From raw material to socks: the introduction of Yarn
Yarn is a textile product processed from various textile fibers to a certain fineness, and is used for weaving, rope making, sewing, knitting, and embroidery in the hosiery industry. It is divided into short fiber yarn and continuous filament yarn.
There are multiple methods of expressing the fineness of yarn, such as yarn count, metric count, English count, denier, etc. The twist of yarn is expressed by the number of twists per meter or per inch.
Woolen yarn and woolen thread are generally used for spinning woolen sweaters, pants, vests, scarves, hats, gloves, and weaving various spring and autumn clothing accessories, which not only keep warm but also have decorative functions.
Yarn is divided into:
Short fiber yarn, which is made from short fibers (natural short fibers or synthetic staple fibers) through spinning processing, and is divided into ring spun yarn, open-end yarn, self-twist yarn, etc.
Continuous filament yarn, such as natural silk and synthetic filament yarn, which is divided into twisted or untwisted, smooth filament or textured filament, etc.
Blend yarn made by combining short fiber and continuous filament yarn, such as polyester-cotton core-spun yarn. Thread is made by combining and twisting two or more single yarns
fineness of yarn:
There are various ways to express the fineness of yarn, such as count, metric count, English count, denier, etc.
The twist of the yarn:
The twist of the yarn is expressed in the number of twists per meter or per inch. The direction of twist is either S-twist or Z-twist. Within a certain range of twist, the strength of the yarn increases as the twist increases. The twist direction of the singles and the ply is chosen based on the intended use of the ply. Typically, singles and ply have opposite twist directions, i.e. ZS or SZ. There is an optimal ratio between the twist of the singles and the twist of the ply. Within this range, the strength of the ply increases as the ply twist increases, but beyond a certain critical value, the strength of the ply decreases.
the performance of the yarn:
The characteristics of the fiber and the spinning method play a decisive role in determining the performance of the yarn.
In ring spinning, during the twisting process, the fiber transfers from the inner layer to the outer layer of the yarn, and then back to the inner layer, repeatedly transferring back and forth, resulting in a spiral shape of the fiber around the axis of the yarn.
The spiral radius alternately increases or decreases along the axis.
Longer fibers tend to be closer to the axis, while shorter fibers tend to be closer to the outer layer of the yarn.
Finer fibers tend to be closer to the axis, while coarser fibers tend to be closer to the outer layer.
Fibers with lower initial modulus tend to be more located in the outer layer, while fibers with higher initial modulus tend to be more located in the inner layer.
textile applications:
Reasonable selection of fibers with different characteristics can result in yarns with different styles to meet different textile applications or improve garment performance.
Since synthetic fibers can be chosen arbitrarily in terms of length, fineness, and cross-sectional shape, for outerwear fabrics, slightly coarser and shorter synthetic fibers are preferred to be blended with cotton to increase the fluffiness of the yarn surface.
For underwear fabrics, slightly finer and longer synthetic fibers are preferred to allow cotton fibers to be located on the outer layer of the yarn for improved moisture absorption and comfort.
Yarns spun using open-end spinning techniques, such as air-jet spinning, electrostatic spinning, vortex spinning, etc., have less inward fiber transfer during twisting, resulting in looser structure with lower strength, poorer fiber straightness, and weaker fiber cohesion. However, they have better dyeing properties and abrasion resistance.
Yarns spun using self-twist spinning, also known as self-twist yarns, use periodic positive and negative false twisting on the roving produced by the twisting rollers. The yarn has periodic areas with no twist points, resulting in lower strength. Therefore, self-twist yarns are generally used to make plies rather than being woven directly.
