BR TBR (High-trans polybutadiene)
Grade
Specialty semi-crystalline BR for golf-ball cores, high green-strength tire components and NR-substitute blends.
Values for the TBR condition
Other BR grades and fills
BR is listed in 9 conditions; see the grade overview at BR.
Compare all 9 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
Shore A 50 compound | Soft, highly resilient BR compound for damping pads, low-temperature seals and soling with maximum rebound. | — | 10 | 550 | 10 Shore D |
Lithium-catalysed low-cis | Choose for HIPS/ABS impact modification and easier mill processing (less cold flow) rather than for maximum abrasion. | — | 12 | 500 | 10 Shore D |
Oil-extended BR | Pick when high-molecular-weight BR must be processed at low mixing energy or when soft, high-filler tread compounds are needed. | — | 12 | 520 | 9 Shore D |
HI-CIS-NIDefault High-cis BR, Ni/Co-catalysed (BR9000 / BR1502 type) | Default workhorse high-cis BR (≈96 % cis) for tire treads/sidewalls, belt covers and shoe soles blended with NR/SBR. | — | 15 | 450 | 12 Shore D |
Shore A 60 compound | Standard reinforced BR vulcanizate — the reference compound for datasheet mechanical values. | — | 15 | 450 | 13 Shore D |
High-vinyl BR | Use where wet grip and damping matter more than low hysteresis — high-performance tread blends with S-SBR. | — | 16 | 420 | 13 Shore D |
neodymium-catalysed very high cis (≥96–99 %) | Pick for the best abrasion resistance and lowest rolling-resistance hysteresis in premium truck and passenger tire treads. | — | 17 | 480 | 12 Shore D |
Shore A 70 compound | Harder, more abrasion-resistant BR compound for belt covers, tread bases and industrial wheels. | — | 18 | 350 | 20 Shore D |
TBRThis page High-trans polybutadiene | Specialty semi-crystalline BR for golf-ball cores, high green-strength tire components and NR-substitute blends. | — | 20 | 400 | 22 Shore D |
What is BR TBR?
BR TBR is BR in the TBR grade — specialty semi-crystalline BR for golf-ball cores, high green-strength tire components and NR-substitute blends. BR TBR has a tensile strength of 20 MPa (2.9 ksi), weaker than 70% of polymer grades. Elongation at break is 400% and the elastic modulus is 0.08 GPa (0.0116 Msi). BR TBR has a density of 0.96 g/cm³ (0.0347 lb/in³), lighter than 74% of polymer grades. Its glass-transition temperature is -80°C (-112 °F). HI-CIS-NI is the default condition FabDigit quotes; TBR is available on request or by drawing note.
Advantages
- Ductile — tolerates forming and impact — 400%, better than 86% of polymer grades
- Low embodied carbon — 3.2 kg CO₂/kg, better than 81% of polymer grades
Limitations
- Needs corrosion protection — 45/100, worse than 98% of polymer grades
- High mold shrinkage — 2.5%, worse than 93% of polymer grades
- Limited service temperature — 55°C (131 °F), worse than 91% of polymer grades
- Degrades in UV without stabilisers — 20/100, worse than 88% of polymer grades
- Difficult to machine — 35/100, worse than 84% of polymer grades
BR TBR properties
Typical room-temperature values for BR TBR; 19 are specific to this condition. Other listed values are BR reference data and may not represent this condition. Bars are the position among polymer grades.
Physical4
BR TBR has a density of 0.96 g/cm³ (0.0347 lb/in³), lighter than 74% of polymer grades. Its glass-transition temperature is -80°C (-112 °F).
Mechanical10
BR TBR has a tensile strength of 20 MPa (2.9 ksi), weaker than 70% of polymer grades. Elongation at break is 400% and the elastic modulus is 0.08 GPa (0.0116 Msi).
Thermal8
BR TBR is rated for continuous service to 55°C (131 °F). It conducts heat at 0.24 W/m·K (0.139 BTU/hr·ft·°F), better than 67% of polymer grades. Thermal expansion is 220 µm/m·K (122.2 µin/in·°F).
Electrical5
BR TBR is an electrical insulator with a dielectric strength of 22 kV/mm (558.8 V/mil) and a resistivity of 1×10¹³ Ω·m.
