PU-Foam-Flexible
PU-Foam-Flexible is a low-density flexible polyurethane casting foam for vacuum-cast cushioning and comfort-simulation parts, offered as standard D350, low-density LD-D180, high-density HD-D550, integral-skin, open-cell, flame-retardant and aliphatic UV-stable conditions (typical product: Axson F16 Flex).
Reference datasheet — PU-Foam-Flexible is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the STD-D350 condition
PU-Foam-Flexible grades and fills
PU-Foam-Flexible is supplied in 7 conditions, soft to hard. STD-D350 is the default FabDigit quotes; the values on this page are for it.
Compare all 7 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
Open-cell breathable soft foam | Pick when air permeability / squeeze-recovery of a real seat or sponge must be simulated; absorbs water and soils easily. | 0.25 | 200 | 12 Shore A | |
Low-density soft foam, 0.15–0.22 g/cm³ | Pick for very soft seat/cushion feel and lightest parts; low tear strength, fragile thin walls. | 0.4 | 180 | 20 Shore A | |
Flame-retardant flexible foam | Pick for automotive interior, rail or transit mock-ups that must pass burn-rate testing; slightly stiffer and darker. | 0.8 | 120 | 45 Shore A | |
STD-D350Default Standard flexible foam, ~0.35 g/cm³ molded density | Default cushioning/comfort prototype foam — balanced softness, tear strength and demold time. | 0.9 | 150 | 40 Shore A | |
Aliphatic / UV-stabilized light-stable flexible foam | Pick for white or light-coloured show models that must not yellow under lighting or sunlight; noticeably more expensive. | 0.9 | 150 | 40 Shore A | |
High-density semi-firm foam, 0.50–0.70 g/cm³ | Pick when the foam part must carry load, hold threads/inserts or survive handling; heavier and firmer. | 2 | 110 | 62 Shore A | |
Self-skinning / integral-skin flexible foam | Pick for grips, armrests and steering-wheel style parts needing a dense paint-ready skin over a soft core. | 2 | 130 | 15 Shore D |
What is PU-Foam-Flexible?
PU-Foam-Flexible is a low-density flexible polyurethane casting foam for vacuum-cast cushioning and comfort-simulation parts, offered as standard D350, low-density LD-D180, high-density HD-D550, integral-skin, open-cell, flame-retardant and aliphatic UV-stable conditions (typical product: Axson F16 Flex). The default 0.35 g/cm³ grade gives 0.9 MPa tensile strength, 150 % elongation, 0.055 W/m·K and service to 80 °C, making it useful for seating and padding mockups. It is a thermoset foam: not weldable, low in strength, and open-cell surfaces need sealing before paint. For rigid lightweight cores use PU-Foam-Rigid instead. PU-Foam-Flexible has a density of 0.35 g/cm³ (0.0126 lb/in³), lighter than 95% of polyurethane grades. Its glass-transition temperature is -45°C (-49 °F). PU-Foam-Flexible has a tensile strength of 0.9 MPa (0.131 ksi), weaker than 100% of polyurethane grades. Elongation at break is 150% and the elastic modulus is 0.01 GPa (7.25×10⁻⁴ Msi).
What is PU-Foam-Flexible used for?
- Cushion/padding prototypes
- Seating mockups
- Ergonomic test parts
- Packaging inserts
Advantages
- Lightweight — 0.35 g/cm³ (0.0126 lb/in³), better than 95% of polyurethane grades
- Good corrosion resistance — 85/100, better than 95% of polyurethane grades
- Forms and bends easily — 85/100, better than 81% of polyurethane grades
- Ductile — tolerates forming and impact — 150%, better than 76% of polyurethane grades
Limitations
- Poor heat conductor — 0.06 W/m·K (0.0318 BTU/hr·ft·°F), worse than 100% of polyurethane grades
- Absorbs moisture — dry before molding — 2.5%, worse than 100% of polyurethane grades
- Low stiffness — 0.01 GPa (7.25×10⁻⁴ Msi), worse than 95% of polyurethane grades
- High mold shrinkage — 1%, worse than 89% of polyurethane grades
- Difficult to machine — 35/100, worse than 81% of polyurethane grades
PU-Foam-Flexible properties
Typical room-temperature values for PU-Foam-Flexible-STD-D350; bars are the position among polyurethane grades.
Physical4
PU-Foam-Flexible has a density of 0.35 g/cm³ (0.0126 lb/in³), lighter than 95% of polyurethane grades. Its glass-transition temperature is -45°C (-49 °F).
Mechanical10
PU-Foam-Flexible has a tensile strength of 0.9 MPa (0.131 ksi), weaker than 100% of polyurethane grades. Elongation at break is 150% and the elastic modulus is 0.01 GPa (7.25×10⁻⁴ Msi).
Thermal8
PU-Foam-Flexible is rated for continuous service to 80°C (176 °F). It conducts heat at 0.06 W/m·K (0.0318 BTU/hr·ft·°F), worse than 100% of polyurethane grades. Thermal expansion is 90 µm/m·K (50 µin/in·°F).
