Materials / Compare
PCB Laminate FR-4 vs. Rubber
Compare PCB Laminate FR-4 vs. Rubber strength, stiffness, weight and thermal properties.
| Try it on a partA sample part to run stress or thermal on, free in your browser | Open in LessCAD | Open in LessCAD |
|---|---|---|
| Mechanical | ||
| Yield strength | not given (tensile used) | not given (tensile used) |
| Ultimate tensile strength | 246–385MPasourcetypical, in-plane: cross direction .. length direction (ASTM D3039) | 23MPasourcetypical |
| Flexural strength | 531–621MPasourcetypical: cross direction .. length direction (IPC-TM-650 2.4.4B) | not sourced |
| Elongation at break | not sourced | 830%sourcetypical |
| Young's modulus (stiffness) | 21.9–25.8GPasourcetypical, in-plane: cross direction .. length direction (ASTM D790-15e2) | not sourced |
| Density | 1,920kg/m³sourcetypical, 50% resin content; another FR-4 producer: Park Nelco N4000-6 (high-Tg multifunctional epoxy), not Isola 370HR | 960kg/m³sourcetypical (specific gravity) |
| Strength to weight | 164kN·m/kg6.86x higher | 24kN·m/kg |
| Stiffness to weight | 12.4MN·m/kg | not sourced |
| Poisson's ratio | 0.171–0.177sourcetypical, in-plane: cross direction .. length direction | 0.5sourcegovernment (NBS J. Res. 68A, 1964): computed by NBS for peroxide-cured gum NR vulcanizate, 25 °C, infinitesimal deformation0.49 in the solver: the linear element locks as the ratio nears 0.5 (nearly incompressible). |
| Shear modulus | 10.2GPa | not sourced |
| Bulk modulus | 12.2GPa | not sourced |
| Speed of sound | 3,525m/s | not sourced |
| Thermal | ||
| Thermal conductivity | 0.4W/m·Ksourcetypical (ASTM E1952); direction not stated by the sheet | 0.151W/m·Ksourcegovernment selected value (US Army Natick Laboratories TR 66-49-PR, 1966), soft vulcanized natural rubber, 25 °C |
| Thermal expansion | 13–14µm/m·Ksourcetypical, in-plane X/Y-axis, below Tg (IPC-TM-650 2.4.24C) | not sourced |
| 100 mm part over a 50 °C swing | 67.5µm growth | not sourced |
| Specific heat | 1,200–1,400J/kg·Ksourcetypical (ASTM E1461); another FR-4 producer: Park Nelco N4000-6 (high-Tg multifunctional epoxy), not Isola 370HR | 1,881J/kg·Ksourcegovernment (NBS J. Res. 68A, Table 7; values observed for unvulcanized NR by Bekkedahl and Matheson), 25 °C |
| Heats up and cools (diffusivity) | 0.16mm²/s1.92x faster | 0.0836mm²/s |
| Thermal shock resistance | 324W/m | not sourced |
| Glass transition | 180°Csourcetypical, DSC (IPC-TM-650 2.4.25C) | not sourced |
| Max service temperature | 130°CsourceUL Relative Thermal Index (UL 796) | 70°Csourcecontinuous use operating range |
| Values for | Isola 370HR FR-4 laminate (Polyclad PCL-FR-370HR, 180 C Tg multifunctional epoxy, E-glass fabric), copper removed; Isola data sheet Revision C, last updated April 15, 2021. Woven-glass laminate: the sheet gives in-plane values per weave direction (length / cross) and the Z-axis CTE separately; the solver is isotropic per material. | Weir Minerals Linatex Premium rubber (95 % natural rubber), typical physical properties, spec sheet WMD0118/202305 |
Every value links to the document that states it. "Not sourced" means no citable source states it (or only a specification minimum); figures computed from it are left out too.
Questions
Is PCB Laminate FR-4 stronger than Rubber?
PCB Laminate FR-4 is stronger: its tensile strength is 315 MPa against 23 MPa for Rubber (13.7x).
Which is lighter, PCB Laminate FR-4 or Rubber?
Rubber is lighter: 960 kg/m³ against 1,920 kg/m³ for PCB Laminate FR-4.
Which is lighter for the same job, PCB Laminate FR-4 or Rubber?
For the same stiffness or strength: PCB Laminate FR-4 is lighter for a strong rod or tie, strong beam, strong panel or plate.
| Part that must be | PCB Laminate FR-4 | Rubber |
|---|---|---|
| Strong rod or tie | lighter | 6.86x heavier |
| Strong beam | lighter | 2.86x heavier |
| Strong panel or plate | lighter | 1.85x heavier |
For the same stiffness or strength, mass scales with density over stiffness (or strength) raised to a power set by how the part is loaded: 1 for a rod in tension, 1/2 for a beam in bending, 1/3 for a panel (the standard material-selection indices).
Which conducts heat better, PCB Laminate FR-4 or Rubber?
PCB Laminate FR-4 conducts heat better: 0.4 W/m·K against 0.151 W/m·K for Rubber.