Far-Infrared Properties And Testing Of Textiles

In the field of textile and clothing, the developed countries in Japan, the United States, Germany, Russia and other developed countries first launched the applied research on far-infrared technology, and promoted the development of far-infrared textiles.

Especially in Japan, the related patents of far infrared fiber products in the mid 1980s have springing up in Japan, forming a boom in developing far-infrared functional textiles.

The Japanese bell spinning company uses ceramic powder to infiltrate nylon or acrylic polymers to spin the "Massoni J N" and "Marceau Nik A" far-infrared fibers respectively. The Asahi chemical company uses zirconium carbide ceramic solution coating to develop a new nylon thermal fabric "SOLAR-V", which is mainly used for snow sweaters.

China began developing far-infrared textiles in 1990s.

The Jiangsu Textile Research Institute has developed far-infrared polyester staple fiber. The far-infrared polypropylene fiber developed by Tianjin University of Technology has good moisture conductivity, low price, light weight, and good antibacterial and anti moth properties.

At present, the far-infrared textiles developed mainly use ultrafine ceramic powders as additives to prepare far-infrared fibers in spinning solution, or finishing liquid made of ceramic powder.

The main application of ceramic powder: metal oxides, such as Al2O3, TiO2, BaO, ZrO, SiO2, and so on; metal carbides, such as SiC, TiC, ZrC, etc.

1. far-infrared ray

Infrared is located between visible and microwave, and the wavelength range of infrared is very wide. It will be divided into three wavelengths in science: near infrared band: 0.77~3 m; mid infrared band: 3~30 m; far infrared band: 30~1000 m.

Due to the narrow range of the mid infrared band, the mid infrared band is incorporated into the far-infrared band in the field of health care.

2. mechanism of action

Thermal radiation is a heat pfer method characterized by the pmission of energy in the form of electromagnetic waves.

Thermal radiation mainly includes ultraviolet, visible and infrared rays.

According to Kirchhoff's law, a good radiator must be a good absorber, that is, the ability of an object to radiate heat is strong, and its absorption capacity is also strong, which is directly proportional to the two.

The human body can radiate far infrared rays and absorb far infrared radiation.

As the body 60%~70% is water, according to the matching absorption theory, when the wavelength and the infrared radiation are

3. function

Far infrared textiles mainly have thermal insulation function, namely, heat preservation function, health care function and antibacterial function.

Far infrared textiles, due to the addition of far infrared radiation materials with high emissivity, their thermal insulation performance is to use the thermal radiation of organisms to absorb and store the energy of external radiation to organisms, so that organisms can produce "greenhouse effect" to prevent heat loss and good thermal insulation effect.

Therefore, far-infrared fabrics have remarkable thermal insulation function and are suitable for making winter clothing with cold resistant fabric and light weight.

The heat absorbed by the skin can be passed through the media.

The addition of particulates in fiber can make the fiber surface porous, the surface area increased, and the adsorption and diffusion characteristics of surface activity and surface state are improved obviously, so that the product has the functions of sweat absorption, deodorization, sterilization and so on.

The bacteriostatic test showed that far infrared textiles had a bacteriostasis rate of 95% against Staphylococcus aureus, Candida albicans, E. coli and other pathogens.

Testing methods and related standards

1. standard

At present, the functional testing standards for far-infrared textiles are mainly national standard GB/T18319 - 2001, test methods for infrared thermal storage and thermal insulation of textiles, textile industry standard FZ/T64010 - 2000 far-infrared textiles, China Standard Association standard CAS115 - 2005 health care functional textiles.

The GB/T18319 - 2001 standard stipulates that the infrared reflectance and pmittance of textiles can be determined by infrared radiometer, the absorptivity is calculated, and the heating rate of irradiation is determined by point thermometer.

Mainly from the infrared absorption rate and infrared radiation heating rate two aspects of testing and evaluation.

The FZ/T64010 - 2000 standard specifies the technical requirements, test methods, inspection rules, result determination and instructions for use of far-infrared textiles.

This standard uses the normal emissivity as the evaluation index of far-infrared textile far-infrared function, and deducts the normal emissivity of the contrast sample (the corresponding non far infrared product) with the normal emissivity of the sample as the normal emissivity to raise the value.

The experimental instruments are infrared spectrometer and blackbody furnace.

Finally, the normal emissivity calculated is the normal emissivity of the 8~15 M band.

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CAS115 - 2005 standard adopts the method of determining the normal emissivity, and has developed the far infrared function evaluation index. It is the only standard applicable to health care functional textiles in China at present. Among them, the part of the textile with far infrared function has standardized its terminology definition, test method, result judgement and sign, etc. it is suitable for the far-infrared normal emissivity detection of far-infrared normal materials with various emissivity of more than 0.2 and heat conduction objects.

The normal emissivity of the sample is measured by the method of sample temperature at 100 C, comparing the full radiation brightness with the standard blackbody method at the same temperature to the full radiance.

The test instruments include infrared spectrometer (or infrared radiometer) and blackbody furnace.

The computer processed the radiant intensity of the blackbody furnace, the radiance of the sample and the radiance of the contrast sample, and calculated the normal emissivity of the 4~16 M band.

The comparison of the three standards is shown in Figure 1.