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What Is ACY Yarn? Air Covered Yarn Complete Guide

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What Is ACY Yarn? A Complete Guide to Air Covered Yarn

If you work with stretch fabrics, sportswear, leggings or knitted textiles, you may often come across the term ACY yarn. But what exactly is ACY yarn, and why is it so widely used in the textile industry?

ACY stands for Air Covered Yarn, a type of elastic composite yarn produced by combining spandex with polyester or nylon filament using compressed air.

Because of its excellent elasticity, comfortable stretch and competitive cost, ACY yarn has become an important raw material for stretch knitted and woven fabrics.

What Is ACY Yarn?

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Air Covered Yarn (ACY) is produced by feeding a spandex yarn together with a polyester or nylon filament through an air-covering machine.

Compressed air creates intermittent entanglement points between the outer filament yarn and the spandex core. This allows the two yarns to form an integrated elastic yarn without the traditional mechanical wrapping process.

Common combinations include:

  • Polyester + Spandex ACY Yarn

  • Nylon + Spandex ACY Yarn

  • Dope Dyed Black Polyester + Spandex ACY

  • Recycled Polyester + Spandex ACY

Among these, Polyester Spandex ACY Yarn is widely used because polyester offers good strength, dimensional stability, dyeability and cost efficiency.

How Is ACY Yarn Produced?

The production of ACY yarn mainly involves feeding spandex and filament yarn simultaneously into an air covering system.

The spandex is stretched at a controlled draft ratio while polyester or nylon filament is supplied as the covering component. Compressed air then creates regular interlacing points that combine the two components.

Several production parameters can influence the final ACY yarn quality, including:

  • Spandex draft ratio

  • Air pressure

  • Yarn feeding speed

  • Intermingling level

  • Polyester or nylon specification

  • Spandex denier

  • Machine speed

Stable production parameters are important for maintaining consistent elasticity, evenness and fabric performance.

Polyester Spandex ACY Yarn

Polyester Spandex ACY Yarn combines the advantages of polyester filament with the elasticity of spandex.

Typical polyester specifications may include:

75D/36F, 75D/72F, 100D/96F, 150D/48F, 150D/144F and other customized constructions.

Common spandex specifications include:

20D, 30D and 40D, depending on the required elasticity and fabric application.

Examples of common ACY specifications include:

  • 75D/36F + 20D Spandex ACY

  • 75D/36F + 40D Spandex ACY

  • 75D/72F + 40D Spandex ACY

  • 100D/96F + 40D Spandex ACY

  • 150D/48F + 20D Spandex ACY

  • 150D/48F + 40D Spandex ACY

  • 150D/144F + 40D Spandex ACY

Different combinations provide different levels of stretch, fabric weight, coverage and hand feel.

What Are the Advantages of ACY Yarn?

The popularity of Air Covered Yarn comes from its balance between performance, productivity and cost.

1. Good Elasticity

The spandex component provides excellent stretch and recovery, making ACY suitable for fabrics that need flexibility and body movement.

2. Comfortable Fabric Hand Feel

When the correct polyester and spandex combination is selected, ACY can produce soft, comfortable and flexible fabrics.

3. High Production Efficiency

Air covering is an efficient process, making ACY suitable for large-scale textile production.

4. Wide Range of Specifications

Different polyester deniers, filament counts and spandex specifications can be combined according to the required fabric performance.

5. Good Cost Performance

Compared with some mechanically covered elastic yarn constructions, ACY yarn can offer an attractive balance between cost and performance for many applications.

ACY Yarn vs SCY Yarn: What Is the Difference?

ACY and SCY are both covered elastic yarns, but their production methods are different.

ACY (Air Covered Yarn) uses compressed air to intermingle the filament yarn with spandex.

SCY (Single Covered Yarn) mechanically wraps a covering yarn around the spandex core.

Because of this structural difference, the two yarns may differ in appearance, elasticity, coverage, production cost and final fabric performance.

ACY is commonly selected for applications where production efficiency, elasticity and cost performance are important, while SCY may be preferred when a more controlled covering structure is required.

The best choice depends on the fabric construction and end-use requirements.

What Is ACY Yarn Used For?

ACY yarn is widely used in stretch textile products, including:

  • Leggings

  • Sportswear

  • Yoga wear

  • Activewear

  • Underwear

  • Socks

  • Seamless garments

  • Stretch knitted fabrics

  • Fashion fabrics

  • Stretch woven fabrics

The appropriate specification depends on fabric weight, machine type, required stretch and desired hand feel.

How to Choose the Right ACY Yarn

When purchasing ACY yarn, price should not be the only consideration.

Buyers should also consider:

Yarn specification: Select the appropriate polyester denier, filament count and spandex denier.

Elasticity: Different spandex contents and draft ratios produce different stretch characteristics.

Intermingling stability: Stable air covering helps improve processing consistency.

Dyeing performance: Uniform raw materials and production control are important for consistent dyeing.

End application: ACY for leggings may require different characteristics from ACY used for socks, underwear or woven stretch fabrics.

Looking for ACY Yarn?

If you are sourcing ACY Yarn, Air Covered Yarn or Polyester Spandex ACY Yarn, choosing the correct specification according to your fabric application is essential.

Suzhou Nextile Fiber Technology Co., Ltd. supplies polyester filament yarn solutions for international textile customers.

For ACY yarn inquiries, please provide your required polyester specification, spandex denier, color, application, quantity and destination port so that we can evaluate a suitable yarn construction and quotation.

Whether you are searching for 75D/72F + 40D ACY, 100D/96F + 40D ACY, 150D/48F + 40D ACY or other polyester-spandex combinations, contact us for more information.

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