PORON® 4701-50 Firm
PORON® 4701-50 is a firm cellular polyurethane foam available in three density grades — 240 (15), 320 (20), and 480 (30) kg/m³ (lb/ft³) — with compression force deflection typical values of 69 (10), 117 (17), and 269 (39) kPa (psi) respectively at 25% deflection. It maintains low compression set (5–10% maximum) at both 23°C (73°F) and 70°C (158°F), with a recommended constant use temperature up to 90°C (194°F) and intermittent use up to 121°C (250°F). Tensile strength is a minimum of 829 kPa (120 psi) across all density grades.
Key Properties
- Compression Force Deflection — Typical, kPa (psi): 69 (10) / 117 (17) / 269 (39) at 240 / 320 / 480 kg/m³; ASTM D3574-95; 0.51 cm/min, 25% deflection
- Tensile Strength, min. kPa (psi): 829 (120); ASTM D3574-75 Test E
- Tensile Elongation, % min.: 100; ASTM D3574-75 Test E
- Compression Set, % max @ 23°C (73°F): 5 / 5 / 10 at 240 / 320 / 480 kg/m³; ASTM D3574-95 Test D
- Density: 240 kg/m³ (15 lb/ft³), 320 kg/m³ (20 lb/ft³), 480 kg/m³ (30 lb/ft³); ASTM D3574-95, Test A
- Recommended Constant Use Temperature (Max.): 90°C (194°F)
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Physical Properties
| Property | Value | Test Method |
| Color (Code) | Black (04) | — |
| Density Tolerance | ± 10% (240 and 320 kg/m³); ± 20% (480 kg/m³) | ASTM D3574-95, Test A |
| Available Thicknesses, mm (inches) | 0.79–1.14 (0.031–0.045), 1.57–3.18 (0.062–0.125), 4.78–12.70 (0.188–0.500) | — |
| Thickness Tolerance | ± 10% | — |
| Compression Force Deflection — Typical, kPa (psi) | 69 (10) / 117 (17) / 269 (39) at 240 / 320 / 480 kg/m³ | ASTM D3574-95; 0.51 cm/min, 25% deflection |
| Compression Force Deflection — Range, kPa (psi) | 55–97 (8–14) / 90–159 (13–23) / 207–415 (30–60) at 240 / 320 / 480 kg/m³ | ASTM D3574-95; 0.51 cm/min, 25% deflection |
| Hardness, Durometer Shore O | 18 / 24 / 55 at 240 / 320 / 480 kg/m³ | ASTM D2240-97 |
| Hardness, Shore A | 13 / 18 / 42 at 240 / 320 / 480 kg/m³ | ASTM D2240-97 |
| Compression Set, % max @ 23°C (73°F) | 5 / 5 / 10 at 240 / 320 / 480 kg/m³ | ASTM D3574-95 Test D |
| Compression Set, % max @ 70°C (158°F) | 5 / 5 / 10 at 240 / 320 / 480 kg/m³ | ASTM D3574-95 Test D |
| Compression Set — Autoclaved 5 hrs @ 121°C | 100 (240 kg/m³) / 90 (320 kg/m³) | ASTM D3574-95 Test J/Test D |
| Tensile Strength, min. kPa (psi) | 829 (120) | ASTM D3574-75 Test E |
| Tensile Elongation, % min. | 100 | ASTM D3574-75 Test E |
| Tear Strength — Typical, kN/m (pli) | 1.1 (6) / 1.8 (10) / 2.3 (13) at 240 / 320 / 480 kg/m³ | ASTM D264-91 Die C |
| Tear Strength — Range, kN/m (pli) | — / 2.1 (12) / 2.8 (16) – 4.2 (24) at 320 / 480 kg/m³ | ASTM D264-91 Die C |
| Dimensional Stability, % max — 22 hrs @ 80°C forced-air oven | ± 1 | — |
Electrical Properties
| Property | Value | Test Method |
| Dielectric Strength, kV/m (V/mil) | 1969 (50) | ASTM D149-97a |
| Dielectric Constant K’ (“DK”) @ 22°C, 50% RH | 1.63 | ASTM D150 |
| Dissipation Factor tan D (“DF”) | 0.05 | ASTM D150-98 |
| Volume Resistivity, ohm·cm (ohm·in) | 2 × 10¹² (7.87 × 10¹¹) | ASTM D257-99 |
| Surface Resistivity, ohm/sq | 7 × 10¹² | ASTM D257-99 |
Thermal Properties
| Property | Value | Test Method |
| Thermal Conductivity, W/m·°C (BTU·in/hr·ft²·°F) | 0.090 | ASTM C518-98 |
| Coefficient of Thermal Expansion | 2.3–3.1 × 10⁻⁴ in/in/°C (1.3–1.7 × 10⁻⁴ in/in/°F) | — |
| Recommended Constant Use Temperature (Max.) | 90°C (194°F) | — |
| Recommended Intermittent Use Temperature (Max.) | 121°C (250°F) | — |
| Embrittlement Temperature | -40°C (-40°F) | ASTM D746-98 |
| Cold Flexibility @ -40°C (-40°F) | Pass | MIL-P-12420D 1991 |
Flame & Fire Performance
| Property | Value | Test Method |
| UL 94 HBF — Min. Thickness Passed, mm (in) | 4.8 (0.188) / 1.6 (0.062) / 1.1 (0.045) at 240 / 320 / 480 kg/m³ | UL 94 HBF (File E20305) |
| FMVSS 302 — Min. Thickness Passed, mm (in) | 4.8 (0.188) / 1.6 (0.062) at 240 / 320 kg/m³ | ISO 3795 / DIN 75200 |
| CSA Comp HBF — Min. Thickness Passed, mm (in) | 3.175 (0.125) at 240 kg/m³ | CSA (File 188149) |
| UL Gasketing & Sealing | Pass | UL JMST2 (File MH15464) |
| Fogging | Pass | SAE J-1756, 3 hrs @ 100°C |
Outgassing
