When consumers purchase warm winter clothing, they often encounter slogans such as: “Far infrared self-heating”, “Far infrared warms skin”, “Far infrared keeps warm”, etc. What exactly does “far infrared” mean? performance? How to detect whether a fabric has far-infrared properties?
What is far infrared?
Infrared rays are a type of light wave whose wavelength is shorter than radio waves and longer than visible light. Infrared rays are invisible to the naked eye. The wavelength range of infrared rays is very wide. People divide infrared rays in different wavelength ranges into near-infrared, mid-infrared and far-infrared regions. Far-infrared rays have strong penetrating and radiating power, and have significant temperature control and resonance effects. They are easily absorbed by objects and converted into the internal energy of the objects.
How to detect whether textiles have far-infrared properties?
GB/T 30127-2013 “Detection and Evaluation of Far-Infrared Performance of Textiles” uses the two items of “far-infrared emissivity” and “far-infrared radiation temperature rise” to evaluate whether fabrics have far-infrared properties.
The far-infrared emissivity is to place the standard blackbody plate and the sample on the hot plate one after another, and adjust the surface temperature of the hot plate in sequence to reach the specified temperature; the standard blackbody is measured separately using a far-infrared radiation measurement system with a spectral response range covering the 5 μm ~ 14 μm band. The radiation intensity after the plate and sample are covered on the hot plate reaches stability, and the far-infrared emissivity of the sample is calculated by calculating the ratio of the radiation intensity of the sample and the standard blackbody plate.
The measurement of temperature rise is to measure the temperature rise on the surface of the test surface of the sample after the far-infrared radiation source irradiates the sample with constant irradiation intensity for a certain period of time.
What kind of textiles can be rated as having far-infrared properties?
For general samples, if the far-infrared emissivity of the sample is not less than 0.88, and the far-infrared radiation temperature rise is not less than 1.4°C, the sample has far-infrared properties.
For loose samples such as flakes, nonwovens, and piles, the far-infrared emissivity is not less than 0.83, and the far-infrared radiation temperature rise is not less than 1.7°C. The sample has far-infrared properties.
It is worth noting that multiple washings also have a certain impact on far-infrared performance. If the above index requirements are still met after multiple washes, the sample is considered to be a product with wash-resistant far-infrared performance.
Post time: Feb-28-2024