Is the cool fabric just a stir-fry concept?
Source： Browse：263 Date：2023-03-09
With the intensification of the global "greenhouse effect", people's demand for summer clothes that are cool, hygroscopic and fast drying is increasing, and the voice for developing new cool fabrics is high. Cool feeling is exactly called "cool feeling at the moment of contact". The instant cool feeling here refers to the cool feeling formed when the skin contacts with the fabric below its temperature, which causes the rapid loss of heat on the skin surface, and the temperature drops immediately, and then reflects to the brain through the temperature-sensitive nerve endings in the skin.
"Cool clothes" were only conceptual clothes at first. Internationally, first of all, it was developed by Japan, but Japan's goal is to achieve the goal of energy conservation through cool clothes, and form a national movement in Japan to slow down the sustainability of global warming. Then a man-made fiber called Cupro respiratory fiber was developed, which has deodorization function. Then, the United States improved Japanese technology and developed a new type of cold fabric patent. Finally, it was officially registered as CoolCore in 2011 ™， This is the sports brand introduced by China Xinyong International.
The cool fabric has the characteristics of moisture absorption and perspiration, dryness and coolness, and instant cooling. When it contacts with the human body, it can quickly export the moisture and heat on the skin surface, keep the skin surface dry and cool, make the clothes become the natural personal air conditioner for the human body, make people feel more cool in the hot summer, and more comfortable in the cool and beautiful world. This is a new innovation in the fabric of sportswear and outdoor casual wear. Cool fiber is made from natural mineral materials such as natural jade powder, shell powder and mica powder by extraction and nanotechnology, and then processed into nanometer particles, and then spun with hydrophilic chips. Through the design of the fiber section, the fiber has the "capillary effect" and strengthens the heat dissipation speed.
The cool feeling performance of cool fiber products is determined by the thermal conductivity of the fiber itself; The dryness of cool products usually refers to the moisture absorption, perspiration and moisture dissipation properties of fabrics. The cool feeling and dryness of cool fiber products are mainly reflected in two aspects: (1) good thermal conductivity, which is manifested by the obvious cold feeling of fabric contact, making the wearer feel cool. (2) Through various processing processes, cool fiber products have changed the original fabric structure, which can make the sweat secreted by the body surface rapidly disperse, and maintain the dry and comfortable contact between the body surface and the fabric.
The existing processing methods of cool fibers on the market include:
(1) The fiber is modified or the structure of the fabric is designed. For example, the fiber is modified to have a microporous structure or a large number of micro grooves are produced on its surface to speed up the transfer of water.
(2) When adding ore particles during melt spinning processing, this composite ore powder can reduce the heat absorption rate of the fiber and accelerate the heat dissipation rate. When the fiber contacts with the skin on the body surface, it can produce a cool feeling with a temperature difference of 1~2 ℃.
(3) Use hydrophilic finishing agent to carry out hydrophilic treatment on the surface of fiber or fabric, so as to make the product reach the feeling of "cool". Senico's ice porcelain cotton skin feeling silicone oil FREETEX-6500 is instantly hydrophilic, soft, smooth and drapable, with superior fineness and flesh feeling, cool and silky. After Guangdong Binggan silicone oil, another new and upgraded product. For more details, please click: http://www.synico.cn/product/79-cn.html
For the current coolness test, we can first refer to the industrial standard of "Verification Specification for Instant Cool Feeling of Fabrics" (FTTS-FA-019) developed by the Taiwan Textile Industry Comprehensive Research Institute. The principle is to place the fabric on the cold plate of the instrument. When the temperature of the fabric is the same as that of the cold plate, quickly place the hot plate on the sample. The heat of the hot plate will be transferred to the cold plate through the fabric. The maximum heat loss of the fabric can be measured at the moment of contact. This value is the Q-max value, and the unit is expressed in the instantaneous cool heat flow rate (W/cm2) of the fabric. The Q-max value is the maximum value of instantaneous heat loss of skin when simulating human contact with the fabric, and also the maximum heat flow that can be taken away by the fabric in a unit area. This value is an indicator of the instantaneous cooling performance of the fabric, expressed in W/cm2. The higher the Q-max value is, the more heat can be taken away. The evaluation qualification standard of this specification: instantaneous cool and sensible heat flow of fabric (W/cm2) ≥ 0.140.
Of course, the new national standard GB/T 35263-2017 "Testing and Evaluation of the Instant Cooling Sensibility of Textiles" will be implemented on July 1, 2018. This standard specifies the testing and evaluation methods of the instant cooling performance of textiles and skin contact, which is applicable to all kinds of fabrics and their products. The test principle is to contact the thermal detection plate with the temperature higher than the sample under the specified test environment conditions, measure the temperature change of the thermal detection plate with time, and calculate its contact cooling coefficient (qmax), which can characterize the instant cooling performance of the sample. The contact coolness coefficient qmax refers to the maximum value of heat flux density in the heat transfer process after contacting the heat detection plate with a temperature higher than the specified temperature difference of the sample at a certain pressure. The larger the qmax value, the stronger the skin feels cool, and the smaller the value, the weaker the skin feels cool. The schematic diagram of the test instrument is shown in the figure below.
Schematic diagram of cooling performance tester
This standard can evaluate the cooling sensation of the sample at the moment of contact. See the table below for the evaluation indexes when △ T=15 ℃.
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