Yarn is divided into: ①Short fiber yarn, which is processed by spinning short fiber (natural short fiber or chemical fiber cut fiber), divided into ring yarn, open-end spinning, self-twisting and so on. ② Continuous filaments, such as natural silk and chemical fiber filaments, with or without twisting, smooth filaments or deformed filaments. ③Combined yarn of short fiber and continuous filament, such as polyester-cotton filament core-spun yarn, etc. The thread is formed by combining two or more single yarns.
There are many ways to express the fineness of DTF yarn, such as number, metric count, imperial count, denier, etc. (see count). The twist of DTF yarn is expressed in the number of turns per meter or inch. The direction of twisting is divided into S twist and Z twist. Within a certain twist range, the strength of the yarn increases as the twist increases. The twist direction of the single yarn and the twist direction of the strand are selected according to the purpose of the strand. Usually single yarns and strands use the opposite twist direction, that is, ZS or SZ. There is an optimal ratio between the twist of the single yarn and the strand. In this range, the strength of the strand increases with the increase of the twist of the strand, and the strength of the strand decreases when the critical value is exceeded. Fiber properties and spinning methods play a decisive role in the performance of DTF yarns. During the twisting process of ring-spun yarn, due to fiber transfer, from the inner layer of the DTF yarn to the outer layer, and then from the outer layer to the inner layer, the transfer is repeated many times. The axial direction increases or decreases alternately. At this time, the long-length fibers tend to the axis of the yarn more, and the short-length fibers tend to the outer layer of the yarn. The finer fiber tends to the axis of the yarn, and the thicker fiber tends to the outer layer of the yarn. The fibers with a smaller initial modulus are more located in the outer layer, and the fibers with a larger initial modulus are more located in the inner layer. Reasonable selection of fibers with different properties can be spun into DTF yarns of different styles to adapt to different fabric uses or improve wearability. Since the length, fineness and cross-sectional shape of the fiber can be arbitrarily selected for the chemical fiber, the outer garment fabric should be a blend of chemical fiber and cotton with a slightly thicker fiber and a shorter length to increase the hairy feel on the surface of the yarn. Underwear fabrics should choose chemical fibers with slightly thinner fibers and longer lengths, so that the cotton fibers are in the outer layer of the DTF yarn, so as to improve the moisture absorption performance and wearing comfort. Open-end spinning includes yarns spun from open-end spinning, electrostatic spinning, vortex spinning, etc. Because the fiber transfers less inward during twisting, the yarn core is tighter on the inside and looser on the outside than the outer layer, the structure is looser, and the fiber straightness Poor, poor cohesion between fibers, low yarn strength, but good dyeability and wear resistance. Self-twisted spinning yarn is also called self-twisted yarn. It uses the twisting roller to produce periodic positive and negative twists on the strands. There are periodic non-twisting points on the finished yarn, so the strength is low. Generally, the twisted yarn Weave after stranding.
Filament yarn is a bundle of filaments (such as natural silk, chemical fiber or rayon) combined together; mainly polyester filament, viscose filament, nylon filament and so on.
Fancy yarns are mainly manifested as changes in the appearance or color of DTF yarns. Mainly include wrapping, core-spun, bamboo joints, belly, colored dots, wave shapes, braids, towels, circles, knots, feathers, toothbrushes, centipedes, ribbons, section dyes, chenilles and so on.