Styrene-butadiene rubber: Emissions
Butadiene and styrene bring most of the carbon
What this tab covers The greenhouse-gas footprint per tonne, split by lifecycle phase (feedstock, production, movement, use, end of life), the global total, other environmental impacts, levers and low-carbon routes, India's position, and where the investment opportunity lies. Emission intensity 3.00 t CO2e per t range 2.5-4.2 · derived: 0.76 t butadiene x 1.3 + 0.24 t styrene x 2.8 = about 1.7 t, plus about 1.2 t polymerisation, stripping and drying and 0.1 t transport; OEKOBAUDAT gives 4.2 kg CO2e/kg for Germany (data year 2018) Global emissions per year 16.5 Mt CO2e per year 2024 · about 5.5 Mt x 3.0 t CO2e/t (derived, indicative)Per t of SBR, cradle-to-gate. Intensity: butadiene and styrene tiles (indicative); OEKOBAUDAT 2023-I via Climatiq (upper range). Global total: derived.
Share of footprint by lifecycle phase
Feedstock 57% Production / process 40% Movement 3%Footprint by lifecycle phase
| Phase | Intensity | Share | Main sources of emissions | Notes | Source |
|---|---|---|---|---|---|
| Feedstock | about 1.7 t CO2e/t | 57% | naphtha cracking, butadiene extraction, styrene dehydrogenation | butadiene uses mass allocation of cracker emissions | derived from butadiene and styrene tiles |
| Production / process | about 1.2 t CO2e/t | 40% | refrigeration (cold ESBR), monomer stripping, solvent recovery (SSBR), drying | SSBR solvent recovery uses more steam | indicative |
| Movement | about 0.1 t CO2e/t | 3% | container shipping of bales | small | indicative |
| Use | not quantified per t of SBR | – | tyre rolling resistance and wear | the use phase dominates a tyre's life-cycle emissions through vehicle fuel or electricity (indicative); tyre wear releases microplastic particles | indicative |
| End of life | about 3.3 t CO2 per t if burned (calculated from about 90% carbon) | – | end-of-life tyres to cement kilns, pyrolysis, crumb rubber or landfill | vulcanised rubber cannot be remelted; devulcanisation and pyrolysis are the recycling routes | calculated (indicative) |
Other environmental impacts
Tyre and road wear particles are one of the largest sources of microplastics (indicative); butadiene emissions; extender oil PAHs (now limited).
Levers to cut emissions
- SSBR with silica cuts rolling resistance, saving vehicle energy across the tyre's life (indicative).
- Bio-attributed or bio-based butadiene (from ethanol) and styrene under mass balance (indicative; Synthos and others have announced programmes).
- Recovered monomers from tyre pyrolysis oil fed back to crackers (indicative).
- Renewable steam and power at rubber plants.
India
India's SBR footprint is in Reliance and Indian Synthetic Rubber plants plus imports. Waste tyre EPR (2022) and India's large tyre pyrolysis industry create a route to circular feedstock, though informal pyrolysis has pollution problems (indicative).
Emission figures are indicative global averages from the life-cycle studies named; actual footprints vary widely by site, energy mix and method.Low-carbon routes
| Route | Intensity | Cost premium | Status | Source |
|---|---|---|---|---|
| Bio-based butadiene from ethanol for SBR | not published in sources reached | large at current ethanol prices (indicative) | pilot and demonstration (indicative) | indicative |
| Circular SBR from tyre pyrolysis oil (mass balance) | not published | not published | early commercial in Europe (indicative) | indicative |