Polyurethane (AU/EU) for Custom Molded Components — Properties, Applications & Specifications
Table of Contents
Polyurethane elastomers achieve their exceptional abrasion resistance through a urethane linkage chemistry that creates both hard and soft segments within the polymer chain — the hard segments act as physical crosslinks while the soft segments provide elasticity, producing a material that can absorb and redistribute surface stress rather than simply resist it. This microphase separation mechanism means a urethane seal or bushing can withstand repetitive sliding, cutting, and impact loads that would cause surface tearing and delamination in softer elastomers like EPDM or standard NBR. Fenlora molds Polyurethane (AU/EU) in Shore A 40–80 across wear strips, hydraulic piston seals, and drive couplings for mobile equipment, material handling, and industrial machinery OEMs.
Material Properties & Specifications
| Common names / abbreviations | Polyurethane Rubber (AU/EU) |
|---|---|
| Polymer structure / monomer system | Diisocyanate and polyol copolymers |
| Density (g/cm³) | 1.02 - 1.20 |
| Hardness range (Shore A/D) | 10 Shore A - 80 Shore D |
| Tensile strength (MPa) | 0.55 - 55.1 |
| Elongation at break (%) | 250 - 800 |
| 100% / 300% modulus (MPa) | 0.17 - 34.4 at 100% |
| Rebound / tanδ (temp + freq) | 5 - 75 % Rebound |
| Compression set (%) | 0.7 - 45 % |
| Continuous service temp (°C) | -40°C to 79°C |
| Environmental & Fluid Resistance | Ozone: Excellent | Oil: Moderate |
| ASTM D2000 Callouts | BG Classification Type |
| Electrical properties | Vol Res: 0.3x10^10 - 4.7x10^13 ohm-cm |
| Thermal properties | Thermal Cond: 0.09 - 0.29 W/mK |
| Tear Resistance | Tier 5 - Excellent |
| Abrasion Resistance | Tier 5 - Excellent |
| Gas Impermeability Resistance | Tier 4 - Strong |
| Oxygen Resistance | Tier 4 - Strong |
| Ozone Resistance | Tier 4 - Strong |
| Weathering Resistance | Tier 4 - Strong |
| Oil Resistance | Tier 4 - Strong |
| Acid Resistance | Tier 1 - Basic |
| Alkaline Resistance | Tier 1 - Basic |
| Water Resistance | Tier 2 - Limited |
| Flame Resistance | Tier 4 - Strong |
When to Specify Polyurethane
Polyurethane is the correct compound choice when load-bearing wear life is the primary design constraint — not just chemical resistance.
| Use Polyurethane when… | Avoid Polyurethane when… |
|---|---|
| Dynamic abrasion is the dominant failure mode — sliding contacts, grit exposure, conveyor surfaces | Continuous service above 80°C (175°F), where hydrolytic degradation of ester-based AU accelerates |
| High compressive load capacity is required without set — Shore A 70–95 for piston and rod seals under 300+ bar hydraulic pressure | Steam, hot water, or high-humidity environments unless ether-based EU compound is explicitly specified |
| Tear resistance under puncture or cut loads is critical — e.g., drive couplings, dock bumpers, tracked rollers | Concentrated ketone, ester, or chlorinated solvent exposure — urethane swells significantly in these media |
| Low-speed, high-load bearing surfaces need dimensional stability without metal inserts | Fuel and oil immersion applications where NBR or FKM gives better swell control at lower cost |
| Noise and vibration damping with load-bearing function must coexist in one component | Outdoor UV/ozone long-term exposure without UV-stabilizer compounding — natural AU/EU degrades faster than EPDM or Neoprene |
Expanded technical note on abrasion resistance: Polyurethane’s wear resistance stems from its ability to elastically deform under a cutting or grinding load and return — rather than fracturing the surface like a harder thermoset would, or deforming permanently like a softer EPDM. In NBS abrasion index testing, cast AU urethane compounds routinely score 300–500% relative to natural rubber as the baseline. For applications involving metal chips, aggregate, or abrasive slurries, this means a 60 Shore A urethane wear strip can outlast a 70 Shore A nitrile seal by a factor of 5–10× in the same environment — the elasticity, not just the hardness, is what drives wear life.
Custom Parts We Make in Polyurethane
Fenlora molds Polyurethane (AU/EU) components across hardness ranges from 40A to 80A, selecting between ester-based (AU) and ether-based (EU) formulations based on the chemical and thermal profile of each application.
→ Wear strips and liner pads — Shore A 60–75 urethane wear strips absorb abrasive impact and surface sliding from metal-on-metal or aggregate contact; commonly specified in aggregate processing equipment, conveyor guide rails, and chute liners where UHMW plastic lacks damping and rubber lacks load capacity.
→ Drive couplings and jaw inserts — Polyurethane’s combination of high shear strength and elasticity makes it ideal for spider/jaw coupling inserts in power transmission applications where torque loads, misalignment dampening, and fatigue life must be balanced simultaneously.
→ Dock bumpers and impact absorbers — Cast or compression-molded EU urethane at 50–65 Shore A provides controlled energy absorption for vehicle impact loading at loading docks and marine fender applications; the material rebounds rather than permanently deforming after repeated high-force impact cycles.
→ Wheels and rollers (solid and semi-pneumatic) — Urethane’s load-bearing capacity, floor non-marking properties, and abrasion resistance make it the preferred compound for material handling wheels in clean manufacturing, cold storage, and warehouse logistics environments.
If your drawing specifies Polyurethane (AU or EU) or you’re working from functional requirements around wear life, load capacity, or sealing performance, contact our engineering team to discuss compound selection and hardness range at contact us.
Industries That Use Polyurethane
Mining & Aggregate Processing
Uses urethane screen panels, chute liner pads, and hydrocyclone liners — environments where silica, iron ore fines, and aggregate create continuous abrasive wear. Ether-based EU compounds are specified here over ester-based AU because the wet slurry environment would hydrolyze AU over time; the wear resistance is retained while hydrolytic stability is preserved.
Construction Equipment
Relies on AU urethane for hydraulic rod seals, piston seals, and wiper seals in excavators, wheel loaders, and crane cylinders. The requirement is maintaining seal geometry and low leakage under cyclic pressure (200–400 bar) combined with dirt and grit exclusion — a performance envelope where nitrile compounds show premature extrusion and wear failure within comparable service hours.
Material Handling & Intralogistics
Specifies solid urethane wheels, guide rollers, and wear strips for pallet jacks, conveyors, and AGV platforms operating on concrete floors in warehouses and cold storage facilities. Urethane wheels carry static loads without flat-spotting (which occurs with softer rubbers under sustained load) and resist floor marking required in food-grade and cleanroom-adjacent facilities.
Compare Materials
If another material better fits your temperature, chemical, or static sealing requirements, Fenlora can help you select the right compound from the start.
| If your application involves… | Consider instead |
|---|---|
| Outdoor UV or ozone weathering | EPDM |
| Budget-sensitive oil resistance only | Nitrile (NBR) |
| Continuous temps above 150°C | Silicone (VMQ) |
| High dynamic flex and tear resistance | Natural Rubber (NR) |
| Air/gas impermeability | Butyl Rubber (IIR) |
| Moderate oil + weather resistance | Neoprene (CR) |
| General-purpose non-oil applications | SBR |
| Extreme chemical resistance | Viton (FKM) |
Not sure which material fits your application? Send us your requirements and we’ll recommend the right compound.