PU Cast Polyester
Matrix
ASTM AU, EU · also Urethane Rubber, Vulkollan
Choose for maximum wear life, cut/tear and oil resistance in dry service; avoid continuous hot-wet or steam exposure (adipate types hydrolyse).
Values for the Polyester condition
Other PU Cast grades and fills
PU Cast is listed in 13 conditions; see the grade overview at PU Cast.
- Microcellular
- Shore A 40
- FR V-0
- Shore A 60
- Shore A 70
- Aliphatic
- Polyether
- Shore A 80
- Polyester
- Shore A 90
- Shore A 95
- Shore D 60
- Shore D 75
Compare all 13 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
Microcellular / cellular cast PU (foamed elastomer) | Choose for jounce bumpers, spring aids, shoe soles and vibration isolators where low stiffness at low density and high energy absorption are wanted. | — | 4 | 250 | 12 Shore D |
Shore A 40Default Soft cast urethane | Pick for soft pads, vibration isolators, gaskets, flexible tooling and skin-friendly grip parts where high elongation matters more than load capacity. | — | 12 | 700 | 10 Shore D |
Flame-retardant cast PU | Choose for potting, cable/rail and enclosure parts needing a V-0 rating; fillers reduce elongation and tear strength. | — | 18 | 350 | 38 Shore D |
Medium-soft cast urethane | Pick for seals, bumpers, printing/feed rollers and low-load wheels needing a compliant but tougher rubber. | — | 22 | 650 | 17 Shore D |
Medium cast urethane | General-purpose workhorse hardness for rollers, drive wheels, wiper blades and dynamic seals combining resilience with good abrasion resistance. | — | 30 | 600 | 22 Shore D |
Aliphatic (HDI/H12MDI) light-stable grade | Choose for clear, non-yellowing outdoor or optical parts (lenses, decorative encapsulation, UV-exposed pads); costs 2–4× aromatic grades. | — | 30 | 450 | 40 Shore D |
hydrolysis resistant | Choose when parts see hot water, steam, humidity, microbes or low temperatures; slightly lower abrasion/strength than polyester types. | — | 35 | 550 | 35 Shore D |
Medium-hard cast urethane | Pick for load-bearing wheels, chute liners, forming pads and stripper plates where higher stiffness is needed but some flex remains. | — | 36 | 550 | 30 Shore D |
PolyesterThis page maximum abrasion & oil resistance | Choose for maximum wear life, cut/tear and oil resistance in dry service; avoid continuous hot-wet or steam exposure (adipate types hydrolyse). | — | 40 | 500 | 38 Shore D |
Hard cast urethane | Pick for heavy-duty wheels, mill liners, press pads and abrasion-critical wear parts at high unit loads. | — | 42 | 500 | 40 Shore D |
Shore A 95 / Shore D 45 | Pick where near-plastic stiffness plus impact toughness is required: scraper blades, cyclone liners, sheet-metal forming punches. | — | 45 | 420 | 45 Shore D |
Rigid cast polyurethane | Pick for structural cast parts, tooling blocks, gears, dies and impact-resistant machine components where a rigid but non-brittle thermoset is wanted. | — | 50 | 300 | 60 Shore D |
Hard rigid cast polyurethane / tooling resin | Pick for rigid urethane tooling boards, jigs, master models and hard structural castings replacing filled epoxy. | — | 60 | 60 | 75 Shore D |
What is PU Cast Polyester?
PU Cast Polyester is PU Cast in the Polyester condition — choose for maximum wear life, cut/tear and oil resistance in dry service; avoid continuous hot-wet or steam exposure (adipate types hydrolyse). PU Cast Polyester has a tensile strength of 40 MPa (5.8 ksi), weaker than 56% of polymer grades. Elongation at break is 500% and the elastic modulus is 0.03 GPa (0.0036 Msi). PU Cast Polyester has a density of 1.22 g/cm³ (0.0441 lb/in³), heavier than 61% of polymer grades. Its glass-transition temperature is -50°C (-58 °F). Shore A 40 is the default condition FabDigit quotes; Polyester is available on request or by drawing note.
Advantages
- Ductile — tolerates forming and impact — 500%, better than 90% of polymer grades
Limitations
- Hard to polish — 25/100, worse than 90% of polymer grades
- Difficult to machine — 48/100, worse than 75% of polymer grades
PU Cast Polyester properties
Typical room-temperature values for PU Cast Polyester; 20 are specific to this condition. Other listed values are PU Cast reference data and may not represent this condition. Bars are the position among polymer grades.
Physical5
PU Cast Polyester has a density of 1.22 g/cm³ (0.0441 lb/in³), heavier than 61% of polymer grades. Its glass-transition temperature is -50°C (-58 °F).
Mechanical12
PU Cast Polyester has a tensile strength of 40 MPa (5.8 ksi), weaker than 56% of polymer grades. Elongation at break is 500% and the elastic modulus is 0.03 GPa (0.0036 Msi).
Thermal8
PU Cast Polyester is rated for continuous service to 95°C (203 °F). It conducts heat at 0.22 W/m·K (0.127 BTU/hr·ft·°F), better than 60% of polymer grades. Thermal expansion is 200 µm/m·K (111.1 µin/in·°F).
