optical brightener agent

White matter normally slightly absorb bluish visible light which belong to middie-short wave, therefore appearance is slight yellowish and impact on whiteness. Optical brightener agent will absorb ultraviolet - wave length is 300-400nm, and radiate violetish or bluish fluorescence - wave length is 400-500nm, it essentially recuperates blue visible light which absorbed by objects, improving whiteness and brightness. So as the solution of white plastic and ink, coating, it is OBA. i.e. solve the problem of yellowish white plastic and ink.