The suntecness of the fluorescent whitening agent

There is a very important indicator in the fluorescent whitening agent, which mainly reflects the sunshine fastness of the whitening agent. 

The sun exposure refers to the tolerance firmness of the sample to the sun or the artificial light source equivalent to the solar spectrum, that is, the degree of fading of the original sample after exposure. The fading of sun exposure is a complex photochemical process. The exposure rate is divided into 8 levels, and the highest level is the highest (equivalent to the exposure of 384h in sunlight and starts to fade). Level 1 is the lowest (equivalent to the exposure of 3h in the sun, starting color)

The sun exposure test adopts the blue label contrast method. The current method is to expose the sample and a group of 8 -level blue labels at the same time and the same conditions. When the sample has fully faded, the samples and samples are rated. If the chroma of the sample is the same as the level 5 of the sample, the daily exposure to the sample is 5.

The exposure conditions include the natural sunlight method and the test mechanism of the exposure tolerance. The light source used in the exposure fastness test machine includes carbon arc light and molten arc light.