We, Dongshin Chemical Ltd. are one of the leading company of dye manufacturing for plastic which are well organized and very specialized in Optical Whitening Agent, OB-1. Please refer to the characteristic of our OB-1 as below ; 1. It is used for Polyester fiber, Polyvinyl Chloride, Polypropylene, ABS, Polyacyl Nylon and other plastics.2. It can be added in any necessary process for optical whitening treatment.3. It is absolutely not soluble in water and soluble in organic solvent.4. It is easy to use by making up for faults of other whitening agent which has high melting points.5. It is very strong at heat-resisting property so, it is used in the process requiring high temperature. 6. Optical whitening agent is a bit sensitive at sunlight but OB-1 is not effected a lot even though it is exposed to sunlight.If necessary, we will send you free sample immediately.Please kindly visit our website at http://dongshinchem.com for your further study.