EPN
Multi-functional novolac-based epoxy giving higher crosslink density and superior thermal/chemical resistance versus standard bisphenol-A epoxy, used in semiconductor and high-performance composite applications.
Reference datasheet — EPN is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the NEAT condition
EPN grades and fills
EPN is supplied in 8 conditions, soft to hard. NEAT is the default FabDigit quotes; the values on this page are for it.
Compare all 8 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
Rubber-toughened (CTBN / core-shell modified) novolac epoxy | Choose when crack resistance, thermal-shock survival or structural adhesive peel strength matters more than peak Tg and modulus. | 60 | 5 | 95 HRM | |
Flame-retardant grade (brominated novolac / phosphorus-modified), UL 94… | Choose where UL 94 V-0 and high LOI are required in electrical encapsulation, laminates or transformer castings. | 68 | 1.7 | 89 Shore D | |
O-Cresol novolac epoxy | Pick the cresol-novolac chemistry for solid-state moulding powders and EMC binders — higher softening point, lower melt tack and slightly higher Tg than phenol-novolac EPN. | 70 | 1.6 | 89 Shore D | |
NEATDefault Unfilled / neat cast resin | Baseline cured novolac epoxy casting or coating film — choose for chemical linings, adhesives and general high-Tg castings where stiffness demand is modest. | 72 | 2 | 108 HRM | |
Fused-silica filled epoxy molding compound | Pick for IC/discrete encapsulation and transfer-molded electronics where low CTE, low ionic content and low moisture uptake are mandatory. | 85 | 0.7 | 90 Shore D | |
Glass-fabric reinforced novolac epoxy laminate | Choose for high-Tg PCB substrates, electrical insulation parts and structural panels needing 180 °C service with good dielectric behaviour. | 330 | 1.8 | ||
Carbon-fibre prepreg laminate, novolac-epoxy matrix | Choose for aerospace/motorsport structures needing 160–190 °C hot-wet capability beyond standard 120 °C-cure DGEBA prepregs. | 1,900 | 1.5 | ||
Thermally conductive mineral filled | Choose for potting power electronics and LED modules where heat removal plus electrical isolation is required. |
What is EPN?
Multi-functional novolac-based epoxy giving higher crosslink density and superior thermal/chemical resistance versus standard bisphenol-A epoxy, used in semiconductor and high-performance composite applications. EPN has a density of 1.21 g/cm³ (0.0437 lb/in³), heavier than 60% of polymer grades. Its glass-transition temperature is 175°C (347 °F). EPN has a tensile strength of 72 MPa (10.4 ksi), stronger than 78% of polymer grades. Elongation at break is 2% and the elastic modulus is 3.3 GPa (0.479 Msi).
What is EPN used for?
- semiconductor encapsulation
- high-temperature composite matrices
- corrosion-resistant coatings
- printed circuit board resin
Advantages
- High service temperature — 170°C (338 °F), better than 83% of polymer grades
- Stiff — 3.3 GPa (0.479 Msi), better than 80% of polymer grades
- Polishes to a fine finish — 70/100, better than 77% of polymer grades
Limitations
- Low fracture toughness — 0.55 MPa·√m (0.501 ksi·√in), worse than 98% of polymer grades
- Limited ductility — 2%, worse than 95% of polymer grades
- Degrades in UV without stabilisers — 22/100, worse than 83% of polymer grades
- High embodied carbon — 6.8 kg CO₂/kg, worse than 75% of polymer grades
EPN properties
Typical room-temperature values for EPN-NEAT; bars are the position among polymer grades.
Physical5
EPN has a density of 1.21 g/cm³ (0.0437 lb/in³), heavier than 60% of polymer grades. Its glass-transition temperature is 175°C (347 °F).
Mechanical15
EPN has a tensile strength of 72 MPa (10.4 ksi), stronger than 78% of polymer grades. Elongation at break is 2% and the elastic modulus is 3.3 GPa (0.479 Msi).
Thermal10
EPN is rated for continuous service to 170°C (338 °F). It conducts heat at 0.2 W/m·K (0.116 BTU/hr·ft·°F), worse than 56% of polymer grades. Thermal expansion is 60 µm/m·K (33.3 µin/in·°F).
Electrical7
EPN is an electrical insulator with a dielectric strength of 19 kV/mm (482.6 V/mil) and a resistivity of 1×10¹³ Ω·m.
Chemical & Environmental3
Corrosion resistance is excellent (88/100), better than 74% of polymer grades. UV resistance is poor.
Sustainability4
Producing a kilogram of EPN takes about 135 MJ of energy and emits 6.8 kg of CO₂ — more than 79% of polymer grades. Typical recycled content is 0%.
