Coatings are an essential aspect of ship construction and maintenance although shipowners are less concerned with the science behind coatings than they are with their effectiveness as protecting their assets against the elements and compliance with whatever regulations govern their application and use. For manufacturers, the challenge is to develop products that meet these two demands.

There is no doubt that the biggest challenge in recent times has been developing new anti-foulings after TBT was outlawed under the IMO’s AFS Convention of 2001 (the convention came into effect in 2008). After more than a decade, shipowners are more appreciative of the work done to develop alternatives. What they may not be so aware of is that coatings manufacturers have already had to grapple with regulation on the level of volatile organic compounds (VOC) that are permitted in coatings and the challenges this has posed.

“Coatings are typically comprised of solvents, pigments, binders and additives. The solvent makes the coating thinner and less viscous and so easier to apply. Once the paint has spread out, the solvent evaporates leaving the paint evenly applied and dry beneath it. Solvents consist of VOCs where many are considered as hazardous air pollution because they can be harmful to human health and are implicated in ozone production,” explains Erik Risberg, Global Marketing Director Jotun Marine Coatings.

New VOC rules looming

VOCs have been regulated across many industries in the US and Europe for over ten years and more recently in Hong Kong and South Korea. Even more stringent regulation is now being formulated around the globe and in particular in South Korea and China with the EU expected to follow suit. This means that a huge amount of work must now be undertaken to ensure that a new generation of suitable products are made available points out Risberg.

“Shipyards are major users of coatings products and to meet the new requirements must reduce solvent use or install very expensive air pollution capture equipment. To that end they are looking to manufacturers such as Jotun to develop new solvent-free products. Another reason for developing solvent-free coatings is that they can aid productivity by removing the fire and explosion risk present when yards want to do hot work and apply paint simultaneously,” Risberg adds.

There are some existing solvent-free coatings in the market but these have been found to have limitations. They have not been popular in the shipbuilding industry as they are not suitable from an application point of view due to high viscosity. This requires not only expensive equipment for application, but also longer time to pre-heat and cure.

“One of the challenges in the market today is the lack of a uniform definition of a solvent-free coating. The definition was established by the CEPE working group in the 2004 Directive ( Directive 2004/42/CE (PD) ), where the definition read ‘Volatile Organic Compound (VOC) means any organic compound having an initial boiling point less than or equal to 250 C measured at a standard pressure of 101,3 kPa.’ Before this definition, solvents such as benzyl alcohol were considered part of the coating system, but they are now looked upon as a solvent. Such solvents migrate from the coating over time, changing their properties, and are not part of a truly solvent-free product,” opines Risberg.

Collaboration on new coatings

In the interest of more sustainable shipping and environmental protection, Jotun has been actively researching solvent-free and low solvent coatings in Norway as well as in conjunction with shipyards and Jotun’s R&D laboratory in South Korea. After 15 years it has succeeded in developing a single coat PSPC approved product that reduces solvent emissions by 97% from approximately 250g per litre to just nine grams per litre. A patent application for this unique technology was filed in 2016 and is expected to be granted soon.

An initial application of Jotun’s single coat product on a newbuild LNG carrier was started in Samsung Heavy Industries in November 2018. Jotun has also signed a MOU with Hyundai Heavy Industries, which “represents the starting point of a closer cooperation and the use of Jotun’s new marine paint,” says Risberg.

In parallel with the research and testing, a working group has been established in Korea to investigate the potential of solvent free coating systems. The group consists of representatives from all the South Korean yards, paint makers and regulatory authorities and will allow the yards to prepare for the impending new regulatory regime due in 2020.

Multiple benefits

According to Risberg, extensive use of the new coating could allow shipyards to save hundreds of millions of dollars by avoiding investments in emission reduction plants as there will be no need to burn off the VOCs. The primer also improves safety from fire and explosion hazards and eliminates the consequences of solvent exposure to yard workers.

“A single coat can also be applied more quickly improving productivity. In addition, it has superior surface protection properties. The product has better corrosion protection than previous systems which helps extend the life of vessels and reduces the need for maintenance – making it also attractive for shipowners. This has been achieved by the strong covalent bonds, typically found in zinc silicate coatings, between the substrate and the coating.” Risberg adds.

“The target of this development was to not only match but also improve the anticorrosive properties compared to all existing products, even when applied as a single coat. This was a challenging task for the lab, but very extensive and severe testing, such as salt-spray testing over a period of up to 6 months, has proven that the target has been met and the product is still standing strong after 38 months in salt spray as a single coat system. This is an astonishing achievement by the chemical researchers and is only one of many results that confirms the durability of this product,” explains Risberg.

Between 60-80% of marine newbuilding coatings are made up of universal primers. “The majority of this volume is typically applied in critical areas such as ballast water tanks which experience high corrosion intensity. These epoxy primers are also used in almost all areas in a vessel, resulting in a high volume of use so a solution addressing such a large volume product can solve environmental related issues on a massive scale. It’s a potential game changer for the industry,” believes Risberg.

The new product is currently available for South Korean shipyards and selected shipbuilders in Europe who have experience applying single coat primers that require careful application techniques. Separate to the cooperation agreements with the South Korean yards, Jotun has a five-years frame agreement to supply all paint to MEYER WERFT GMBH & CO. KG in Germany.

Further details of the product will be released later this year.

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Volatile Organic Compounds (VOCs) have been regulated across many industries in the US and Europe for over ten years. Even more stringent regulation is now being formulated around the globe and in particular in South Korea and China with the EU expected to follow suit. Some European countries, notably Germany, have already implemented strict VOC requirements. This means a huge amount of work is being undertaken to ensure that a new generation of suitable products are made available to meet the new requirements.