A Seaworthy Solution

The U.S. Coast Guard has taken a big step in reducing maintenance costs by minimizing the time spent on ship bottom refurbishing, thanks to an innovative, high performance antifouling paint made by E Paint Company, East Falmouth, MA.

E Paint SN-1 coating provides Coast Guard vessels with good control over a wide array of common soft and hard fouling species. Vessels coated with E Paint SN-1 solventborne antifouling paint can operate for up to two years before they must be hauled, pressure-washed and repainted. This is longer than is possible with virtually all approved non-metallic biocide antifouling paints. Extending the interval between maintenance significantly reduces vessel downtime. Equally impressive, despite its efficacy, E Paint SN-1 coating is "environmentally-responsible" to aquatic species-it has produced no harmful effects on the growth, development and reproduction of non-targeted marine organisms.

This excellent balance of efficacy and minimal threat to the environment is achieved by a dual-action biocidal system that combines E Paint's patented photoactive technology and an innovative booster biocide.The system keeps ship bottoms smooth and clean without leaching harsh toxicants that persist in the environment.

"Sunlight and water are photochemically combined by our paint to produce hydrogen peroxide, a potent antiseptic, on the paint's surface," said Christine Greene, sales and marketing director. "The hydrogen peroxide continuously bleaches the hull, discouraging the accumulation of fouling organisms. While discouraging the settling of a wide variety of fouling organisms, hydrogen peroxide has the additional benefit of decomposing into oxygen and water. The booster biocide works in combination with the photoactive surface and is required in warm water environments, which are particularly congenial to the growth of foulants. To qualify for this role, a biocide must be very effective against both hard and soft fouling species, especially algae, and should not present any undue hazard to the aquatic environment."

To meet these requirements, E Paint chose Sea-Nine 211, an isothiazolone biocide specifically developed by Rohm and Haas Company for use in heavy-duty antifouling paints. Sea-Nine 211 biocide controls such fouling organisms as algae, bacterial slime, barnacles, tunicates, tubeworms, bryozoa and diatoms. Equally significant, Sea-Nine 211 biocide provides excellent performance while posing a minimal long-term environmental threat. Sea-Nine 211 compound degrades very rapidly in seawater, binds to sediment instead of remaining in the water, and does not accumulate in the tissues of marine animals. Because of the "environmentally-positive" performance features of Sea-Nine 211 marine paint antifouling agent, Rohm and Haas was the recipient of the first United States Presidential Green Chemistry Challenge Award in the category of designing safer chemical products.

E Paint SN-1 coating was formulated specifically for the United States Coast Guard to be environmentally compliant without sacrificing effectiveness. Exhibiting low VOC content, positive effectiveness and environmental effectiveness has led to E Paint SN-1 becoming the only U.S. EPA-approved, biocide-containing paint authorized for use on all aluminum-hulled U.S. Coast Guard vessels. The U.S. Coast Guard has been a major customer for E Paint since 1996. Since that time E Paint SN-1 antifoulant with Sea-Nine 211 biocide has been used to control biofouling on hundreds of aluminum-hulled vessels. These ships include 55' ANB (aids to navigation boats), 47' MLB (motorized life boats) designed for use in heavy weather and 41-foot UTB (utility boats). Three E Paint SN-1 colors are employed for Coast Guard ships: gray signal coat, white for bottom paint and black for boat top striping along the waterline.

"Our E Paint SN-1 antifouling paint is particularly important to the Coast Guard's motorized life boats," said Ms. Greene. "Especially made for use in rough weather, these craft are precisely balanced to right themselves if capsized. If the buildup of fouling organisms is not controlled, it can adversely impact the balance, and thus, the self-righting properties of these boats, a definite safety hazard."

