As the global warming becomes increasingly serious and the ambient temperature rises, especially in the unbearably hot summer, people are keen on the “coolness” as if they are looking forward to the rain after a long drought, and the research on the coolness in the textile printing and dyeing industry has never stopped. , from the early cooling fibers, to the popular “ice-feeling” silicone oil, to today’s contact cooling finishing agents launched by some foreign chemical companies.
In addition, domestic and foreign clothing brands have also launched “cool-sensing clothing”. LEVI’S has launched COOLMAX jeans, and UNIQLO has also launched AIRISM cooling-sensing clothing, etc.
What is the feeling of coolness?
The so-called cooling sensation is accurately called the instant cooling sensation upon contact. Just like holding a glass of ice water with your hands, you will definitely feel cold when you first hold it. Touching the cool fabric is like holding ice water with your hands. You will feel cool the moment you touch it. As time goes by, the ice cubes melt and your hands The temperature will reach thermal equilibrium with the water temperature, and the cool feeling will not be obvious. Contact with cool fabrics transfers the temperature from high temperature to low temperature through heat conduction to achieve the purpose of cooling.
Testing principles and methods of coolness
Instant cooling fabrics have been launched on the market, but the public is often skeptical about the efficacy advertised by such products. Therefore, only through professional inspection can consumers’ doubts be eliminated.
The Japanese company’s KES-F7 precision instantaneous thermal physical property tester||contact cold and warm feeling tester is used for cooling sensation testing. The main principle is that the fabric’s instant cooling sensation test experiment places the fabric on the cold plate of the instrument. When the fabric temperature and coldness When the plates are the same, quickly place the hot plate on the sample. The heat from the hot plate will be transmitted 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 Qmax value, and the unit is Expressed by the instantaneous cooling heat flow (W/cm2) of the fabric.
The Q-max value is the maximum instantaneous heat loss from the skin when simulating the human body’s contact with the fabric. It is also the maximum heat flow that can be taken away instantly per unit area of the fabric. This value is an indicator of the instantaneous cooling performance of the fabric, and the unit is expressed in W/cm2 , the larger the Q-max value, the more heat can be taken away.
Mature application tests include medical antipyretic patches, cosmetics, thermal clothing, etc.
At present, there is no cooling sensation test standard released in China, but in 2016, the National Textile Standards Committee and the Basic Standards Branch of the National Textile Standards Committee have approved the “Testing and Evaluation of Cooling Feeling Performance of Textiles upon Contact” (National Standard). That is to say, the release of this standard is just around the corner. We can first refer to the “Fabric Instant Coolness Verification Specification” (FTTS-FA-019) formulated by the “Functional and Industrial Textiles Certification and Verification Evaluation Committee” of the Taiwan Textile Industry Research Institute in October 2010. Industry standards for industry reference.
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Cooling requirements: |
Knitted fabric≥0.130W/cm2 |
Woven fabric≥0.170W/cm2 |
How to deal with the instant cool feeling on contact
There are many ways to achieve rapid thermal conductivity and cooling of fabrics,
1. When drawing chemical fiber, add ore or jade powder; such as Smartkool® fabric,
Smartkool® makes the heat transfer speed of the fabric faster by blending jade material into the yarn. In this way, the temperature of the skin will exchange heat with the air temperature faster, resulting in a cool feeling on contact. Smartkool® fabric also has a quick-drying effect.
2. Hydrophilic modification or processing of fabrics (hydrophilic agent treatment, bamboo carbon fiber, Viscose or Cupra, Rayon fiber); such as Coolmax® fabric
Coolmax® achieves a cool feeling by absorbing moisture and drying quickly. The working principle of Coolmax can be simply summarized in three points: helping to take away moisture from the body surface; absorbing and diffusing moisture to enhance evaporation and drying capabilities; air passes in to keep the moisture dry. Coolness and dryness of the body.
3. The fabric adopts three-dimensional weaving method;
4. Use paraffin microcapsules to absorb heat (the production is time-consuming and the effect is limited, and it is rare in the market)
5. Use a contact cooling finishing agent
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Specification for verification of instant coolness of fabrics (FTTS-FA-019) |
1. Scope of application
This standard is suitable for testing textile-related products with instant cooling, judging whether they can achieve the degree of heat dissipation and cooling, and judging whether they and their semi-finished products have quality requirements to evaluate whether they have a cooling effect. This test is suitable for knitted and woven fabrics
2. Interpretation of terms
Touch Feeling of Warmth or Coolness/Q-max: Simulates the maximum instantaneous heat loss from the skin surface when the human body comes into contact with fabric, which is the instantaneous excess heat flux of the fabric. The unit is Watt (W) per square centimeter. /cm2) expressed.
3. Standard
Evaluation criteria for this specification:
Fabric instant cooling heat flow (W/cm2) ≧0.140
3.1 General requirements
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Project |
General requirements |
According to standards |
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Washing resistance |
Divided into three levels: initial, 20 times washing, and 50 times washing (Note 1) |
【A】Knitted fabrics are manufactured in accordance with AATCC 135(2)III(A)ii method. |
Note 1: In addition to the above three levels, water wash resistance can be determined according to customer needs.
4. Test methods
4.1 Test sample:
The test sample is 20 x 20 square centimeters (the actual measured area is 5 x 5 square centimeters). The sample to be tested must be placed at an ambient temperature of 20±2℃ and a relative humidity of 65±2%RH for 24 hours before testing. .
4.2 Test environment:
Turn on the programmable constant temperature and humidity machine, set the ambient temperature to 25±2℃, and the humidity to 65±5%RH, and wait for at least 1 hour to confirm that the environment is constant temperature and humidity before testing.
4.3 Test equipment:
Thermal effect measuring instrument KES-F7 THERMO LABO II, or equivalent testing instrument.
4.4 Test steps:
4.4.1. Turn on the power of ThermoLaboⅡ equipment, confirm the parameters and heat it up for about 15 minutes.
4.4.2 Turn the main hot plate heater (Heater) switch to the starting position (ON), and also set the temperature of the hot plate (Temperature-Box) to 35±0.1°C. When it reaches 35°C, heat the guard ring Switch the Guard Heater switch to the starting position (ON).
4.4.3 Set the cold plate (Water-Box) to the required temperature (simulating the external environment), which is usually 25°C. After the temperature (25°C) is reached, place the sample fabric on the cold plate (the fabric’s close-fitting side faces (above), when the temperature of the hot plate (Temperature-Box) reaches the set temperature (35°C), press the qm key, and at the same time quickly place the hot plate (Temperature-Box) on the sample fabric (note that the angle of placement needs to be Vertical, as shown in Figure 1), record the qm value on the display screen. This value is the cool feeling of the fabric on contact (maximum instantaneous heat loss), which is the experimental result, and the unit is W/cm2.
4.5 Test results:
4.5.1 The test result is the average of 5 test data.
4.5.2 The valid data in the test report is the average to the third decimal place.
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