Schematic diagram of core-spun yarn structure

Core-spun yarn—a unique composite yarn—consists of an outer fiber layer tightly wrapped around a core yarn, resulting in a dense structure and uniform yarn characteristics. Thanks to its core-and-sheath construction, core-spun yarn not only transcends the single-function limitations of conventional ring-spun yarns but also combines the aesthetic appeal and hand feel of the outer fibers with the superior performance of the core yarn. This complementary combination of advantages gives core-spun yarn an overall superior quality, making it highly popular among consumers. Next, we will introduce several methods for spinning core-spun yarn.

Among these methods, the spinning process for ring-spun core-spun yarn has attracted considerable attention. By modifying a conventional ring spinning frame and adding a set of continuous filament feeding devices, the continuous filaments are fed directly from behind the front roller without undergoing drawing. Meanwhile, the covering fibers are fed in the traditional ring-spinning manner—unwound from the roving bobbin and passed through a tapering nozzle—then drawn and merged with the continuous filaments at the front roller, where they are wrapped around the filaments. Subsequently, the combined yarn is twisted and wound together to finally produce the core-spun yarn.

Due to its wide range of producible yarn types, practical raw material options, and high-quality yarn performance, ring-spun core-spun yarn has become the most commonly used and most mature core-spun spinning method. However, during the ring-spinning process, the core filament of the core-spun yarn sometimes becomes exposed, which prevents proper dye uptake during dyeing and severely affects the fabric's end-use performance.

To address this issue, the Siro-spun core-spun yarn technology was developed. Building upon the traditional ring spinning process, this technology introduces an additional core-yarn guide device and modifies the feeding method—from single-roving feeding to dual-roving feeding—while incorporating a specially designed double-bell-mouth configuration to adjust the spacing between the two rovings. During the spinning process, after being drawn through the drafting zone by the rollers, the rovings merge and are twisted together at the nip of the front rollers with a continuous filament fed in via the guide device positioned midway between the two rovings. The combined yarn is then wound onto the bobbin by means of a guide hook, thus producing the Siro-spun core-spun yarn.
In the spinning process of Siro-spun core-spun yarn, the two slivers maintain a certain distance from each other and actively wrap around the core filament. After undergoing two twists—once above the convergence point and again at the convergence point itself—the internal stresses within the yarn are evenly distributed. As a result, the resulting yarn exhibits a tightly packed structure, stable quality, and superior performance in all aspects compared to conventional core-spun yarns.

Next, we’ll introduce compact-spun core-spun yarn.

Compact spinning is a new ring-spinning technology that uses negative-pressure airflow and corresponding mechanisms to eliminate or reduce the spinning triangle zone, thereby effectively controlling fiber movement and significantly minimizing the generation of edge fibers and floating fibers. As a result, the occurrence of fuzzing in the yarn is markedly reduced, tensile strength is enhanced, and the number of cotton knots is also decreased accordingly. Compact core-spun yarns produced using compact spinning technology exhibit a substantial reduction in fiber fuzziness, while simultaneously improving the sliding resistance of the covering fibers against the filament yarns. This leads to clearer stitch definition in knitted fabrics during garment production and allows for reductions in yarn count and twist level, making the resulting fabrics softer and more comfortable.

Now let’s take a look at rotor-spun core-spun yarn.

It achieves this by modifying a conventional rotor spinning machine, using a hollow spindle for the spinning cup and adding a filament unwinding device. During the spinning process, the filaments enter the spinning cup through the axial hollow spindle and, under the high-speed rotation and twisting action of the spinning cup, combine with short fibers to form a rotor-spun core-spun yarn. The yarn is then drawn out by a drafting roller and wound onto a bobbin. It is worth noting that in the production of rotor-spun core-spun yarns, the filaments do not have free ends; therefore, the core filaments are not twisted. In other words, the filaments are wrapped around the high-speed rotating fiber sliver rather than being twisted after being enveloped by the fiber sliver.