When it comes to protecting metal surfaces, primers play a crucial role in ensuring durability and longevity. They provide a variety of benefits, including exceptional corrosion protection, improved edge coverage, enhanced adhesion and increased film build. Together, these advantages help extend the lifespan of assets. The decision to use a liquid or powder primer involves a number of factors like substrate material, the level of corrosion resistance needed for operating use and setting, desired film thickness and environmental considerations.
Among these options, powder primers stand out due to their unique advantages, including formulations made without solvents that emit volatile organic compound (VOC) emissions during the curing process, excellent durability, application ease and a uniform finish. Manufacturers and OEMs in automotive, building and construction, appliance, consumer goods, heavy-duty machinery and metal furniture industries are some of the biggest users of powder primer technologies. But not all powder primers are created equal.
For both pretreated and shot-blasted steel, zinc-rich epoxy powder primers are often the preferred choice due to the mineral’s exceptional corrosion protection properties. Zinc primers not only add an extra layer of protection, the nature of zinc itself elevates its protective performance. Because it is more reactive, it corrodes instead of the underlying steel (acting as a sacrificial anode), sparing the base metal from degradation, a process called galvanic cathodic protection.
While powder primers with high zinc content excel at corrosion resistance, they do have some drawbacks, particularly in transfer efficiency due to the weight and density of the zinc, making coverage more challenging and costly.
In 2024, scientists at PPG developed a breakthrough zinc powder primer that has all the corrosion protection of standard zinc-rich primers, but with higher transfer efficiency. This new primer contains an optimized amount of zinc, less than the 70% found in most standard zinc-rich powder primers but with the volume necessary for exceptional corrosion protection.
With a much lower specific gravity than standard zinc-rich primers (2.0 vs. 3.6), PPG PRIMERON® Optimal zinc-rich powder primer is less dense and easier to apply. With a transfer efficiency of 85%, about half as much product is needed for coverage than with standard zinc-rich primers.
Despite lower zinc volume, Primeron Optimal meets rigorous ISO C5 corrosivity specifications for use in high humidity and aggressive environments. This specification is the industry benchmark for safeguarding steel structures against corrosion through protective paint systems.
What truly distinguishes this new powder primer technology is its excellent adhesion on smooth steel surfaces, a substrate where standard zinc-rich primers often struggle. This strong bond resists peeling, chipping and degradation.
On blasted steel, the primer surpassed 10,000 hours of salt spray performance in laboratory testing. It is engineered for use on steel, hot-dip galvanized steel, metallized steel and aluminum, and is suitable for a wide range of applications, including trailers, gas tanks, pipes, automotive parts and machinery.
In summary, PPG’s new Primeron Optimal zinc-rich powder primer delivers robust corrosion protection, higher transfer efficiency and a better overall balance of properties than standard zinc-rich primers, making it a real breakthrough in primer technology.
Discover how Switch-N-Go, a leading manufacturer of interchangeable truck bodies, reduced oven time by 10 minutes and temperature for curing by 15 degrees, enabling the company to improve cycle times and reduce energy consumption by leveraging Primeron Optimal’s low-bake capabilities. The result was better coverage with fewer defects, less overspray and cleanup.