They are not usually found in nature. That is the reason that a majority of these pigments are chemically synthesized. They contain carbon and comes with relatively low levels of toxicity, not providing any major environmental concern. Raw materials can include coal tar and petroleum distillates that are transformed into insoluble precipitates. Traditionally organic pigments are used as mass colorants. They are popular in plastics, synthetic fibres and as surface coatings-paints and inks. In recent years, the organic pigments are used for hi-tech applications that includes photo-reprographics, opto-electronic displays and optical data storage.
Categories of Organic Pigments
Organic pigments are generally categorized into six types :
Acid and base dye Pigments
Other polycyclic Pigments
Key features and characteristics of Organic Pigments
Consistency and unique shades
Good tinctorial strength
Organic pigments shows good color strength
Very bright, pure, rich colors
Very good stability to solvents, light, heat, and weathering
Metallic Pigments are a very popular category of Pigments, it can be of two types: aluminum and zinc.
Aluminium Pigments: These pigments are further divided into two categories namely leafing grade and non-leafing grade. The aluminum pigments are produced from aluminium that has purity in the range of 99.3-99.97%. The particle has lamellar shape with 0.1-2 um in thickness and diameter of 0.5-200 um. These pigments founds use in automotive topcoats.
Some of the preferred applications of Aluminium Pigments are the following:
As Corrosion protection coats
As Reflective paints
In Marine paints (covering coats)
In Heat-proof and highly heat-resistance paints
Chrome effect paints
Zinc Pigments: They come in two forms of powder and dust. Usually the zinc dust is finer as compared to powder and is spherical in shape. The dust also has a light coating of zinc oxide.
Though every pigments has industrial application, but for understanding a few popular pigments have been given below that have very wide use.
Organic vs Inorganic Pigments
Mixed Metal Oxide Pigment
Synthetic Iron Oxide Pigments
Natural Iron Oxide Pigments
Performance Criteria for commercial organic pigments
The commercial performance of organic pigments are guided by the following capabilities:
Resistance to heat