EPP Foam
EPP Foam is a closed-cell bead foam made by fusing pre-expanded polypropylene beads in a steam chest, normally 20–200 g/L; the default 45 g/L grade gives 0.5 MPa tensile strength, 15 % elongation and service to about 100 °C.
Values for the Closed Cell condition
EPP Foam grades and fills
EPP Foam is supplied in 9 conditions, soft to hard. Closed Cell is the default FabDigit quotes; the values on this page are for it.
Compare all 9 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
EPP 20 g/L | Pick for lightest-weight void fill and light-goods packaging where load is very low. | 0.2 | 14 | ||
EPP 30 g/L | Common packaging / RC-model and drone-airframe density: light, still resilient after repeated impacts. | 0.33 | 15 | ||
Conductive EPP | Use for ESD-safe trays needing true dissipative/conductive path; also improves UV resistance from carbon black. | 0.44 | 11 | 31 Shore A | |
Flame-retardant EPP | Choose where rail/transport or appliance fire specs (e.g. FMVSS 302, UL 94 HF-1) must be met. | 0.45 | 12 | 30 Shore A | |
ESD / antistatic EPP | Pick for electronics returnable packaging where charge build-up on the foam must be limited. | 0.47 | 13 | 30 Shore A | |
Closed CellDefault standard steam-molded EPP bead foam (≈45 g/L) | Default all-round EPP for automotive energy absorbers, returnable packaging and cushioning; best strength/weight compromise. | 0.5 | 15 | ||
EPP 60 g/L | Choose for higher-energy automotive bumper cores and returnable dunnage needing more crush strength. | 0.66 | 16 | ||
EPP 90 g/L | Use where crush strength and stiffness matter more than weight: seat structures, tool trays, load-bearing inserts. | 0.95 | 16 | ||
EPP 120 g/L | Top of the density range for structural/semi-load-bearing foam cores and heavy-duty pallet or fixture bodies. | 1 | 16 |
Supply forms, finishes and certifications
Ways EPP Foam is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
FOOD | Food-contact / FDA-compliant EPP | Certification |
UV | UV-stabilized EPP | Grade option |
What is EPP Foam?
EPP Foam is a closed-cell bead foam made by fusing pre-expanded polypropylene beads in a steam chest, normally 20–200 g/L; the default 45 g/L grade gives 0.5 MPa tensile strength, 15 % elongation and service to about 100 °C. Unlike EPS, which crushes once, it recovers a high proportion of its shape after repeated impacts, resists chemicals and absorbs little water, so it is used for bumper energy absorbers, seat and headrest cores, returnable containers and robot or drone cushioning. Strength and modulus are low in absolute terms and scale with density by a power law, non-UV-stabilised grades chalk and yellow outdoors, and parts require dedicated steam tooling with high mould cost, looser tolerances and poorer surface finish than injection moulding. EPP Foam 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). EPP Foam 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).
What is EPP Foam used for?
- Car bumper energy-absorbing inserts
- Seat cores and headrests
- Protective packaging foam
- Returnable shipping containers
- Robot and drone bumpers
- Automotive interior trim padding
Advantages
- Lightweight — 0.05 g/cm³ (0.0016 lb/in³), better than 90% of polymer grades
- Good corrosion resistance — 90/100, better than 82% 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 88% of polymer grades
- Low stiffness — 0.01 GPa (0.0012 Msi), worse than 82% of polymer grades
- High mold shrinkage — 2%, worse than 81% of polymer grades
- Absorbs moisture — dry before molding — 0.6%, worse than 75% of polymer grades
EPP Foam properties
Typical room-temperature values for EPP Foam-Closed Cell; bars are the position among polymer grades.
Physical5
EPP Foam 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 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 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 88% of polymer grades. Thermal expansion is 90 µm/m·K (50 µin/in·°F).
Electrical4
EPP Foam has an electrical resistivity of 1×10¹³ Ω·m.
Chemical & Environmental3
Corrosion resistance is excellent (90/100), better than 82% of polymer grades. UV resistance is poor.
Sustainability4
Producing a kilogram of EPP Foam 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'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.
Strength versus weight in the polymer family
Yield strength against density for every polymer grade FabDigit runs. EPP Foam is highlighted; hover a dot for its name, or open the interactive family chart.
Working with EPP Foam
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.
Manufacturability
The process limits FabDigit applies to EPP Foam. Every EPP Foam part is priced by an engineer; design inside these and the quote comes back without a redesign loop.
Injection molding
| Mold shrinkage | — |
|---|---|
| Wall thickness | — – — |
| Recommended draft | — |
| Pre-drying | — |
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) |
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.
Surface treatments FabDigit runs on polymer parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Injection Molding Coating
Metallization / Functional
Equivalent designations
Standards and trade names that resolve to EPP Foam in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Also called
- Expanded Polypropylene
How much does EPP Foam cost?
EPP Foam is a standard-cost polymer ($$), cheaper than about 62% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
EPP Foam — frequently asked
What is EPP Foam used for?
EPP Foam is typically used for car bumper energy-absorbing inserts, seat cores and headrests, protective packaging foam, returnable shipping containers, robot and drone bumpers and automotive interior trim padding. In short: lightweight closed-cell EPP.
What is the tensile strength of EPP Foam?
EPP Foam has a typical tensile strength of 0.5 MPa (0.0725 ksi) — weaker than 89% of polymer grades. Strength varies by condition: see the 9 listed tempers.
Is EPP Foam easy to machine?
Reasonably — machinability is rated good (60/100, better than 51% of polymer grades). Cuts easily with hot wire, band saw, oscillating knife, CNC router (sharp single-flute, high feed) or waterjet; expect fuzzy bead-fracture edges and static-clinging debris.
Can EPP Foam be welded?
With care — weldability is rated fair (45/100). Blocks and skins can be joined by hot-plate/hot-air fusion or PP-compatible hot-melt; solvent bonding does not work, and most PSA tapes need corona/flame treatment or primer.
What surface finishes work on EPP Foam?
Cannot be polished or plated; use in-mold film/skin, flocking, water-based PP-adhesion-promoter paint or laser-marked labels, and use molded-in inserts rather than tapped threads.
Can EPP Foam be formed, bent or molded?
Shaped by steam-chest molding of pre-expanded beads (saturated steam ≈0.15–0.40 MPa); allow ~1.2–3% shrinkage plus post-mold shrink/aging, and design draft, vent-pin layout and uniform wall thickness.
What is the maximum service temperature of EPP Foam?
EPP Foam is rated for continuous use to about 100°C (212 °F), and briefly to 120°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does EPP Foam cost?
EPP Foam is a standard-cost polymer ($$), cheaper than about 62% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Can FabDigit make parts in EPP Foam?
Yes — EPP Foam is available for injection molding; every part is priced by an engineer rather than instantly. 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; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.