E-44 FR (Flame-retardant formulation)
Flame-retardant grade
Required for electrical potting, cable joints and laminates that must meet UL 94 V-0 / GB fire codes.
Values for the FR condition
Other E-44 grades and fills
E-44 is listed in 9 conditions; see the grade overview at E-44.
Compare all 9 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
Conductive / ESD filled | Static-dissipative floorings, coatings and potting where charge build-up must be avoided. | — | 45 | 1.2 | 88 Shore D |
Rubber-toughened | Pick when peel strength and crack resistance matter more than stiffness and heat resistance — structural adhesives. | — | 50 | 9 | — |
Solution / coating grade | Supplied pre-dissolved for anticorrosion primers, tank linings and epoxy-ester/amine-cured paints. | — | 50 | 3 | 82 Shore D |
Mineral / fused-silica filled potting compound | Use for electronic potting and tooling where low CTE, low shrinkage and better heat removal are required. | — | 55 | 1.2 | — |
FRThis page Flame-retardant formulation | Required for electrical potting, cable joints and laminates that must meet UL 94 V-0 / GB fire codes. | — | 58 | 3 | 88 Shore D |
NEATDefault Neat / unfilled amine-cured casting | Baseline E-44 cured with an aliphatic/polyamide amine hardener — adhesives, primers, small castings. | — | 62 | 4.5 | 85 Shore D |
Anhydride-cured (MTHPA/MeHHPA) casting | Choose for electrical casting/potting where higher Tg, low dielectric loss and low colour are needed. | — | 70 | 3 | 88 Shore D |
Glass-fibre reinforced laminate / FRP | Structural laminates, tanks, insulating boards — huge strength gain but anisotropic and abrasive to tooling. | — | 350 | 2 | — |
Carbon-fibre reinforced laminate | For high specific stiffness and near-zero CTE structures; costly and electrically conductive (galvanic risk with Al). | — | 900 | 1.3 | — |
What is E-44 FR?
E-44 FR is E-44 in the FR grade — required for electrical potting, cable joints and laminates that must meet UL 94 V-0 / GB fire codes. E-44 FR has a tensile strength of 58 MPa (8.41 ksi), stronger than 66% of polymer grades. Elongation at break is 3% and the elastic modulus is 4 GPa (0.58 Msi). E-44 FR has a density of 1.35 g/cm³ (0.0488 lb/in³), heavier than 75% of polymer grades. Its glass-transition temperature is 110°C (230 °F). NEAT is the default condition FabDigit quotes; FR is available on request or by drawing note.
Advantages
- Stiff — 4 GPa (0.58 Msi), better than 86% of polymer grades
- Polishes to a fine finish — 70/100, better than 77% of polymer grades
Limitations
- Low fracture toughness — 0.7 MPa·√m (0.637 ksi·√in), worse than 93% of polymer grades
- Limited ductility — 3%, worse than 83% 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
E-44 FR properties
Typical room-temperature values for E-44 FR; 24 are specific to this condition. Other listed values are E-44 reference data and may not represent this condition. Bars are the position among polymer grades.
Physical5
E-44 FR has a density of 1.35 g/cm³ (0.0488 lb/in³), heavier than 75% of polymer grades. Its glass-transition temperature is 110°C (230 °F).
Mechanical15
E-44 FR has a tensile strength of 58 MPa (8.41 ksi), stronger than 66% of polymer grades. Elongation at break is 3% and the elastic modulus is 4 GPa (0.58 Msi).
Thermal10
E-44 FR is rated for continuous service to 105°C (221 °F). It conducts heat at 0.25 W/m·K (0.144 BTU/hr·ft·°F), better than 72% of polymer grades. Thermal expansion is 60 µm/m·K (33.3 µin/in·°F).
Electrical7
E-44 FR is an electrical insulator with a dielectric strength of 18 kV/mm (457.2 V/mil) and a resistivity of 1×10¹³ Ω·m.
Chemical & Environmental3
Corrosion resistance is very good (82/100), better than 56% of polymer grades. UV resistance is poor.
Sustainability4
Producing a kilogram of E-44 FR takes about 137 MJ of energy and emits 6.5 kg of CO₂ — more than 80% of polymer grades. Typical recycled content is 0%.
Manufacturability4
E-44 FR's machinability is good (55/100, worse than 64% of polymer grades).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with E-44 FR
Is E-44 easy to machine?
Cured castings drill/turn/mill with sharp carbide, low feed and good chip clearance; keep tools cool to avoid softening near Tg, and use dust extraction for filled or fibre-reinforced versions.
Can E-44 be welded?
Thermoset — cannot be welded or remelted; joints are made by adhesive bonding with fresh resin or mechanical fastening.
Can E-44 be formed, bent or molded?
Mix with amine/polyamide (RT–80 °C) or anhydride (120–150 °C) hardener at the stoichiometric ratio; degas under vacuum for potting, control exotherm in thick sections (<25 mm per pour) and post-cure to develop full Tg.
What surface finishes work on E-44?
Sand and solvent-wipe before overcoating; cured epoxy takes paint and primers well but needs a PU or acrylic topcoat outdoors because it chalks under UV.
E-44 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 |
|---|---|---|
| epoxide value (eq/100 g)GB/T 13657 spec window; grade name derives from 0.44 | 0.41 – 0.47 | 0.44 |
| volatilesGB/T 13657 limit, wt% | ≤ 2 | — |
| inorganic chlorine≤0.001 mol/100 g, expressed approx. as wt% | ≤ 0.04 | — |
| saponifiable (hydrolysable) chlorine≤0.02 mol/100 g, expressed approx. as wt% | ≤ 0.7 | — |
| bisphenol-A diglycidyl ether (DGEBA) oliepoxy value 0.41–0.47 eq/100 g, EEW about 213–244 g/eq | balance | — |
E-44 FR — frequently asked
What is E-44 FR used for?
E-44 FR is typically used for structural adhesives, protective coatings, composite matrix resin and tooling compounds. In short: chemical-resistant epoxy grade; adhesive and coating workhorse; higher crosslink density.
What is the tensile strength of E-44 FR?
E-44 FR has a typical tensile strength of 58 MPa (8.41 ksi) — stronger than 66% of polymer grades. Strength varies by condition: see the 9 listed tempers.
Is E-44 FR easy to machine?
Reasonably — machinability is rated good (55/100, worse than 64% of polymer grades). Cured castings drill/turn/mill with sharp carbide, low feed and good chip clearance; keep tools cool to avoid softening near Tg, and use dust extraction for filled or fibre-reinforced versions.
Can E-44 FR be welded?
Thermoset — cannot be welded or remelted; joints are made by adhesive bonding with fresh resin or mechanical fastening.
What surface finishes work on E-44 FR?
Sand and solvent-wipe before overcoating; cured epoxy takes paint and primers well but needs a PU or acrylic topcoat outdoors because it chalks under UV.
Can E-44 FR be formed, bent or molded?
Mix with amine/polyamide (RT–80 °C) or anhydride (120–150 °C) hardener at the stoichiometric ratio; degas under vacuum for potting, control exotherm in thick sections (<25 mm per pour) and post-cure to develop full Tg.
What is the maximum service temperature of E-44 FR?
E-44 FR is rated for continuous use to about 105°C (221 °F), and briefly to 140°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- ASM Engineered Materials Handbook Vol. 3: Adhesives and Sealants / Vol. 2: Engineering Plastics — ASM International (1990)
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.