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Integral Skin PU Foam

Integral Skin PU Foam is a semi-rigid to rigid polyurethane moulded so that a dense solid skin forms over a cellular core in one shot, tested to ASTM D3574 methods.

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Reference datasheet — Integral Skin PU Foam 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 SR-350 condition

Integral Skin PU Foam grades and fills

Integral Skin PU Foam is supplied in 9 conditions, soft to hard. SR-350 is the default FabDigit quotes; the values on this page are for it.

Compare all 9 grades and fillsHide
Grade · open for datasheetBest forYield MPaTensile MPaElong. %Hardness
Low-density soft semi-rigid integral skin, ~0.25 g/cm³
Pick when cushioning feel and low part weight matter more than stiffness (headrests, armrest pads, wheelchair pads).218012 Shore D
Flame-retardant integral skin
Use where rail/transit (EN 45545), aircraft interior or electrical-enclosure fire requirements apply.311027 Shore D
Carbon-black filled antistatic/dissipative integral skin
Use for electronics and medical enclosures or handles that must bleed off static charge.39027 Shore D
Light-stable aliphatic integral skin
Choose when the molded skin is the visible finished surface in sunlight and no topcoat is allowed (light-colored interior trim, medical housings).314025 Shore D
SR-350Default
Semi-rigid integral skin, ~0.35 g/cm³ molded density
General-purpose self-skinning semi-rigid system for armrests, grips, covers and soft-touch panels.415065 Shore A
High-density semi-rigid integral skin, ~0.50 g/cm³
Choose for wear- and grip-critical parts (steering wheels, shift knobs, handles) needing a tough, thick skin.614080 Shore A
Microcellular self-skinning elastomer, ~0.6 g/cm³
Pick for shoe soles, rollers, seals and vibration pads where high tear/abrasion resistance and rubbery resilience are required.932018 Shore D
Rigid structural integral skin (RIM structural foam), ~0.70 g/cm³
Use for load-bearing paint-ready housings and covers (medical equipment, kiosk, instrument enclosures) as a low-tooling-cost alternative to injection molding.24865 Shore D
Milled-glass / mineral reinforced rigid integral skin
Pick for large rigid panels needing higher stiffness, lower CTE and better dimensional stability than unfilled structural foam.30572 Shore D

Supply forms, finishes and certifications

Ways Integral Skin PU Foam is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.

OptionWhat it isType
MED
Medical gradeCertification

What is Integral Skin PU Foam?

Integral Skin PU Foam is a semi-rigid to rigid polyurethane moulded so that a dense solid skin forms over a cellular core in one shot, tested to ASTM D3574 methods. Engineers use it for rigidity plus cushioning and a finished, tool-grained surface without secondary coating; parts are RIM or open-pour mouldings at about 0.35 g/cm³, 3.5 MPa tensile strength and 150 % elongation. As a thermoset it cannot be welded or reground, service temperature is capped at 90 °C, and aromatic systems yellow unless topcoated or ordered as light-stable aliphatic. Semi-rigid PU foam is cheaper where no skin is needed. Integral Skin PU Foam has a density of 0.35 g/cm³ (0.0126 lb/in³), lighter than 84% of polymer grades. Its glass-transition temperature is -30°C (-22 °F). Integral Skin PU Foam has a tensile strength of 4 MPa (0.508 ksi), weaker than 83% of polymer grades. Elongation at break is 150% and the elastic modulus is 0.05 GPa (0.0073 Msi).

What is Integral Skin PU Foam used for?

  • automotive steering wheels and armrests
  • office chair armrests
  • shoe soles
  • furniture handles and decorative parts

Advantages

  • Lightweight — 0.35 g/cm³ (0.0126 lb/in³), better than 84% of polymer grades

Limitations

  • Absorbs moisture — dry before molding — 2%, worse than 97% of polymer grades
  • Difficult to weld — 5/100, worse than 89% of polymer grades
  • Poor heat conductor — 0.06 W/m·K (0.0347 BTU/hr·ft·°F), worse than 84% of polymer grades
  • Hard to polish — 30/100, worse than 82% of polymer grades
  • Needs corrosion protection — 70/100, worse than 78% of polymer grades

Integral Skin PU Foam properties

Typical room-temperature values for Integral Skin PU Foam-SR-350; bars are the position among polymer grades.

Physical3

Integral Skin PU Foam has a density of 0.35 g/cm³ (0.0126 lb/in³), lighter than 84% of polymer grades. Its glass-transition temperature is -30°C (-22 °F).