Electrical5
PU Cast Polyester is an electrical insulator with a dielectric strength of 20 kV/mm (508 V/mil) and a resistivity of 1×10¹⁰ Ω·m.
Chemical & Environmental3
Corrosion resistance is very good (72/100), worse than 70% of polymer grades. UV resistance is fair.
Sustainability4
Producing a kilogram of PU Cast Polyester takes about 102 MJ of energy and emits 5 kg of CO₂ — less than 55% of polymer grades. Typical recycled content is 0%.
Manufacturability7
PU Cast Polyester's machinability is fair (48/100, worse than 75% of polymer grades); weldability poor (20/100); formability good (60/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with PU Cast Polyester
Is PU Cast easy to machine?
Machinable by turning/grinding with very sharp, high-rake carbide tools, high surface speed and low feed; soft grades (<70A) need chilling, mandrel support or wet grinding to stop smearing and deflection, Shore D grades cut like a tough plastic.
Can PU Cast be welded?
Thermoset — cannot be melt-welded; join by two-part urethane or polyurethane-compatible adhesive, or by casting fresh material against a cleaned, primed cured surface for a chemical bond.
Can PU Cast be formed, bent or molded?
Open or closed-mould gravity casting of a hot (70–90 °C) degassed prepolymer/curative mix into 100–110 °C moulds, demould in 0.5–2 h and post-cure 16 h at 100 °C; centrifugal casting for rollers and metal-insert bonding with primed, grit-blasted cores.
What surface finishes work on PU Cast?
Surface quality replicates the mould, so use polished or lacquered tools and mould release; PU can be ground, sanded and flash-trimmed, and painted or printed only with flexible urethane-based coatings after solvent wipe or plasma/primer treatment.
PU Cast 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 |
|---|---|---|
| diisocyanate (MDI/TDI/NDI/H12MDI)prepolymer hard segment; aromatic MDI/TDI standard, aliphatic for light stability | 15 – 35 | 25 |
| chain extender / curative (1,4-BDO, HQEEsets hardness and hot strength; MOCA restricted in many markets | 3 – 12 | 7 |
| catalyst, antioxidant, hydrolysis stabil | 0.1 – 3 | 1 |
| filler (talc/silica/ATH/FR) — filled graused in rigid tooling and FR formulations | 0 – 30 | 0 |
| polyol (polyether PTMEG/PPG or polyestersoft segment; determines hydrolysis vs abrasion balance | ≥ 50 (balance) | — |
PU Cast Polyester — frequently asked
What is PU Cast Polyester used for?
PU Cast Polyester is typically used for drive and conveyor rollers, forklift and caster wheels, wear pads and scraper blades, suspension bushings and spring elements, vacuum-cast prototype housings and die-cushion and press pads. In short: vacuum-cast urethane prototype.
What is the tensile strength of PU Cast Polyester?
PU Cast Polyester has a typical tensile strength of 40 MPa (5.8 ksi) — weaker than 56% of polymer grades. Strength varies by condition: see the 13 listed tempers.
Is PU Cast Polyester easy to machine?
Reasonably — machinability is rated fair (48/100, worse than 75% of polymer grades). Machinable by turning/grinding with very sharp, high-rake carbide tools, high surface speed and low feed; soft grades (<70A) need chilling, mandrel support or wet grinding to stop smearing and deflection, Shore D grades cut like a tough plastic.
Can PU Cast Polyester be welded?
Not readily — weldability is rated poor (20/100). Thermoset — cannot be melt-welded; join by two-part urethane or polyurethane-compatible adhesive, or by casting fresh material against a cleaned, primed cured surface for a chemical bond.
What surface finishes work on PU Cast Polyester?
Surface quality replicates the mould, so use polished or lacquered tools and mould release; PU can be ground, sanded and flash-trimmed, and painted or printed only with flexible urethane-based coatings after solvent wipe or plasma/primer treatment.
Can PU Cast Polyester be formed, bent or molded?
Open or closed-mould gravity casting of a hot (70–90 °C) degassed prepolymer/curative mix into 100–110 °C moulds, demould in 0.5–2 h and post-cure 16 h at 100 °C; centrifugal casting for rollers and metal-insert bonding with primed, grit-blasted cores.
What is the maximum service temperature of PU Cast Polyester?
PU Cast Polyester is rated for continuous use to about 95°C (203 °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 PU Cast Polyester?
Yes — PU Cast Polyester 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
- Adiprene / Vibrathane cast urethane prepolymer datasheets — LANXESS (formerly Chemtura) (2022)
- Cast polyurethane elastomer property charts (rollers, wheels, wear parts) — Gallagher Corporation (2023)
- VytaFlex / Task urethane casting resin technical bulletins — Smooth-On (2023)
- Engineered Materials Handbook Vol. 2: Engineering Plastics — ASM International (1988)
- ASTM D412 / D624 / D2240 / D395 rubber test methods — ASTM (2021)
- GB/T 531.1 / GB/T 528 (2009)
- CES/Granta EduPack polymer & eco property records (PU elastomer) — Ansys Granta (2023)
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.