Architectural Record BE - Building Enclosure

Scuff-Resistant Paint

New technology addresses durability in commercial high-traffic environments
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Sponsored by Benjamin Moore
By Layne Evans

Scuff Resistance vs. Scrub Resistance

As noted above, constant wear and tear in high-traffic environments leaves daily marks. This creates an inherent dilemma. The surfaces must frequently be cleaned and scrubbed, often with conventional cleaners, to remove severe stains and scuffs.

But the cleaning itself causes damage. Cleaning and scrubbing are mechanical processes that remove not only the marks but, in most latex paints, also molecules of paint, eventually wearing away the paint film. Many conventional latex paints in high-traffic areas may be subject to “burnishing,” a disfiguring increase in sheen creating an uneven appearance (see image below) in paint that has repeatedly been rubbed, particularly by frequent washing and spot cleaning. Burnishing occurs most often in flatter finishes and deep colors, but some paints may burnish in both light and dark colors. Sooner or later, burnishing will require retouching and then repainting. Depending on the characteristics of the space and the paint, “sooner” can be within months.

burnishing paint

Paint that is repeatedly rubbed, particularly during cleaning and scrubbing, develops a disfiguring, uneven appearance called “burnishing.”

As a result, one of the primary characteristics of paint selected for high-traffic environments has been its scrub resistance, reflecting the reality of the need for frequent cleaning. The assumption is that the marks will have to be scrubbed off the surface. Removing the marks involves some level of mechanical erosion of the paint film.

Scrub resistance is a paint’s ability to withstand the scrubbing necessary to remove stains or marks with no changes to the coating’s appearance or its protective functions. Scrub resistance is measured in scrub cycles and scrub ratings, determined by a test method in ASTM D2486. Dried paint samples are repeatedly scrubbed with an abrasive brush until the surface of the paint deteriorates. A high scrub rating indicates that the paint will hold up to frequent abrasive cleaning longer than a paint with a lower rating before it is physically damaged.

This is an attribute of paints in high-traffic environments. However, coatings such as two-component and pre-catalyzed epoxies with a high scrub cycle do not reliably resist scuffs and marks.

In contrast, the technology in new scuff-resistant waterborne latex paint takes an entirely different approach. It creates a surface that resists the scuffs and marks themselves. Contact from people and objects that would leave marks on conventional commercial and industrial paints does not adhere to the new scuff-resistant paint. If scuffs appear at all, they wipe away easily with soap and water—without scrubbing. Less cleaning, retouching, and repainting is required, which lowers the total maintenance cost.

scuff resistant paint vs. scrub resistance paint

The left side of the sample board was painted with scuff-resistant paint and the right side with scrub-resistant paint. Both sides suffered repeated scuffing, but the left side of the sample board with scuff-resistant paint does not show it.

In addition to the reduction in the cost of maintenance, the scuff-resistant paint solves another challenge in high-traffic environments. By definition, these places are constantly used by many people, so closing them for extended periods is difficult for the businesses and activities that are operating there, and in some cases, such as hospitals, nearly impossible. Scuff-resistant paint dries to the touch in an hour and can be recoated in 2–3 hours and rapidly returned to service. Downtime and disruption are minimized.

Engineering a Breakthrough

Paint is one of the oldest and most basic manmade substances in the world, and the four basic components of paint have not changed:

Pigments: Fine particles in various chemical shapes that provide color and determine many other attributes, including sheen (gloss), protection of the substrate, and hide.

Resins or binders: Also called vehicles or polymers. Resins bind the pigment particles together in a film and promote adhesion to the substrate. The composition of the resin will determine how well the paint resists peeling, blistering, and cracking, and is key to application properties such as flow and leveling. Coatings are often categorized based on their resin system; examples are latex, alkyds, epoxies, and various urethanes. (Although “latex” originally referred to a milky substance found in rubber trees, today’s latex paints are composed of synthetic resins dispersed in water and do not contain rubber tree latex compounds.)

Solvents (thinners): The solvent enables the thin coating to spread on the surface. The solvent evaporates as the coating dries. Solvents have two principal functions: to transfer the paint from the applicator to the substrate and to control the viscosity to make the paint workable. Solvents are selected in the formula based on the type of resin and the desired dry time and performance.

Additives: Chemical ingredients that add or enhance specific properties. The choice and quality of additives affect almost every aspect of application, performance, and durability. For example, the exact characteristics and concentration of additives will determine water repellency, package stability, viscosity, adhesion, flow and leveling, mildew and microbe resistance, and stain resistance.

While sharing the same fundamental components, the paints available today still differ widely in quality and performance. Paint chemistry has advanced significantly, especially in recent years. For example, the scuff-resistant paint discussed in this course uses a unique formula developed specifically to meet the demands of high-traffic environments. The quality of individual ingredients and manufacturing also varies. Most paint manufacturers purchase resins from large chemical companies, but a small number produce their own resins and colorants, which not only improves quality control but also fosters innovation.

Comparing Coatings for High-Traffic Commercial Environments

Architectural coatings have evolved rapidly in recent years. Only a few years ago, extended durability in demanding applications was only available in formulas that were complicated to mix and apply and contained high levels of VOCs. Intense research and pressure for more environmentally responsible, more versatile paints led to improved formulas.

Paints can be compared in a number of ways—by their resin, curing mechanism, function, thinner type, use, or finish. Coatings for high-traffic and other demanding applications have been developed to solve a range of problems. The primary division is between solvent-based and waterborne applications, although many hybrid types also exist.

This course focuses on waterborne formulas specifically developed for high-traffic environments. Latex coating systems have inherent advantages, including good gloss retention and superior resistance to fading, yellowing, and rub-off. They can also be engineered for superior stain blocking, durability, and flexibility.

The major options available for applications where durability is a key factor include: commercially available conventional latex coatings in higher sheens, two-component systems, pre-catalyzed one-component epoxies, and the new scuff-resistant paint. Each of these has specific characteristics that can meet a project’s specific needs. Often, these needs can vary even among different areas within the same project.

 

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Originally published in Architectural Record

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