Japan – eco-friendly ship bottom paint developed

Researchers of the Nara Institute of Science and Technology have succeeded in developing an organotin-free substance for ship paint that does not leach out any organometallic compounds into the surrounding seawater. Japan for Sustainability (FfS) reports that the research team, led by Professor Michiya Fujiki and represented by Assistant Professor Masanobu Naito, announced the research results in May 2004, which have been drawing attention as the world‘‘s leading research on ship bottom paint that does not exude any hazardous substances.



Organotin compounds were once used worldwide to coat the bottoms of ships to prevent sea life such as barnacles and oysters from attaching to the hull and slowing the vessels down. Endocrine-disrupting effects of organotin compounds were reported in shellfish in the 1980s, and some countries stopped using these substances at that time. By 2008, all anti-fouling paints containing organotins are expected to be totally banned by the International Maritime Organization.



As alternatives to organotins, other organometallic compounds such as cuprous oxide and zinc are now used, but these still leach out of the paint into the seawater. To cope with this problem, the research team has successfully encapsulated a special type of antibacterial silicone, which is often used as a glass defogger, into the microscopic mesh-structured polymer by means of strong chemical bonds.



In cooperation with Japan‘‘s major paint maker Nippon Paint Co., the research team has been conducting a field test that involves soaking panels coated with the newly developed paint in the Seto Inland Sea. The interim results as of May 2004 were found to be promising. They intend to commercialize the product by 2008, after improving its performance and functionality