Summary of Core-Spun Yarn Knowledge: What is Core-Spun Yarn, and Why is Knitted Core-Spun Yarn So Popular

1.Definition

2.Characteristics

3.Applications

4.Classification

5. Differences between core-spun yarn and covered yarn

6. Spinning process flow

7.Spinning methods

1.Definition of Core-Spun Yarn

As we all know, core-spun yarn consists of two or more fibers with a core-sheath structure.

• One part of the fibers is restricted along the axis, called the core, made of filament or fine denier short staple yarn;
• The other part of the fibers wraps around the outer layer of the yarn, called the sheath, made of short fibers, with a clear boundary between the two parts.

 

2. Characteristics of Core-Spun Yarn

First of all, core-spun yarn can fully utilize the excellent physical properties of the core yarn and the surface characteristics of the outer short fibers, maximizing the strengths of two or more fibers while compensating for their shortcomings.

2.1 Advantages:

The specific advantages depend on the different properties of the inner core yarn and the outer covering fibers.

For example, polyester-cotton core-spun yarn can leverage the advantages of polyester filaments being crisp, wrinkle-resistant, and quick-drying, while also utilizing the good moisture absorption, low static, and anti-pilling properties of the outer cotton fibers. The resulting fabric is easy to dye and finish, comfortable to wear, easy to wash, and has bright, vivid colors.

Core-spun yarn can also reduce the weight of the fabric while maintaining and improving its performance. Additionally, it can utilize the different chemical properties of synthetic filaments and outer fibers to create devoré fabrics with three-dimensional patterns by etching away part of the outer fibers during dyeing and finishing processes.

Moreover, there are two key advantages that make core-spun yarn popular in the market:

• The yarn feels very comfortable, easily mimicking the feel of expensive animal fibers like wool. Continuous improvements have even made it surpass some animal fiber yarns in terms of feel.
• It is inexpensive. For instance, the price of core-spun yarn is only 3% to 5% of 100% cashmere yarn, while the feel and performance are not significantly inferior.

These two advantages have made core-spun yarn highly sought after in the past three years. As a low-end yarn, many garment manufacturers both domestically and internationally use core-spun yarn as the main raw material.

2.2 Disadvantages:

• High requirements for weaving technology: The structure of core-spun yarn is much more complex than ordinary yarn, requiring higher technical levels and spinning skills during weaving. Otherwise, various problems can arise. For yarn production factories, new spinning equipment and updated skills for technicians are necessary.
• The outer layer of the yarn is prone to breakage: Due to the large contact area between the outer covering and the inner filament fibers, the yarn is prone to breaking or defects when subjected to significant tension or bending. Poor control during production can affect the durability of the fabric.

As a seasoned yarn manufacturing factory, we have ways to avoid the above two disadvantages, making them not significant drawbacks. In my opinion, the main disadvantage of core-spun yarn is its weight.

Although the feel of core-spun yarn can closely resemble wool yarn and other animal fibers, the loftiness of the resulting fabric never matches that of high-end animal fiber yarns. The clothing does not have the same fluffiness as wool garments.

After experiencing the loftiness brought by wool and other animal fiber yarn garments, especially in winter, the heavier clothing made from core-spun yarn becomes unacceptable to high-end consumers.

 

3. Applications of Core-Spun Yarn

• Sweaters
• Work uniforms
• School uniforms
• Socks
• Curtains
• Tablecloths
• Sofa Covers
• Bedsheets

4.Classification of Core-Spun Yarn

4.1 Classification by Product Application

• Fancy core-spun yarn (e.g., hollow core-spun yarn, colored core-spun yarn, cryofield core-spun yarn, bamboo core-spun yarn, etc.)
• Sewing core-spun yarn
• Devoré core-spun yarn
• Functional core-spun yarn
• High-performance fabric core-spun yarn
• Stretch fabric (including knitted and woven fabrics) core-spun yarn

4.2 Classification by Core Yarn

• Rigid core-spun yarn: Polyester, acrylic, vinylon (including water-soluble vinylon), nylon, etc.
• Elastic core-spun yarn: Spandex, PTT fibers, PBT fibers, DOW XLA elastic fibers, etc.