| Property | Value | Test Method |
| Outgassing TML, % | 0.6 (240 kg/m³) / 0.8 (320 kg/m³) | ASTM E595-93, 24 hrs @ 125°C, <7 kPa |
| Outgassing CVCM, % | 0.04 / 0.05 / 0.06 at 240 / 320 / 480 kg/m³ | ASTM E595-93 |
| Outgassing WVR, % | 0.1 / 0.3 / 0.4 at 240 / 320 / 480 kg/m³ | ASTM E595-93 |
Environmental Performance
| Property | Value | Test Method |
| Moisture Absorption — High Humidity, % Weight Gain (Typical) | 2 | AMS 3568-95 |
| Water Absorption — Immersion, % Weight Gain (Typical) | 8 / 13 / 5 at 240 / 320 / 480 kg/m³ | ASTM D570-95 |
| UV Resistance | Good | ASTM G53-96 |
| Ozone Resistance | Pass | GM 4486P-95 |
| Corrosion Resistance | Pass | AMS 3568-91 |
| Mildew / Bacteria Resistance | Good | ASTM G21 |
| Staining | No Stain | ASTM D925 |
Compliance
- UL 94 HBF — Compliant (File E20305)
- FMVSS 302 — Compliant (ISO 3795 / DIN 75200)
- CSA Comp HBF — Compliant (File 188149)
- UL Gasketing & Sealing — Compliant (UL JMST2, File MH15464)
- Firm gaskets and seals for electronics enclosures and industrial equipment requiring higher compression loads
- EMI and environmental sealing in automotive interior assemblies
- Cushioning and vibration dampening in electronics and industrial assemblies
- Dimensional stability-critical sealing applications across multi-density configurations
- Automotive interior components requiring FMVSS 302 flame compliance
Common industries: automotive, electronics, industrial manufacturing.
PORON® 4701-50 is a firm grade within the PORON® cellular polyurethane foam family, designed for sealing, gasketing, and cushioning applications that require higher compressive loads than softer PORON grades. It is available in three density grades — 240 (15), 320 (20), and 480 (30) kg/m³ (lb/ft³) — providing a range of compression force deflection values to accommodate varied design requirements while maintaining excellent resilience and dimensional stability.
The material exhibits low compression set at both ambient and elevated temperatures, retaining its sealing force over time. Electrical properties include a dielectric strength of 1969 kV/m (50 V/mil), a dielectric constant of 1.63 at 22°C and 50% RH, and a volume resistivity of 2 × 10¹² ohm·cm. Thermal conductivity is 0.090 W/m·°C.
Environmental testing confirms good UV resistance, ozone resistance, corrosion resistance, and mildew/bacteria resistance, with no staining per ASTM D925. Cold flexibility is maintained at -40°C (-40°F), and fogging performance passes SAE J-1756 at 3 hrs @ 100°C.
Compliant with UL 94 HBF (File E20305), FMVSS 302 (ISO 3795 / DIN 75200), CSA (File 188149), and UL Gasketing & Sealing JMST2 (File MH15464).
What differentiates PORON® 4701-50 from softer PORON® grades?
PORON® 4701-50 delivers higher compression force deflection — 69 to 269 kPa (10–39 psi) typical at 25% deflection depending on density — compared to softer PORON grades, making it suited for applications where higher sealing loads and dimensional stability are required.
Why is compression set critical for a foam sealing material?
Compression set measures how much a foam permanently deforms after being held under load at temperature. A low compression set — 5% maximum for the 240 and 320 kg/m³ grades at both 23°C and 70°C — means the material continues to exert sealing force over the service life of the assembly rather than relaxing and losing contact pressure.
hat is the service temperature range for PORON® 4701-50?
The recommended constant use temperature is 90°C (194°F) maximum, with intermittent use up to 121°C (250°F). Cold flexibility is maintained at -40°C (-40°F) per MIL-P-12420D 1991, and embrittlement does not occur above -40°C (-40°F).
Is PORON® 4701-50 suitable for flame-rated environments?
Yes. PORON® 4701-50 is compliant with UL 94 HBF (File E20305), FMVSS 302 (ISO 3795 / DIN 75200), and CSA Comp HBF (File 188149), with minimum passing thicknesses that vary by density grade. It also carries UL Gasketing & Sealing approval under JMST2 (File MH15464).
How should PORON® 4701-50 be specified?
Specify grade (PORON® 4701-50), density (240, 320, or 480 kg/m³), thickness, compliance requirements, dimensional tolerances, and finished format.