Electrical3
PU-Foam-Flexible has an electrical resistivity of 1×10¹⁰ Ω·m.
Chemical & Environmental3
Corrosion resistance is excellent (85/100), better than 95% of polyurethane grades. UV resistance is poor.
Sustainability4
Producing a kilogram of PU-Foam-Flexible takes about 103 MJ of energy and emits 4.6 kg of CO₂ — less than 62% of polyurethane grades. Typical recycled content is 0%.
Manufacturability5
PU-Foam-Flexible's machinability is fair (35/100, worse than 81% of polyurethane grades); weldability not recommended (0/100); formability excellent (85/100).
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 polyurethane family
Yield strength against density for every polyurethane grade FabDigit runs. PU-Foam-Flexible is highlighted; hover a dot for its name, or open the interactive family chart.
Working with PU-Foam-Flexible
Is PU-Foam-Flexible easy to machine?
Trim with sharp blades, hot wire or band knife; milling smears and tears — use very sharp single-flute tools, high rpm, low feed and vacuum support.
Can PU-Foam-Flexible be welded?
Not weldable; join with PU or contact adhesive, or overpour a second shot against the cured foam skin.
Can PU-Foam-Flexible be formed, bent or molded?
Degas A/B, mix by weight, pour into a silicone vacuum-casting mould with vents and 15–30 % overpack; cream time ~30–60 s, demold 20–60 min, full properties after 24 h (post-cure 60–70 °C accelerates).
PU-Foam-Flexible 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 |
|---|---|---|
| polyether polyol (polyol component A)triol/diol blend, incl. chain extender and cell-opener | 45 – 62 | 55 |
| water (chemical blowing agent)generates CO2 for expansion | 0.3 – 2.5 | 1.2 |
| silicone surfactantcell regulation | 0.3 – 1.5 | 0.8 |
| amine / tin catalystgel + blow balance | 0.1 – 1 | 0.4 |
| pigment / flame retardant / UV stabilizevariant dependent | 0 – 12 | 2 |
| polymeric MDI / modified MDI (component aromatic isocyanate; aliphatic HDI/IPDI in light-stable grades | ≥ 32 (balance) |
What surface finishes work on PU-Foam-Flexible?
Integral-skin surfaces take flexible PU primer/paint or flock; open-cell foam must be skinned or sealed before painting; sand only with the surface chilled or with abrasive mesh.
Equivalent designations
Standards and trade names that resolve to PU-Foam-Flexible in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Also called
- Flexible Foam PU Resin
How much does PU-Foam-Flexible cost?
PU-Foam-Flexible is a high-cost polyurethane ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
PU-Foam-Flexible — frequently asked
What is PU-Foam-Flexible used for?
PU-Foam-Flexible is typically used for cushion/padding prototypes, seating mockups, ergonomic test parts and packaging inserts. In short: softest vacuum-cast foam; high-elongation cushioning grade; integral-skin option available.
What is the tensile strength of PU-Foam-Flexible?
PU-Foam-Flexible has a typical tensile strength of 0.9 MPa (0.131 ksi) — weaker than 100% of polyurethane grades. Strength varies by condition: see the 7 listed tempers.
Is PU-Foam-Flexible easy to machine?
Not especially — machinability is rated fair (35/100, worse than 81% of polyurethane grades). Trim with sharp blades, hot wire or band knife; milling smears and tears — use very sharp single-flute tools, high rpm, low feed and vacuum support.
Can PU-Foam-Flexible be welded?
Not readily — weldability is rated not recommended (0/100). Not weldable; join with PU or contact adhesive, or overpour a second shot against the cured foam skin.
What surface finishes work on PU-Foam-Flexible?
Integral-skin surfaces take flexible PU primer/paint or flock; open-cell foam must be skinned or sealed before painting; sand only with the surface chilled or with abrasive mesh.
Can PU-Foam-Flexible be formed, bent or molded?
Degas A/B, mix by weight, pour into a silicone vacuum-casting mould with vents and 15–30 % overpack; cream time ~30–60 s, demold 20–60 min, full properties after 24 h (post-cure 60–70 °C accelerates).
What is the maximum service temperature of PU-Foam-Flexible?
PU-Foam-Flexible is rated for continuous use to about 80°C (176 °F), and briefly to 100°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does PU-Foam-Flexible cost?
PU-Foam-Flexible is a high-cost polyurethane ($$$$), pricier than about 78% 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.
Sources
- Flexible polyurethane foam casting systems (F-series foam resins) — Axson Technologies / Sika Advanced Resins (2021)
- Vacuum casting polyurethane foam and elastomer resins — H&K / Hei-Cast, Smooth-On (2022)
- ISO 1856 Compression set / ISO 3386 Compression stress-strain of flexible cellular materials — ISO (2018)
- ASM Engineered Materials Handbook Vol. 2 — Engineering Plastics (polyurethane foams) — ASM International (1988)
- CES EduPack / Granta eco-property data, flexible PU foam — Ansys Granta (2022)
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.