Colour in plastics

Pigments. I gments are used to produce colours in plastics. 

European Commission On the Use of Colourants in Plastic Materials Coming in Contact with Food, Resolution AP (89) 1., Sept. 13, 1989. 

F. Pellerin, J. L. Kiger, and J. Caporal-Gauter, Synthetic organic colours in plastic packaging materials for pharmaceutical use, II Identification in plastics and detection of their release into drugs, Ann. Pharm. Fr., 32 421 (1974). 

Vicki Barwick obtained a first degree in Chemistry from the University of Nottingham. She then joined the Laboratory of the Government Chemist (which became LGC in 1996) as an analyst in the Consumer Safety Group. Vicki was involved with a number of projects to assess the safety of consumer products, including developing test methods for the identification of colourants in cosmetics and the quantitation of phthalate plasticizers in child-care items. 

The three main application areas for coloured pigments are in printing inks, paints and coatings and in plastics, comprising some 88% of the total. The only other areas of any significant importance are textile printing, pigmented fibres and paper (see Table 2.12). 

This is not surprising since plastics are light, cheap, relatively unreactive, can be easily moulded and can be dyed bright colours. However, plastics have contributed significantly to the household waste problem, up to 10% in some countries, and it s getting worse (Figure 14.22) ... 

Disperse dyes were originally developed for incorporation into certain cellulose acetate fibers. Applications of disperse dyes include the coloring of nylons, polyesters, and acrylics. Since many of these dyes were also designed to be mixed— dispersed —with a dispersant, care must be exercised in avoiding dispersed versions of these dyes, since the dispersants used are not meant to be incorporated in plastics and seriously diminish the brightness and transparency of the dye. Disperse dyes in their pure form are often also classified as solvent dyes, carrying both Colour Index names. Many disperse dyes developed for polyesters are finding use in other polymers. 

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