Global coatings supplier Hempel, has launched HEMPADUR AvantGuard, a portfolio of three new anti-corrosive zinc primers. Based on  patented AvantGuard technology, HEMPADUR AvantGuard coatings provide better anti-corrosion protection than zinc epoxies without AvantGuard, according to the company.

AvantGuard OGAvantGuard OGZinc coatings are used to protect industrial structures and equipment in C4 and C5 corrosive conditions, where saltwater and high humidity corrode unprotected steel. Based on new, patented AvantGuard® technology, HEMPADUR AvantGuard activated zinc primers are developed for a range of industries and applications, from offshore oil & gas platforms to wind turbines.

AvantGuard is the result of an extensive R&D program run specifically to solve an issue discovered in Hempel’s labs in 2007: only one-third of the zinc in a zinc epoxy primer is utilised for galvanic protection.

Pernille Lind Olsen, Group Protective Product director at Hempel, said: “AvantGuard is perhaps the biggest change in anti-corrosive technology since zinc coatings were first introduced during the 1960s. The technology gives customers strong anti-corrosion performance in a coating that has high mechanical strength.”

AvantGuard uses hollow glass spheres and a proprietary activator to activate more zinc in the coating, ensuring a significantly higher galvanic effect than zinc primers without the AvantGuard technology. The technology also enables barrier and inhibitor protection, and so combines three protective effects in one.

Furthermore, the unique formulation improves the coating’s mechanical strength, which is essential for applications with, for example, extreme temperature and humidity fluctuations.

“In a standard zinc epoxy protective system, the zinc primer is the weakest mechanical point and, as a result, cracks can form in the coating as the steel expands and contracts under extreme conditions,” said Josep Palasi, Hempel R&D director. “AvantGuard zinc coatings are different as the glass spheres and sub-products that result from the unique zinc activation process stop micro-cracks as soon as they form. This, we can say, makes the coating self-healing.”

The increased protection and durability has been proven in extensive Hempel tests, including salt spray tests (ISO 12944 part 6), cyclic corrosion tests (ISO 20340 – NORSOK M-501 revision 6) and thermal cycling resistance tests (NACE cracking test and Hempel’s welding test).

HEMPADUR AvantGuard primers can be applied using the same application techniques as standard zinc epoxies.

“In our tests, HEMPADUR AvantGuard shows a high tolerance to different application conditions, such as high temperatures and humidity, and we even see high crack resistance when the coating is applied with an excessive dry film thickness,” Pernille Lind Olsen said

The HEMPADUR AvantGuar series currently includes three different zinc primers and was released worldwide on 23 September 2014.