How Many Index to Evaluate The UV Protection Property of Textile?
The expressive method of textile’s UV protection property usually have UV passing rate/ UPF value/UVR transmittance and UVR obstruct rate etc.
(1)UV passing rate. Spectrophotometric method is using integrating sphere ultraviolet spectrophotometer test the textile’s UV passing rate. The less the UV passing rate is, the better the textile’s UV protection effect have. Generally UV ray reflect on the human body less than 10% is treated as safe. Transmittance is in the radiation spectrum and polarization state and geometric distribution of a given condition, the transmission of the radial flux and the percentage of the radial flux of the incident, can express via available formulas.
(2)UPF value. UPF value also called UV protection coefficient/ UV shelter coefficient is ability of textile’s UV protection. It’s the specific value between average radiation amount of the UV ray reflect to un-protected skin and radiation amount of sheltering by tested fabric.
(3)UVR transmission. It’s the value between having a sample of UV radiation transmission and no sample of UV radiation transmission, often divided into UVA (320~400nm) transmittance and UVB transmittance (280~320nm).
(4)UVR obstruct rate. Also called UVR folding rate, calculation formula is: UVR obstruct rate=1-UVR transmittance.
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