Natural effects pigments

Pigment slurries are one of the major components in paints and coatings that contribute to or affect the performance of a formulation. The nature of pigment slurries makes them extremely susceptible to microbiological contamination that can degrade the final formulation. Often biodeterioration can be prevented with plant sanitation and the use of a preservative, but formulators must not rely on the precept that a particular preservative that works today will always remain effective down the road. In complex environments, contaminants can enter the system at different points, or a formulation change may render the original preservative less effective. Manufacturers must remain aware of trends in the industry to ensure their products are properly protected. 

Figure 71. Optical principles of conventional and luster pigments A) Conventional pigment that absorbs and scatters light B) Metal effect pigment with complete regular reflection C) Natural pearl composed of alternating layers of protein and CaC03 D) Nacreous pigment the pearl is simulated by parallel orientation of the pigment platelets...

Ultramarine pigments are used in decorative paints, staving finishes, transparent lacquers, industrial paints, and powder coatings. The transparent nature of the pigment leads to some impressive flamboyant coatings in combination with effect pigments such as mica [3.166]. 

Special effect pigments, which can be natural or synthetic, show outstanding qualities of luster, brilliance and iridescent color effects based upon optically thin layers [5.122-5.125]. This visual impression develops by reflection and scattering of light on thin multiple layers. In nature this is not limited to pearls and mussel shells alone there are a multitude of birds, fish, precious stones and minerals, even insects, that... 

Fig. 5.15 Optical properties of absorption pigments, effect pigments and natural pearls.

A) conventional pigment B) metal effect pigment C) natural pearl D) pearl luster pigment... 

Effective use of these pigments can be best made if they are adequately dispersed in the syrup. Obviously, it is more difficult to disperse pigment than it is to dissolve dye. The dusty nature of pigments sometimes requires the use of air filtration and dust collection systems to avoid contamination of other areas of the plant. 

Now, back to beets and urine. The naturally occurring pigment in beets, called betacyanin, is a deep red color. It can give you quite a start if it shows up in your urine, but this doesn t happen to everyone. The Technicolor effect is only seen in people who do not have the ability to metabolize betacyanin, and this is a genetic trait. There are no health consequences to this phenomenon. 

A new type of intumescent additive is expandable graphite. This material has already found uses as a special effect pigment due to its metallic sheen and grey-black colour. Nord-Min has been developed by suppliers Nordmann Rassmann with flame retarding of plastics in mind. It is a halogen-free fire barrier additive from Chinese sources, based on natural graphite flakes with... 

Dyes. Dyes similar to pigments are listed according to their class, generic name, and Color Index (Cl) name and number. The dyes are essential without them, many transparent effects in plastics could not be achieved. Dyes are soluble in plastic, and therefore more transparent by nature than pigments. Dyes are known for poor lightfastness in tinted application. This is not as great a concern in masstone or transparent parts as failure occurs on the surface, and the color beneath is unaffected. 

Anthocyanins are naturally occurring pigments responsible for the different colors of many fruits and vegetables. About 500 different anthocyanins have been described in literature. Anthocyanins are bioactive compounds in food that have an impact on the sensorial properties of food products and exhibit therapeutic protective effects on cardiovascular disease [33],... 

Melanin Drying. One development (ca 1993) in hair coloring involves the formation of pigments within the hair that are very similar to natural melanin. Thus either catalytic or air oxidation of 5,6-dihydroxyindole [3131-52-0] can be effectively used to permanently dye hair within a short time (38). The formed color can, if required, be further modulated with dilute H2O2 or can be even totally removed from hair by this oxidant. 

Mg4Al2(OH) 2C02 3H20, is commonly written however, these minerals are generally non stoichiometric by nature and can include some amounts of alternative elements in then compositions. They function similarly to the zeoHtes but exist in layered stmctures and have a different trapping mechanism. In addition to then performance enhancement, the hydrotalcite minerals are compatible with PVC and can be used effectively in clear PVC appHcations as well as the pigmented formulations. 

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