Chemical & Environmental3
Corrosion resistance is fair (45/100), worse than 98% of polymer grades. UV resistance is poor.
Sustainability4
Producing a kilogram of BR TBR takes about 96 MJ of energy and emits 3.2 kg of CO₂ — less than 67% of polymer grades. Typical recycled content is 0%.
Manufacturability6
BR TBR's machinability is fair (35/100, worse than 84% of polymer grades); weldability fair (40/100); formability very good (70/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with BR TBR
Is BR easy to machine?
Cured BR is best cut by water-jet, die-cutting or cryogenic grinding; conventional machining smears and heats the part.
Can BR be welded?
Not weldable — join by vulcanised splices, unvulcanised gum-strip build-up or cyanoacrylate/chloroprene adhesives after abrasion and primer.
Can BR be formed, bent or molded?
Raw BR cold-flows and bands poorly on the mill, so it is normally masterbatched with NR/SBR and 30–60 phr black; compression, transfer or injection cure at 145–180 °C with sulfur/CBS systems.
What surface finishes work on BR?
Deflash by cryogenic tumbling; surfaces can be chlorinated or plasma/primer treated for adhesion; add wax, antiozonant and carbon black for outdoor colour and ozone protection.
BR 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 |
|---|---|---|
| cis-1,4 microstructureNi/Co/Nd high-cis grades; Li grades ≈30–40 % cis | 92 – 99 | 96 |
| trans-1,4 microstructurehigh-cis grades; TBR grades >70 % | 1 – 5 | 2 |
| 1,2-vinyl microstructureHVBR grades 50–90 % | 1 – 4 | 2 |
| volatile matterGB/T 8657 bale specification | ≤ 0.75 | 0.4 |
| ashGB/T 8657 | ≤ 0.3 | 0.15 |
| antioxidant (non-staining)added to bale rubber | 0.2 – 1 | 0.5 |
| carbon black (in typical vulcanizate)phr, not wt % of polymer; N330/N550 typical | 30 – 60 | 50 |
| 1,3-butadiene (repeat unit)homopolymer; no comonomer | balance | — |
BR TBR — frequently asked
What is BR TBR used for?
BR TBR is typically used for tire sidewalls, golf ball cores, conveyor belts and rubber blends. In short: highest-resilience diene rubber; lowest Tg at -105 °C; blend component, poor green strength.
What is the tensile strength of BR TBR?
BR TBR has a typical tensile strength of 20 MPa (2.9 ksi) — weaker than 70% of polymer grades. Strength varies by condition: see the 9 listed tempers.
Is BR TBR easy to machine?
Not especially — machinability is rated fair (35/100, worse than 84% of polymer grades). Cured BR is best cut by water-jet, die-cutting or cryogenic grinding; conventional machining smears and heats the part.
Can BR TBR be welded?
With care — weldability is rated fair (40/100). Not weldable — join by vulcanised splices, unvulcanised gum-strip build-up or cyanoacrylate/chloroprene adhesives after abrasion and primer.
What surface finishes work on BR TBR?
Deflash by cryogenic tumbling; surfaces can be chlorinated or plasma/primer treated for adhesion; add wax, antiozonant and carbon black for outdoor colour and ozone protection.
Can BR TBR be formed, bent or molded?
Raw BR cold-flows and bands poorly on the mill, so it is normally masterbatched with NR/SBR and 30–60 phr black; compression, transfer or injection cure at 145–180 °C with sulfur/CBS systems.
What is the maximum service temperature of BR TBR?
BR TBR is rated for continuous use to about 55°C (131 °F), and briefly to 120°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- GB/T 8657 (BR) — SAC (2019)
- ASTM D5900 / D3568 — Standard practices for rubber test recipes and BR evaluation — ASTM (2020)
- Engineered Materials Handbook Vol. 2 — Engineering Plastics & Elastomers — ASM International (1988)
- Rubber Technology: Compounding and Testing for Performance — Hanser (2009)
- Buna CB / Nd-BR grade datasheets — ARLANXEO / LANXESS (2023)
- Polymer Handbook (4th ed.) — polybutadiene thermal and optical constants — Wiley (1999)
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.