Density0.35 g/cm³0.01 lb/in³
Glass Transition (Tg)-30°C-22 °F
Water Absorption (24 h)2%

Mechanical11

Integral Skin PU Foam has a tensile strength of 4 MPa (0.508 ksi), weaker than 83% of polymer grades. Elongation at break is 150% and the elastic modulus is 0.05 GPa (0.0073 Msi).

Elastic (Young's) Modulus0.05 GPa0.01 Msi
Poisson's Ratio0.35
Tensile Strength (Ultimate)4 MPa0.51 ksi
Elongation at Break150%
Compressive Strength0.6 MPa0.09 ksi
Compressive Modulus0.02 GPa0 Msi
Flexural Strength3 MPa0.36 ksi
Flexural Modulus0.05 GPa0.01 Msi
Hardness, Shore A65 Shore A
Tear Strength3 kN/m17.1 lbf/in
Compression Set (22 h, 70 °C)10%

Thermal8

Integral Skin PU Foam is rated for continuous service to 90°C (194 °F). It conducts heat at 0.06 W/m·K (0.0347 BTU/hr·ft·°F), worse than 84% of polymer grades. Thermal expansion is 150 µm/m·K (83.3 µin/in·°F).

Thermal Conductivity0.06 W/m·K0.03 BTU/hr·ft·°F
Specific Heat Capacity1,600 J/kg·K0.38 BTU/lb·°F
Thermal Expansion (CTE, 20–100 °C)150 µm/m·K83.3 µin/in·°F
Max Service Temperature (continuous)90°C194 °F
Min Service Temperature-30°C-22 °F
Flammability (UL 94)HB (standard aromatic system); V-0 achievable only with FR-loaded grades
Limiting Oxygen Index20%
Max Service Temperature (short-term)120°C248 °F

Electrical3

Integral Skin PU Foam has an electrical resistivity of 1×10¹¹ Ω·m.

Electrical Resistivity1×10¹¹ Ω·m3.94×10¹⁸ µΩ·in
Dielectric Constant (1 MHz)1.9
Volume Resistivity1×10¹³ Ω·cm

Chemical & Environmental3

Corrosion resistance is very good (70/100), worse than 78% of polymer grades. UV resistance is poor.

Corrosion ResistanceVery good70/100
UV / Weathering ResistancePoor25/100
Chemical Resistance SummaryGood against water, dilute salts, aliphatic hydrocarbons, greases and most alcohols; attacked by strong acids and bases, hot water/steam (hydrolysis of ester polyols), chlorinated solvents, DMF/DMSO and concentrated ketones. Polyether-based integral skin systems are notably more hydrolysis-resistant than polyester types.

Sustainability4

Producing a kilogram of Integral Skin PU Foam takes about 105 MJ of energy and emits 4.6 kg of CO₂ — more than 54% of polymer grades. Typical recycled content is 2%.

Embodied Energy (primary production)105 MJ/kg45,142 BTU/lb
Embodied Carbon (primary production)4.6 kg CO₂/kg
Embodied Water220 L/kg26.4 gal/lb
Typical Recycled Content2%

Manufacturability6

Integral Skin PU Foam's machinability is fair (50/100, worse than 73% of polymer grades); weldability not recommended (5/100); formability poor (20/100).

MachinabilityFair50/100
WeldabilityNot recommended5/100
Formability (cold)Poor20/100
PolishabilityPoor30/100
Mold Shrinkage1%
Mold Temperature (typ.)50°C122 °F

Common Calculations4

Specific Strength (UTS / density)calculated10 kN·m/kg
Specific Stiffness (E / density)calculated0.1 MN·m/kg
Thermal Diffusivitycalculated0.1 mm²/s
Thermal Shock Resistance Indexcalculated0

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. Integral Skin PU Foam is highlighted; hover a dot for its name, or open the interactive family chart.

0.1110100123Density (g/cm³)Yield strength (MPa) — log scale

Working with Integral Skin PU Foam

Is Integral Skin PU Foam easy to machine?

Trim flash and drill with sharp, high-rake or hot-knife tooling and vacuum extraction; the cellular core tears if fed too fast and dust must be captured, so most parts are net-shape molded with in-mold inserts instead.

Can Integral Skin PU Foam be welded?

