What's Really in a Can of Paint?

Benjamin Moore & Co. Provides the Answer

Paint is a creation of man used from the beginning of recorded history -- from the the caves of Lascaux in France to the ceiling of the Sistine Chapel, on the figureheads of the Spanish ships which founded the New World, to the decorative symbols on teepees of Native Americans. It is used for decoration, for communication, as a preservative and as a maintenance tool. Today, paint has evolved into the protector, preserver and beautifier of home, workplace, public spaces and even houses of worship.

A thin film of paint -- a few thousanths of an inch thick -- protects, seals, hides, and decorates. Simply put, paint offers long term protection at a very moderate price. It keeps existing structures from deteriorating and, in so doing, preserves natural resources such as trees, water, and a variety of energy sources. To further appreciate the merits of paint, it is important to understand what actually goes into the can.

Paint is a simple mixture of ingredients including pigments, a binder and a diluent, or thinner (in latex paint it is water; in solvent paints, it is a petroleum solvent).

Today's pigments, not unlike the mud, blood and chalk used centuries ago, provide the texture, color and hiding properties of paint. The pigments, usually in the form of dry powder, can be organic (containing carbon), inorganic (no carbon), synthetic or naturally-occurring. Today, with the utmost concern for consumer safety, architectural coatings are formulated to be as safe as possible by carefully selecting pigments.

Titanium dioxide is the primary pigment ingredient that provides hiding in light color paints. While any powder, even baby powder, can pose a health hazard if inhaled in high concentrations, titanium dioxide which is also used in cosmetics, soaps and certain food products, when used in a paint film is not respirable and poses no risk to the user. Other inert pigments include calcium carbonate (limestone), talc, clay, sand (silica). All of these are naturally occurring materials that are tightly bound in the paint film and contribute various properties like gloss control, flow, and film build. Iron oxides are inorganic color pigments, chemically akin to rust on metal, that are used to produce reds and yellows.



The binder portion of architectural coatings consist of synthetic and natural resins which start out as liquids but dry to form tough durable films. The properties of the binder largely determine the properties of the paint film. In waterborne coatings the binder is usually a latex emulsion composed of vinyl and/or acrylic copolymers. In solventborne coatings the binder is usually an alkyd, which is a natural drying oil modified chemically to be especially tough and long-lasting.

As most people know, today's latex emulsion paints are thinned with water and represent the ultimate in safety and ease of use. Solvent-based or oil paints are thinned with petroleum solvent which make them less convenient and require more care to be used safely. Over the years, use of solventborne paint has diminished because of concern over volatile organic compounds (VOCs). However, solventborne paints still play an important role today because of their unique durability and adhesion properties.

Before using any coating carefully read and follow label instructions.

Other ingredients in paint, called additives, impart a variety of properties including flow, stability, drying, defoaming, mildew resistance and viscosity.

Coalescents (a.k.a. film forming aids) are solvents used in waterborne coatings which help fuse, or coalesce, latex particles in latex emulsion paints during the drying process. They make possible better paint films by permitting the use of harder resins in the coatings formulation. These harder resins result in interior paints that are scrub resistant and durable.

Anti-skinning agents, used only in solventborne coatings, prevent undesirable surface drying, or skinning, in the container during storage and shipment.

Pigment suspending aids, dispersants, and surfactants are present in most paints in very small quantities. They impart stability and promote shelf-life.

Viscosity and flow enhancers provide superior application properties, as their description implies. They are needed to achieve the best possible hiding and film appearance.

While solventborne coatings use is on the decline, especially in the consumer sector, these paints still provide important, unique properties not always available in waterborne coatings.