Optical brightener (OB) and Optical Brightener -1(OB-1) are brightening agents that are often confused. Both are used for brightening but on different types of materials. Therefore, it is essential to understand the details and differences between them before selecting.

What is an Optical Brightener(OB)?

Optical Brighteners are fluorescent whitening agents designed to brighten colors or mask yellowing in plastics, lacquers, paints, inks, photo-processing solutions, and fibers. They function by absorbing invisible ultraviolet radiation and re-emitting it as visible light in the blue range of the spectrum. Optical brighteners are particularly effective in masking the yellowish cast sometimes observed in plastics and fibers after high-temperature processing operations. They are also used in substrates containing pigments or dyes to make the colors appear more brilliant.

Optical Brighteners have a wide range of applications, including fabric whitening. Materials such as plastics have a certain level of yellowness that gives them a dull finish. To add brightness to the material, OB is added to the plastics. A similar application takes place for the fabric. Other colorants are used along with the Optical Brightener to derive the required color and shade in the materials. Optical Brighteners are easily used in plastics as they have a high melting point, which helps them easily mix with the molten plastic.

What is OB-1?

OB-1 has a similar effect but with different chemical formulas and applications. It is also used in textiles and plastics to increase the whiteness of the product. The final whiteness derived using OB-1 has a light reddish-blue effect. 

One of the main differentiators can be the products on which OB and OB-1 can be used. This is decided based on the melting point. The melting point of OB(200 degrees) is less than OB-1. However, the latter has a high melting point of about 360 degrees. Therefore, it is unsuitable for high-temperature products, and OB can be used in such cases. On the other hand, OB1 can be used in materials that require high-temperature processing.

OB is known to have better dispersibility and stability than OB-1. This is why OB is recommended for ink coatings, as the OB is not prone to the yellowing that might start early with OB-1.

References

[1] https://www.meghmaniglobal.com/difference-between-ob-and-ob-1/