Optical brightener is a kind of benzoxazole compound, lt is odorless, hard to dissolve in water, soluble in paraffin, fat, mineral oil, wax and common organic solvents. It can be used for whitening thermoplastic plastics, PVC, PS, PE, PP, ABS, Acetate fiber, paint, coating, printing ink, etc. It can be added at any stage in the process of whitening the polymers and make the finished products emitt a bright bluish white glaze.It can also be used as special marks in identify fakless material if used in printing ink.