Weekly Market Outlook for the C5 Industry Chain (September 14, 2026)

I. Key Points

1. Although tensions in the Middle East persist, diplomatic efforts to de-escalate risks have led to a decline in international crude oil prices. NYMEX WTI futures for October closed at $100.05/bbl, down $2.43/bbl (-2.37%); ICE Brent futures for November closed at $104.61/bbl, down $3.02/bbl (-2.81%). INE Shanghai Crude Oil futures contract SC2610 rose by 41.5 yuan/barrel to 809.9 yuan/barrel, with night session trading up 40.2 yuan/barrel to 850.1 yuan/barrel.

2. As of September 11, Japanese naphtha closed at $968.5/ton, up $60/ton from the previous trading day. Singapore naphtha closed at $103.21/bbl, up $6.59/bbl from the previous trading day.

3. Last week, domestic pyrolysis C5 prices from major producers rose, while blended C5 prices in Shandong remained stable. The increase in crude oil prices provided some market support. Regulatory standards in the fuel sector are tightening, impacting residual liquid products in certain regions and leading to a wait-and-see attitude. Regarding downstream processing, piperylene monomer prices remained firm, and resin prices were supported by costs, but end-user purchasing enthusiasm remained weak.

4. Last week, the domestic pyrolysis C5 residual liquid market remained largely stable, with sporadic price increases from some refineries. Gasoline prices in the Shandong market generally rose, but downstream buying sentiment declined. Blended C5, a substitute product, initially fell before rising again. With stricter market compliance regulations, the pyrolysis C5 residual liquid market maintained stability amid a wait-and-see approach, with only minor price adjustments from isolated plants.

5. Piperylene prices rose last week, primarily supported by cost factors and supply constraints. Suppliers maintained firm pricing, while downstream demand was driven by essential needs. Mainstream ex-factory prices ranged from 8,500 to 9,300 yuan/ton.

6. Domestic isoprene prices rose last week as the tight supply situation persisted. This was compounded by rising crude oil and pyrolysis C5 prices, which supported costs and pushed the market higher. Mainstream offer prices in the East China market ranged from 13,200 to 13,800 yuan/ton.

7. Dicyclopentadiene (DCPD) continued its upward trend last week, with prices ranging between 8,300 and 8,900 yuan/ton. Prices stabilized at the lower end, while spot transactions leaned towards the upper end; some small-volume auction lots exceeded 9,000 yuan/ton. Spot supply remained tight, although demand also softened slightly. High price levels are expected to continue in the short term.

8. Mainstream prices for road marking grade C5 petroleum resin rose by 300 yuan/ton last week, reaching 9,600–10,600 yuan/ton. Sustained rises in international crude oil prices and tight domestic C5 resources drove significant price increases, leading to localized negative margins (price inversion) for some resins. Overall demand continued to rise slightly, pushing negotiated prices higher.

9. Mainstream prices for piperylene-based adhesive grade C5 petroleum resin rose by 500 yuan/ton last week to 11,000–13,000 yuan/ton. Hydrogenated adhesive grade C5 petroleum resin prices ranged from 10,600 to 11,000 yuan/ton. Spot availability remained tight, and costs continued to rise. Downstream hedging sentiment was strong, with a slight increase in stocking activity. Shortages dominated the market in the short term, continuing to push negotiated prices higher.

Core Logic: Pyrolysis C5 prices rose; isoprene saw a slight increase; piperylene remained stable; DCPD prices rose; C5 petroleum resin prices held steady with modest upward pressure.

II. Price Summary

Table 1: Domestic Pyrolysis C5 Industry Chain Summary (Unit: Yuan/ton)

III. Market Outlook

Domestic pyrolysis C5 prices are expected to remain firm. Crude oil closed significantly higher, and blended C5 prices in Shandong remain at high levels, maintaining a price gap relative to pyrolysis C5. Auction prices from private enterprises remain robust. Regarding pentadiene monomers, low inventory levels support continued price increases. While resin sales volumes are moderate, strong cost support is driving resin prices upward.

The pyrolysis C5 residual liquid market is expected to trade strongly within a fluctuating range. Refinery gasoline inventories are at low levels, providing suppliers with confidence to maintain prices. However, favorable supply-demand dynamics in the blended C5 market are weakening, leading to a slight decline in that segment. Considering these combined factors, Chempricehub forecasts that today's refinery prices for pyrolysis C5 residual liquid will fluctuate weakly.

Crude oil prices rose during intraday trading, and refinery gasoline inventories remain low, giving suppliers some leverage to hold prices. Meanwhile, circulating volumes in the blended C5 market have increased. With bullish and bearish factors in stalemate, Chempricehub expects the blended C5 market to operate somewhat weakly today.

Isoprene is expected to trade firmly. Crude oil opened higher, and the tight supply landscape persists, supporting manufacturers' reluctance to sell and their intent to maintain prices. Prices are forecast to consolidate at elevated levels.

Piperylene is expected to trade firmly. Recent strengthening on the cost side, combined with reduced plant output and increased internal consumption, has limited tradable resources in the market. Piperylene prices are projected to maintain an upward-biased trend.

DCPD prices are expected to remain at high levels. While downstream demand performance is average, spot supplies are tight and unlikely to ease in the short term. Additionally, raw material prices provide clear cost support. Coinciding with the pre-holiday stocking period for the Mid-Autumn Festival and National Day, supply and cost factors will dominate the market in the short term, sustaining firm high-level prices.

For road marking grade C5 petroleum resin, downstream construction activity is concentrated in northern regions. Significant increases in raw material C5 prices, coupled with sustained high production costs and reduced willingness to produce among some manufacturers, will likely drive further modest price increases. For adhesive grade C5 petroleum resin, rising cost pressures on manufacturers and steadily increasing essential downstream demand suggest that prices will continue to see modest upward adjustments due to cost constraints.

IV. Data Calendar

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