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Liquid Optical Brighteners


Gerwin Elzinga


March 2017


Fluorescentoptical brightener

Liquid Optical Brighteners

Artists have long known that colors are not what they seem. Light and dark is not simply a matter of adding black or white to a color, but also a matter of adding contrasting color. For example, when painting an orange,  yellow can make a area look lighter, while a touch of blue can give the depth to the darker parts of the fruits peel.

"Artists have long known that colors are not what they seem."



This is the principle behind bluing, the predecessor to modern day optical brightener. With light, different than with paint though, combining colors will not result in darker shades, but in a purer white light. Bluing agents, as their name implies, are dyes that reflect blue light to cancel out the natural yellowish hue that most naturally occurring whites have.

Paint is different from light. When you mix red, green, and blue paints, you get a mess. When you mix red, green, and blue light, you get white.

Today, optical brighteners fluoresce, giving off light and making colors seem brighter and whites whiter. All of the brighteners in Sirius’s Britemax  line absorb ultraviolet light and emit blue and yellow light. The ratio between the light absorbed and light emitted is inversely proportional to the brightening effect.  This has the effect of making paper look whiter, enhancing the appearance of clothes after a wash (for that “cleaner than clean” look), in toothpastes, and even in some cosmetics.

However, optical brighteners are not biodegradable. Their chemical structure is too complex and the double bonds are too difficult for enzymes to break. In fact, they are so stable in the environment that they can be used as a marker for water pollution. And while these compounds themselves may not be toxic to the environment, sunlight can photodegrade them, and these degradation products may be irritating to people with sensitive skin, or toxic. Furthermore, photodegradation may be incomplete – the molecules that result may still be unusable to living things. Biodegradation, on the other hand, usually has a useful product as an end result (which is why Sirius encourages the use of biodegradable chemicals wherever possible). However, given that there are approximately 90 different optical brighteners that have a significant market share, the exact impact of these chemicals remains uncertain.

Fortunately, a little goes a long way. Optical brighteners are generally used at a concentration along the order of 0.01% by weight. They are relatively insoluble powders, a factor that puts them at odds with the European consumer market, which is beginning to favor liquid detergents for cleaning. Using optical brighteners that have already been solubilized in a concentrated masterbatch makes formulating liquid detergents much easier. Britemax BA550 (23%) is not only one of the few optical brighteners that is sold in a liquid formulation, but its solubility is more than double that of the next most-soluble brightener – a factor that enables you to use less volume to achieve the same degree of enhancement.

The Sirius Effect:

Sometimes we have to make the best of a difficult situation. Using less may not be as good as having a biodegradable optical brightener, but until one such product comes along, optimizing is what we need to do in order to minimize our impact. Curious about whether Britemax BA550 can replace your current optical brightener? Get bright and call us today.

© Copyright Sirius International Detergents BV | Sirius International Water Treatment BV
+31(0)355485898 | info@siriusint.com | http://www.siriusint.com



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