1. Basic information
Chemical formula: C28H18N2O2
CAS number: 1533-45-5
Chemical name: 2,2'-(4,4' -stilbenyl -) dibenzoxazole
Appearance: bright yellowish-green or light greenish-yellow crystalline powder
Melting point: 350~360℃ (data from different sources are slightly different)
Purity: ≥98% (some products ≥98.50% or ≥99.0%)
Maximum absorption wavelength: 374nm
Maximum fluorescence emission wavelength: 434nm

2., performance characteristics
Good heat resistance: fluorescent whitening agent OB-1 is particularly resistant to high temperature, decomposition temperature of up to 450℃ or more, suitable for high temperature molding of various plastics and plastic products.
Strong light resistance: has a strong fluorescent effect, pure color, whitening effect is significant.
Chlorine bleaching resistance: Good tolerance to chlorine bleaching.
Migration resistance: stable performance, not easy to migrate.
Good compatibility: Good compatibility with most polymers.

3. Main uses
Chemical fiber whitening: suitable for polyester fiber, nylon fiber, polypropylene fiber and other chemical fiber whitening, polyester fiber and polyester and cotton and other fiber blended fabric whitening effect is particularly ideal.
Plastic brightening: It can be used for brightening polypropylene plastics, hard PVC, ABS, EVA, polystyrene, polycarbonate and other plastics.
Whitening of polyester stock solution: Adding in the conventional polymerization of polyester and nylon can improve the whiteness of the stock solution.
Whiteness of recycled materials: Adding OB-1 to recycled polyester waste, bottles and slices makes recycled materials appear whiter, and the chrominance in different recycled materials becomes more consistent.

4. Methods of use
The fluorescent whitening agent OB-1 is fully mixed with the material before various plastic products are formed or polyester fibers are drawn, at 0.010.05% (or 0.10.5‰) of the weight of the plastic or polyester pellets. It is also possible to dissolve the fluorescent whitening agent with an organic solvent (such as plasticizer, lubricant, etc.) and then add it by drip.

5. Packaging and storage
Packaging: Usually used 20kg or 25kg cardboard drum packaging.
Storage: Should be stored in a cool and ventilated place, avoid direct sunlight and high temperature environment.
In summary, fluorescent brightener OB-1 is a kind of brightener with excellent performance and wide use, especially suitable for the brightener of plastic products and chemical fibers formed at high temperature. When in use, the amount of addition should be determined according to the specific application field and material characteristics, and follow the correct use method.