What are coatings?

A coating is a substance applied to the surface of an object. This can serve decorative or protective purposes, or both.

Why are coatings important?

Without coatings, many everyday objects would be impossible to use for long periods. The iron on a bridge, for instance, would rust within months if left uncoated. The wood of a window frame would begin to rot even quicker. If a coating is applied, however, both these objects can last for decades.

Coatings also have significant aesthetic value. Because they are applied to an object’s surface, they are often the first thing about a product that users can see – and touch. Manufacturers can use them to enhance visual and tactile appeal by adding colour, shine, or texture to an object.

How do coatings work?

Different materials have different properties; this means they require different types of coating. The coating should be closely aligned to the properties of the original object. Metal, for example, requires a hard coating, whereas rubber requires a more flexible coating.

What elements does a typical coatings consist of?

A typical coating has four key elements:

  • Binder – this converts a liquid coating to a solid after it is applied.

  • Pigments – these give a coating its colour while offering some protection against weathering and corrosion

  • Additives – these are added to a coating to enhance its performance (e.g., making the coating UV-resistant)

  • Solvents – these are chemicals added to a binder so that it can be effectively applied to a substrate

Coatings can be applied as a solid, liquid, or gas. In a liquid form, the most famous type of coating is paint, which serves both decorative and protective purposes. More technically complex techniques include powder coating, in which incredibly thin layers of coating are applied with a spray gun.

 

What does the future hold for coatings?

In recent years, proponents of responsible chemistry have developed a wide range of high-performance coatings that contain zero VOCs; these coatings typically use water as a base instead. The Stahl EVO® range is a good example: these top coats, adhesives, and foams are fully compliant with regulations governing the discharge of hazardous chemicals.