The classic treatment of metal surfaces uses two different lines: one for pretreatment and one for
passivation. With the conventional process, the parts go either directly to the user or on to the
painting line. The rust preventive (RP) oil used before painting must be removed in the subsequent
cleaning and rinsing stage. If a passivation coat is applied, a single rinse prior to the subsequent
application of paint is sufficient.
Henkel’s new development enables users to substantially shorten their process. Bonderite M CR
1405 has unique properties as it can be used as a passivation for bare substrates and pretreatment
for painted substrate, notes a press release from the company. After passivation, the coils are either
sent directly to the end user or on for painting. Bonderite M CR 1405 has good recoatability and coils
passivated with this product can be used on the color coating line without a cleaning step and can
only be rinsed with hot water to remove any contamination. This results in major savings with
respect to energy and water usage, since the cleaner that has now been eliminated is typically used
in large tanks at temperatures between 60 and 70ºC. The absence of chemical cleaning agents also
means that wastewater pollution is significantly lower.
This combination is made possible by a newly developed product: As a chromium III-based
passivation pretreatment, Bonderite M CR 1405 combines both processes. “Normally, when paint is
applied to a passivated coil without subsequent treatments, insufficient paint adhesion and
corrosion resistance is achieved. Conversely, pretreatment used as passivation usually fails within
one day,” says Gerko Odink, Senior Manager PD Metals EU at Henkel Adhesive Technologies. “We
have an agent here that combines the best of both worlds and is compatible with both chromium-
based and chromium-free primers.”
As this is a chromium III-based product, it meets users’ performance expectations for high corrosion
protection while also being RoHS-compliant. Testing on galvanized and Galvalume substrate shows
blank corrosion resistance of more than 96 hours. The salt spray test shows resistance of 800 hours
with a chromium primer and 500 hours with a chromium-free primer.