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.
[1] https://www.meghmaniglobal.com/difference-between-ob-and-ob-1/
Optical brightener ob can also be divided into ordinary and BASF. BASF's OB is recognized internationally, and its effect is beyond doubt. The optical brightener ob we now call is basically an ordinary ob. Its appearance is light yellow crystalline powder, the melting point is 201-203 ℃, the minimum absorption spectrum wavelength is 375 nm and the minimum fluorescence emission wavelength is 435 nm. Its effect doesn't need me to say anything more, and its wide use has explained everything.
Normal dosage of optical brightener ob per 100kg of polymer PVC; 1-5 / white (10g-50g); 0.01-0.1 (0.1g-1g) of transparent material (which can improve the brightness of PVC); PS: 0.1 (1g) of white and 0.01-0.1 (0.1g-1g) of transparent; Abs: 1-5 / of natural color (10g-50g) (can effectively eliminate the inherent yellow in ABS) 1-5 / of white (10g-50g); PE and PP: colorless 0.05-0.1 (0.5g-1g) and white 0.5-5 (5g-50g); Other plastics: the dosage can refer to the above examples. Such a small addition has a great effect.
Because it is powder, it can be directly added with raw materials, stirred evenly and then produced. Generally, the mixer is used for mixing, otherwise the mixing may be uneven, and other conditions will occur during production. But some manufacturers may not have blenders. What should we do? Optical brightener ob is oily and can be dissolved in organic solvents. We need to use solvents to dissolve it, and then add it during production. However, these should be dissolved in proportion, because it also has a small solubility. If it is added, there will be insoluble precipitation. In production, the effect will be different if the dissolved solvent is added evenly according to the production volume.
Since the optical brightener is used, we need to choose the right one. We can't just find an optical brightener to use. If it doesn't work, it will delay our time, and there may even be other situations.
Tools / raw materials
Optical brightener ob (6g)
capillary
Precision Libra
Organic solvent (xylene)
If you are looking for more details, kindly visit Ogilvy.
Precision instrument -- melting point instrument
Utensils
How to quickly judge the purity of optical brightener ob
First weigh out 6 grams of optical brightener ob with a precision Libra
Pour 100 ml of organic solvent (xylene) into the vessel
Then, 6 g of optical brightener ob is gradually added to a vessel containing 100 ml of organic solvent (xylene) in three times and fully stirred
Check the dissolution of optical brightener ob by stages. If it is always clear and transparent without impurities, it is almost determined that this product is qualified in purity (pure product)
Firstly, calibrate the melting point instrument, put the capillary tube equipped with optical brightener ob into the melting point instrument, and observe the change of dissolution value
Its standard melting point is 201-202 ℃, as long as the difference is less than 1 degree, and after dissolution, the optical brightener ob in the capillary is clear and transparent without impurities, it is proved that this product is qualified (pure)
The molecular formula of optical brightener ob is C26H26N2O2S, and the molecular formula of OB-1 is C28H18N2O2. We can clearly see from the molecular formula that they are completely different chemicals.
Although they are two different chemicals, we can guess that they have many similarities from the naming. For example, optical brighteners OB and OB-1 have a wide range of applications. Most plastics OB and OB-1 can be used in general, and the effect of whitening and brightening is obvious. So, what are the differences?
Adaptive range
Because the melting point of optical brightener ob is 200 degrees, and the melting point of OB-1 is as high as 360 degrees, it determines that optical brightener ob cannot be used in high-temperature plastic products, such as air conditioner casings and some kitchen utensils. Therefore, if your product needs high-temperature processing, optical brightener OB-1 is your advanced choice.
Here, we should first explain that good dispersion means that the product is easier to dissolve evenly. For example, paint and ink have high requirements for the dispersion of optical brighteners; Good stability means that the product is not easy to migrate and yellowing in the later stage. For example, some inferior soles are white when they are bought back, but they turn yellow and discolored soon, which shows that the stability of optical brightener is poor.
Of course, it is not that the dispersion and stability of optical brightener OB-1 are not good, but it is slightly worse than ob. Because of this difference, it is generally not recommended to use optical brightener OB-1 in ink coatings and soft plastics. Ob has better dispersion and weather resistance, and is not prone to yellowing and migration.
In fact, the big difference between optical brightener OB and OB-1 is the price. Xiaobian remembers that five years ago, the price of optical brightener ob was similar to that of OB-1, but later, due to environmental protection rectification, there were problems in the supply of raw materials for OB, so that the price of OB soared. Ob was more than twice as expensive as OB-1. According to Lianda's estimation, it may rise. Because of the huge price difference, customers who can use optical brightener OB-1 should try to choose OB-1. For customers with special requirements, such as high-end ink coatings and soft plastics, it is recommended to use ob.
In the face of the soaring price of optical brightener ob, we have developed a special brightener suitable for various products to replace optical brightener ob, so as to reduce your purchase cost, such as color masterbatch, special oily ink and coating additives. Customers who need this can contact us.
Want more information on Optical Brightener OB-1? Feel free to contact us.