Comfort of textiles and moisture absorption and perspiration of fibers
With the improvement of living standards, people have higher and higher requirements on the performance of textiles, especially the comfort performance. Comfort is the physiological feeling of the human body to the fabric, mainly including thermal and wet comfort and contact comfort. From the analysis of current textile technology, the contact comfort and pressure comfort can generally be basically solved in the post-treatment process of textile, while the thermal and wet comfort refers to that the excessive energy of the human body is radiated through the breathing of the skin, and its manifestation is to dissipate heat and moisture to the surrounding environment. The role of textiles is the intermediate between the human body and the environment, which plays a medium role in the breathing process of the human skin, That is to say, it can keep the skin warm in cold weather and help the skin quickly release heat and sweat in hot weather.
For clothing, the comfort of wearing requires that it has the effects of moisture absorption, dryness, ventilation and warmth. In the past, people liked to choose pure cotton fabrics because cotton fiber macromolecules have more hydrophilic groups and excellent moisture absorption performance. However, after being soaked by sweat, the pure cotton fabric dries very slowly and will stick to the human skin, resulting in an extremely uncomfortable sticky wet and cold feeling. While the ordinary synthetic fiber has fast perspiration, but its moisture absorption is poor, and the comfort of its fabric is not very high. Therefore, when a new type of moisture absorbing and sweat wicking fiber that combines the advantages of the two is developed, it immediately receives extensive attention and is applied to textiles such as T-shirts, socks, underwear, sports clothes, etc., and has a broad market prospect.
Moisture absorption and perspiration fiber is to use the capillary phenomenon generated by the micro grooves on the surface of the fiber to make the sweat rapidly migrate to the surface of the fabric and disperse through wicking, diffusion and transmission. In addition, the contact point between the fiber and the skin is reduced due to the design of the cross-section, so as to ensure that the skin still maintains a superior dry feeling after perspiration, so as to achieve the purpose of moisture conduction and quick drying. Capillary effect is the most commonly used and intuitive method, which can show the perspiration absorption and diffusion ability of fabrics.
Moisture absorption and perspiration fiber is a functional fiber focusing on moisture absorption and perspiration characteristics and comfort in clothing. In the past, the combination of natural fibers and synthetic fibers was the mainstream for the endowments of moisture absorption and perspiration, and the use was only carried out in a narrow range. Now, the processing methods such as hollow cross-section fibers or profiled cross-section fibers to make the fibers special and the blending of moisture absorption and moisture drainage polymers are the mainstream. The fibers with moisture absorption and perspiration function generally have high specific surface area, and there are many micropores or grooves on the surface. They are generally designed as special-shaped cross-sections. By using the capillary principle, the fibers can quickly absorb water, transport water, diffuse and volatilize, so they can quickly absorb moisture and sweat on the skin surface and discharge them to the outer layer for evaporation. Coolmax fiber and Coolplus Fiber are typical two kinds of moisture absorption and perspiration.
Coolmax fiber
Coolmax fiber is developed by DuPont company of the United States. It is a polyethylene terephthalate (PET) fiber with special section. Coolmax fiber has a flat cross-section so that four tetra channels are formed on its surface,
This flat four groove structure can make adjacent fibers close together easily, forming many small wicking pipes with strong capillary effect, and has the function of rapidly discharging sweat to the fabric surface. At the same time, the specific surface area of the fiber is 19.8% larger than that of the circular cross-section fiber with the same fineness, so after the sweat is discharged to the surface of the fiber fabric, it can quickly evaporate to the surrounding atmosphere, as shown in Fig. 2A. There is a large gap between the fibers due to the profiled cross section, as shown in Fig. 2 (b), which makes it have good air permeability. Therefore, the structure of Coolmax fiber endows the fabric with the property of moisture conduction and quick drying.
Under the standard conditions, 7 kinds of fibers such as cotton, electrospun polyester staple fiber, nylon, silk, polypropylene fiber, acrylic fiber and Coolmax fiber were tested. The results of water loss rate at different times are shown in Fig. 3. The water loss rate of Coolmax fiber is almost 100% in 30 min, compared with that of cotton fiber, which is only about 50% and that of acrylic fiber is 85%. It can be seen that the clothing made of Coolmax fiber can keep the skin dry and comfortable, and has excellent warmth and cold protection.
Coolplus Fiber
Coolplus Fiber is a new type of polyester fiber with good moisture absorption and perspiration function developed by Taiwan ZTE Co., Ltd. Coolplus is a combination of pet and special polymers. Its fiber cross-section is “cross”, as shown in Figure 4. In addition to the moisture transmission function achieved by the four channels of “cross”, special polymers are added to make use of the difference in solubility of each component of the material to give the fiber numerous fine grooves.
Under the condition of no external force field, the capillary tube generated by the fine groove of Coolplus Fiber will bend due to the action of boundary tension to form additional gravitational force. The tension can automatically guide the liquid flow, which is called “wicking”. Through the capillary phenomenon generated by these tiny groove tips, the moisture and sweat discharged from the skin surface are instantly discharged from the body surface through wicking, diffusion and transmission, so as to keep the skin dry and cool. As shown in Figure 5:
Drop a water drop on Coolplus fabric, cotton fabric, polyester fabric and nylon fabric respectively. After 2S, the water drop on polyester fabric and nylon fabric does not diffuse, but the water drop on Coolplus fabric and cotton fabric has diffused to about 6 times of the area.
In addition, during the dyeing process, the concave convex slit structure on the surface of Coolplus causes diffuse reflection of light and most of it is absorbed by the fiber. As a result, the color yield is greatly increased and the brightness is improved. At the same time, it plays a good role in saving dyes and reducing dyeing costs. Coolpius fabric loses some weight after scouring, and the fabric strength decreases with the increase of weight loss rate, so that the fabric has anti pilling and anti pilling property after scouring.
Coolplus Fiber has good moisture absorption and air permeability. The finished product has the advantages of ordinary pure cotton fabric and synthetic fiber fabric. It is easy to handle and has excellent wearability. See Table 1 for the comparison of the wearability of Coolplus fabric with cotton, polyester and nylon fabrics
Conclusion
(1) Coolmax fiber has a flat cross-section, with four perspiration grooves on its surface, large specific surface area, and numerous fine grooves in the fiber, making Coolmax fiber have excellent moisture absorption and perspiration. In terms of dryness, the drying rate in the same time is about twice that of cotton, leading other fibers.
(2) Coolplus Fiber has a cross-section, which enables sweat to quickly migrate to the surface of the fabric through wicking, diffusion and transmission. In terms of moisture absorption, compared with cotton, nylon and polyester fabrics, Coolplus fabrics have the best moisture absorption and perspiration.
The document from—-FabricClass
Post time: Aug-09-2022