Anti-Corrosion Coatings

Anti-corrosion coatings are an indispensable tool in fighting the battle against rust. