It conducts heat at 0.35 W/m·K (0.202 BTU/hr·ft·°F), better than 91% of polymer grades. Thermal expansion is 50 µm/m·K (27.8 µin/in·°F).
Electrical7
HDPE-GF20 is an electrical insulator with a dielectric strength of 22 kV/mm (558.8 V/mil) and a resistivity of 1×10¹⁴ Ω·m.
Chemical & Environmental3
Corrosion resistance is excellent (85/100), better than 63% of polymer grades. UV resistance is poor.
Sustainability4
Producing a kilogram of HDPE-GF20 takes about 74 MJ of energy and emits 2 kg of CO₂ — less than 92% of polymer grades. Typical recycled content is 0%.
Manufacturability8
HDPE-GF20's machinability is good (55/100, worse than 63% of polymer grades); weldability fair (40/100); formability poor (25/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other HDPE grades and fills
HDPE is also supplied in 13 other conditions. The full side-by-side table is on the HDPE overview.
- FDA CompliantDefaultChoose for cutting boards, food processing parts, potable water and pharma contact; additive package limited to FDA 21 CFR 177.1520 / EU 10-2011 listed stabilizers.26 MPa yield · 65 Shore D
- GF40Highly reinforced HDPE with 40% coupled short glass fiber — maximum stiffness, strength and dimensional stability in the PE family, used for structural and under-hood-type mouldings.78 MPa yield · 73 Shore D
- GF30Coupled glass-filled compound for structural housings and pallets needing 4–5× stiffness and much lower creep/shrinkage; loses ductility and weldability.55 MPa tensile
- GF20HDPE compound with 20% coupled short glass fiber — roughly triples stiffness and doubles heat-deflection temperature versus unfilled HDPE, at the cost of ductility.50 MPa yield · 70 Shore D
- INJHigh-flow, lower-molecular-weight resin for thin-wall caps, crates and housings; fast cycles but lower ESCR and impact.28 MPa yield · 66 Shore D
- UnfilledStandard natural/white HDPE resin, sheet or machined part where chemical resistance and toughness matter more than stiffness.26 MPa yield · 65 Shore D
- UV StabilizedPick for outdoor tanks, pipe, marine and geomembrane service where multi-year sunlight exposure is expected.26 MPa yield · 66 Shore D
- BMLow-flow bimodal resin for bottles, drums and IBCs where melt strength and stress-crack resistance dominate.24 MPa yield
- PE100Use for buried gas/water pressure pipe and fittings needing 50-year MRS 10 MPa rating and slow-crack-growth resistance.24 MPa yield
- ESDSpecify for fuel-handling parts, powder chutes and electronics handling where charge build-up must be dissipated.24 MPa tensile
- HMWHigher-Mw ram-extruded sheet for chute liners, tanks and wear parts; much better impact and ESCR than standard HDPE, slightly lower stiffness.23 MPa yield · 63 Shore D
- MF40Low-cost stiffened compound for crates, pipe fittings and automotive parts; higher modulus and HDT, lower impact and higher density.23 MPa yield
- PCRRecycled bottle/crate regrind for non-critical mouldings, pipes and lumber; property spread is wide and colour is limited to dark shades.22 MPa yield
- FRUse where UL 94 V-0 or low-smoke behaviour is required in cable ducts, mine liners and enclosures; heavily filled, so strength and ductility drop sharply.16 MPa tensile
Working with HDPE-GF20
Is HDPE easy to machine?
Cuts easily with sharp, high-rake, polished tools and high speed/low feed; use air blast and generous support since heat build-up and low modulus cause gumming, burrs and part distortion.
Can HDPE be welded?
Excellent hot-plate, butt-fusion, electrofusion, hot-gas and extrusion welding (DVS 2207); adhesive bonding requires corona, flame or plasma pre-treatment.
Can HDPE be formed, bent or molded?
Injection, blow, rotational and profile extrusion all standard; melt 200–260 °C, mould 20–60 °C, allow 1.5–3% shrinkage with strong anisotropy and post-mould shrink over 24 h.
What surface finishes work on HDPE?
Cannot be plated or anodized and holds paint poorly; use in-resin colour, laser marking, hot stamping or corona-treated printing, and flame-polish or scrape edges for smooth finishes.
HDPE 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 to tune density and ESCR | 0 – 2 | 0.5 |
| antioxidant / process stabilizerhindered phenol + phosphite | 0.05 – 0.5 | 0.2 |
| carbon black2.0–2.5% only in UV-stabilized / pipe grades | 0 – 2.5 | 0 |
| ethylene (polyethylene chain)linear homopolymer backbone | ≥ 97 (balance) | — |
HDPE-GF20 — frequently asked
What is HDPE-GF20 used for?
HDPE-GF20 is typically used for cutting boards and food-contact surfaces, PE100 pressure pipe and fittings, chemical and water storage tanks, blow-moulded bottles and jerricans, playground equipment panels and conveyor wear strips and guides. In short: chemical resistant; budget.
What is the yield strength of HDPE-GF20?
HDPE-GF20 has a typical yield strength of 50 MPa (7.25 ksi) and a tensile strength of 55 MPa (7.98 ksi) — weaker than 52% of polymer grades. Strength varies by condition: see the 14 listed tempers.
Is HDPE-GF20 easy to machine?
Reasonably — machinability is rated good (55/100, worse than 63% of polymer grades). Cuts easily with sharp, high-rake, polished tools and high speed/low feed; use air blast and generous support since heat build-up and low modulus cause gumming, burrs and part distortion.
Can HDPE-GF20 be welded?
With care — weldability is rated fair (40/100). Excellent hot-plate, butt-fusion, electrofusion, hot-gas and extrusion welding (DVS 2207); adhesive bonding requires corona, flame or plasma pre-treatment.
What surface finishes work on HDPE-GF20?
Cannot be plated or anodized and holds paint poorly; use in-resin colour, laser marking, hot stamping or corona-treated printing, and flame-polish or scrape edges for smooth finishes.
Can HDPE-GF20 be formed, bent or molded?
Injection, blow, rotational and profile extrusion all standard; melt 200–260 °C, mould 20–60 °C, allow 1.5–3% shrinkage with strong anisotropy and post-mould shrink over 24 h.
What is the maximum service temperature of HDPE-GF20?
HDPE-GF20 is rated for continuous use to about 100°C (212 °F), and briefly to 120°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between HDPE FDA Compliant and HDPE-GF40?
FDA Compliant is the default condition — choose for cutting boards, food processing parts, potable water and pharma contact; additive package limited to FDA 21 CFR 177.1520 / EU 10-2011 listed stabilizers. GF40: highly reinforced HDPE with 40% coupled short glass fiber — maximum stiffness, strength and dimensional stability in the PE family, used for structural and under-hood-type mouldings. Yield strength is 26 MPa in FDA Compliant versus 78 MPa in GF40.
Can FabDigit make parts in HDPE-GF20?
Yes — HDPE-GF20 is available for CNC machining, sheet metal and injection molding with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- ASTM D4976 — Standard Specification for Polyethylene Plastics Molding and Extrusion Materials — ASTM International (2020)
- ISO 1872-1/-2 — Plastics: Polyethylene (PE) moulding and extrusion materials — ISO (2015)
- Engineered Materials Handbook Vol. 2 — Engineering Plastics — ASM International (1988)
- CAMPUS Plastics — HDPE datasheets (ISO 10350 property set) — CAMPUS Consortium (2024)
- Hostalen / Lupolen HDPE grade datasheets — LyondellBasell (2023)
- Sclair HDPE resin datasheets — NOVA Chemicals (2023)
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.