EPP Foam · grade · default condition
EPP Foam Closed Cell
Properties of the Closed Cell condition, compared with the other EPP Foam grades.
Default all-round EPP for automotive energy absorbers, returnable packaging and cushioning; best strength/weight compromise.
What is EPP Foam Closed Cell?
EPP Foam Closed Cell is EPP Foam in the Closed Cell grade — default all-round EPP for automotive energy absorbers, returnable packaging and cushioning; best strength/weight compromise. EPP Foam Closed Cell has a tensile strength of 0.5 MPa (0.0725 ksi), weaker than 89% of polymer grades. Elongation at break is 15% and the elastic modulus is 0.01 GPa (0.0012 Msi). EPP Foam Closed Cell has a density of 0.05 g/cm³ (0.0016 lb/in³), lighter than 90% of polymer grades. Its glass-transition temperature is -10°C (14 °F).
Advantages
- Lightweight — 0.05 g/cm³ (0.0016 lb/in³), better than 90% of polymer grades
- Good corrosion resistance — 90/100, better than 81% of polymer grades
Limitations
- Hard to polish — 5/100, worse than 99% of polymer grades
- Poor heat conductor — 0.04 W/m·K (0.0225 BTU/hr·ft·°F), worse than 87% of polymer grades
- Low stiffness — 0.01 GPa (0.0012 Msi), worse than 83% of polymer grades
- High mold shrinkage — 2%, worse than 81% of polymer grades
- Absorbs moisture — dry before molding — 0.6%, worse than 76% of polymer grades
EPP Foam Closed Cell properties
Typical room-temperature values for EPP Foam Closed Cell — 13 properties are specific to this condition; the rest are grade-level values shared by every EPP Foam grade. Each bar shows where the value sits among the polymer grades in FabDigit's library — further right is higher.
Physical5
EPP Foam Closed Cell has a density of 0.05 g/cm³ (0.0016 lb/in³), lighter than 90% of polymer grades. Its glass-transition temperature is -10°C (14 °F).
Mechanical11
EPP Foam Closed Cell has a tensile strength of 0.5 MPa (0.0725 ksi), weaker than 89% of polymer grades. Elongation at break is 15% and the elastic modulus is 0.01 GPa (0.0012 Msi).
Thermal8
EPP Foam Closed Cell is rated for continuous service to 100°C (212 °F). It conducts heat at 0.04 W/m·K (0.0225 BTU/hr·ft·°F), worse than 87% of polymer grades. Thermal expansion is 90 µm/m·K (50 µin/in·°F).
Electrical4
EPP Foam Closed Cell has an electrical resistivity of 1×10¹³ Ω·m.
Chemical & Environmental3
Corrosion resistance is excellent (90/100), better than 81% of polymer grades. UV resistance is poor.
Sustainability4
Producing a kilogram of EPP Foam Closed Cell takes about 105 MJ of energy and emits 3.6 kg of CO₂ — more than 54% of polymer grades. Typical recycled content is 5%.
Manufacturability6
EPP Foam Closed Cell's machinability is good (60/100, better than 51% of polymer grades); weldability fair (45/100); formability poor (30/100).
Common Calculations4
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other EPP Foam grades and fills
EPP Foam is also supplied in 10 other conditions. The full side-by-side table is on the EPP Foam overview.
- Closed CellDefaultDefault all-round EPP for automotive energy absorbers, returnable packaging and cushioning; best strength/weight compromise.0.5 MPa tensile
- EPP-120Top of the density range for structural/semi-load-bearing foam cores and heavy-duty pallet or fixture bodies.1 MPa tensile
- EPP-90Use where crush strength and stiffness matter more than weight: seat structures, tool trays, load-bearing inserts.0.95 MPa tensile
- EPP-60Choose for higher-energy automotive bumper cores and returnable dunnage needing more crush strength.0.66 MPa tensile
- EPP-30Common packaging / RC-model and drone-airframe density: light, still resilient after repeated impacts.0.33 MPa tensile
- EPP-20Pick for lightest-weight void fill and light-goods packaging where load is very low.0.2 MPa tensile
Working with EPP Foam Closed Cell
Is EPP Foam easy to machine?