Manufacturability5
EPN's machinability is good (55/100, worse than 64% of polymer grades).
Common Calculations4
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. EPN is highlighted; hover a dot for its name, or open the interactive family chart.
Working with EPN
Is EPN easy to machine?
Machines like a hard brittle thermoset — sharp carbide or PCD tools, high speed, low feed, no coolant needed but strong dust extraction; chipping at exits and drill breakout must be controlled with backing.
Can EPN be welded?
Not weldable — thermoset; join by structural epoxy bonding, mechanical fasteners or co-cure of uncured plies.
Can EPN be formed, bent or molded?
Processed hot (resin softens 60–100 °C): casting, RTM/infusion, prepreg autoclave cure (180 °C typical) or transfer moulding at 165–185 °C with 60–180 s gel; a 180–200 °C post-cure is needed to reach full Tg, and high exotherm plus ~1–2 % cure shrinkage require thin sections or filler loading.
EPN 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 |
|---|---|---|
| epoxy phenol-novolac resin (phenol–formaEEW ≈ 170–185 g/eq, functionality 2.2–6; ECN variant EEW ≈ 195–220 | 55 – 100 | 65 |
| curing agent (phenolic novolac / anhydristoichiometric to epoxy equivalents; determines Tg | 0 – 45 | 34 |
| accelerator (imidazole, TPP, tertiary am | 0.1 – 2 | 0.5 |
| hydrolysable chlorine≤300 ppm for semiconductor-grade resin | ≤ 0.05 | 0.02 |
| fused silica / mineral filler0 for the neat default variant; 70–88 wt% in EMC | 0 – 88 | 0 |
| glass or carbon fibrereinforced variants only | 0 – 65 | 0 |
What surface finishes work on EPN?
Surfaces sand and polish well and take epoxy or PU paint after light abrasion; pigmented or UV-blocking topcoat is recommended outdoors because the aromatic backbone chalks and yellows.
How much does EPN cost?
EPN is a premium-cost polymer ($$$), cheaper than about 51% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
EPN — frequently asked
What is EPN used for?
EPN is typically used for semiconductor encapsulation, high-temperature composite matrices, corrosion-resistant coatings and printed circuit board resin. In short: higher Tg than bisphenol-A epoxy; standard chip encapsulation resin; brittle at 2 % elongation.
What is the tensile strength of EPN?
EPN has a typical tensile strength of 72 MPa (10.4 ksi) — stronger than 78% of polymer grades. Strength varies by condition: see the 8 listed tempers.
Is EPN easy to machine?
Reasonably — machinability is rated good (55/100, worse than 64% of polymer grades). Machines like a hard brittle thermoset — sharp carbide or PCD tools, high speed, low feed, no coolant needed but strong dust extraction; chipping at exits and drill breakout must be controlled with backing.
Can EPN be welded?
Not weldable — thermoset; join by structural epoxy bonding, mechanical fasteners or co-cure of uncured plies.
What surface finishes work on EPN?
Surfaces sand and polish well and take epoxy or PU paint after light abrasion; pigmented or UV-blocking topcoat is recommended outdoors because the aromatic backbone chalks and yellows.
Can EPN be formed, bent or molded?
Processed hot (resin softens 60–100 °C): casting, RTM/infusion, prepreg autoclave cure (180 °C typical) or transfer moulding at 165–185 °C with 60–180 s gel; a 180–200 °C post-cure is needed to reach full Tg, and high exotherm plus ~1–2 % cure shrinkage require thin sections or filler loading.
What is the maximum service temperature of EPN?
EPN is rated for continuous use to about 170°C (338 °F), and briefly to 220°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does EPN cost?
EPN is a premium-cost polymer ($$$), cheaper than about 51% 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.
Sources
- Epoxy phenol novolac resin (EPN-type) technical data — Huntsman Advanced Materials (2020)
- Novolac epoxy resins EPICLON N-770 / N-680 series — DIC Corporation (2022)
- Phenol/cresol novolac epoxy KD-211 / F-51 series — Kukdo Chemical / (2023)
- Engineered Materials Handbook Vol.3: Adhesives and Sealants / Vol.1 Composites — ASM International (1990)
- Epoxy Resins: Chemistry and Technology, 2nd ed. — Marcel Dekker (1988)
- GB/T 13657 Solid epoxy resin / GB/T 2567 Test methods for cast resin properties — SAC (2021)
- ISO 527 / ISO 178 / ISO 75 / IEC 60243 / UL 94 — ISO, IEC, UL (2019)
- Semiconductor epoxy molding compound (EMC) property tables — Sumitomo Bakelite / Hysol (2021)
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.