What is Paint? Paints are made up of 4 types of components:
Pigments, which give colour and opacity/covering power, are finely dispersed solid particles. In some cases they can be used to impart certain protective properties e.g. rust prevention and to control gloss levels. Varnishes, which form transparent or semi-transparent films, are made up of the last three components, with coloured varnishes containing small amounts of pigment. Paints and varnishes may contain pigments or additives to lower the gloss levels in satin or matt finishes.
The binder is the material that forms the film, giving protection to the substrate and keeping the pigment in place and evenly dispersed. It may be made up of a single component, or a combination of several resins or polymers.
Solvent/liquid carrier - the binder and pigment remain in the dry paint film. The solvent is used to effect the application of the coating. It thins the paint or varnish, allowing it to be brushed or sprayed. Once on the substrate, the solvent will evaporate, leaving the dry film. The term liquid carrier is considered more appropriate as it may not be a true solvent for the binder, but may act as a carrier. This may be water or an organic solvent (or a mixture of both).
Additives are used, in small amounts, to modify the film or paint. Examples are driers ¨C promoting the drying time of some coatings, flow control agents ¨C giving a smooth surface, defoamers ¨C preventing the formation of bubbles that could dry in the film, anti-skinning agents ¨C preventing the paint from skinning in the can.