# Unsaturated polyester resins: Emissions

Styrene, glycols and anhydrides carry the carbon

Source page: https://www.materialinsights.org/chemicals/upr/emissions/

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 2.80 t CO2e per t range 2.3-3.5 · indicative (basis: 0.35 t styrene x 2.8 + 0.27 t propylene glycol x about 2.4 + 0.26 t phthalic anhydride x about 1.5 + 0.18 t maleic anhydride x about 2.0, plus about 0.4 t for batch processing and transport) Global emissions per year 19.0 Mt CO2e per year 2024 · 2.8 t CO2e/t x about 6.8 Mt (indicative)

Per t of liquid UPR (with styrene), cradle-to-gate. Intensity: derived from styrene and PO tiles; anhydride footprints indicative. Global total: derived.

#### Share of footprint by lifecycle phase
 Feedstock 85% Production / process 11% Movement 4%

#### Footprint by lifecycle phase

| Phase | Intensity | Share | Main sources of emissions | Notes | Source |
|---|---|---|---|---|---|
| **Feedstock** | about 2.4 t CO2e per t | 85% | Styrene (about 1.0 t), glycols (about 0.65 t), anhydrides (about 0.75 t) |  | derived |
| **Production / process** | about 0.3 t CO2e per t (indicative) | 11% | Gas or thermal oil heating of batch reactors for 10-20 hours |  | indicative |
| **Movement** | about 0.1 t CO2e per t (indicative) | 4% | Road and short-sea freight in drums |  | indicative |
| **Use** | styrene VOC emissions during moulding | – | Open moulding releases part of the styrene as VOC (indicative) | Light, corrosion-free pipes and car parts can save energy in use | indicative |
| **End of life** | about 2.3 t CO2 per t of resin if incinerated (indicative) | – | Thermoset composites are landfilled or co-processed in cement kilns | Glass and filler go into clinker; resin acts as fuel (indicative) | indicative (about 63% carbon) |

#### Other environmental impacts

Styrene exposure for workers; dust from cutting composites; composite waste that cannot be remelted; silica dust in engineered stone fabrication (a serious silicosis risk for stone workers).

#### Levers to cut emissions

- Recycled-PET glycolysate and bio-glycols in the polyester
- Low-styrene and styrene-free reactive diluents
- Closed moulding (infusion, RTM, SMC) to cut VOCs
- Cement kiln co-processing and mechanical recycling of composite waste
- Renewable heat for batch reactors

#### India

No Indian UPR footprint is published. Indian resin relies on imported styrene and PG, so most emissions occur abroad. The main domestic lever is in use: GRP pipes and tanks for water supply and sewage, and composite waste handling (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 |
|---|---|---|---|---|
| **Recycled-PET-based UPR** | not published; lower than ortho (indicative) | small or none when flake is cheap (indicative) | commercial at several producers (indicative) | indicative |
| **Bio-based UPR (bio-PG, bio-succinic or itaconic acid)** | not published | premium (indicative) | small volumes | indicative |

 For a climate investor UPR itself is a mature, fragmented resin with modest decarbonisation upside beyond recycled-PET and bio-glycol inputs. The more interesting angles are downstream: composite pipes and tanks for India's water infrastructure, and composite waste co-processing and recycling. A climate fund would need evidence of buyer demand for recycled or bio content and of reliable waste collection.

## Other sections

- [Summary](https://www.materialinsights.org/chemicals/upr/index.md)
- [Overview](https://www.materialinsights.org/chemicals/upr/overview/index.md)
- [Correlation](https://www.materialinsights.org/chemicals/upr/correlation/index.md)
- [Production route](https://www.materialinsights.org/chemicals/upr/routes/index.md)
- [Production](https://www.materialinsights.org/chemicals/upr/production/index.md)
- [Feedstocks](https://www.materialinsights.org/chemicals/upr/feedstocks/index.md)
- [Cycles](https://www.materialinsights.org/chemicals/upr/cycles/index.md)
- [Trading](https://www.materialinsights.org/chemicals/upr/trading/index.md)
- [Movement](https://www.materialinsights.org/chemicals/upr/movement/index.md)
- [Regulation](https://www.materialinsights.org/chemicals/upr/regulation/index.md)
- [Characteristics](https://www.materialinsights.org/chemicals/upr/characteristics/index.md)
- [Relationships](https://www.materialinsights.org/chemicals/upr/links/index.md)