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Part 1: Paints & Coatings: Low-VOC Formulations Meet EPA Standards
By Thomas A. Westerkamp
May 2011 -
Paints & Coatings Article Use Policy
Paints and coatings have changed a great deal in recent years, due largely to formulation changes driven by demands for greater sustainability, durability, and ease of use. Despite these changes, maintenance managers specifying paints and coatings must ensure all specified products perform cost-effectively.
By understanding recent trends in the formulation of paints and coatings, as well as challenges presented by the most common surfaces, managers will be better able to develop tactics for successfully matching available paint options to interior and exterior surfaces.
All four components in paints and coatings — pigments, vehicles, solvents, and additives — have undergone important changes in recent years.
The pigment is the hard coating that remains after the volatile organic compounds (VOC) evaporate during drying and curing. Manufacturers are using titanium oxide in pigments more frequently because it is effective and imparts high brightness.
But it is very costly, so manufacturers looking for ways to reduce the amount needed have developed pre-composite polymer technology, which gives paint the same hiding ability while using 20 percent less titanium oxide.
The trend in vehicles, or binders — which bind the pigment to form a film and bind the film to the substrate — is an expanding array of options. Vehicles are either synthetic or natural resins, which have grown to include alkyds, acrylics, epoxies, vinyl-acrylics, vinyl acetate/ethylene, polyurethanes, polyesters, melamine resins, and oils.
The trend in solvents is the reduction of VOCs used in oil-based paints. VOCs, such as aliphatic hydrocarbons, ethyl acetate, glycol ethers, and acetone, are essential for spreading paint film.
To meet U.S. Environmental Protection Agency (EPA) regulations mandating lower levels of VOCs, paint and coating manufacturers have developed lower-VOC oil-based paints. They also have expanded the use of high-solid, powder, and radiation-cured latex products as alternatives. Some disadvantages of these products are low surface performance, longer drying times, and higher costs.
Manufacturers have developed more additive formulations to overcome these disadvantages. So while only accounting for 0.5-5 percent by weight, additives satisfy the need for surfactants, rheology modifiers, driers, foam-control agents, and biocides.
Paints & Coatings: The Match Game
Part 2: Paints: How to Match Formulation with Substrate
Part 3: Paints and Coatings: Understanding Labels and Material Safety Data Sheets
Part 4: Product Focus: Paints and Coatings