# Unsaturated polyester resins

Low-cost thermosetting resins of maleic and phthalic polyesters dissolved in styrene, the matrix for glass-fibre pipes, tanks, boats, panels and engineered stone.

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

Pseudo-commodities · Resins & fibres · No. 65

- Single chemical
- Feedstock: Oil, gas or coal
- about 6.5-7 Mt a year (2024-2025, indicative, basis: China demand of 3.31 Mt in 2024 at roughly half of world volume); China output 3.45 Mt (2024e)
- 2.8 t CO₂e per t
- HS 390791
 Pseudo-commodities · Resins & fibres · Foundation · Matter

The kitchen quartz counter, the fibreglass boat and the water tank on your roof may all share one cheap resin.

Chart: Illustration: Unsaturated polyester resins

##### Where it comes from

Chart: Map of where it comes from

Glycols and maleic and phthalic anhydrides are cooked in batch reactors at about 190-210 C for 10-20 hours, then thinned in styrene to make the saleable resin.

##### Three things to know

1. China made 3.23 Mt of UPR in 2023 and about 3.45 Mt in 2024, slightly above its own demand of about 3.31 Mt.
2. UPR is about one-third styrene, so styrene prices, $1,030 a tonne in Asia on 2 March 2026, drive resin cost.
3. Resin has a shelf life of only about 3-6 months, so most is sold close to where it is made.

##### The journey

1. 1 **Feedstocks**Anhydrides, glycols and styrene
2. 2 **Polyesterification**190-210 C for 10-20 hours
3. 3 **Styrene thinning**Dissolved in about 30-40% styrene
4. 4 **Compounding**Glass fibre, quartz and calcium carbonate
5. 5 **Curing**Peroxide and cobalt set it hard

##### Go deeper pick a tab to open it in full

## Other sections

- [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)
- [Emissions](https://www.materialinsights.org/chemicals/upr/emissions/index.md)
- [Relationships](https://www.materialinsights.org/chemicals/upr/links/index.md)