A report on paints and their chemicals

Essay by steady__eddieA-, October 2004

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Paint is a mixture of organic coatings that are applied to various surfaces which develops a film between the surface and the environment. This film or surface coating may have a pigmented or clear composition that dries to form an opaque solid film.

Paint is made up of a complex mixture of chemicals, mainly polymers that each provide a specific function to allow the paint to work. These are placed in three categories: The binder, pigment and medium. The binder holds the pigment together and provides adhesion for the rest of the chemicals, and also provides integrity and strength to the dry paint film. It consists of high molecular weighted polymers, generally co-polymers that contain two or more monomers. These include methyl methacrylate, styrene and vinyl acetate which are mixed with butyl acrylate. They are submerged in water based paint so the hydrophobic polymer it is made out of is dispersed as microscopic particles in water.

One of these microscopic particles contains many polymer chains and as the water based paint coalesces, it dries and evaporates which draws the particles closer together, so they fuse into a continuous plastic film. The pigment is a finely ground mixture of natural or synthetic particles or powders, that are dispersed in the paint to provide properties such as colour, opacity and the volume of gloss. They are classified as either prime or extender pigments. Prime pigments provide colour and opacity, whereas extender pigments provide the bulk of the paint at a low cost, as they extend it and also control the volume of gloss. The pigments are dispersed in the medium before the binder can be added. The medium, or solvent, is the liquid proportion of the paint which allows it to easily be applied the various surfaces...