Abstract: Moisture-absorbing and quick-drying fibers and their fabrics are favored by consumers because of their comfort. In this paper, the characterization methods of moisture conductivity of fibers, the preparation principles of various physical and chemical modification methods, and the newly introduced moisture-absorbing and fast-drying fibers and fabrics at home and abroad are reviewed.
introduce
Pure cotton products bring people good comfort because of their excellent hygroscopicity and breathability, but their application range is limited because of their high water retention rate and poor moisture conductivity. On the other hand, the traditional polyester fiber, because of its hydrophobic characteristics, limits its application in the fields that need high hygroscopicity or water absorption [1]. Therefore, fibers and fabrics with moisture absorption and quick drying characteristics have broad development prospects.
I. Research status quo
(1) mechanism
Traditional comfortable fabrics mainly use hydrophilic fibers such as cotton, which absorbs water quickly, but the soaked fabrics can't transfer heat and moisture to the air in time, which makes people uncomfortable. Fabrics made of modern moisture-absorbing and quick-drying polyester fibers can quickly guide the sweat on the skin from the inner layer of the fabric to the outer surface of the fabric and radiate it into the air, so that the close-fitting layer is always dry and comfortable [2].
(2) Characterization method [3]
1. Capillary effect or vertical capillary method
Capillary effect is the most commonly used and intuitive method, which can show the sweat absorption and diffusion ability of fabrics. The test method was carried out according to ZB wo4 0 19-90 "Testing Method for Capillary Effect of Textiles", and was measured on YG(B)87 1 Capillary Effect Instrument, and the climbing height of water on the fabric strip after 30 minutes was recorded.
2. Moisture permeability
This is a measure of the water vapor permeability of the fabric when there is a water vapor pressure difference between the two sides of the fabric. The test method is to put distilled water into a moisture-permeable cup, cover the sample with the mouth of the cup, and put it into a dryer at a specified temperature ((38℃ 0.5)℃. When the pressure difference between the two sides of the sample remains constant, weigh the mass of the moisture-permeable cup at an appropriate time interval. When the quality degradation is proportional to the time interval, the moisture permeability is measured by the quality degradation, that is, MVT=(A2-A 1)/S? T, where A 1 is the weight (g) of the moisture-permeable cup after the test 1h; A2 is the weight (g) of the capped moisture-permeable cup after continuous testing for 2 hours; S is the moisture permeable area of the sample (m2); T is the time interval (h) between weighing.
3. Liquid carrying rate
This is a method to measure the water absorption capacity of fabric. During the test, the fabric sample to be tested was dried in an oven at 60℃ for 65438±00h, and then weighed (W0). Then soak the fabric sample in distilled water for 3 hours, take it out and dehydrate it for 2 minutes, and weigh it (W 1). The liquid carrying rate (i) is: I=( W 1-W0)/. 100%
4. Drying rate
The fabric sample containing liquid was dried in an oven at 37℃ for 5 min, and then weighed (W2). The drying rate (Vdrying) is: vdrying = (w1-w2)/(w1-w0)? 100%
Second, the production method
By modifying polyester, polyamide, polypropylene and other chemical fibers, the organic combination of fiber moisture absorption and moisture conduction is realized. These methods generally include physical modification, chemical modification and their combinations.
(1) Physical modification method
1. Special-shaped section method
Fibers with moisture absorption and quick drying function generally have high specific surface area, and their cross sections must have grooves. When weaving, these grooves are used to form channels between fibers, and the effect of moisture absorption and quick drying is achieved through the wicking effect of these grooves.
2. Porous hollow section method
Porous hollow cross-section fiber is a hollow fiber with many through holes from the fiber surface to the hollow part, which has excellent moisture conductivity and perspiration function. Its production process is first mixed with special micropore forming agent and then dissolved out.
3. Two-component composite spinning method
With the aid of * * yoke melt spinning technology, two kinds of polymers are continuously melt extruded by two screw extruders, quantitatively fed into the spinning assembly by a metering pump through their respective melt pipes, and the two components are combined in a certain way in an appropriate position in the assembly, and then ejected from the same spinneret and wound to form, and finally the segmented composite superfine fiber with star-shaped, orange petal-shaped and herringbone structure in cross section and monofilament fineness less than 0.3dtex or sea-island composite superfine fiber with monofilament fiber less than 0.08dtex is obtained.
4. Fine denier fiber method
The fine fibers on the surface of the fabric woven by fine denier fibers form countless fine concave-convex structures, which are equivalent to countless capillaries, so the capillary wicking effect of the fabric is obviously increased, which can transfer water molecules and greatly improve the air permeability and water and sweat conductivity of the fabric. At present, the fine denier moisture transfer process is mainly used for polypropylene fabrics.
