Materials / Compare
PCB Laminate FR-4 vs. Plastic PBT GF30
Compare PCB Laminate FR-4 vs. Plastic PBT GF30 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) | 140MPasourcestress at break, 23 °C |
| Flexural strength | 531–621MPasourcetypical: cross direction .. length direction (IPC-TM-650 2.4.4B) | 210MPasourcetypical, 23 °C |
| Elongation at break | not sourced | 3%sourcestrain at break, 23 °C |
| Young's modulus (stiffness) | 21.9–25.8GPasourcetypical, in-plane: cross direction .. length direction (ASTM D790-15e2) | 9.8GPasourcetypical, 23 °C |
| Density | 1,920kg/m³sourcetypical, 50% resin content; another FR-4 producer: Park Nelco N4000-6 (high-Tg multifunctional epoxy), not Isola 370HR | 1,530kg/m³sourcetypical |
| Strength to weight | 164kN·m/kg1.8x higher | 91.5kN·m/kg |
| Stiffness to weight | 12.4MN·m/kg1.94x higher | 6.41MN·m/kg |
| Poisson's ratio | 0.171–0.177sourcetypical, in-plane: cross direction .. length direction | not sourced |
| Shear modulus | 10.2GPa | not sourced |
| Bulk modulus | 12.2GPa | not sourced |
| Speed of sound | 3,525m/s | 2,531m/s |
| Thermal | ||
| Thermal conductivity | 0.4W/m·Ksourcetypical (ASTM E1952); direction not stated by the sheet | 0.27W/m·Ksourcetypical (DIN 52612-1) |
| Thermal expansion | 13–14µm/m·Ksourcetypical, in-plane X/Y-axis, below Tg (IPC-TM-650 2.4.24C) | 25µm/m·Ksourcelongitudinal (flow), mean 23-55 °C |
| 100 mm part over a 50 °C swing | 67.5µm growth1.85x less | 125µm growth |
| 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 | 1,050J/kg·Ksourcetypical, 23 °C |
| Heats up and cools (diffusivity) | 0.16mm²/s | 0.168mm²/s5% faster |
| Thermal shock resistance | 324W/m | not sourced |
| Melting point | not sourced | 223°CsourceDSC (ISO 11357) |
| Glass transition | 180°Csourcetypical, DSC (IPC-TM-650 2.4.25C) | not sourced |
| Max service temperature | 130°CsourceUL Relative Thermal Index (UL 796) | 205°CsourceHDT 1.8 MPa |
| 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. | BASF Ultradur B 4300 G6 (PBT, 30% glass fibre), injection moulding grade; product information sheet 09/2026, typical values for uncoloured product at 23 °C. |
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 Plastic PBT GF30?
PCB Laminate FR-4 is stronger: its tensile strength is 315 MPa against 140 MPa for Plastic PBT GF30 (2.25x).
Which is lighter, PCB Laminate FR-4 or Plastic PBT GF30?
Plastic PBT GF30 is lighter: 1,530 kg/m³ against 1,920 kg/m³ for PCB Laminate FR-4.
Which is stiffer, PCB Laminate FR-4 or Plastic PBT GF30?
PCB Laminate FR-4 is stiffer: Young's modulus 23.9 GPa against 9.8 GPa for Plastic PBT GF30, so the same part in PCB Laminate FR-4 deflects less under the same load.
Which is lighter for the same job, PCB Laminate FR-4 or Plastic PBT GF30?
For the same stiffness or strength: PCB Laminate FR-4 is lighter for a stiff rod or tie (tension), stiff beam (bending), stiff panel or plate, strong rod or tie, strong beam, strong panel or plate.
| Part that must be | PCB Laminate FR-4 | Plastic PBT GF30 |
|---|---|---|
| Stiff rod or tie (tension) | lighter | 1.94x heavier |
| Stiff beam (bending) | lighter | 24% heavier |
| Stiff panel or plate | lighter | 7% heavier |
| Strong rod or tie | lighter | 1.8x heavier |
| Strong beam | lighter | 37% heavier |
| Strong panel or plate | lighter | 20% 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 Plastic PBT GF30?
PCB Laminate FR-4 conducts heat better: 0.4 W/m·K against 0.27 W/m·K for Plastic PBT GF30.
Which expands less with temperature?
PCB Laminate FR-4 expands less: 13.5 µm/m·K against 25 µm/m·K for Plastic PBT GF30.