4.3 Classification by Sheath Yarn

Generally divided into

• Cotton
• Hemp (including ramie, flax, hemp, etc.)
• Silk
• Wool
• Polyester
• Acrylic
• Viscose fiber
• Modal
• Tencel
• Soybean Fiber
• Milk Fiber
• Bamboo pulp fiber
• Other colored synthetic fibers

4.4 Classification by Spinning Equipment

Based on the main production equipment used during spinning:

• Ring spinning equipment
• Rotor spinning equipment
• Friction spinning equipment
• Air-jet spinning equipment

4.5 Classification by Filament (Core Yarn) Content

The filament content in core-spun yarn can be used for classification. The filament content significantly impacts the yarn's performance and cost.

• Low filament content (<10%): Low-ratio core-spun yarn
• Medium filament content (10%-40%): Medium-ratio core-spun yarn
• High filament content (>40%): High-ratio core-spun yarn

The elastic core-spun yarn content is generally below 10%, around 3%-5%. The higher the proportion, the higher the cost. Pure polyester sewing core-spun yarn can have a core-spun yarn proportion of 50%-60%. Devoré core-spun yarn content ranges from 40%-60%, with general rigid core-spun yarn content at 20%-40%. The core-spun yarn content should not be too high to avoid defects. Theoretically, the wrapping width of the outer fibers should be greater than the circumference of the core yarn to prevent exposed filaments.

4.6 Classification by Yarn Density

• Coarse yarn: Yarn density above 32 tex.
• Medium yarn: Yarn density between 21 tex and 31 tex.
• Fine yarn: Yarn density between 11 tex and 20 tex.
• Extra fine yarn: Yarn density of 10 tex or below

5. Differences between Core-Spun Yarn and Covered Yarn

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Difference between core and cover yarn, structure schematic diagram, core and cover yarn structure difference, yarn01

In the industry, spandex core-spun yarn and spandex covered yarn are often used to illustrate their differences:

• Spandex core-spun yarn uses short fibers to wrap spandex, with spandex filament as the core and non-elastic short fibers wrapped around it. When stretched, the spandex core filament generally does not get exposed.
• Spandex covered yarn uses synthetic filament to wrap spandex, with spandex filament as the core and non-elastic short fibers or filaments spirally wrapped around the stretched spandex filament, forming elastic yarn. When stretched, the spandex filament may be exposed.

In comparison, core-spun yarn has slightly less elasticity but is less prone to exposure and reflection; covered yarn is prone to reflection but has better elastic elongation.

6. Spinning Process Flow

At present, there are two processes for spinning core-spun yarn, taking polyester-cotton core-spun yarn as an example:

• Carded system: Opening - Carding - Drawing - Roving - Spinning (core-spun).
• Combed system: Opening - Carding - Lap forming - Combing - Drawing (multiple stages) - Roving - Spinning (core-spun).

The choice of process flow for core-spun yarn depends on the desired yarn quality and the spun yarn count. The general principle is to use carded processes when possible and avoid combing if unnecessary. If combing is required, the process should be shortened to reduce production costs. For instance, some manufacturers have good combed sliver quality, with high fiber straightness and parallelism, allowing for fewer drawing stages. The process can then be: Opening - Carding - Lap forming - Combing - Drawing (single stage) - Roving - Spinning (core-spun).

7. Spinning Methods

There are two methods for spinning core-spun yarn:

• The first method places polyester filament (or other filament) on the roving frame of an ordinary spinning machine, with cotton roving (or short fiber roving) fed from below. The cotton roving is fed through a trumpet nozzle and drafting system. The polyester filament is guided directly into the nip of the front rollers without passing through the drafting system, combining with the drafted cotton sliver to form core-spun yarn through twisting. This method is generally used for mass production as a single filament can be spun into core-spun yarn with high cotton content, making the fabric comfortable to wear and allowing for finer core-spun yarn.
• The second method feeds two filaments behind the front rollers, combining and twisting them with the drafted cotton sliver to form core-spun yarn. This method is known as the improved core-spun yarn method or pseudo-core-spun yarn method. The two filaments are positioned on either side of the cotton sliver, increasing the cohesion between short fibers and filaments, reducing the "peeling" phenomenon during weaving caused by the cotton fibers' poor cohesion with the central polyester filament in the first method.

After reading this, you will have a certain understanding of core-spun yarn in detail. If you need to know more, or get a quote for our yarn products, please feel free to contact us.