As a major marine paint manufacturer, Sigma Coatings is responsive to changes in the marine industry including changes in ship production, ship use, rules in cargo carriage and legislation affecting both shipping and the products used by the industry.

In response to the move by the International Maritime Organisation (IMO) to stop the use of tributylin (TBT) in antifouling coatings, Sigma Coatings, part of the SigmaKalon Group of companies, a leading coatings manufacturer with annual global production of over 600,000 tonnes of paint and employing 10,000 people worldwide, has been in the forefront of TBT-free antifouling technology, pioneering tailor-made binders that underpin product performance.
A recent example of this is the “Alpha” polymer – researched, developed and patented by Sigma Coatings and Successfully used in the Sigma AlphaGen and Sigma AlphaTrim products.
An important product it has launched is the Sigma EcoFleet range, whose antifoulings products can be used for high-, medium- and low-activity vessels. The range has evolved from technologies providing better control over biocide release.

Inside story on antifouling technologies
Effective antifoulings works by controlled release of biocides into the seawater. This release mechanism is the key to consistent performance – too slow and fouling settles, too fast and the service lifetime is threatened. Development of world-class binders is only part of the story; they still need to be combined with the biocides that repel or kill the settling stages of fouling organisms before they settle.
The choice of biocides is critical – they should prevent settling of the widest range of fouling organisms, they should have low/no impact on non-target organisms, they should not persist in the environment after release and they should also be acceptable to the biocide regulating authorities around the world. Testing of new binders and biocides combinations is therefore critical for new antifouling development.
This testing requires access to specialist and sophisticated equipment. Coatings are assessed for fouling prevention on specially designed rafts; they are evaluated on rotors for consistency in polishing behaviour at controlled speed; they are tested on bilge keel panels and test patches on ships for real-life simulation. Regular cross-sectional analysis of flakes removed at different time intervals allows the development of the leached zone to be evaluated. In addition biocide release rates are measured and environmental risk assessments carried out in order to confirm to regulating authorities that the products can be used with minimum impact on the environment.
 
Sigma EcoFleet: the new polishing tin-free antifoulings for total IMO AFS compliance
The Sigma EcoFleet range is based around technologies to give products better control over biocide release.
“Sigma Coatings chemists have identified raw materials and biocides that work well together to give coordinated polishing and biocide release and in so doing control fouling,” a spokesman of Sigma Coatings Middle East said. “The polishing mechanism derives from a combination of chemical and physical reactions of the coating after immersion with seawater. These effects occur in synchrony to release biocides from the film and in so doing the film thickness is sequentially reduced – the process referred to as polishing,” he said.
 “Sigma EcoFleet antifouling coatings also have extra co-biocides to improve fouling resistance, particularly against algae. Sigma EcoFleet film properties are good and 2-3 coats can be specified at dry film thickness up to 150 microns.”
The leached layer is more controlled, and typical projected service lifetimes are up to 36 months for deep sea vessels, with up to 60 months possible for certain situations/operating conditions. Fouling control is further enhanced by tailoring the products to vessel type, adjusting both polishing and biocide composition to the intended operational performance.
“The Sigma EcoFleet antifoulings portfolio has products designed for high, medium and low activity vessels, giving you a flexible, dependable, service-predictable solution for both newbuilding and maintenance and repair ships,” the spokesman observed. The range offers products suited to deep sea as well as coastal-operating vessels and for every market from fishing vessels to tankers, bulk carries and container ships. Sigma EcoFleet products have seen widespread successful use with operators looking for antifouling protection on ships at newbuilding, converting from TBT-containing systems and also normal dry-docking maintenance work, he added.
“Cost-effectiveness is assured with EcoFleet, since you can confidently specify for the period of fouling control that your sailing and dry-docking schedules dictate – not too much protection – not too little. Created to enable owners and operators to select the specific level of antifouling protection they need for the duration that suits their schedules, the Sigma EcoFleet range represents the perfect response to the demands of changing legislation affecting the use of antifoulings the world over.”