TBT containing antifoulings have been under environmental scrutiny for some years and from January 2003 the International Marine Organization (IMO) has banned new applications. From January 2008 the ban will be extended to prohibit the leaching of TBT antifoulings into the environment.
This has meant that marine coatings manufacturers have been forced to develop new technologies to replace their premier antifouling ranges, because they have almost all relied on TBT for fouling control. However, Ameron International (now PPG Protective and Marine Coatings) has marketed high performance TBT-free antifouling for many years. Today, PPG Protective and Marine Coatings is the only supplier able to offer economical and proven TBT-free technology that meets both Owners' operational requirements and recent and pending legislation.
This technology is used in Ameron's ABC antifouling range. The premier product, ABC®3, utilizes a tin-free biocide package to control shell, slime, weed and other marine growth for in-service periods up to 60 months. The biocide is released in a controlled manner by the polishing action of the antifouling as the vessel moves through water. This polishing effect also reduces hull roughness and drag on underwater surfaces, consistently reducing fuel consumption over the service life of the coating system. The performance of ABC®3 is well documented in hundreds of project references and case histories (www.ABC-3.com). For over 20 years it has consistently provided Owners with long-term fouling free performance, rivaling TBT containing materials.

Mechanism
ABC®3 is based on unique engineered terpolymer binder technology that provides controlled polishing and biocide release.
• The binder has both hydrophobic and hydrolyzing characteristics.
• The binder's hydrophobic characteristics limit the ingress of water, thus limiting contact of the coating with seawater to a very thin surface layer.
• The coating erodes via controlled hydrolysis of the terpolymer in contact with water. The hydrolyzed terpolymer residue or fragments are washed away by the water movement. The result is controlled polishing. Unlike traditional rosin based antifouling, only a very thin spent or depleted layer remains.
• Controlled polishing or ablation of the binder results in regulated delivery of the biocide package.
• Both the polishing and biocide release rates of ABC®3 are self-regulating, depending on the vessel's speed and the trading conditions. This provides the significant advantage that only one formulation of ABC®3 is needed for all vessels under all conditions, as opposed to different formulations being required for differing operating conditions.

Binder
ABC®3 is not a low-tech rosin-based antifouling. The binder matrix is an engineered terpolymer resin that contains a proportion of rosin as one of several constituents. The terpolymer resin system was designed to provide several key properties:

• good surface tolerance to give excellent adhesion to a variety of substrates and old coatings
• an indefinite recoat window with itself
• a 2-year shelf-life
• easy application without restrictive application and weather condition requirements

ABC3 – The tin-free antifouling with a unique track record.

This blended terpolymer binder differentiates ABC technology from traditional antifoulings based on rosin alone. It takes advantage of the positive aspects of rosin, whilst overcoming the drawbacks normally associated with these types of materials - short service life, UV sensitivity and no polishing or biocide leach control. The terpolymer binder developed for the ABC range was a quantum upgrade of the traditional rosin binder. This type of terpolymer binder matrix also provides the additional benefit of no maximum time before launching.

Biocide Package

In the ABC range, the biocide package that replaces the organo-tin used in the old antifoulings controls, slime, algae and weed growth (like TBT), but also imparts some additional properties:

• controlled solubility that reduces premature depletion of the film and provides increased protection time
• control of barnacle and other shell and animal fouling

Like most effective formulations, the excellent performance of the ABC range is due to the synergistic effect of a series of carefully chosen components. The controlled polishing of the binder results in regulated delivery of the biocide package to the surface of the coating film for maximum fouling control over an extended period. This very controlled release of biocides throughout the service life minimizes the required biocide loading and helps make ABC®3 an ecologically sensitive, cost-effective formulation that still provides protection for the specified service life. The theories behind antifouling paints are interesting, but in practice it is performance that really counts.
Performance
Actual service experience is still the only way of being sure that an antifouling meets all the supplier's claims and really provides Owners with value for their money. This experience must be gained under a wide range of operating conditions and on a variety of vessel types over a realistically long period.
ABC®3 has been in service for twenty years and has consistently achieved 5-years performance and better under all types of conditions and on a wide range of commercial, military, and recreational vessels. This makes the product unique. There is no other tin-free product on the market with a track record that matches ABC®3. It has a loyal following of repeat customers that includes the US Navy and commercial Owners operating on a worldwide basis. It is compatible with most existing antifoulings and its five-year capability is well documented.