Hollow Fiber: The "Air Pipeline" Reshaping China's Thermal Textile Market - Set to Exceed RMB 40 Billion in 2026

SHANGHAI, Oct 15 - A filament thinner than a human hair is quietly rewriting the rules of thermal textiles. Hollow fiber - polyester filaments with a hollow channel running through the core - is racing from low-cost filling material to the front line of high-end functional fabrics, and industry research shows the market is accelerating through a high-value upgrade cycle.

According to a 2026 industry report by Boyan Consulting, China's hollow polyester fiber market reached RMB 34.52 billion in 2025, up 15.8% year on year - outpacing the 11.2% average growth of the broader chemical fiber industry - and is forecast to hit RMB 40.21 billion in 2026, with production expected to exceed 2.25 million tons.豆丁网

A 37% hollowness rate becomes the new global benchmark

The technical race is being defined by one metric: hollowness rate - the share of the axial air channel inside each filament. "The bigger the channel, the more still air it traps, and the better the warmth and breathability," explains Chai Senguang, R&D manager at Jiangsu Hengke New Materials in Nantong.

Hengke's independently developed high-hollow thermal polyester fiber "Mianweisi" has achieved a hollowness rate above 37% - the industry's only mass-produced product at this level and a global-leading figure, according to the company. The filament measures just 1/20 the diameter of a human hair, and Hengke says it can mass-produce tows of 300,000–700,000 meters that maintain the 37%+ rate with no voids.

The breakthrough came from an unexpected source: in June 2023, a Japanese client asked for thermal materials for extreme-cold environments. Hengke's team ran more than 100 spinning trials, built material rheology models and a big-data process system, and finally cracked what the industry calls the common challenge of "abrasion resistance versus cavity integrity." The project entered Nantong's major sci-tech achievement transformation list in 2024, and sales are expected to exceed 20,000 tons by 2027.南通市人民政府

Beyond a single hollow channel: next-generation structures

The industry is already moving past simple hollow tubes toward hierarchical pore architectures.

At Donghua University, the team of Prof. Ding Bin developed an ultrathin carbon nanofiber metafabric with a hollow aerogel architecture - just 85 micrometers thick - capable of electric heating from 28°C to 163°C, a photothermal temperature rise of 44°C under sunlight, and passive insulation that keeps surface temperature about 4°C closer to ambient than commercial cotton. The research was published in ACS Nano in April 2026.湖北省先进纤维材料综合型技术创新平台

Tianjin University's team, led by Prof. Feng Wei, went further with a bio-inspired molecular solar thermal (MOST) fabric published in Advanced Materials, which heats to 40°C after just 12 seconds of light exposure - a "smart warmth" textile that needs no electronic devices.新华网天津大学新闻网

At the same time, PBT core-sheath hollow fibers produced by melt in-line foaming are targeting plateau and high-altitude regions, where strong winds strip away still air and defeat conventional insulation.

Market snapshot: exports rise, applications diversify

The numbers tell a story of structural upgrade. In 2025:

Production reached 1.983 million tons, up 7.2% year on year, while functional modified fibers (antibacterial, flame-retardant, far-infrared) rose to 36.7% of output, with a 42% target for 2026;

Bio-based hollow polyester fiber output broke 82,000 tons, about 4.1% of the total;

Exports hit 516,000 tons worth USD 930 million, up 14.7%, with average prices rising 3.9% to USD 1,802 per ton - mainly to Southeast Asia (42.3%), the EU (23.1%) and North America (15.8%);

Application mix: home textiles remain the largest segment (35.2% of demand), followed by apparel fabrics (28.7%), where sportswear and lightweight winter wear are driving growth; industrial textiles (22.3%) are the fastest-growing major segment, boosted by automotive interiors; and the medical/health segment, though small at 1.4%, grew a remarkable 31.5%.

The fiber's physical credentials underpin the shift: thermal conductivity as low as 0.028–0.032 W/(m·K) and density of 0.91–0.95 g/cm³ give it a bulk 30–50% higher than solid polyester, with compression recovery of 85–92%.豆丁网

Industry landscape: East China consolidates, global players respond

Concentration is rising. The top five producers - Hengli Petrochemical (22.6% share), Rongsheng (14.2%), Tongkun (9.1%), Xinfengming (7.2%) and Eastern Shenghong (5.2%) - now control 58.3% of the market, up 2.1 points from 2024. Jiangsu and Zhejiang together account for 68.5% of national capacity; Hengli started up a 150,000-ton intelligent hollow fiber line in Suzhou in Q3 2025, while melt direct spinning reached 71.2% of capacity.豆丁网

Overseas, Japanese fiber maker Teijin Frontier unveiled a polyester-based textile in June 2026 that combines structural heat retention with high breathability for sports and outdoor thermal apparel, positioning it for the fall/winter 2027 season after earlier trials with hollow 8-fin cross-section yarns. The Textile Magazine Its joint venture with Asahi Kasei, TA Frontier, is set to begin operations in October 2026 focused on recycled polyester filament. Mordor Intelligence™ Globally, the hollow polyester staple fiber market is estimated at around USD 4.39 billion in 2026.PW Consulting

Outlook: from "cheap filling" to engineered fabric

The direction of travel is clear: hollow fiber is being repositioned from a low-cost down substitute to a high-performance engineered material. Watch for four trends - deeper functionalization (antibacterial, flame-retardant, far-infrared), bio-based raw materials, smart manufacturing with AI-driven online inspection (Hengke's defect miss rate is 0.016%, versus 0.035% for manual checks), and new application frontiers in EV interiors, medical rehabilitation and premium outdoor gear. As one industry executive put it, the segment is shifting "from low-end manufacturing to high-end creation" - one hollow channel at a time.