Paints

colored materials consisting of film-forming substances (binders) and finely disperse inorganic or organic pigments. In addition to these basic components, paints may contain solvents, fillers, driers, and plasticizers. The binders may be vegetable oils or drying oils, varnishes (that is, solutions of natural or synthetic oligomers or polymers in organic solvents), aqueous dispersions of polymers, aqueous solutions of plant or animal glues, or water glass.

The binding materials contained in paints impart the necessary mechanical properties (durability and hardness) to the coating formed after application of the paint to a surface, provide adhesion of the coating to the substrate, and, in addition, firmly bind the particles of pigment and filler. Pigments (particle diameter, 0.5-2.0 microns) impart to the coating color and opacity, or covering power (the ability to cover a surface painted another color), as well as anticorrosion and some other special proper-ties.

In industry, paints are made mainly in the form of concentrated or dilute suspensions. The former are made by mixing pigments with a binder, with subsequent fine dispersion of the pigment particles in the mixture thus formed. To produce sus-pensions diluted to working viscosity (ready-to-use paints), concentrated paints are diluted with the corresponding solvents or drying oil. Paint suspensions are applied to metal, wood, con-crete, and plaster surfaces with a roller, brush, or sprayer or by immersion. Paints are also made in the form of pressed slabs (for example, watercolor paints), or powdered mixtures of pigments with film-forming substances and other materials. Such powdered paints are applied to surfaces by spraying, with simultaneous or subsequent melting.

A distinction is made between construction and artist’s paints and printer’s ink, depending on their purpose. Art paints, as distinct from other kinds, may be not only opaque but also transparent (scumbling paints); this is achieved by the addition of translucent pigments (for example, ultramarine). Other paints with specific purposes include luminescent paints; heat-sensitive paints, which make possible monitoring of the temperature on the painted surface; and growth-deterring paints, which inhibit the growth of barnacles on the underwater parts of ships.

Paint is used in the national economy and in everyday life for two main reasons: to impart to objects an attractive external appearance and to protect surfaces from the destructive effects of moisture, solar radiation, chemical reagents, high temperatures, and mold.