The effectiveness of E Paint SN-1 antifouling paint on Coast Guard vessels has led other agencies, such as the Woods Hole Oceanographic Institution, Channel Island National Park Service, U.S. Army Corps of Engineers and the National Oceanographic Atmospheric Admin-istration to use E Paint SN-1 on their aluminum vessels and on buoys and underwater equipment exposed to biofouling.

In gaining Coast Guard business, E Paint SN-1 paint supplanted coatings employing tributyl tin oxide (TBTO) antifouling agents because of the long-term environmental risk posed by the organotin compounds.

"The trend away from paints containing TBTO, long the dominant antifouling agents, is a significant one for the marine coatings industry," commented Ms. Greene. "This reflects the growing global commitment toward preserving coastlines, decreasing use of harmful heavy metals in seawater, and the creation of products that are effective but don't persist in the environment and pose minimal hazard to the applicator when handled properly."

E Paint SN-1 antifouling coatings are currently EPA- registered for use by the Depart-ment of Defense, U.S. Coast Guard, U.S. Army Corps of Engineers, U.S. EPA Research Vessels, National Park Service Vessels and Oceanographic Research Vessels.

In addition to its line of biocide-containing antifouling formulations such as E Paint SN-1, E Paint markets other photoactive antifouling paints. These include E Paint ZO, recommended for use on any type of hull material and formulated for commercial or recreational vessels, EP 2000 waterborne, hard mar-resistant anti-fouling paint for high speed racing craft and EP 21 soft ablative antifoulant for small boats.

E Paint Company was established in 1991 as the marketing arm of Cape Cod Research, one of the country's leading firms dedicated to "green" coating research, to market environmentally-friendly marine coatings. Since then E Paint has established itself as a leader in environmentally-friendly coatings research.

The primary thrust of the company's marketing efforts has been toward specialty coatings to control ship bottom biofouling. These coatings contain no tin or copper, and are positioned as more environmentally acceptable alternatives to antifoulants made with heavy metals. The firm's line of products is finding expanding use for demanding applications in the government, commercial and recreational markets. E Paint sells its antifoulants through a nationwide network of dealers and marine service yards.

What's Ahead for E Paint?
The future for improvements is bright at E Paint. With generous support from the National Science Foun-dation, the firm has developed several new materials to improve the efficiency of peroxide production. One of these materials, a proprietary porphyrin, is similar to chlorophyll, a substance used by plants for photosynthesis. Improvements in the coatings formula allow for longer life and a smoother surface. Further support by the EPA is allowing E Paint to focus on improvements in foul-release coatings. E Paint expects its new generation foul-release coatings to offer a low-cost, easy-to-use, eco-friendly alternative to current state-of-the-art products.

"One of our most exciting initiatives involves working with Rohm and Haas to create a water-based antifouling paint having a service life very comparable to the four to five years provided by TBTO antifoulants, but without posing a threat to non-targeted marine species," said Myles A. Walsh, president of E Paint. "Another promising new product under development is a waterborne barrier coat paint characterized by ease of application and excellent protection of the substrate.

The future is in waterborne coatings. They will replace the the high-VOC solventborne barriercoats, primers and antifouling paints. Current water-based coatings have been plagued with difficulties ranging from adhesive failure to cracking. Overcoming these difficulties, E Paint's innovative research has resulted in several proprietary waterborne binders for use in coatings. Waterborne coatings are by far safer for both the applicator and the environment."

"On a general basis, we intend to remain highly competitive by recognizing important trends and quickly responding to them," added Dr. Walsh. "With our cutting-edge research capabilities, we can precisely meet the needs of our customers by significantly upgrading our current products and by bringing innovative new materials to the marketplace. At the same time we shall remain committed to 'green boat maintenance' by responsibly marketing antifouling paints that are safe to both the aquatic environment and to those persons who apply them."

Given E Paint's considerable research expertise and the increasing acceptance of its products by diverse segments of the marine coatings industry, it's likely this company's aspirations will soon become commercial realities.

Cliff Keevan is a communications consultant with Rohm and Haas Company.