Paints & Coatings
South Korea’s Hyundai Mipo Dockyard
WBT coating from Chugoku Following many years of extensive prototype trials in field tests, Japan’s Chugoku Marine Paints (CMP), is ready to launch a new solventfree epoxy coating that can be applied to water ballast tanks (WBT) with standard application equipment that meets new South Korean regulations under the Atmospheric Environment Conservation Act for the management of volatile organic compounds (VOCs). CMP has provided solvent-free epoxy coatings for the drinking water tanks of commercial ships for over 20 years as a standard product for most of the shipyards world-wide. However, solvent-free products require special equipment and the warming of the paints due to high viscosity in a cold temperature. Therefore, their use has been limited to specific areas due to difficulties of treatment. To overcome existing limitations in the application of solvent-free coatings in WBTs, due to the severe application conditions and limited revision margin in performance standard for protective coatings (PSPC) regulations, South Korea’s Hyundai Mipo Dockyard (HMD) and CMP have found the best solution to coat WBTs with a solvent-free epoxy coating that has matched quality control and best performance after delivery without failure. CMP’s new solvent-free epoxy coating Bannoh 5000 will be applied to the WBTs of three MR tankers to be built in HMD from April 2020. This will be the first application of a solventfree coating to a WBT in the world. Through the use of this new product, the shipyard could reduce solvent emissions by up to 90% for WBT.
This makes Bannoh 5000 indispensable for South Korean shipyards for reducing total VOC emissions while maintaining current working processes. Additionally, Bannoh 5000 will be the first protective coating for ships that is applicable for all areas as a solvent-free multipurpose primer. CMP’s R&D director, Hideyuki Tanaka, said, “This new generation coating will catalyse a paradigm shift, changing the conventional approaches of protective coatings in the marine newbuilding market. Throughout this success, CMP’s solvent-free epoxy will be standardised for ballast water tanks as well as for the general areas of ships to protect the global environment in the future.”
Corrosion problem can be solved According to a spokesman for Subsea Industries, suppliers of Ecospeed, “We are so used to corrosion on ships that no-one raises an eyebrow at the rust-stained hulls in any port or dock. It is, apparently, considered to be the way
An ‘Ecospeed’ hull
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of things. It is true that steel will rust. But with the knowledge and resources available, we have long passed the point when we should have recognised that this is a problem, and solved it. “Corrosion on ships is rarely recognised as a failure of the coating, but that is precisely what it is. The first job of a hull coating is to prevent the gradual weakening and destruction of marine assets that is caused by corrosion. It remains a massive problem for shipping despite coating repairs every few years, eating up valuable days in drydock. Not only that, but current coating compounds also leak a million tonnes of toxic material into our oceans every year. “Corrosion is not some unavoidable fact of life. The basics of the subject have been well known for centuries, but they are worth reiterating. The iron in a steel hull is, effectively, trying to return to the state in which it was taken as an oxidised ore. Three things are needed for rust to form - metal, water, and oxygen. Energy, the galvanic difference between metals, stimulates the process, and impurities in the metal, seawater, water vapour, acids, salts, carbon dioxide and stresses hasten it. “While cathodic protection slows the corrosion on a ship, total prevention is only achieved by preventing metal, water and oxygen from coming into contact with each other. That is the primary job of a coating. The problem is simply that most coatings fail poorly in that task. “One reason for their failure is the permeability of zinc primers, epoxies and anti-fouling coatings usually used. Water can get through and behind the layers of coating where it can start the corrosion process while accelerating it by causing coating delamination. This is the sequence of coating degradation which opens the door for further corrosion. “A second reason is the use of heavy metals in coating systems such as copper. These have a high galvanic differential with the steel of the hull. In practice we see copper-based coatings
