1. Introduction to Covered Yarns

Covered Yarn is a high-tech technical yarn created by combining an elastic core (typically Spandex or Rubber) with one or more layers of covering yarn (such as Polyester or Nylon). This technology maximizes the elasticity of the core while utilizing the surface aesthetics and durability of the covering fibers. In the textile industry, there are three primary covering technologies: SCY (Single Covered Yarn), DCY (Double Covered Yarn), and ACY (Air Covered Yarn). Each type has a distinct production process, leading to differences in strength, elasticity, and fabric hand-feel to meet various needs from everyday fashion to high-end shapewear.

2. Composition and Structure

• Single Covered Yarn (SCY): Consists of a central Spandex core and one layer of covering yarn (Polyester/Nylon) wrapped around the core in a specific direction (S-twist or Z-twist).
• Double Covered Yarn (DCY): Consists of a Spandex core and two layers of covering yarn. The first layer wraps in one direction, while the second layer wraps over it in the opposite direction, canceling out torsional forces and creating absolute balance.
• Air Covered Yarn (ACY): Does not use mechanical wrapping. The core yarn and covering yarn are fed through a high-pressure air nozzle. The turbulent airflow causes the covering fibers to interlace and adhere to the core yarn at specific nip points.

3. Key Characteristics

• SCY Yarn: Offers good elasticity and a smoother surface compared to ACY but has a slight tendency to twist due to the single-directional wrap. Fabrics made from SCY provide a soft drape and hand-feel.
• DCY Yarn: The most durable and stable type. The double-cover structure protects the Spandex core exceptionally well, prevents fabric spirality, and results in a thick, luxurious surface with uniform elasticity.
• ACY Yarn: Features the lowest cost due to high-speed production. The yarn is bulkier with a drier, rougher hand-feel. Notably, ACY fabrics offer better breathability because the structure is not as tight as mechanically covered yarns.

4. Technical Specification Table (Reference)

5. Practical Applications Table

6. Comparison Table: SCY, DCY, and ACY