Optical brightener OB-1

Description

Optical brightener OB-1 also called fluorescent brightener OB-1, optical brightener agent OB-1, OB-1 has the highest melting point among the optical brighteners and is also the most widely applicable and the most sold brightener. Optical brighteners OB-1 have two appearance colors, yellow and green. Worldwide use it for all kinds of plastics, or make masterbatches, then the optical brightener masterbatches and compounds are used in the plastics industry.

Chemical Properties

solid

Uses

4,4′-Bis(2-benzoxazolyl)stilbene (BBS) is suitable for use in the preparation of poly(propylene) (PP) films containing different concentrations of BBS. BBS may be employed as a viscosity-sensitive fluorophore to investigate the curing parameters in fabrication of UV-cured automotive organic protective coatings. BBS may be used in the preparation of polymeric film sensors based on excimer luminescence and responsive to both mechanical and temperature stress, by its dispersion into a thermoplastic aliphatic biodegradable polyester [poly(1,4-butylene succinate).

General Description

4,4′-Bis(2-benzoxazolyl)stilbene (BBS) is reported to exhibit consistently high absolute fluorescence quantum yields and a monoexponential lifetime in solutions. The photophysics of BBS dispersed in poly(propylene) (PP) films has been investigated. BBS is reported as a food-grade dye. BBS is also reported as excimer-forming, photoluminescent chromophore.

Flammability and Explosibility

Not classified

Synthesis

(2) Sulfide reaction. 2-(p-tolyl)benzo[d]oxazole (A) was placed in a sulfide reactor with a mass ratio of A to sulfur of 1:1 to 3:1, heated to 210-250°C and reacted for 16-24 hours. After completion of the reaction, xylene was added as a solvent, the solution was heated and filtered to give the crude product (0B-1) of (E)-1,2-bis(4-(benzo[d]oxazol-2-yl)phenyl)ethylene (B). (3) Crude refinement. The crude product B with trichlorobenzene was added to a refining kettle with activated carbon and 30% NaOH solution, heated to 220°C and kept for 2 h to dissolve B. Subsequently, the temperature of the solution was adjusted to 200-210°C, and the activated carbon was removed by filtration. The filtrate was transferred to a crystallization kettle and cooled to 20-30°C to obtain the liquid mixture C. (4) Solid-liquid separation. The liquid mixture C was filtered to separate the solid product and trichlorobenzene mother liquor. The solid cake was dried to obtain 2,2'-(4,4'-stilbenzylphenyl)phenylidenebenzobisoxazole. The trichlorobenzene mother liquor can be used directly in the next batch of the refining process. The product 0B-1 prepared in Example 1 has a purity of 99% and a yield of 93%.

Properties and Applications

TEST ITEMS	SPECIFICATION
APPEARANCE	BRIGHT YELLOW CRYSTALS POWDER
SHADE	GREENISH
METLING POINT	355-360 ° C
PURITY	98.5% min
FINENESS	300 mesh min

References

[1] Patent: CN103772309, 2016, B. Location in patent: Paragraph 0014-0019
[2] Chemistry of Heterocyclic Compounds, 1981, vol. 17, # 4, p. 328 - 332