Do-It-Yourself Paints

Rhoplex advertisement painting over graffiti

Advertisement for Rhoplex, ca. 1960s. Rhoplex AC-388 promised to cover the graffiti on these test fences near Philadelphia in just one coat.

It all began with the post–World War II housing boom. Soaring rates of home production left a lot of homes needing paint, inside and out. Solvent-based paints, which dominated the market at the time, were made with alkyd or linseed oils. These paints were odorous, toxic, flammable, and especially hard to clean up.

Improvement in the production of household paints was necessary. One promising avenue was acrylic chemistry, a field in which the Philadelphia-based chemical company Rohm and Haas had much experience. The company’s leading product was acrylic Plexiglas, a lightweight, shatterproof glass substitute used in airplanes and other military vehicles.

Rohm and Haas chemists suggested using aqueous acrylic-emulsion technology to make house paints. This technology already had produced two leading products for Rohm and Haas—Primal, a waterproof leather coating, and Rhoplex, a textile finish. In 1953 the scientists developed an acrylic called Rhoplex AC-33, a binder that has become critical in paint formulas. It prevents various ingredients in the paint from separating and enables paint to bond to surfaces and withstand the onslaught of wind, sun, cold, and rain.

From the beginning Rhoplex AC-33 impressed customers because it cleaned up easily in water, maintained color, resisted cracking and yellowing, and was not malodorous. In fact, early advertisements suggested painting with acrylics was so easy that women could do it dressed in pearls, cocktail dresses, and high heels.

Nevertheless, a number of challenges remained. Early acrylic paints had low gloss, and they cost more to produce than other latex emulsions and traditional oil paints. Of the 320 million gallons of house paint manufactured in the United States in 1958, only 2% was acrylic latex.

Even a decade after it was introduced, acrylic paint had a limited market and showed little sign of growth. But Rohm and Haas chemists persisted; gradually they resolved many of the technical challenges, developing emulsions that enhanced paint durability, ease of application, gloss, and adhesiveness. From that point on, success flowed, and the range of available interior and exterior paints, with flat, semi-gloss, or gloss finishes, multiplied.

These improvements led to tremendous sales growth. Sherwin-Williams, Pratt and Lambert, PPG, and Behr are among the paint companies that use the acrylic-emulsion technology developed by Rohm and Haas. By 1973 Rohm and Haas topped the interior semi-gloss market, and two years later paint emulsion surpassed Plexiglas as the company’s top-selling domestic product line. By 1978 acrylic emulsions had virtually replaced oil-based exterior paint in the United States. Rohm and Haas’s acrylic-emulsion innovations found niches in other markets as well. The technology successfully expanded into inks, textile finishes, floor polishes, cement modifiers, and roof resins. But the most lasting contribution of Rohm and Haas’s innovation was in paints; acrylic emulsions fostered the do-it-yourself movement, making it easier for a new generation of homeowners to improve the look and condition of their homes.

Judah Ginsberg is manager of the National Historic Chemical Landmarks Program at the American Chemical Society.