China Advances 35K Carbon Fiber for Large Wind Turbine Blades

Published date:15/05/2026 | Last updated date:15/05/2026

China’s Jilin Carbon Valley Carbon Fiber Co., Ltd., a subsidiary of Jilin Chemical Fiber Group, has achieved a major step in large-tow carbon fiber manufacturing, supporting the growing use of advanced composites in offshore wind turbine blades.

The development centers on 35K large-tow carbon fiber, a material now being applied at industrial scale in China’s wind energy sector.

What 35K carbon fiber means

In carbon fiber terminology, “K” refers to the number of filaments within a tow.

• 1K = 1,000 filaments
• 35K = 35,000 filaments bundled together

Producing large-tow carbon fiber at this scale requires extremely consistent filament quality across all 35,000 strands.

According to engineers at Carbon Valley, maintaining uniformity in:

• length,
• diameter,
• and mechanical performance

is one of the biggest technical challenges.

Wind energy drives demand for large-tow carbon fiber

The project was developed jointly by:

• Jilin Chemical Fiber Group,
• Donghua University,
• and multiple research institutions and industry partners.

The research focused on:

• large-scale manufacturing of large-tow carbon fiber,
• composite materials,
• and industrialization of large offshore wind turbine blades.

The breakthrough is significant because offshore wind blades continue growing longer, requiring materials with:

• high stiffness,
• low weight,
• and strong fatigue resistance.

Scaling from lab success to industrial production

Carbon Valley first identified 35K carbon fiber as a strong balance between:

• performance,
• productivity,
• and cost efficiency.

But moving from laboratory development to industrial production created new challenges.

Unlike small experimental batches, commercial production requires:

• continuous 100,000-meter-long tow manufacturing,
• stable winding,
• low filament breakage rates,
• and consistent mechanical properties.

To improve stability, the company:

• redesigned transmission systems,
• upgraded roller support structures,
• improved cleaning and filtration processes,
• optimized equipment materials,
• reduced friction-related filament damage.

Why large-tow carbon fiber matters

Large-tow carbon fiber can significantly reduce production costs compared with smaller-tow aerospace-grade materials.

This makes it especially attractive for:

• wind energy,
• industrial composites,
• pressure vessels,
• infrastructure applications.

For wind turbine blades, lower-cost carbon fiber helps manufacturers build:

• larger blades,
• lighter structures,
• more efficient turbines.

China strengthens domestic carbon fiber capability

For years, large-tow carbon fiber technology was dominated by foreign suppliers.

Carbon Valley’s industrial-scale 35K production reflects China’s broader effort to:

• localize advanced material supply chains,
• reduce dependence on imports,
• strengthen renewable energy manufacturing capability.

The company now supplies major domestic wind turbine manufacturers through long-term agreements.

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This article is developed based on real engineering experience, machine testing data, and practical production knowledge from Jota Machinery’s work in advanced composite manufacturing.

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Editorial perspective

This development highlights an important shift in the composites industry.

Carbon fiber is no longer limited to aerospace and premium applications alone. As production scales and costs improve, large-tow carbon fiber is becoming increasingly important for energy infrastructure.

Offshore wind may become one of the largest long-term growth drivers for industrial carbon fiber demand worldwide.