Rubber-Like · hardness band
Rubber-Like Shore A 50
Properties of the Shore A 50 condition, compared with the other Rubber-Like grades.
General-purpose soft seals, grommets and over-mould-look prototype parts.
What is Rubber-Like Shore A 50?
Rubber-Like Shore A 50 is Rubber-Like heat treated to Shore A 50 — general-purpose soft seals, grommets and over-mould-look prototype parts. Rubber-Like Shore A 50 has a tensile strength of 11 MPa (1.6 ksi), weaker than 78% of polyurethane grades. Elongation at break is 570% and the elastic modulus is 0 GPa (4.64×10⁻⁴ Msi). Rubber-Like Shore A 50 has a density of 1.15 g/cm³ (0.0415 lb/in³), heavier than 63% of polyurethane grades. Its glass-transition temperature is -45°C (-49 °F). Shore A 60 is the default condition FabDigit quotes; Shore A 50 is available on request or by drawing note.
Advantages
- Ductile — tolerates forming and impact — 570%, better than 104% of polyurethane grades
- Readily welded — 15/100, better than 100% of polyurethane grades
- Forms and bends easily — 90/100, better than 100% of polyurethane grades
- Good UV / weathering resistance — 35/100, better than 85% of polyurethane grades
Limitations
- Low stiffness — 0 GPa (4.64×10⁻⁴ Msi), worse than 100% of polyurethane grades
- High mold shrinkage — 1.2%, worse than 98% of polyurethane grades
- Difficult to machine — 20/100, worse than 96% of polyurethane grades
- Absorbs moisture — dry before molding — 0.8%, worse than 85% of polyurethane grades
- Hard to polish — 30/100, worse than 83% of polyurethane grades
Rubber-Like Shore A 50 properties
Typical room-temperature values for Rubber-Like Shore A 50 — 8 properties are specific to this condition; the rest are grade-level values shared by every Rubber-Like grade. Each bar shows where the value sits among the polyurethane grades in FabDigit's library — further right is higher.
Physical5
Rubber-Like Shore A 50 has a density of 1.15 g/cm³ (0.0415 lb/in³), heavier than 63% of polyurethane grades. Its glass-transition temperature is -45°C (-49 °F).
Mechanical9
Rubber-Like Shore A 50 has a tensile strength of 11 MPa (1.6 ksi), weaker than 78% of polyurethane grades. Elongation at break is 570% and the elastic modulus is 0 GPa (4.64×10⁻⁴ Msi).
Thermal8
Rubber-Like Shore A 50 is rated for continuous service to 80°C (176 °F). It conducts heat at 0.2 W/m·K (0.116 BTU/hr·ft·°F), worse than 57% of polyurethane grades. Thermal expansion is 170 µm/m·K (94.4 µin/in·°F).
Electrical7
Rubber-Like Shore A 50 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 (78/100), better than 73% of polyurethane grades. UV resistance is fair.
Sustainability4
Producing a kilogram of Rubber-Like Shore A 50 takes about 100 MJ of energy and emits 5 kg of CO₂ — less than 83% of polyurethane grades. Typical recycled content is 0%.
Manufacturability6
Rubber-Like Shore A 50's machinability is poor (20/100, worse than 96% of polyurethane grades); weldability poor (15/100); formability excellent (90/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other Rubber-Like grades and fills
Rubber-Like is also supplied in 6 other conditions. The full side-by-side table is on the Rubber-Like overview.
- Shore A 60DefaultDefault all-round grade: seals, keypads, damping mounts and rubber-look functional prototypes.16 MPa tensile
- Shore A 90Highest load-bearing elastomer grade: press pads, die springs, mining screens, high-pressure seal backups.42 MPa tensile
- Shore A 80Wear-duty parts: rollers, scraper blades, wheel treads, heavy-load bushings and impact pads.32 MPa tensile
- Shore A 70Choose where a seal or bushing must resist extrusion and moderate load while staying elastomeric.24 MPa tensile
- Shore A 50General-purpose soft seals, grommets and over-mould-look prototype parts.11 MPa tensile
- Shore A 40Soft gaskets, vibration pads and flexible bellows needing large deflection at low load.7 MPa tensile
- Shore A 30Pick for gel-like pads, soft grips, skin/tissue mock-ups and low-force seals where maximum compliance matters.5 MPa tensile
Working with Rubber-Like Shore A 50
Is Rubber-Like easy to machine?
