EPS Foam Core EPS-GR
Additive grade
ASTM C578 · GB GB/T 10801.1
EPS-GR = graphite-enhanced EPS
Choose when insulation value per thickness is critical — graphite IR blocker cuts λ ~15–20 % at equal density.
Values for the EPS-GR condition
Other EPS Foam Core grades and fills
EPS Foam Core is listed in 8 conditions; see the grade overview at EPS Foam Core.
Compare all 8 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
EPS 12 kg/m³ | Cheapest, lightest grade — void fill, packaging and non-structural insulation only. | — | 0.13 | 2.5 | — |
EPS 15 kg/m³ | The commodity construction board; use where insulation matters more than load. | — | 0.17 | 3 | — |
EPS-GRThis page Graphite-enhanced EPS | Choose when insulation value per thickness is critical — graphite IR blocker cuts λ ~15–20 % at equal density. | — | 0.2 | 3 | — |
EPS 18 kg/m³ | Common SIP and wall-panel core — best cost/strength balance in building use. | — | 0.21 | 3 | — |
Flame-retardant EPS | Mandatory grade for building envelopes and any panel that must meet GB 8624 B1/B2 or DIN 4102 B1. | — | 0.24 | 3 | — |
EPS-22Default EPS 22 kg/m³ | Default sandwich-panel core: enough shear strength for skin-bonded panels at still-low cost. | — | 0.25 | 3.5 | — |
EPS 29 kg/m³ | Pick when the core must carry real compressive/shear load — geofoam, floor and roof panels. | — | 0.35 | 4 | — |
EPS 38–48 kg/m³ | Highest-density EPS for hardpoints, tooling blocks, surfboard blanks and heavily loaded geofoam. | — | 0.48 | 4.5 | — |
What is EPS Foam Core EPS-GR?
EPS Foam Core EPS-GR is EPS Foam Core in the EPS-GR grade — choose when insulation value per thickness is critical — graphite IR blocker cuts λ ~15–20 % at equal density. EPS Foam Core EPS-GR has a tensile strength of 0.2 MPa (0.029 ksi), weaker than 100% of composite grades. Elongation at break is 3% and the elastic modulus is 0 GPa (6.53×10⁻⁴ Msi). EPS Foam Core EPS-GR has a density of 0.02 g/cm³ (6.5×10⁻⁴ lb/in³), lighter than 100% of composite grades. Its glass-transition temperature is 100°C (212 °F). EPS-22 is the default condition FabDigit quotes; EPS-GR is available on request or by drawing note.
Advantages
- Lightweight — 0.02 g/cm³ (6.5×10⁻⁴ lb/in³), better than 100% of composite grades
- Low embodied carbon — 3.3 kg CO₂/kg, better than 94% of composite grades
- Easy to machine — 85/100, better than 90% of composite grades
- Ductile — tolerates forming and impact — 3%, better than 75% of composite grades
Limitations
- Low stiffness — 0 GPa (6.53×10⁻⁴ Msi), worse than 100% of composite grades
- Degrades in UV without stabilisers — 12/100, worse than 100% of composite grades
- Hard to polish — 5/100, worse than 99% of composite grades
- Poor heat conductor — 0.03 W/m·K (0.0179 BTU/hr·ft·°F), worse than 97% of composite grades
- Limited service temperature — 75°C (167 °F), worse than 96% of composite grades
EPS Foam Core EPS-GR properties
Typical room-temperature values for EPS Foam Core EPS-GR; 17 are specific to this condition. Other listed values are EPS Foam Core reference data and may not represent this condition. Bars are the position among composite grades.
Physical4
EPS Foam Core EPS-GR has a density of 0.02 g/cm³ (6.5×10⁻⁴ lb/in³), lighter than 100% of composite grades. Its glass-transition temperature is 100°C (212 °F).
Mechanical11
EPS Foam Core EPS-GR has a tensile strength of 0.2 MPa (0.029 ksi), weaker than 100% of composite grades. Elongation at break is 3% and the elastic modulus is 0 GPa (6.53×10⁻⁴ Msi).
Thermal8
EPS Foam Core EPS-GR is rated for continuous service to 75°C (167 °F). It conducts heat at 0.03 W/m·K (0.0179 BTU/hr·ft·°F), worse than 97% of composite grades. Thermal expansion is 65 µm/m·K (36.1 µin/in·°F).
