Some narrative optical brightener

Optical brightener (Optical whitener) is a type of fabric and can enhance the whiteness of paper and other organic compounds. Also known as optical brighteners . Fabric, etc. are often  PVC profile stabilizer contained as impurities, and yellow colors , in the past are used for bleaching chemical bleaching methods , are used in the product add brighteners approach. Its role is to absorb the products of invisible ultraviolet radiation into fluorescence radiation purple blue , yellow with the original two colors, a white light radiation , improve the whiteness in the sunlight . Brightener has been widely used in the textile , paper, detergent , soap , rubber, plastics, pigments  iron oxide yellow and paints and so on. Classification
According to the chemical structure can be divided into five categories :
① stilbene , and certain synthetic fibers for cotton fiber , paper , soap and other industries , with a blue fluorescence ;
② coumarin type, having the basic structure coumarone for celluloid , polyvinyl chloride , etc., with a  dibutyl phthalate strong blue fluorescence ;
③ pyrazoline type , for wool, polyamide, acrylic and other fibers , a green fluorescent color;
④ benzo type of oxygen and nitrogen , for acrylic and other fibers and polyvinyl chloride , polystyrene and other plastics , with a red fluorescence ;
⑤ phthalimide type, used for polyester, acrylic, nylon and other fibers , with a blue fluorescence.