Moisture-wicking fibers use the capillary phenomenon produced by the micro-grooves on the fiber surface to allow sweat to quickly migrate to the surface of the fabric and disperse through wicking, diffusion, transmission, etc., thereby achieving the purpose of moisture conduction and quick drying.
The shortcomings of ordinary fibers in moisture absorption and perspiration:
Natural fibers such as cotton, for example, have good moisture absorption properties and are comfortable to wear. However, when a person sweats a lot, the cotton fiber will expand due to moisture absorption, and its performance will decrease and stick to the skin. At the same time, the water dissipation speed will also increase. It is slower, thus causing a cold and wet feeling to the human body; synthetic fibers such as polyester have low water absorption and poor moisture permeability. Due to their accumulation of static electricity, they can easily cause entanglement when wearing, especially during activities. Feeling of stuffiness.
Mechanism of moisture absorption and perspiration
What is moisture wicking? This term refers to a non-hydrophilic fabric that is both hygroscopic and quick-drying. Generally speaking, it is difficult for both natural and synthetic fibers to have both properties, but moisture-wicking processing technology can achieve this. Therefore, for polyester fiber that does not absorb water at all, moisture wicking processing technology gives it new life.
The water absorption and release properties of moisture-absorbing and sweat-wicking fibers
The moisture wicking performance of fiber depends on its chemical composition and physical structure. The gaseous moisture that evaporates from the skin surface is first absorbed by the fiber material (i.e., hygroscopic), and then releases moisture through the material surface; while the liquid moisture on the skin surface is absorbed by the pores (pores, micropores, grooves) inside the fiber and the gaps between the fibers. The capillary effect produced by the voids causes the adsorption, diffusion and evaporation of moisture on the surfaces between materials (ie, moisture release). The two effects result in water migration. The former effect is mainly related to the chemical composition of the fiber macromolecules, and the latter effect is related to the physical structure of the fiber.
Moisture-absorbing and sweat-wicking fibers generally have a high specific surface area, with numerous pores or grooves on the surface, and their cross-sections are generally of special shapes. The capillary effect is used to enable the fibers to quickly absorb moisture and sweat from the skin surface, and through diffusion and Pass to outer layer of hair.
The water absorption of fiber
Moisture-wicking fibers are water-absorbent. The surface of the fiber has many micropores or fibril gaps and surface grooves that communicate with the inside and outside, making it easy for moisture to enter between the fibers. At the same time, there are many tubular grooves or grooves along the fiber axis. Capillaries provide channels for the migration of water, so the fiber has good water absorption. After absorbing water, it does not swell due to water absorption like the phase.
Fiber dryness
The moisture between polyester fibers is mainly held by the fibers by the attraction of a large number of microporous capillary tubes, or is mechanically maintained in the capillary tubes between the fibers. Under normal ambient temperatures, moisture is easily transported to the fiber surface and evaporates.
Common manufacturing methods for moisture-absorbing and sweat-wicking fibers
1)Special shaped fiber
Changing the spinneret hole shape is a simple, intuitive and effective method to improve fiber moisture conductivity. Many grooves are mainly produced in the longitudinal direction of the special-shaped fibers. The fibers wick away moisture through the wicking effect of these grooves. “coolmax” polyester produced by DuPont in the United States. Its cross-section is a unique flat cross shape, with four longitudinal grooves on the fiber surface. Secondly, the area is 20% larger than the conventional circular cross-section, so the perspiration performance is higher than that of conventional polyester.
2) Polymerized styrene dilute blending or composite spinning
The polymer containing hydrophilic groups is blended with polyester chips, and a specially designed special-shaped spinneret is used to produce moisture-absorbing and sweat-wicking fibers.
Polyester slices and hydrophilic polymers are combined into special-shaped moisture-absorbing and sweat-wicking fibers with a spun sheath and core. Usually the hydrophilic polymer is used as the core layer of the composite fiber, and polyester is used as the skin layer. Hydrophilic polymers are generally polyether-modified polyesters and hydrophilic-modified polyamides. The two components play the role of moisture absorption and moisture conduction respectively. Such composite fibers have the functions of moisture absorption and moisture conduction, achieving the effect of moisture absorption and perspiration.
3)Graft copolymerization
Through the graft copolymerization method, hydrophilic genes are introduced into the macromolecular structure to increase the moisture absorption and perspiration function of the fiber. Usually, carboxyl groups, amide groups, hydroxyl groups, amino groups, etc. are introduced to increase the affinity for water. While the raw materials are modified, appropriate spinning processes are also required to make the fibers have a porous structure and a larger specific surface area. .
Judging from the current industrialization of moisture-wicking polyester, physical methods are mainly used to spin three types of special-shaped fibers: “+”, “Y” and “T”. There are also a varying number of micro-grooves on the surface to facilitate strengthening. Moisture wicking function.
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