Electrical4
EPS Foam Core EPS-GR has an electrical resistivity of 1×10¹² Ω·m.
Chemical & Environmental3
Corrosion resistance is very good (80/100), better than 54% of composite grades. UV resistance is not recommended.
Sustainability4
Producing a kilogram of EPS Foam Core EPS-GR takes about 98 MJ of energy and emits 3.3 kg of CO₂ — less than 69% of composite grades. Typical recycled content is 5%.
Manufacturability3
EPS Foam Core EPS-GR's machinability is excellent (85/100, better than 90% of composite grades).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with EPS Foam Core EPS-GR
Is EPS Foam Core easy to machine?
Hot-wire cut or CNC route with sharp, fast, low-rake tools and vacuum extraction; avoid melt smearing and static bead scatter.
Can EPS Foam Core be welded?
Not weldable in the metal sense — blocks are joined by hot-plate/steam fusion, EPS-safe PU or water-based adhesives, or foam-safe spray glue.
Can EPS Foam Core be formed, bent or molded?
Pre-expand beads to target density, age 6–24 h, then steam-mould at ~0.8–1.1 bar (110–125 °C steam) or cut shapes from large moulded blocks; allow post-mould drying/stabilising.
What surface finishes work on EPS Foam Core?
Skin with FRP, cement board, metal or paper facings; only water-based or epoxy coatings — polyester/vinylester styrene and solvent paints dissolve the cells.
EPS Foam Core 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 |
|---|---|---|
| pentane (blowing agent, residual)highest as-expanded, decays with ageing | 0.1 – 6 | 1 |
| flame retardant (polymeric brominated, PFR grades only; HBCD phased out | 0 – 1 | 0.7 |
| graphite / carbon IR blockergrey/GPS grades only | 0 – 4 | 2 |
| nucleating & antistatic additives | 0 – 0.5 | 0.2 |
| polystyrene (styrene homopolymer)solid phase; foam is >95 vol % air | ≥ 92 (balance) | — |
EPS Foam Core EPS-GR — frequently asked
What is EPS Foam Core EPS-GR used for?
EPS Foam Core EPS-GR is typically used for structural insulated panels (SIPs), surfboard cores, low-load architectural panels and packaging sandwich structures. In short: cheapest sandwich core; lowest strength of the foams; epoxy or water-based adhesives only.
What is the tensile strength of EPS Foam Core EPS-GR?
EPS Foam Core EPS-GR has a typical tensile strength of 0.2 MPa (0.029 ksi) — weaker than 100% of composite grades. Strength varies by condition: see the 8 listed tempers.
Is EPS Foam Core EPS-GR easy to machine?
Yes — machinability is rated excellent (85/100, better than 90% of composite grades). Hot-wire cut or CNC route with sharp, fast, low-rake tools and vacuum extraction; avoid melt smearing and static bead scatter.
Can EPS Foam Core EPS-GR be welded?
Not weldable in the metal sense — blocks are joined by hot-plate/steam fusion, EPS-safe PU or water-based adhesives, or foam-safe spray glue.
What surface finishes work on EPS Foam Core EPS-GR?
Skin with FRP, cement board, metal or paper facings; only water-based or epoxy coatings — polyester/vinylester styrene and solvent paints dissolve the cells.
Can EPS Foam Core EPS-GR be formed, bent or molded?
Pre-expand beads to target density, age 6–24 h, then steam-mould at ~0.8–1.1 bar (110–125 °C steam) or cut shapes from large moulded blocks; allow post-mould drying/stabilising.
What is the maximum service temperature of EPS Foam Core EPS-GR?
EPS Foam Core EPS-GR is rated for continuous use to about 75°C (167 °F), and briefly to 90°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- ASTM C578 — Rigid Cellular Polystyrene Thermal Insulation — ASTM International (2022)
- EN 13163 — Thermal insulation products: factory made EPS — CEN (2016)
- Cellular Solids: Structure and Properties (Gibson & Ashby) — Cambridge University Press (1997)
- Neopor / Styropor EPS technical data — BASF (2023)
- ICE Embodied Carbon Database v3 — EPS — Circular Ecology (2019)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.