Canadian Finishing & Coatings Manufacturing - Sept/Oct '23 - 17

INDUSTRIAL FINISHING: CORROSION INHIBITORS
The above research was conducted by Dr Phil Ansell
of SPECIFIC Innovation & Knowledge Centre, Swansea
University. The independent research aimed to understand
the relationship and optimal loadings between Intelli-ion and
zinc phosphate (ZnP) corrosion inhibitor co-blends. Various
volume combinations (PVF - pigment volume fractions)
of Intelli-ion and ZnP were applied to a steel substrate, and
timelapse photography was used to measure the combined
inhibitor effect on the rate of cathodic disbondment (Kdel)
over 24 hours.
In Figure 4, the blue line represents the rate of coating
delamination when Intelli-ion is held at a low PVF (0.025) and
the PVF of zinc phosphate is increased from 0.025 to 0.075.
Coating delamination increased with higher concentrations
of ZnP. Conversely, the orange line shows that when the
PVF Intelli-ion is kept high and constant (0.75 PVF) and
the amount of ZnP varies from low (0.025) to high (0.075)-
disbondment dramatically decreases. This demonstrates the
synergistic effect of the co-blend is optimised when there is a
higher loading of Intelli-ion within the coating system. Figure
5 shows the best performing co-blend combination where
Intelli-ion and ZnP are both at higher levels.
Industry-Standard Salt-Spray Testing
Sustainability is a key market driver within
the coatings industry. In the past, mandatory
regulation was the most important factor, but
now, we are seeing a fundamental shift in the
societal demand with respect to sustainability
and responsible business behaviour. In short,
customers are looking for products that are
environmentally sound.
Industry standard accelerated weathering tests with onthe-market
phosphate-based coatings versus Intelli-ioncontaining
primers also demonstrate comparable or better
performance.
The above mild steel samples were coated with an alkyd
primer (+/- topcoat) and then scribed using an Elcometer 1638
DIN scratching tool fitted with a 1 mm cutter. The samples
were then placed in a salt spray chamber (at a 45-degree
angle) and run-in accordance with ASTM B117 continuous
salt spray fog testing. Following 500 hours, the samples were
rinsed using distilled water and dried using lint free cloth
before being analysed.
The inhibitor loading level was optimised for cost
and environmental benefits-at a 3:2 ratio-to lower the
phosphate content to below 2.5 per cent. This co-blend
approach removes the environmental warning labels from
packaging. However, the imagery clearly demonstrates that
Intelli-ion offers a synergistic relationship in performance
with both zinc phosphate and polyphosphates too.
In 2021, the top 15 paints and coatings companies
accounted for a total market share of approximately 58.52 per
cent, according to AKI Research. In an industry dominated
by so few, it's increasingly important to differentiate your
coatings and offer customers quality at a cost they can afford.
Co-blending Intelli-ion anti-corrosives with phosphatestep-change
based
systems
offers
a
alternative
that
enhances
current coating systems without changes to the
manufacturing process. At an optimised 3:2 ratio, coatings
manufacturers can remove hazard warning labels from
their packaging, reduce their anticorrosion costs, all while
benefiting from comparable or better performance.
Figures 6 and 7 demonstrate industry standard salt spray testing
(ASTM B117) of phosphate-based systems (top) versus Intelli-ion
(bottom).
Ella Newington is the marketing manager for
Hexigone Inhibitors. She can be reached at
ella.newington@hexigone.com.
September/October 2023
17
Canadian Finishing & Coatings Manufacturing - Sept/Oct '23

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