The commodity price data for the 34th week of 2026 (Aug 24-28) reveals a key signal: the polyester filament chain collectively strengthened, while acrylonitrile and PTA corrected sharply, showing an unusual hot-cold divergence within the sector. Polyester POY, DTY, and FDY rose 2.00%, 1.76%, and 1.70% respectively, all up over 21% year-on-year. Meanwhile, acrylonitrile plunged 4.46% in a single week, PTA fell 3.67%, and polyester staple fiber dropped 0.96%. The overall average change was only 0.03%, indicating that most products were in a stalemate, lacking a single-directional driver.
Event Background
From the start to the end of the week, polyester filament was the only category showing a trending rise. POY rose from 8596 yuan/ton to 8767.5 yuan/ton, DTY from 9759.29 to 9930.71 yuan/ton, and FDY from 8820 to 8970 yuan/ton. Notably, year-on-year gains of 21%-24% suggest this is not short-term speculation but a cumulative result over the past year. In contrast, the nylon chain also maintained positive momentum (DTY +0.97%, POY +0.86%), showing overall resilience in the chemical fiber sector.
Meanwhile, upstream raw materials experienced sharp divergence. PTA fell 3.67% in a week to 6213.25 yuan/ton, despite still being up 26.54% year-on-year. Acrylonitrile dropped 4.46% to 11433.33 yuan/ton, with year-on-year gain narrowing to 44.12%. Polyester staple fiber fell 0.96%, diverging from filament, indicating a shift in downstream demand structure. Natural and regenerated fibers such as raw silk, viscose staple fiber, and viscose yarn saw mild changes between 0.42% and 0.85%, with raw silk down 9.16% year-on-year, one of the few negative annual changes.
Industry Impact
The divergence between polyester filament and PTA/staple fiber reveals subtle changes in profit distribution along the chain. Rising filament prices with falling PTA costs mean processing margins for polyester producers are expanding. This typically occurs when terminal orders recover while raw material supply is relatively loose. For weaving mills, grey fabric cost pressure may temporarily ease, but if filament prices continue to climb, cost transmission will appear in the coming weeks. The sharp drop in acrylonitrile is more complex—still 44% higher year-on-year, a 4.46% weekly plunge points to new capacity coming online or weak downstream demand from acrylic and ABS resins, rather than a trend reversal.
From a regional cluster perspective, polyester filament hubs like Shengze and Changxing likely maintain high operating rates, while acrylonitrile producers in Shandong and Jiangsu may face inventory pressure. Cotton spinning products (21S, 32S) remained flat, and cotton lint only rose 0.06%, indicating a wait-and-see period in the cotton market. For buyers, the current polyester filament strength may extend into the 'golden nine silver ten' stockpiling season, but the PTA decline provides a cost buffer, leaving room for negotiation. Exporters should be wary of short-term volatility in acrylonitrile downstream products (e.g., acrylic yarn) to avoid mispricing due to raw material jumps.