Specialty pigment-Fluorescent pigments

摘要

Specialty pigments are those which offer certain effects which are special such as glow, interference, brightness etc.. They are costly and consumed in less quantity. Fluorescent pigment is one type of specialty pigment. An emission of light by a luminescent pigment under excitation is fluorescent. Fluorescent pigments are bright and intense in colour and glow in day light pigment (also called daylight fluorescent).Unlike fluorescence, phosphorescent material does not immediately re-emit the radiation it absorbs.Absorbed radiation is re-emitted at a lower intensity for up to several hours after the original excitation, (e.g., glow-in-the-dark). Fluorescent pigments are classified into three categories viz. Day light fluorescent pigment, UV fluorescent pigments and IR Fluorescent Pigments. Fluorescent pigments are solid dye solutions in polar resin carriers. Fluorescent pigment manufacturing process involves dissolution of dyes in polymer matrix and pulverizing the resultant matrix into fine powder. Polymer matrix can be thermoplastic resin such as P-toluene sulphonamide (PTS amide), melamine and formaldehyde, polyamide, polyester, acrylate and can be thermoset plastics such as Ptoluene sulphonamide (PTS amide), melamine and formaldehyde and benzoqunamine formaldehyde . Fluorescent pigments are bright and attractive coloured pigments but poor light and thermal stability. Fluorescent pigments are used in plastics, paints, inks, textiles, cosmetics, and security papers.