Optical Brightening Agent OB-1
Performance:
Optical brighteners are added to many materials to reduce yellowing, improve whiteness, and
to enhance the brightness of a product. OB-1 is used widely in the plastic market. Because of
its excellent brightening ability, good thermal stability, and compatibility with many polymers.
Typical Properties:
Chemical name: 2,2-(1,2-Ethenediyldi-4, 1-phenylene) bisbenzoxazole
Molecular weight: 414.4
CAS No.: 1533-45-5
C.I.: 393
Specifications:
Ash %: 0.3max
Empirical Formula: C28H18N2O2
Melting Point(DTA),C: 353-359
Appearance: Yellowish Green Powder
Odor: Free of odor
Volatile Content %: 0.3max
Assay %: 99min
Particle Size: 200 meshes
Effect of Optical Brighteners on the Whiteness of Polymers:
Optical brighteners function by absorbing ultraviolet radiation and remitting blue light. The
emitted blue light will reduce the yellow color of a polymer. In the presence of a whitening
agent, such as TiO2, the use of OB-1 will produce a brilliant white or " white than white"
appearance.
Two primary factors affect the whiteness/yellowness of a formulation. They are the color of the
base polymer and the level of brightener added. If no whitening agent, such as TiO2, is used,
the level of OB-1 required will likely be lower than when a whitening agent is preset. This level
might be as little as 25-50 ppm. In determining the optimum concentration of brightener, the
effect of any other UV-absorbing materials in the plastic should be considered. It is important
that users perform sufficient evaluations to determine the optimum level of OB-1 for their
specific end uses.