Product Description of Optical Brightener OB-1 CAS#1533-45-5
Optical Brightener OB-1, also named 2,2-(4,4-diphenylethylene) bisbenzoxazole, is a Yellowish or yellowish-green crystalline compound whose melting point ranges from 359-362℃. This substance is odorless, insoluble in water and delivers stable chemical behaviors. It shows maximum absorption wavelength at 374 nm and generates intense fluorescent emission at 434 nm. As a high-efficiency fluorescent whitening agent, OB-1 is specially developed for polyester fiber materials.
Fluorescent whitening agents operate by absorbing invisible ultraviolet light roughly from 360-380 nm, then transforming such radiation into blue-or-violet visible light with longer wavelengths. Such photoconversion counteracts undesirable yellowish hues inside material substrates and boosts visible-light reflection within 400-600 nm, thus end-products acquire superior whiteness, brightness and better visual color performance.

Optical Brightener OB-1 Chemical Properties
| Melting point | >300 °C(lit.) |
| Boiling point | 533.34°C (rough estimate) |
| density | 1.2151 (rough estimate) |
| vapor pressure | 0Pa at 25℃ |
| refractive index | 1.5800 (estimate) |
| storage temp. | Sealed in dry,Room Temperature |
| solubility | DMSO (Slightly, Heated) |
| pka | 1.45±0.10(Predicted) |
| form | crystalline powder |
| color | Yellowish or yellowish-green |
| Water Solubility | 10μg/L at 25℃ |
| Stability: | Stable. Incompatible with strong oxidizing agents. |
| InChIKey | ORACIQIJMCYPHQ-KTKRTIGZSA-N |
| LogP | 5.499 at 25℃ |
| CAS DataBase Reference | 1533-45-5(CAS DataBase Reference) |
| EPA Substance Registry System | Benzoxazole, 2,2'-(1,2-ethenediyldi-4,1-phenylene)bis- (1533-45-5) |
| Hazard Codes | Xi |
| Risk Statements | 36/37/38 |
| Safety Statements | 26-37/39-24/25 |
| WGK Germany | 1 |
| HS Code | 29349990 |

Product Application of Optical Brightener OB-1 CAS#1533-45-5
Optical Brightener OB-1 is a high-performance, newly developed fluorescent whitening agent widely used to enhance the whiteness and surface brightness of various polymer materials, including PE, PVC, ABS and PC. It boasts outstanding comprehensive performance with low dosage demand, excellent compatibility and superior dispersibility in substrate systems.
This brightener is applicable for both polymerization and post-processing procedures of polymer products. Materials treated with OB-1 present high whiteness, remarkable heat resistance and excellent weather resistance. Furthermore, it can be prepared into slurry formulations and applied for fluorescent whitening treatment in the textile industry.


