Natural weather-aging test methods are usually divided into two kinds. The first one is to simulate the aging of ultraviolet light and the second one is to simulate all-sunshine aging.
The main reason is that the results of the natural climate aging experiment are more realistic and the costs are low and easy to operate.
Although we can do natural weathering tests anywhere, the internationally recognized test site is Florida in the United States because of its sunshine.
But the downside of the natural weathering experiment is that it takes a long time to test, and the experimenter may not have been waiting for a product to test the results for years.
Ultraviolet lamp irradiated by fluorescent uv lamp is used to simulate the destructive effect of sunlight on durable materials.
It has difference with the aforementioned xenon arc lamp, fluorescent uv lamp on the electrical theory and common fluorescent lamp, lighting cold light but can generate more ultraviolet rather than visible or infrared light.
For different exposure applications, there are different types of lamps with different spectra for selection.
The uva-340 lamp in the main short-wavelength ultraviolet spectral range can simulate sunlight well.
The spectral energy distribution (SPD) of UVA lamp is similar to that of spectra of 360nm from the solar spectrum.
UVB lights are also used to speed up artificial weathering tests.
It is faster than the UVA lamp to destroy the material, but its shorter wavelength energy output than 360 nm results in a deviation from the actual test results.
The xenon arc radiation test is thought to be the most capable of simulating a full solar spectrum because it produces ultraviolet, visible and infrared light.
Because of this, it is considered the most widely used method at home and abroad.
GB/T1865-1997 (equivalent to IS0113411:1994) introduces this approach in detail.
But this method also has its limitations, namely the stability of the xenon arc light source and the complexity of the experimental system.
The xenon arc light source must be filtered to reduce unwanted radiation.
There are many types of filter glass for different irradiance distribution.
The type of glass selected depends on the type of material being tested and its end-use.
Changing the filter glass can change the type of short-wavelength ultraviolet light through which the material suffers damage.
There are three types of filtering commonly used: sunlight, window glass, and extended uv types (methods 1 and 2 mentioned in GB/t1865-1997 are corresponding to the first two types).