BR LI-BR
Grade
LI-BR = lithium-catalysed low-cis
Choose for HIPS/ABS impact modification and easier mill processing (less cold flow) rather than for maximum abrasion.
Values for the LI-BR 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 |
LI-BRThis page 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 |
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 LI-BR?
BR LI-BR is BR in the LI-BR grade — choose for HIPS/ABS impact modification and easier mill processing (less cold flow) rather than for maximum abrasion. BR LI-BR has a tensile strength of 12 MPa (1.74 ksi), weaker than 76% of polymer grades. Elongation at break is 500% and the elastic modulus is 0 GPa (5.08×10⁻⁴ Msi). BR LI-BR has a density of 0.93 g/cm³ (0.0336 lb/in³), lighter than 78% of polymer grades. Its glass-transition temperature is -93°C (-135 °F). HI-CIS-NI is the default condition FabDigit quotes; LI-BR is available on request or by drawing note.
Advantages
- Forms and bends easily — 90/100, better than 91% of polymer grades
- Ductile — tolerates forming and impact — 500%, better than 90% of polymer grades
- Low embodied carbon — 3.2 kg CO₂/kg, better than 81% of polymer grades
- Lightweight — 0.93 g/cm³ (0.0336 lb/in³), better than 78% of polymer grades
Limitations
- Needs corrosion protection — 30/100, worse than 100% of polymer grades
- Difficult to machine — 25/100, worse than 93% of polymer grades
- Low stiffness — 0 GPa (5.08×10⁻⁴ Msi), worse than 92% of polymer grades
- Degrades in UV without stabilisers — 20/100, worse than 88% of polymer grades
- High mold shrinkage — 2%, worse than 81% of polymer grades
BR LI-BR properties
Typical room-temperature values for BR LI-BR; 16 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 LI-BR has a density of 0.93 g/cm³ (0.0336 lb/in³), lighter than 78% of polymer grades. Its glass-transition temperature is -93°C (-135 °F).
Mechanical10
BR LI-BR has a tensile strength of 12 MPa (1.74 ksi), weaker than 76% of polymer grades. Elongation at break is 500% and the elastic modulus is 0 GPa (5.08×10⁻⁴ Msi).
Thermal8
BR LI-BR is rated for continuous service to 85°C (185 °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 220 µm/m·K (122.2 µin/in·°F).
Electrical5
BR LI-BR 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 poor (30/100), worse than 100% of polymer grades. UV resistance is poor.
Sustainability4
Producing a kilogram of BR LI-BR 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 LI-BR's machinability is poor (25/100, worse than 93% of polymer grades); weldability poor (20/100); formability excellent (90/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with BR LI-BR
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 LI-BR — frequently asked
What is BR LI-BR used for?
BR LI-BR 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 LI-BR?
BR LI-BR has a typical tensile strength of 12 MPa (1.74 ksi) — weaker than 76% of polymer grades. Strength varies by condition: see the 9 listed tempers.
Is BR LI-BR easy to machine?
Not especially — machinability is rated poor (25/100, worse than 93% 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 LI-BR be welded?
Not readily — weldability is rated poor (20/100). 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 LI-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.
Can BR LI-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 is the maximum service temperature of BR LI-BR?
BR LI-BR is rated for continuous use to about 85°C (185 °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.