Weekly Market Outlook for the C5 Industry Chain (September 20, 2026)

I. Key Points

1. Crude Oil Prices Decline: Expectations of improved repair work on Saudi oil pipelines, combined with signs of easing tensions in the Middle East, led to a drop in international crude oil prices. The NYMEX WTI futures contract for October delivery fell by USD 1.61/bbl to USD 100.30 (-1.58% WoW). The ICE Brent futures contract for November delivery dropped by USD 0.95/bbl to USD 103.87 (-0.91% WoW). China's INE crude oil futures contract for November 2026 delivery fell by CNY 50.6 to CNY 754.4/bbl, with night session trading dropping another CNY 19.6 to CNY 734.8/bbl.
2. Naphtha Prices Soften: As of the 18th, Japanese naphtha closed at USD 902.25/ton, down USD 18.5/ton from the previous trading day. Singapore naphtha closed at USD 97.26/bbl, down USD 2.4/bbl from the previous trading day.
3. Pyrolysis C5 Price Adjustment: Last week, industrial pyrolysis C5 prices rose by CNY 200-300/ton to approximately CNY 7,300/ton. This increase was primarily supported by higher costs for crude oil, refined products, and competitive bidding prices for private enterprise pyrolysis C5. Private enterprise prices remained firmer than those of major state-owned enterprises, which also adjusted their prices upward. The current rise in pyrolysis C5 is largely driven by strong refined product prices supporting residual liquid values. In terms of deep processing, piperylene monomer prices remain firm due to low inventory levels, while resin prices are rising due to cost support.
4. Residual Liquid Market Mixed: The pyrolysis C5 residual liquid market saw some companies maintaining stable prices and adopting a wait-and-see approach, while sporadic declines occurred. Gasoline market conditions in Shandong deteriorated, leading to lower prices for mixed C5 (a homogeneous substitute). With bearish sentiment dominating the market, part of the residual liquid market held steady while other segments declined.
5. Piperylene Prices Rise: Piperylene prices increased last week. Tight raw material supply and generally low industry operating rates constrained output. Although yield improvements at some units and the stable operation of restarted facilities slightly increased market availability, downstream demand for resins and curing agents pushed prices up passively. Order transactions improved as downstream inventories remained low, with end-users chasing higher prices due to essential demand and pre-holiday stocking. Mainstream ex-factory prices ranged from CNY 8,900 to 10,000/ton.
6. Isoprene Prices Increase: Domestic isoprene prices rose last week. High costs for crude oil and pyrolysis C5 provided strong support. Raw material supply was tight, and overall industry operating rates were low. Slight increases in market availability came from yield improvements and stable operations at restarted plants. Downstream SIS producers restarted maintenance units, maintaining essential industry demand. Combined with the start of pre-holiday stocking, purchasing activity increased, leading to passive price chasing. Mainstream bid prices in East China ranged from CNY 13,600 to 14,200/ton.
7. DCPD Lower Bound Shifts Upward: The lower bound of dicyclopentadiene (DCPD) prices shifted upward last week, with the range moving to CNY 8,900-9,300/ton. Lower-end suppliers maintained stability, while high-end spot deals involved negotiation. As mainstream prices rose, procurement interest weakened. Additionally, limited orders from end-users ahead of the holiday prevented a boost in pre-holiday stocking sentiment among factories. While private enterprise raw material prices have fallen significantly, major state-owned enterprises maintain firm pricing, keeping relative costs stable. Overall DCPD supply remains limited, providing continued support for a high-level trend.
8. Road Marking Paint Resin Prices Surge: Mainstream prices for road marking paint C5 petroleum resin rose to CNY 9,600-10,800/ton last week. Driven by amplified downstream demand, supply shortages, and high production costs, resin prices continued to climb, subsequently prompting resin plants to increase operating rates.
9. Adhesive Resin Prices Climb: Mainstream prices for piperylene adhesive C5 petroleum resin rose by CNY 500-600 to CNY 11,500-13,600/ton. De-cyclized adhesive C5 petroleum resin prices ranged from CNY 10,800 to 11,200/ton. Tight spot availability and rising costs, coupled with short-term supply-demand imbalances, drove negotiated prices higher.

Core Logic: Pyrolysis C5 consolidates; Isoprene stabilizes; Piperylene stabilizes; DCPD rises; C5 petroleum resins show modest gains within a stable framework.

II. Price Table

Table 1: Summary of Domestic Pyrolysis C5 Industry Chain Prices (Unit: CNY/ton)

III. Market Outlook

Domestic pyrolysis C5 prices are expected to remain temporarily stable. However, mixed C5 prices in Shandong are predicted to continue declining. Private enterprises are engaging in pre-holiday destocking, exerting downward pressure on prices. Poor recent shipments of residual liquids have reduced refiners' willingness to accept raw materials. Regarding deep processing, piperylene monomers currently have low inventories, providing some support, while resin terminals are primarily purchasing based on essential needs.

The market for pyrolysis C5 residual liquids is expected to weaken further. Refinery gasoline inventories have accumulated for several consecutive days, suggesting continued downside potential for mixed C5. With bearish market sentiment prevailing, Chempricehub forecasts that refinery prices for pyrolysis C5 residual liquids will primarily decline in the near term.

Overnight crude oil prices fell, though the impact on the broader market is limited. Refinery gasoline stocks continue to build, leading to a slight decline today. Guided by bearish sentiment, Chempricehub expects the mixed C5 market to dip slightly today.

Isoprene prices are expected to consolidate at high levels. The tight supply pattern persists, and factories maintain firm pricing attitudes. However, crude oil volatility and weakening private enterprise pyrolysis C5 prices have made traders cautious. Consequently, prices are likely to trade sideways at high levels while participants observe.

Piperylene prices are expected to stabilize temporarily. While falling private enterprise pyrolysis C5 prices have weakened cost support, tight product supply and rising downstream resin prices are attracting attention. Therefore, piperylene markets are projected to hold steady.

(Note: The original text contains a duplicate/redundant paragraph regarding Piperylene outlook below, translated for completeness)
Piperylene is expected to remain stable with a wait-and-see attitude. Although crude oil closed lower, factors such as reduced factory output and increased self-consumption limit available tradable resources. Thus, piperylene prices are expected to stabilize.

DCPD prices are expected to remain elevated. While downstream demand is average, spot tightness is unlikely to ease in the short term. Additionally, the pre-holiday stocking period for Mid-Autumn and National Day festivals means supply constraints and cost factors will dominate, sustaining a firm high-level trend.

For road marking paint C5 petroleum resin, construction volumes may be delayed due to high raw material costs, and downstream acceptance of current prices is weak. However, slight increases in resin supply suggest prices will remain firm at high levels in the short term. For adhesive C5 petroleum resin, prices have risen sharply recently. Despite peak season demand, supply gaps persist, leading to expectations of continued modest price increases.

IV. Data Calendar

Table 2: Domestic Pyrolysis C5 Industry Chain Data Overview (Unit: 10,000 tons)

Notes:

1. ↓↑ indicates significant fluctuation, highlighting data dimensions with changes exceeding 3%.
2. ↗↘ indicates narrow-range fluctuation, highlighting data with changes within 0-3%.