The essential component of daylight fluorescent pigments is its unique dyes; chemical compounds that have the capacity to absorb shorter and even invisible UV wavelengths of sunlight and re-emit this energy as intense visible radiation. Coatings and objects compounded with daylight fluorescent pigments appear intensely luminous, emitting as much as four times more light than that reflected from conventional pigments and invariably attracting more attention. The intense visibility of fluorescent pigments has made them ideal in safety applications such as traffic cones, barriers, safety vests and signage in roadwork, construction and marine applications.
In addition to the intense visual appearance of daylight fluorescent compounded objects and coatings, there's an aesthetic, almost magical impression experienced as a result of its luminosity that makes it a favorite coloring component in sporting gear and clothing, children's toys, product packaging and even for adding a special extra "zing" to conventional paint colors. The huge list of applications is too numerous to mention but because they are so diverse, daylight fluorescent pigments must be tailored to be compatible with and maximize performance in a wealth of diverse applications and in a rainbow of brilliant colors.
From Fluorescent Dye to Brilliant Daylight Fluorescent Pigment
The green square on the top shows a sample of Rhodamine B, a fluorescent dye in a solid powder form capable of yielding an intense pink to magenta daylight fluorescent color when properly compounded. The square below it is, in fact, a sample of finely ground Brilliant daylight fluorescent pigment incorporating a significant amount of Rhodamine and other fluorescent dyes.
A Little Explanatory Chemistry is in Order
As is obvious from the previous section, something has to be done to go from a dull green dye powder to the intensely fluorescent pigment--in fact, quite a lot. The dye molecules responsible for generating fluorescence can exist in several molecular forms. The polymer matrix in which the dye is captured to create the daylight fluorescent pigment must not only hold it in that form but also assist in both maximizing the fluorescent process and protecting the dye from degradative agents which can quench fluorescence by altering the dye's molecular structure.
The challenge doesn't end there because each pigment class not only requires optimized color and fluorescent intensity but compatible pigment chemistry as well. Pigments designed for paints, inks or plastic colorants require entirely different polymer chemistries, production methods and properties suited to the application.
Grey = carbon
Red = Oxygen
Blue = Nitrogen
White = Hydrogen
Quality Control is Key
Producing a range of products in a set of standard colors that does not vary from batch to batch is a demanding task in any pigment production process. It is doubly demanding with daylight fluorescent pigments. The very processes responsible for the complexity of visual properties mean that quality control is at the heart of Brilliant's post-production color standardization. Purchasers of daylight fluorescent products must be assured that the color of the last batch of pigment, ink or plastic colorant will match exactly with the color of future batches.
Daylight fluorescent pigment color control is extremely sensitive because of the multiplicity of visual effects involved. At Brilliant, we usually recommend that customers not attempt to blend daylight fluorescent pigments to achieve a specific shade without first consulting us. Our technical expertise in color matching can often help customers arrive at a desired solution without a great deal of time-wasting trial and error in color mixing.
Post-Production Protection
Caption: Xenon arc simulated 8-hr daylight exposure of two Brilliant pigment samples in different polymer resin systems. Note that sample colors differ before (left) and after exposure (right). Daylight fluorescent colors and the color shift they undergo on exposure can vary depending on the pigment matrix, dyes used and exposure conditions. Brilliant's technical experts can provide guidance in choosing a pigment type and color with properties best suited to your application.
Users of daylight fluorescent products may need to take extra care to preserve the intensity and brilliance of their fluorescent color application. Despite the extensive effort Brilliant makes in designing pigments that maximize the daylight fluorescent intensity and cleanliness of color, daylight fluorescent pigments are more fugitive and will fade more rapidly than conventional color. Just as the intense luminescence is a function of the interaction with light, the energized state from which fluorescence occurs is more susceptible to attack by oxygen and other active chemical species in the environment.
For that reason, daylight fluorescent pigments are often compounded or over-coated with small amounts of UV absorbers or other agents to protect the dye molecule from the most energetic part of the solar spectrum and/or to scavenge oxygen or other reactive molecules in the environment that can degrade the fluorescent-capable molecular structure. Here again, Brilliant's technical experts can help by recommending the types of additives best suited to extend the life of the color intensity, purity and luminescence in your application.