About UV Aging.

UV aging belongs to sunlight aging. UV is the abbreviation of Ultraviolet (ultraviolet), which is usually used to evaluate the aging speed of products under ultraviolet rays. Sunlight aging is the main aging damage to materials used outdoors. For materials used indoors, it is also Will be subject to a certain degree of aging caused by sunlight radiation or ultraviolet rays in artificial light sources (such as ultraviolet lamps, ultraviolet bands in fluorescent lamps, etc.).

Solar radiation is mainly concentrated in the visible light part (0.4-0.76 μm), and the infrared rays with wavelengths greater than visible light (>0.76 μm) and ultraviolet rays (<0.4 μm) with wavelengths smaller than visible light are less. Among the total radiant energy, wavelengths between 0.15 and 4 μm account for more than 99%, and they are mainly distributed in the visible light region and red and ultraviolet regions. The visible light region accounts for about 50% of the total solar radiation energy, and the infrared region accounts for about 43%. The solar radiation in the ultraviolet region is very little, accounting for only about 7% of the total.

Ultraviolet light is a general term for radiation with wavelengths from 0.01 to 0.40 microns in the electromagnetic spectrum, which cannot cause people's vision. Ultraviolet light is divided into A rays, B rays and C rays (referred to as UVA, UVB and UVC), and the wavelength ranges are 400-315nm, 315-280nm, 280-190nm respectively.

According to ASTM G154, UV (ultraviolet) cannot simulate full-spectrum sunlight. Its principle is that for durable materials exposed outdoors, the short-band wavelength of ultraviolet rays of 300~400nm is the most important cause of aging damage. As can be seen from the figure below, in the short-wave region of ultraviolet light, that is, from 365nm to the lowest wavelength band of sunlight, UV fluorescent lamps can simulate sunlight well.