SunSirs: Cost Factors Drove Volatile and Downward Trends in the Phthalic Anhydride Market in 2025, and the Market May Rise Firstly and Then Stabilize in 2026

The phthalic anhydride market fluctuated downward in 2025

According to SunSirs' commodity price analysis system, as of December 31st, the price of phthalic anhydride was 5,966.67 RMB/ton, a fluctuating decrease compared to the price of 6,600 RMB/ton on January 1st, representing a drop of 9.60%. In 2025, the phthalic anhydride market showed a volatile downward trend, with a rebound at the end of the year. The average price of phthalic anhydride in East China for the whole year was 6,653.97 RMB/ton, a decrease of 9.60% compared to 2024, reaching a new low in the past three years. The combined pressure of falling raw material prices, oversupply, and weak downstream demand led to a deep adjustment in the phthalic anhydride industry.

The cost of phthalic anhydride decreased

On December 31st, Sinopec's OX price was 5,800 RMB/ton, a significant drop from the January 1st price of 6,700 RMB/ton, representing a decrease of 13.43%. The average price of ox in 2025 was approximately 12% lower than in 2024. While OX prices rebounded slightly at the end of the year, the cost of phthalic anhydride decreased. With weaker cost support from OX, the downward pressure on phthalic anhydride prices increased in 2025.

Phthalic anhydride production capacity was expanding, leading to oversupply

The total domestic phthalic anhydride production capacity was approximately 2.4 million tons (including 1.63 million tons from the OX process and 770,000 tons from the naphthalene process).  An additional 50,000 tons of capacity was added in 2025, from a new OX process phthalic anhydride plant built by Aekyung (Ningbo). In 2025, the operating rate of phthalic anhydride production fluctuated between 50% and 75%, with the OX process maintaining an operating rate of 60%-75%, while the naphthalene process had a lower operating rate of only 50%-60% due to cost pressures. Despite the relatively high operating rate, there was an overall surplus of phthalic anhydride supply.

Demand side: DOP prices fluctuated and declined in 2025

According to SunSirs' commodity market analysis system, as of December 31st, the price of DOP was 7,325.84 RMB/ton, a fluctuating decrease compared to 8,226.25 RMB/ton on January 1st, a drop of 10.95%. In 2025, DOP prices initially remained stable before falling, with a slight rebound at the end of the year. The overall price level for the year was significantly lower than in 2024. Weak downstream demand increased downward pressure on phthalic anhydride prices. Over 60% of phthalic anhydride demand depende on the DOP and other plasticizer industries. In 2025, the operating rate of DOP enterprises was only 50%-65%, and the decline in the DOP plasticizer market led to cautious purchasing of phthalic anhydride, mainly based on immediate needs, resulting in low inventory levels and significant downward pressure on phthalic anhydride prices.

Market Outlook

According to SunSirs' phthalic anhydride product data analyst, in 2025, the oversupply of phthalic anhydride and declining costs led to volatile and downward price trends. Overall, in terms of costs, there will be no new domestic o-xylene capacity in 2026, and some companies will switch their production to PX. Coupled with expected maintenance in the Asian market in the second quarter, OX prices may fluctuate upwards in 2026, increasing cost support for phthalic anhydride. In terms of supply, the operating rate of phthalic anhydride was relatively high in 2025, but may decrease in 2026, and there will be no new phthalic anhydride capacity, so the supply of phthalic anhydride is expected to decrease in 2026. In terms of demand, with the relaxation of real estate policies, the demand for plasticizers is expected to recover, providing continued support for phthalic anhydride demand. Looking ahead, with cost support and a supply-demand imbalance favoring demand, phthalic anhydride prices are expected to fluctuate upwards in 2026, possibly reaching a high point in the second quarter before stabilizing at a weaker level.

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