POWDER POINTS
Powder coatings with purpose: functional technologies for hygiene, safety, and surface protection Eric Casebolt Vice President, The ChemQuest Group, Inc.
ecasebolt@chemquest.com
I
n the world of powder coatings, the term “functional coatings” has
The most common method of creating the antimicrobial properties in
historically been used to describe fusion-bonded epoxies used in
powder coatings is through the incorporation of silver-ion additives. These
pipeline and rebar applications. However, today’s powder coatings
additives release Ag+ ions when exposed to moisture or humidity, acting as
offer specialised functionalities that would fit in with the broader definition
the active antimicrobial agents by disrupting the microbes’ cell membranes
of that term. That is, they are specifically designed to provide a function
and enzymatic systems. While other materials (e.g., copper, zinc, or
beyond aesthetics and substrate protection. Among these functionalities,
quaternary ammonium compounds) may be used in antimicrobial coatings,
three stand out for their relevance in today’s environment: antimicrobial,
silver is more common due to its broad-spectrum efficacy, long-lasting
electrostatic dissipative (ESD), and anti-graffiti powder coatings.
activity, and proven effectiveness against a wide range of microorganisms. Additionally, silver is compatible with various types of coatings and has a
Antimicrobial powder coatings
long history of safe use in medical and industrial applications.
Antimicrobial powder coatings are designed to inhibit the growth of
Antimicrobial coatings are important not only for reducing the spread of
microbes such as fungi, mould, and bacteria on coated surfaces. While
pathogens but also for preventing discoloration, unpleasant odours, and
these coatings have been traditionally used in environments where
material degradation, all of which can be caused by microbial growth.
hygiene is critical, such as hospitals and food processing plants, the
Their passive, long-term functionality makes these coatings ideal for high-
COVID-19 pandemic has expanded their usage into many high-traffic
touch surfaces, and integration with the coating means the antimicrobial
areas such as fitness centres, public transit centres, and even playground
function does not require the frequent reapplication required for surface
equipment.
disinfectants, making it a reliable, low-maintenance solution.
ESD powder coatings Electrostatic dissipative powder coatings are designed to safely dissipate static electricity from coated surfaces. These coatings are often used on components or in areas where an electrostatic discharge could damage sensitive electronic components, ignite flammable materials, or disrupt operations. Common applications include electronic enclosures, electronic assembly areas, server casings, or robotic components. ESD functionality is achieved by incorporating conductive or semiconductive pigments into the powder coating formulation. The most common materials used in powder coatings are conductive carbon black and carbon nanotubes. Since they are most often interior coatings, the binder is typically an epoxy or hybrid powder coating, although other types of resins can be used if an exterior-durable coating is required. In any case, the binder provides the main coating properties (e.g., adhesion), and the conductive filler provides the pathway for the electrical current. The surface resistivity requirement for ESD coatings typically falls with the range of 105 and 109 ohms per square, although the specific range may © Adobe Stock
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vary by application.