Cuts easily with hot wire, band saw, oscillating knife, CNC router (sharp single-flute, high feed) or waterjet; expect fuzzy bead-fracture edges and static-clinging debris.
Can EPP Foam be welded?
Blocks and skins can be joined by hot-plate/hot-air fusion or PP-compatible hot-melt; solvent bonding does not work, and most PSA tapes need corona/flame treatment or primer.
Can EPP Foam be formed, bent or molded?
Shaped by steam-chest molding of pre-expanded beads (saturated steam ≈0.15–0.40 MPa); allow ~1.2–3% shrinkage plus post-mold shrink/aging, and design draft, vent-pin layout and uniform wall thickness.
What surface finishes work on EPP Foam?
Cannot be polished or plated; use in-mold film/skin, flocking, water-based PP-adhesion-promoter paint or laser-marked labels, and use molded-in inserts rather than tapped threads.
EPP Foam 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 |
|---|---|---|
| blowing agent residue (pentane / CO2 / alargely diffused out after aging; cells finally air-filled | 0 – 2 | 0.5 |
| nucleating agent, stabilizers, pigmentantioxidant/HALS, talc nucleant, carbon black or color masterbatch | 0.3 – 2 | 1 |
| antistatic / FR / conductive additiveonly in ESD, COND and FR variants | 0 – 8 | 0 |
| polypropylene (random copolymer base resPP-R / PP block copolymer bead matrix | ≥ 95 (balance) | — |
EPP Foam Closed Cell — frequently asked
What is EPP Foam Closed Cell used for?
EPP Foam Closed Cell is typically used for car bumper energy-absorbing inserts, seat cores and headrests, protective packaging foam, returnable shipping containers, robot and drone bumpers and automotive interior trim padding. In short: lightweight closed-cell EPP.
What is the tensile strength of EPP Foam Closed Cell?
EPP Foam Closed Cell has a typical tensile strength of 0.5 MPa (0.0725 ksi) — weaker than 89% of polymer grades. Strength varies by condition: see the 11 listed tempers.
Is EPP Foam Closed Cell easy to machine?
Reasonably — machinability is rated good (60/100, better than 51% of polymer grades). Cuts easily with hot wire, band saw, oscillating knife, CNC router (sharp single-flute, high feed) or waterjet; expect fuzzy bead-fracture edges and static-clinging debris.
Can EPP Foam Closed Cell be welded?
With care — weldability is rated fair (45/100). Blocks and skins can be joined by hot-plate/hot-air fusion or PP-compatible hot-melt; solvent bonding does not work, and most PSA tapes need corona/flame treatment or primer.
What surface finishes work on EPP Foam Closed Cell?
Cannot be polished or plated; use in-mold film/skin, flocking, water-based PP-adhesion-promoter paint or laser-marked labels, and use molded-in inserts rather than tapped threads.
Can EPP Foam Closed Cell be formed, bent or molded?
Shaped by steam-chest molding of pre-expanded beads (saturated steam ≈0.15–0.40 MPa); allow ~1.2–3% shrinkage plus post-mold shrink/aging, and design draft, vent-pin layout and uniform wall thickness.
What is the maximum service temperature of EPP Foam Closed Cell?
EPP Foam Closed Cell is rated for continuous use to about 100°C (212 °F), and briefly to 120°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Can FabDigit make parts in EPP Foam Closed Cell?
Yes — EPP Foam Closed Cell is available for CNC machining, sheet metal and injection molding with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- ARPRO expanded polypropylene grade data (density series) — JSP (2023)
- Neopolen P particle foam product range — BASF (2022)
- Eperan-PP expanded polypropylene technical data — Kaneka (2022)
- ISO 844 — Rigid cellular plastics, compression test — ISO (2021)
- ISO 1798 — Flexible cellular polymeric materials, tensile strength and elongation — ISO (2008)
- Engineered Materials Handbook Vol. 2: Engineering Plastics (polypropylene data) — ASM International (1988)
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.