Core-spun Thread
Core-spun yarn is a sewing thread made by spinning short fibers around a filament core that provides strength, making it easy to achieve both strength and a texture suited to the material.
Contents6 sections
Definition and Overview
Core spun yarn is a yarn with a core-sheath structure at its center. In general, it is spun by using a continuous long fiber filament as the core and wrapping short fibers around it. It makes it possible to take advantage of the core’s strength while giving the surface the appearance and feel of the wrapped fibers.
“Buttonhole thread” may also refer to the yarn placed at the center itself, and is not necessarily synonymous with the entire core spun yarn. Core spun yarn is used as a name for a structure and manufacturing method that combines fibers for the core and sheath.
Materials, Twist, and Structure
A typical combination is polyester filament for the core and cotton short fibers for the sheath. In this case, the polyester core supplements tensile strength, and the cotton-covered surface contributes to an appearance and feel that blends well with cotton materials. The sheath material may also be other than cotton.
After spinning, the yarn is twisted, and if necessary, multiple yarns may be combined and twisted together. The direction and amount of twist, and whether it is single yarn or ply yarn, affect hairiness, luster, strength, the appearance of the seam, and sewability, so confirmation according to the intended application is necessary.
How Thickness Is Expressed
The thickness of core spun yarn is indicated by count or nominal count. Count is a unit for expressing yarn thickness, but the numerical meaning differs depending on the system used. In general, some systems use larger numbers for finer yarns, but you cannot compare them by number alone without checking the notation system.
For sewing thread, manufacturer-specific nominal counts may also be used. Nominal count is convenient as a practical thickness classification, but yarns with different materials, structures, twists, and standards are not necessarily the same thickness simply because the nominal count matches. In specifications, the yarn type, material, count, and nominal count are listed together.
- Fine yarn is used for sewing thin fabrics and delicate seams.
- Thick yarn is used for heavy fabrics, areas under stress, and stitches meant to stand out.
- Suitability is checked in combination with the fabric, needle, and seam type.
Main Applications
Core spun yarn is used for sewing where both strength and good surface blending are desired, such as shirts, pants, casual wear, and uniforms. In sewing cotton and cotton-blend materials, there is an approach of matching the sheath material on the surface to the appearance of the fabric.
It is used not only for lockstitch construction seams but also for stitching. However, when the thread is meant to be visible as a stitch, the color, thickness, hairiness, and luster affect the finished result. Before mass production, it is important to make sewing samples under the actual fabric and sewing conditions.
How to Choose and Sewing Considerations
When selecting it, check the fabric material, thickness, stretch, the load on the seam, whether washing or garment washing will be done, and the desired appearance of the seam. A thread that is extremely thick compared with the fabric can lead to puckering and stiffness in the seam, while a thread that is too thin may not provide enough seam strength.
In sewing, adjust the machine needle size suitable for the thread, needle hole, upper and lower thread tension, and sewing speed. Check in advance for fuzzing or abrasion that exposes the core filament, seam shrinkage, thread breakage, and skipped stitches. For stretch fabric, also evaluate how well it follows the stretch.
Frequently Asked Questions
What is the difference between core spun yarn and polyester spun yarn?
Core spun yarn is generally a yarn with a filament core covered by short fibers. Polyester spun yarn, on the other hand, refers to yarn spun from polyester short fibers. The former makes it easier to give strength through the core, while the latter gives the entire yarn the feel of a spun yarn.
Can core spun yarn be used for stretch fabric?
Yes, but it is necessary to check whether the yarn and seam can follow the fabric’s stretch sufficiently. For fabrics with high stretch, consider the seam specifications and yarns with stretch as well. Before full production, test for thread breakage and seam waviness during stretch and recovery.
If the nominal count is the same, can it be replaced with another core spun yarn?
Even if the nominal count is the same, the core and sheath materials, twist, actual thickness, strength, hairiness, and finish may differ. When replacing it, review the sewing conditions including the needle and tension, and confirm seam strength, appearance, and the condition after washing with a trial sample.