Machinable only with very sharp, high-rake or skiving tools, high speed and low feed; soft grades benefit from freezing or water-jet/laser-free die cutting, and parts must be fully supported to avoid deflection.
Can Rubber-Like be welded?
Cast (thermoset) urethane is not weldable — join by cyanoacrylate/urethane adhesive or over-moulding; TPU equivalents can be hot-plate, ultrasonic or HF welded.
Can Rubber-Like be formed, bent or molded?
Two-component cast: degas prepolymer, mix at 1:1–10:1 ratio, pour at 40–80 °C into silicone or metal tooling, gel in minutes and post-cure 8–16 h at 70–100 °C for full properties; allow 0.6–1.8 % shrink and avoid moisture (CO₂ bubbling).
What surface finishes work on Rubber-Like?
Surface replicates the mould — gloss, matte or textured; can be pad-printed, dyed in the mix, or coated with flexible urethane paint; aromatic grades should be UV-stabilised or aliphatic-topcoated to prevent yellowing.
Rubber-Like 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 |
|---|---|---|
| MDI/TDI isocyanate prepolymeraromatic diisocyanate hard segment; aliphatic (HDI/IPDI) used for non-yellowing grades | 25 – 45 | 35 |
| chain extender (BDO / MOCA / HQEE)sets hard-segment content and hence Shore hardness | 3 – 12 | 8 |
| catalyst, pigment, UV/antioxidant additi | 0.1 – 3 | 1 |
| polyester or polyether polyolsoft segment; polyester = oil/abrasion resistance, polyether = hydrolysis resistance | ≥ 45 (balance) | — |
Rubber-Like Shore A 50 — frequently asked
What is Rubber-Like Shore A 50 used for?
Rubber-Like Shore A 50 is typically used for gaskets, seals, overmolds and grips. In short: cast elastomer; pick Shore A hardness per application.
What is the tensile strength of Rubber-Like Shore A 50?
Rubber-Like Shore A 50 has a typical tensile strength of 11 MPa (1.6 ksi) — weaker than 78% of polyurethane grades. Strength varies by condition: see the 7 listed tempers.
Is Rubber-Like Shore A 50 easy to machine?
Not especially — machinability is rated poor (20/100, worse than 96% of polyurethane grades). Machinable only with very sharp, high-rake or skiving tools, high speed and low feed; soft grades benefit from freezing or water-jet/laser-free die cutting, and parts must be fully supported to avoid deflection.
Can Rubber-Like Shore A 50 be welded?
Not readily — weldability is rated poor (15/100). Cast (thermoset) urethane is not weldable — join by cyanoacrylate/urethane adhesive or over-moulding; TPU equivalents can be hot-plate, ultrasonic or HF welded.
What surface finishes work on Rubber-Like Shore A 50?
Surface replicates the mould — gloss, matte or textured; can be pad-printed, dyed in the mix, or coated with flexible urethane paint; aromatic grades should be UV-stabilised or aliphatic-topcoated to prevent yellowing.
Can Rubber-Like Shore A 50 be formed, bent or molded?
Two-component cast: degas prepolymer, mix at 1:1–10:1 ratio, pour at 40–80 °C into silicone or metal tooling, gel in minutes and post-cure 8–16 h at 70–100 °C for full properties; allow 0.6–1.8 % shrink and avoid moisture (CO₂ bubbling).
What is the maximum service temperature of Rubber-Like Shore A 50?
Rubber-Like Shore A 50 is rated for continuous use to about 80°C (176 °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 Rubber-Like Shore A 50?
Yes — Rubber-Like Shore A 50 is available for urethane casting with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- ASTM D2240 — Rubber Property, Durometer Hardness — ASTM (2021)
- ASTM D412 / D624 / D395 — Tensile, Tear and Compression Set of Elastomers — ASTM (2021)
- Engineered Materials Handbook Vol. 2: Engineering Plastics (polyurethane elastomers) — ASM International (1988)
- Castable polyurethane elastomer system datasheets (Shore A 30–A 90) — Huntsman / Hexion / Smooth-On (2023)
- CAMPUS / UL Prospector polyurethane elastomer property records — CAMPUS & UL (2024)
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.