| 1. | What is Fluorescence? | |
| Fluorescence is the phenomenon in which absorption of light of a given wavelength by fluorescent molecule is followed by the emission of light at longer wavelengths. The distribution of wavelength-dependent intensity that causes fluorescence is known as the fluorescence excitation spectrum, and the distribution of wavelength-dependent intensity of emitted energy is known as the fluorescence emission spectrum.
Where a clean, bright conventional colour is able to reflect a maximum of 90% of a colour present in the spectrum; a fluorescent colour can reflect as much as 200% to 300%. |
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| 2. | What is the construction of Fluorescent Pigment? | |
| Fluorescent pigments consist of a fluorescence agent locked in a transparent organic resin matrix which can be added to a variety of mediums, such as plastics, paints, aqueous coatings, etc., The final effect is a coloured surface which is bright and glows compared to other ordinary substrates. | ||
| 3. | What are the advantages of fluorescent pigments? | |
| High visibility from distance | ||
| Extra brilliancy Sensitivity | ||
| Specificity | ||
| Wide concentration range | ||
| Simplicity and speed | ||
| Low cost. | ||
| 4. | What are the limitations of fluorescent pigments? | |
| Poor light fastness | ||
| 5. | Why fluorescent objects fade fast when exposed to direct sun light? | |
| All coloured surfaces fade when exposed to day light; this fading is also caused by the UV wavelengths. The UV light breaks down the chemical bonds within the pigments themselves and eventually makes any coloured surface white or transparent. Different types of pigments can withstand this attack to varying degrees and fluorescent has the lowest tolerance and therefore fade the quickest. | ||
| 6. | What are Night glow / Luminescent Pigments and what makes difference between fluorescent and luminescent pigments? | |
| Luminescent pigments are glow in dark i.e., glow after light source is removed. Whereas fluorescent pigments glow in presence of light source only. | ||
| 7. | What is the basic difference between dye and pigment? | |
| The objective of both the materials is to deliver colour for the medium, when the material dissolves in the medium it is called to be as dye, when the material disperses in the medium it is said to be pigment | ||
| 8. | Why loading of fluorescent pigments more compared to ordinary? | |
| Pigments like CPC/Pigment violet 21 etc., Fluorescent pigments consists of 95% white transparent organoresenous particles, coloured with 5% fluorescening agent where as other ordinary pigments consists of 100% colouring agents there by strength of the pigment is high. To attain the required colour small concentrations are enough. | ||
| 9. | How will you measure the quality of fluorescent pigment? | |
| The quality of fluorescent agent is measured in terms of particle size, size distribution, thermal stability, solvent resistance, compatibility towards the substrate, brilliancy etc. | ||
| 10. | Are these fluorescent pigments can provide consistent shades? | |
| Yes, Provided same quality and conc. of fluorescent pigments, with consistent quality of pigment associated chemicals with identical parameters we can achieve consistent shades. | ||
| 11. | What is the role of particle size in pigment quality? | |
| Slight variation in the particle size affects the physical appearance of the pigment and compatibility towards the application. Fine particle size provides good coverage and good hiding power compared against bigger particles. Generally small particles with low strength give better results than bigger particles with higher strength. | ||
| 12. | Can we mix fluorescent pigments with ordinary pigments? | |
| (Non fluorescent pigment) No, Non-fluorescent pigment can destroy the brilliancy, strength of fluorescent pigments. Ultimately no fluorescence observes at end application. | ||
| 13. | How we can disperse the fluorescent pigments in water? | |
| As the specific gravity of fluorescent pigments less compared to water, they float on water, with thorough mixing of pigment with binder, dispersing agent we can disperse fluorescent pigment in water easily. | ||
| 14. | Are these fluorescent pigments are radioactive and toxic? | |
| No, Fluorescent pigments are free from toxic and hazardous elements. Our fluorescent pigments are in compliance with EN-71, Part 3, 1988 and approved from Duke University for non-hazardous and non-toxicity. They are absolutely no radioactive. | ||
| 15. | How can you measure light fastness / fading of colour? | |
| The measurement of light fastness / fading of any colour measured in Blue Wool Scale the ratings are 1-8. BWS Reading 1 Stands for Very poor —–8 Stands for outstanding / Excellent.
Fastness Rating Equivalent General |
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| C I Acid Blue 104 Very Poor | ||
| C I Acid Blue 109 Poor | ||
| C I Acid Blue 83 Fair | ||
| C I Acid Blue 121 Average | ||
| C I Acid Blue 47 Good | ||
| C I Acid Blue 23 Very good | ||
| C I Sol.Vat Blue 5 Excellent | ||
| C I Sol.Vat Blue 8 Outstanding | ||
| 16. | How we reduce the foam in operation? | |
| Generation of foam is the universal problem, The foam is generated due to air entangled along with the solid materials while addition. By addition of deformers and slow addition of solids into liquid can minimize the generation of foam. Pre-wetting of pigments with low viscous liquids can also prevent foam. | ||