(2) Chemical modification method
1. Preparation of melt crystalline polymers from hydrophilic compounds
Hydrophilic compounds used to prepare polyethylene glycol melt crystalline polyester are a typical example. Foreign reports show that in order to make the fiber surface hydrophilic, hydrophilic polymers are usually used to cover the fiber surface, but hydrophilic compounds are not easy to fall off when washing.
2. Synthesis of hydrophilic polymer blended yarn with the third monomer.
For example, sodium 5- sulfoisophthalate is used as the third monomer to synthesize polyester, and then blended with ordinary polyester to make hollow fiber, and then the fabric is treated with alkali deweighting. Because polyester is easily hydrolyzed by alkaline solution, many micropores communicating with hollow parts are formed in the fiber, which makes it have good water absorption and moisture permeability.
3. Sericin polyester
Sericin extracted from silk fabric scouring is attached to polyester fiber molecules by chemical methods. Sericin has good hygroscopicity, and its composition is close to the amino acids that constitute human skin, so it makes the fiber more hygroscopic and has no adverse effects on the skin.
Third, the status quo of research and development
In order to improve the comfort of wearing, famous fiber companies such as the United States, Japan, South Korea, China and Taiwan Province Province of China have successively researched and introduced polyester fibers with moisture absorption and perspiration performance. This kind of products increase the capillary effect through the fiber cross section, so that the fabric has hygroscopicity and moisture conductivity due to the capillary channels on or between fibers [3].
(A) the development of foreign research [4]
The main products in the United States are: Coolmax functional fiber fabric exclusively developed by DuPont, which adopts special-shaped cross-section shape? Ten? Glyphs and? CO？ Forming dispersed moisture and fast drying; Dri-Release high hygroscopicity yarn developed by Optimer company adopts? In the process of cotton fiber spinning, a small amount of special polyester is spun by micro-mixing, which gives full play to the advantages of cotton and polyester in moisture absorption and quick drying.
The main products in Japan are: CoolDry polyester fabric successfully developed by Toyo Textile, which dissipates moisture through Y-shaped section; Hygra fiber introduced by unika Fiber Company absorbs moisture and dissipates heat through core-sheath composite fiber coated with water-absorbent polymer with special network structure by nylon.
South Korea's main products are: Aerocool new polyester fiber developed by Hyosung Company, through images? Alfalfa's "four-leaf" slots and pores absorb water and sweat; I-COOL series fibers developed by Dongguo Trading Co., Ltd. also absorb moisture and sweat through capillary phenomenon of special cross section.
(2) Domestic R&D
CoolDry, jointly developed by National Textile Product Development Center and Quanzhou Haitian Textile Group, has the function of moisture absorption and perspiration through special surface grooves. China Petrochemical Yizheng Chemical Fiber Co., Ltd. produces Coolbst series fibers, Coolbst? FCLS-75？ Physical modification and chemical modification are used to give it the function of moisture absorption and perspiration, and Coolbst differential short fiber adopts a brand-new fiber cross-sectional shape to absorb moisture and perspiration; The Coolnice fiber developed by Guangdong Shunde Jinfang Group in cooperation with Donghua University absorbs moisture and sweats through the special-shaped section; Hong kong aolihua chemical fiber co., ltd. cooperates with Korean companies to jointly develop? Ellie, cool sweat-absorbent yarn? Coolplus fiber developed by Taiwan Province Zhongxing Textile Factory.
Four. Concluding remarks
At present, the development of moisture-conducting and quick-drying fiber is mainly reflected in the development of high-tech polyester fiber Cool series. This series of fibers mainly use the mechanism of increasing surface area and enhancing capillary effect of profiled fibers to conduct moisture. In international large-scale sports competitions, new moisture-absorbing and quick-drying fibers have been widely used and loved by athletes. It can be predicted that the adoption of moisture-absorbing quick-drying fiber and its fabrics can expand the middle and high-end market and improve the market positioning of textile products, and its economic effect is immeasurable.
refer to
[1], Qin,, Wang, Development of New Moisture Absorption and Sweating Polyester Fiber [J], Polyester Industry, 2006,3 (3): 31-33.
[2] Zhai Han, Wang Qi, Study on Moisture Absorbing and Sweating Fiber and Its Action Principle [J], Shanghai Textile Science and Technology 2004,4: 6-7.
Hu Panpan, Pan Wanlian, Wu Xuhua, et al. Study on moisture conductivity of profiled polyester [J]. Synthetic fiber industry, 2002,25 (5):15-17.
[4] Liu Jun, the progress of moisture conductivity modification of fiber and the development of new products [J], Textile Guide 2005, 1: 24-28.