MERCER02-14
13
5.1.2.3.
Self-polishing antifouling/hybrids
These hybrid paints combine the copolymer SPC technology (polishing rate control, control of
biocide release, reduced leached layer size) with rosin based CDP technology (surface tolerance
and attractive volume solids). Some types of this paint have added booster biocides to enhance
the antifouling properties. These paints are effective for three years in dynamic conditions and
five years in static conditions (Watermann et al. 2004).
5.1.3.
EpoxyBasedPaints
Copper/epoxy coatings are composed of a hard, non-ablative epoxy resin that contains metallic
copper powder. The copper powder is suspended in an epoxy or polyestermatrix and the surface
is activatedbymechanicalmeans, such as sanding or blasting, that expose the copper particles.
Examples:
A.
Epco-Tek 2000
Epco-Tek is composed of an epoxy primer undercoat and successive layers of epoxymixedwith
copper powder. It has a lifespan of approximately five years inmarine systems. This coating has
been studied on concrete, cast iron and fiberglass substrates. The coating is durable and forms a
smooth, hard, scratch-resistant, and flexible surface.
Application requires a bare surface to be coated with a low-viscosity 100% epoxy primer
undercoat. Five coats of the epoxy-copper coating are then applied. The system is activated by
blasting or sanding the topcoat to expose the copper particles. Substrates that were sanded have
good fouling protection for the first three years, then fair performance for four years. Substrates
that were blasted are well protected for the first three years and had good performance for up to
five years. Improper blasting can degrade the coatings performance.
More information is needed regarding the environmental compliance of the copper leach rates of
this coating. In a three-year static panel experiment, copper leach rateswere between 1.0 and 3.0
µg cm
-2
d
-1
, but rates as high as 8µg cm
-2
d
-1
have beenmeasured (Wells andSytsma 2009).
5.1.4.
FluorinatedPowderCoatings
Fluorinated powder coatings require shop application and need to be baked on at 500°F in an
industrial oven. Therefore, the item to be coatedmust fit in an industrial oven. Items coatedwith
fluorinatedpowderwere easier to clean, but after one year, foulingwas observed (Skaja 2012).
5.2. BiocideFree/Non-ToxicCoatings
Nontoxic coatings were developed to address fouling without leaching a biocide into the water,
potentially harming the environment. Nontoxic coatings don’t contain biocides but they do not
completely prevent organism growth. The coatings allow for only a weak adhesion between the
organism and the substrate. This weak bond causes the foulant to become detached, preventing
massive buildups. As a result, the fouling is more manageable, but periodic cleaning and unit
outages are still required (Mussalli 1989).
5.2.1. Foul-ReleaseCoatings
