Coatings for marine and offshore applications must achieve a delicate balance� they must be tough enough to withstand the harshest conditions, yet use materials that conform to the latest environmental regulations. It is an especially arduous task to develop coatings to meet the particular needs of the offshore coatings market. Coating massive steel structures that will be constantly exposed to the elements is no easy task and a variety of factors�water temperature, local environmental regulations and substrate condition�must be calculated in order for the coating to perform effectively.
"Many considerations must be made when selecting heavy duty marine coatings, such as suitability for use as recommended by the manufacturer, whether the product is VOC compliant for the geographical area of applications, does it pose problems for the applicator, proven performance (track record) of the product and of course, economics," said Tom Brown, director of marine marketing, Ameron International. "Many heavy duty marine products have value added features that make price a secondary concern, such as the ability to cure properly during ambient temperatures, surface tolerance to lesser methods of surface preparation and other enhanced performance characteristics."
"Depending on the area of the rig of exposure several tests are taken into consideration," said Gerard de Vries, market manager oil and gas, SigmaKalon. "Apart from the area on the oil rig, legs, splash zone, atmospheric exposure and also environmental factors play a role. Typical tests that are being carried out during the development of a coating for offshore are salt spray, cathodic protection, sea water immersion, UV exposure, etc., for the areas on the platform where these tests apply."
|The Alaska Ocean underwent a two-month dry-dock period used to inspect the vessel, install new equipment, perform maintenance and give the ship a quality paint job.|
Marine coatings aren't immune to the effects of the economy. "Hull roughness and the ability to minimize surface irregularities by the use of polishing matrixes is also getting a lot of attention especially due to increased fuel costs and the desire to transport goods and commodities at a faster and more cost efficient pace," said Eric J. Bosanac, director, marine and offshore, The Sherwin-Williams Company. Bosanac insists knowing your customer is vital. "It is also very important to listen to the needs of the customer and in doing so meet the requirements and expectations they have established. What may be good for one operator or owner is not acceptable to another. Normally this is a function of effective antifouling performance. Some operators only require a 36 month system while many others are looking for systems in excess of 60 months based upon class/insurance requirements."
Addressing customer needs is essential on the recreational yacht side of marine coatings as well, where ease of use is one of the most highly prized attributes. Consumers are looking for products that require minimum prep-work, but deliver maximum protection.
"In yacht, about 50% of the coatings are DIY applied and 50% are professionally applied in the local boat yard," said John Ludgate VP sales and marketing, Pettit Marine. "As a result, we are very aware of making the products as consumer friendly as possible�fast dry times, minimum surface prep and low odor. The average boater paints each spring, so the antifouling paint needs to be effective for twelve months."
|Vivid from Pettit Marine Paint contains copper thiocynate and biological boosters to combat fouling.|
PREDICTING FUTURE TRENDS
There is always the prospect that the biocides used in antifouling coatings today may become tightly regulated or even banned in the future.
"When developing antifouling coatings in today's environmental climate, one must look for future trends and possible active ingredients that may not be acceptable in the future," noted Bosanac. "This is a difficult task, but one that is very necessary given the substantial amount of investment by both the biocide/active ingredient suppliers and the end product developmental chemists."
"The recent global ban on TBT has drastically changed the complexion of marine antifouling coatings," added Bosanac. "This is certainly evident by the enormous influx in new product introductions and increased R&D work on alternatives to replace, and the attempt to meet the performance of the former organo-tin containing antifouling coatings. Manufacturers have placed an increasingly higher amount of time and resources in trying to protect existing market share and develop solutions to hold on to and maintain current customers."
The increased R&D efforts, as a consequence of the TBT ban, have resulted in the development of a variety of new chemistries and biocide packages for antifoulings. "Many of these products, although formulated to provide a level of performance similar to discontinued TBT containing products, do not have any significant or proven track record," said Brown. "Ameron does not use TBT as the primary biocide in our antifoulings and can boast of 20-plus years of well-proven performance rivaling that of TBT containing materials with our ABC family of premium antifouling coatings."
Developing compliant technologies is a lengthy process. Sigma Kalon started R&D twenty years ago to develop TBT-free antifouling coatings for the offshore and marine market. "It takes a considerable amount of time for testing to be complete, typically eight to 10 years," said de Vries. "Factors like the differences in fouling types present, ocean temperatures and operational patterns are very demanding for an antifouling to meet completely."
As is the case for most of the coatings industry, environmental issues such as the move to lower VOC products and higher volume solids is now, and will continue to be a focus. "The U.S. with the National Emissions Shipyards Hazardous Air Pollutant Regulation (NESHAP) and EU have already established criteria to limit the use of high VOC containing coatings," said Bosanac. "In many sectors solvent free/ultra high solids (UHS) products are routinely being specified and requested by owners.
