In-depth | COATINGS
Company
Product name
Special Features
Hempel A/S International Paint Chugoku Marine Paints
Hempasil NEXUS Intersleek 737 Bioclean tie coat
Three pack mechanically durable epoxy-siloxane tie-coat , specified down to 10 o
C Three pack, silicone elastomer tie-coat specified down to 0 o C One pack silicone elastomer tie-coat specified down to 5 o C
result, NEXUS X-Tend provides both faster throughput in dry-dock (fewer steps; Figure 10) and safeguards excellent final adhesion compared to current tie-coats. The touch-up and repair of Fouling
PPG-Sigma Coatings Sherwin-Williams
SigmaGlide 790 SeaGuard tie coat
Two pack silicone elastomer specified down to 10 o C Two pack “durable” silicone-based tie-coat specified down to 5 o C
Release vessels can now be accomplished in a few stages and with an excellent final result. As an example, the full repair of a 3500 TEU container vessel has recently been completed in less than 5 days between indocking and flooding partly thanks to NEXUS X-Tend. A final example of the exceptional
Jotun A/S SeaLion tie coat Three pack silicone elastomer tiecoat specified down to 5 o C Table 3: Tie-coat systems used in combination with the top-coats listed in Table 7. Company Hempel A/S Product name
NEXUS X-Seal Hempasil topcoat
International Paint Chugoku Marine Paints
PPG-Siga Coatings Sherwin-Williams Jotun A/S
Intersleek 717 Intersleek 7180 Intersleek 737 Intersleek topcoat Bioclean sealer Bioclean tie-coat Bioclean HB Unknown Unknown Unknown
Description
Epoxy-siloxane modified sealer Topcoat
Epoxy link coat
Novel epoxy-modified link coat Tie-coat Top coat
Pure epoxy paint Tie-coat Top coat
surface tolerance of X-Tend is detailed next. Unexpectedly, the boottop area subject to frequent wet-dry cycles has been found to be especially challenging to overcoat. A combination of phenomena, such as e.g. atmospheric contamination and pollution at the seawater surface, causes weak adhesion of the new topcoat, as shown in Figure 11. Applying NEXUS X-Tend is strongly recommended in those intact silicone areas which have a higher risk of being exposed to any sort of surface contamination jeopardizing a safe overcoating.
Table 4: Commercial specifications to convert vessels already coated with antifouling into a Fouling Release system without the need for full blasting.
So what is next? Te evolution of the Fouling Control market in the coming years will be determined, to a large extent, by factors external to the marine business. While it is indeed possible to foresee some general trends, the uncertainty lies on how fast events will develop and to which extent they will impact the market (regional vs. global trends, voluntary vs. mandatory measures, etc.). Some obvious examples are:
• Upcoming and future legislation such as registration schemes for chemical
• Increasing environmental consciousness (e.g. carbon footprint, ocean pollution,
• Economical factors (crude oil price, shiſt to distillate fuels, price and availability of
invasive species) key raw materials (e.g. metals), etc).
Figure 7: Internal stress build-up upon curing (ASTM D6991-05) showing that NEXUS X-Seal has lower residual stress and, consequently, lower risk of failure, than a commercial epoxy link-coat used to seal aged antifoulings.
24 The Naval Architect January 2011
(e.g. REACH) and biocidal (e.g. BPD) products, Volatile Organic Compounds regulations, etc. (see Pereira and Ankjægård, 2009)
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