FabDigit

RPU vs Polyurea and 2 more: properties

RPUPolyureaRubber-LikeClear Rubber-Like

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

2.4 GPa0.35 Msi
0.06 GPa0.01 Msi
0 GPa6.82×10⁻⁴ Msi
0.01 GPa8.7×10⁻⁴ Msi

Shear Modulus

0.87 GPa0.13 Msi
0 GPa2.32×10⁻⁴ Msi

Bulk Modulus

3 GPa0.48 Msi
2 GPa0.29 Msi

Poisson's Ratio

0.38
0.45
0.49
0.48

Tensile Strength (Ultimate)

55 MPa8 ksi
18 MPa2.6 ksi
16 MPa2.3 ksi
5 MPa0.73 ksi

Elongation at Break

6%
380%
520%
180%

Compressive Strength

95 MPa13.8 ksi
25 MPa3.6 ksi
2 MPa0.29 ksi

Compressive Modulus

2.2 GPa0.32 Msi

Flexural Strength

80 MPa11.6 ksi

Flexural Modulus

2.5 GPa0.36 Msi
0.08 GPa0.01 Msi

Shear Strength

40 MPa5.8 ksi
10 MPa1.5 ksi
10 MPa1.5 ksi
4 MPa0.51 ksi

Fracture Toughness (K_IC)

1.3 MPa·√m1.2 ksi·√in

Izod Impact, Notched

40 J/m0.75 ft·lbf/in

Hardness, Shore D

80 Shore D
50 Shore D
16 Shore D
14 Shore D

Hardness, Rockwell M

75 HRM

Hardness, Rockwell R

110 HRR

Hardness, Shore A

95 Shore A
60 Shore A
60 Shore A

Tear Strength

70 kN/m400 lbf/in
40 kN/m228 lbf/in
16 kN/m91.4 lbf/in

Compression Set (22 h, 70 °C)

25%
28%
25%

Physical

Density and transition temperatures.

Density

1.15 g/cm³0.04 lb/in³
1.05 g/cm³0.04 lb/in³
1.15 g/cm³0.04 lb/in³
1.13 g/cm³0.04 lb/in³

Glass Transition (Tg)

95°C203 °F
-55°C-67 °F
-45°C-49 °F
-15°C5 °F

Water Absorption (24 h)

0.3%
0.7%
0.8%
1.2%

Water Absorption (Saturation)

1.2%
2.5%
2%
2.5%

Refractive Index

1.51
1.5

Light Transmission

80%

Thermal

How each material carries heat and how hot it can run.

Thermal Conductivity

0.21 W/m·K0.12 BTU/hr·ft·°F
0.2 W/m·K0.12 BTU/hr·ft·°F
0.2 W/m·K0.12 BTU/hr·ft·°F
0.2 W/m·K0.12 BTU/hr·ft·°F

Specific Heat Capacity

1,600 J/kg·K0.38 BTU/lb·°F
1,700 J/kg·K0.41 BTU/lb·°F
1,800 J/kg·K0.43 BTU/lb·°F
1,650 J/kg·K0.39 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

80 µm/m·K44.4 µin/in·°F
130 µm/m·K72.2 µin/in·°F
170 µm/m·K94.4 µin/in·°F
180 µm/m·K100 µin/in·°F

Max Service Temperature (continuous)

85°C185 °F
120°C248 °F
80°C176 °F
65°C149 °F

Min Service Temperature

-50°C-58 °F
-40°C-40 °F
-40°C-40 °F
-20°C-4 °F

Heat Deflection Temp. @ 0.45 MPa

85°C185 °F

Heat Deflection Temp. @ 1.8 MPa

65°C149 °F

Limiting Oxygen Index

22%
22%
22%
19%

Max Service Temperature (short-term)

130°C266 °F
180°C356 °F
120°C248 °F
90°C194 °F

Electrical

Conductivity and insulation.

Electrical Resistivity

1×10¹¹ Ω·m3.94×10¹⁸ µΩ·in
1×10¹¹ Ω·m3.94×10¹⁸ µΩ·in
1×10¹⁰ Ω·m3.94×10¹⁷ µΩ·in
1×10¹² Ω·m3.94×10¹⁹ µΩ·in

Dielectric Strength

18 kV/mm457 V/mil
20 kV/mm508 V/mil
20 kV/mm508 V/mil
20 kV/mm508 V/mil

Dielectric Constant (1 MHz)

4
4
5
4.5

Dissipation Factor (1 MHz)

0.04
0.05
0.05

Volume Resistivity

1×10¹³ Ω·cm
1×10¹³ Ω·cm
1×10¹² Ω·cm
1×10¹⁴ Ω·cm

Surface Resistivity

1×10¹³ Ω
1×10¹³ Ω
1×10¹⁴ Ω

Comparative Tracking Index (CTI)

600 V
600 V

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

70 / 100
90 / 100
78 / 100
82 / 100

UV / Weathering Resistance

25 / 100
35 / 100
35 / 100
25 / 100

Manufacturability

FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.

Machinability

85 / 100
25 / 100
25 / 100
15 / 100

Weldability

5 / 100
5 / 100
15 / 100
5 / 100

Formability (cold)

5 / 100
90 / 100
88 / 100

Polishability

60 / 100
20 / 100
30 / 100
45 / 100

Mold Shrinkage

0.9%
1.2%
0.6%

Processing Melt Temperature (typ.)

35°C95 °F

Mold Temperature (typ.)

55°C131 °F
70°C158 °F

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

103 MJ/kg44,282 BTU/lb
105 MJ/kg45,142 BTU/lb
100 MJ/kg42,992 BTU/lb
115 MJ/kg49,441 BTU/lb

Embodied Carbon (primary production)

4.6 kg CO₂/kg
5.2 kg CO₂/kg
5 kg CO₂/kg
5.6 kg CO₂/kg

Embodied Water

230 L/kg27.6 gal/lb
250 L/kg30 gal/lb
250 L/kg30 gal/lb
250 L/kg30 gal/lb

Typical Recycled Content

3%
0%
0%
0%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

48 kN·m/kg
17 kN·m/kg
14 kN·m/kg
4 kN·m/kg

Specific Stiffness (E / density)

2.1 MN·m/kg
0.1 MN·m/kg
0 MN·m/kg
0 MN·m/kg

Thermal Shock Resistance Index

0
0
4
1

Same in both: Thermal Diffusivity 0.1 mm²/s

Strength versus weight

Yield strength against density for every polyurethane grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.

71015203050701.11.21.31.4Density (g/cm³)Yield strength (MPa) — log scaleRubber-LikeClear Rubber-Like

Manufacturing and finishing

CapabilityRPUPolyureaRubber-LikeClear Rubber-Like
Urethane castingYesYes
Default conditionShore A 60Shore A 60
Relative cost$$ Standard$$$ Premium$ Budget$$ Standard
Min. machined wall
Best machined surface

Ready to make it?

Upload a CAD file and FabDigit prices the part in RPU and Polyurea side by side — material, machining time, tolerance and finish in one quote. Certified material data ships with the order on request.

Typical handbook values for the conditions named above, normalised for comparison. Hardness on non-Brinell scales is converted approximately for charting only. Request certified data with your order for design-critical properties.