The Universal Selection Source: Coatings Ingredients

Pigments for Paints, Coatings and Inks

Pigments are important constituents in paints, coatings and inks. They are added to paints and coatings formulations to impart color, bulk or a desired physical and chemical property to the wet or dry film.

This selection guide will help you understand more about use of pigments, differences between pigments and dyes, types & different families of pigments, their properties & performances, pigment dispersions, applications in the paints & coatings industry and much more.

Pigment Selection


Pigment Selection

These significant characteristics have been explained below, in detail, for better selection

Crystal Structure

Pigments can be crystalline or non-crystalline (amorphous). In crystalline pigments the atoms within each molecule are arranged in a well structured pattern, however, in amorphorous pigments the atoms are randomly arranged. It is also possible for materials to have several different crystalline forms - known as polymorphism.

Color is dependent on these different structures. There exists pigments which have chemically identical entities in different crystal forms, yet these polymorphic pigments are not suitable for use as a pigment. Titanium dioxide, phthalocyanine blue, and linear trans quinacridone are examples of such polymorphic pigments.

Techniques for influencing the formation of a desired crystal form and particle distribution, for the purpose of optimizing the commercial product for end applications, are currently being developed by pigment manufacturers.

Particle Shape

The chemical structure, the crystalline structure or the synthesis of a pigment determine the shape of particles. The primary particles of a pigment may be nodular, spherical, prismatic, acicular or lamellar. Primary particles are composed of single particles. The smaller these particles, the greater their surface energy and therefore the more likely it is that they will clump together during manufacturing. It is not practical to supply pigments in the form of primary particles as they would be more like smoke than a powder. In practice, they only exist as the pigment is synthesized. When the particles clump together during the manufacturing process they form either aggregates or agglomerates.

  

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