Thermoset and non-weldable — join with PU or MS-polymer adhesives, over-molding onto a metal/plastic armature, or in-mold bonded inserts.

Can Integral Skin PU Foam be formed, bent or molded?

Low-pressure open-pour or closed-mold RIM at 40–65 °C tool temperature, mold release each shot, 2–6 min demold; skin thickness and hardness are tuned by tool temperature, blowing-agent level and shot overpack (typically 10–30 %).

Integral Skin PU 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.

ElementSpec limit (wt %)Nominal
polymeric MDI (diphenylmethane diisocyanA-component; NCO index typically 100–11030 – 5040
chain extender / crosslinker (ethylene gsets skin hardness1 – 63
blowing agent (water and/or HFO-1233zd, controls core density and skin thickness0.3 – 41.5
amine + tin catalysts0.3 – 21
silicone surfactant / cell regulator0.2 – 1.50.7
pigment paste, UV stabilizer (HALS/benzohigher in light-stable LS-ALI grades0.5 – 52
flame retardant (phosphate ester / melamFR-V0 variant only0 – 200
milled glass fiber / mineral fillerGF15 / RRIM variant only0 – 200
polyether polyol (polyoxypropylene/EO-caB-component base≥ 40 (balance)

What surface finishes work on Integral Skin PU Foam?

As-molded skin replicates the tool grain and is usually the finished surface; aromatic systems need a flexible 2K PU topcoat or in-mold coating for UV and abrasion, while aliphatic light-stable grades ship paint-free.

Equivalent designations

Standards and trade names that resolve to Integral Skin PU Foam in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.

Also called
Integral Skin Foam

How much does Integral Skin PU Foam cost?

Integral Skin PU Foam is a premium-cost polymer ($$$), cheaper than about 51% 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.

Integral Skin PU Foam — frequently asked

What is Integral Skin PU Foam used for?

Integral Skin PU Foam is typically used for automotive steering wheels and armrests, office chair armrests, shoe soles and furniture handles and decorative parts. In short: molded-in dense surface skin; skin and core in one shot; cushioning with structural stiffness.

What is the tensile strength of Integral Skin PU Foam?

Integral Skin PU Foam has a typical tensile strength of 4 MPa (0.508 ksi) — weaker than 83% of polymer grades. Strength varies by condition: see the 9 listed tempers.

Is Integral Skin PU Foam easy to machine?

Reasonably — machinability is rated fair (50/100, worse than 73% of polymer grades). Trim flash and drill with sharp, high-rake or hot-knife tooling and vacuum extraction; the cellular core tears if fed too fast and dust must be captured, so most parts are net-shape molded with in-mold inserts instead.

Can Integral Skin PU Foam be welded?

Not readily — weldability is rated not recommended (5/100). Thermoset and non-weldable — join with PU or MS-polymer adhesives, over-molding onto a metal/plastic armature, or in-mold bonded inserts.

What surface finishes work on Integral Skin PU Foam?

As-molded skin replicates the tool grain and is usually the finished surface; aromatic systems need a flexible 2K PU topcoat or in-mold coating for UV and abrasion, while aliphatic light-stable grades ship paint-free.

Can Integral Skin PU Foam be formed, bent or molded?

Low-pressure open-pour or closed-mold RIM at 40–65 °C tool temperature, mold release each shot, 2–6 min demold; skin thickness and hardness are tuned by tool temperature, blowing-agent level and shot overpack (typically 10–30 %).

What is the maximum service temperature of Integral Skin PU Foam?

Integral Skin PU Foam is rated for continuous use to about 90°C (194 °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 Integral Skin PU Foam cost?

Integral Skin PU Foam is a premium-cost polymer ($$$), cheaper than about 51% 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

  1. ASTM D3574 — Flexible Cellular Materials: Slab, Bonded, and Molded Urethane Foams — ASTM International (2017)
  2. ASTM D1621 / D1622 — Compressive Properties and Apparent Density of Rigid Cellular Plastics — ASTM International (2020)
  3. Baydur / Bayfill integral skin and structural foam systems — Covestro (2022)
  4. Elastoflex / Elastofoam I integral skin system data — BASF Polyurethanes (2021)
  5. Specflex / VORANOL self-skinning system literature — Dow Polyurethanes (2021)
  6. ASM Engineered Materials Handbook, Vol. 2: Engineering Plastics (polyurethane foams) — ASM International (1988)
  7. CES EduPack polymer foam property records — Granta/Ansys (2023)

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.