1. Key Market Focus This Week

• East China mixed C5 prices fell by 0.33%, while Shandong pyrolysis C5 residual liquid prices dropped by 1.1%.
• Deep processing piperylene prices rose, and petroleum resin prices were pushed up by varying amounts ranging from 500 to 800 RMB/ton.
• Supply volumes of pyrolysis C5 increased slightly.

2. Weekly Market Analysis

During the week (September 11–17, 2026), industrial pyrolysis C5 prices increased by 200–300 RMB/ton to approximately 7,300 RMB/ton. Private enterprise prices initially rose but subsequently declined. On Thursday, September 17, North China pyrolysis C5 prices rose by 200 RMB/ton to a quoted price of 7,300 RMB/ton; East China prices rose by 300 RMB/ton to 7,300 RMB/ton; Northeast prices stood at 6,950–7,060 RMB/ton; South China prices rose by 350 RMB/ton to 7,150–7,300 RMB/ton. Some private enterprises raised their prices to 7,550–7,900 RMB/ton.

(Note: Image captions regarding price trend charts for 2025-2026 have been omitted as per instructions.)

3. Analysis of Market Influencing Factors

Dicyclopentadiene (DCPD)
This period, the domestic dicyclopentadiene market continued its upward trend. Market supply remained tight. However, as prices rose, downstream demand weakened significantly, with transactions limited to essential needs. Export negotiations also slowed slightly. Nevertheless, factory inventories were generally low, so there was no sign of increased overall supply yet. During the week, raw material pyrolysis C5 prices remained relatively stable; although private enterprise prices pulled back, they still provided cost support for DCPD. Downstream unsaturated polyester resin (UPR) producers maintained essential stockpiling, while hydrogenated DCPD resin producers continued to raise prices under cost pressure. As of September 17, ex-factory pickup prices for DCPD ranged from 8,900 to 9,300 RMB/ton. The lower end remained stable for long-term clients, while some auction prices settled slightly higher.

Piperylene
This period, domestic piperylene prices continued to rise. The lower end increased by 400 RMB/ton, and the upper end rose by 700 RMB/ton, bringing ex-factory prices to 8,900–10,000 RMB/ton. Crude oil and pyrolysis C5 remained at high levels, sustaining cost support. Raw material supply was tight, and overall industry operating rates were low. Production from some units increased due to improved yields, and combined with the stable operation of restarted units, market circulation volume rose slightly. Downstream resin and curing agent prices were passively pushed up, and order execution improved. With downstream raw material and product inventories at low levels, passive chasing of high prices occurred driven by essential demand and pre-holiday stockpiling.

Isoprene
This period, domestic isoprene prices continued to rise. In mainstream markets, the lower end of bid/ask quotes increased by 300 RMB/ton, and the upper end rose by 600 RMB/ton to 13,600–14,200 RMB/ton. Crude oil and pyrolysis C5 remained at high levels, providing strong cost support. Raw material supply was tight, and overall industry operating rates were low. Production from some units increased due to yield improvements, and alongside stable operations from restarted units, market circulation volume rose slightly. Some downstream SIS units undergoing maintenance resumed operations, maintaining essential industry demand. Coupled with the start of pre-holiday stockpiling, procurement enthusiasm increased during the week, leading to passive chasing of high prices.

Pyrolysis C5 Residual Liquid
The market for pyrolysis C5 residual liquid traded sideways at high levels, with average prices rising. As of September 17, the national weekly average price index for pyrolysis C5 residual liquid was 7,629 RMB/ton, an increase of 143 RMB/ton or 1.91% compared to last week's average. Specifically, domestic market prices ranged from 7,619 to 7,635 RMB/ton during the week. International crude oil prices rose then fell, resulting in a higher weekly average. Finished oil market conditions in Shandong remained firm. Homogeneous product mixed C5 fluctuated at high levels. Bullish and bearish factors intertwined, causing pyrolysis C5 residual liquid prices to consolidate sideways. Refineries stabilized prices to sell inventory, while traders and downstream factories purchased based on essential needs. Transaction sentiment was moderate throughout the week.

4. Next Week Market Forecast

Pyrolysis C5 prices are expected to remain stable in the next period. Key points to watch include:

1. As downstream product prices rise, improved profits will drive higher operating rates.
2. Demand from non-deep processing sectors remains weak; therefore, support for pyrolysis C5 residual liquid prices is limited, and prices are likely to decline.
3. In deep processing sectors, piperylene prices are expected to trade mostly sideways. Downstream acceptance of petroleum resin prices is weak, so these prices will likely run stably.