"Increasing restriction on the use of hazardous solvents, VOC emissions and heavy metals discharges are driving much of the R&D effort of major manufacturers," said Brown. "In addition to more environmentally friendly products, a higher degree of performance is also being demanded by end users which is making formulators look 'outside of the box' in many cases for new chemistry."
While the trend to lowering solvents is taking hold in North America and Europe, other regions of the world have been slower to adopt the same regulations. "The whole marine and offshore market is rather conservative in this respect," said de Vries. "The trend to lowering solvents emissions is gaining momentum very slowly. It is a trend that started in Western Europe and North America, but is still not an issue in other areas such as Asia- Pacific. The building of the offshore platforms is mainly focused in Asia-Pacific countries such as Japan, South Korea and China."
According to Bosanac, other areas across the globe such as Japan and Singapore are looking at initiatives to also move to more environmentally friendly products.
Lowering solvents in antifouling coatings will continue to be a key issue in new product development. Much of this work is centered around lowering solvent content in existing formulations, rather than developing altogether new ones. "The focus is mainly on lowering the amount of solvents in existing technologies, which are polyurethane and epoxy," said de Vries. "It is very difficult to develop entirely new technologies in this area, but I think that polysiloxane is one of the latest technologies."
Ameron is taking a proactive approach with its PSX line of polysiloxane finishes, tank linings and heat-resistant coatings�updating them in advance so that they are compliant with pending environmental regulations. "We are also being proactive with our experience in TBT-free antifouling technology to develop high performance materials with a greatly reduced dependency upon copper and other heavy metals," said Brown.
SigmaKalon has launched SigmaPrime, Sigma AlphaGen and Sigma AlphaTrim. "More recently we have introduced Sigma Cover 1500, which is a solvent-free primer/buildcoat that can be used on steel structures," said de Vries. "Further on, a complete new durable finish range including polysiloxane and a polymeric engineered polyurethane are being introduced as well as Sigma FireBarr 2000, which is a hydrocarbon intumescent."
Sherwin-Williams has launched a line of products under the ExpressTech banner. Fast Clad urethane and Fast Clad DTM urethane are polyaspartic urethanes that are high build in one application. Fast Clad DTM urethane can be applied directly to a properly prepared substrate. These new generation polyurethanes can eliminate a traditional coat of anticorrosive or polyurethane topcoat as they are high build five to nine mils dry film thickness in a one coat applications. For tank coatings and linings for ballast and fuel, Sherwin-Williams has developed Fast Clad ER, a UHS, solvent-free, edge-retentive coating that can be applied at 20 mils dry film thickness in one coat. It is dry to walk on in four hours and ready for immersion service in 24 hours. The company has also added a general purpose anticorrosive under its Seaguard brand of marine and offshore coatings. Seaguard 6000 is a high solids, multi-purpose, surface tolerant anticorrosive for use above and below the water line in range of environmental conditions including temperatures down to 20�F.
Akzo Nobel's International Marine Coatings division has introduced two new high-performance marine finishes, Interfine 979 and Interfine 691. Interfine 979 is a patented, polysiloxane finish that provides excellent long-term durability and significantly improves the gloss and color retention exhibited by typical polyurethane finishes, according to the company. The product, which was made available worldwide in December, was initially developed for the offshore market, according to International.
The main chemical bond in Interfine 979 is inorganic silicone-based and is comparatively less reactive and better able to resist degradation caused by UV radiation compared to organic-based bonds, according to the company.
Interfine 691 is an isocyanate-free epoxy acrylic finish that provides good long-term durability and offers performance comparable to typical recoatable polyurethane finishes. Interfine 691, which is available only in Europe, is designed for external above-water areas and is suitable where recoatable polyurethane performance is required over extended in-service periods and where the use of isocyanate cured coatings is not acceptable.
New product launches haven't been relegated to the marine and offshore sector. For the recreational boater, Pettit Marine Paint has developed Vivid Bright Color antifouling paint. Vivid uses copper thiocynate instead of copper oxide which allows for bright colors including white, blue, black and red. Vivid, which can be applied by brush, roller or spray, adheres well to fiberglass, wood and steel hulls, according to Pettit. The coating's hard finish is ideal for high performance racing, sailing and trailer boats.
Constant innovation and research is key to staying ahead in the antifouling market. According to Bosanac, new technologies continue to center around high performance coatings, with low VOC, rapid return to service properties and environmental acceptance. "New waterborne formulations that can perform as good, if not better than their generic counterparts will also find a place in marine and offshore applications. And certainly, anti-fouling coating development will continue to be an ongoing concern with solutions developed that will be metal free and much greener than today's alternatives."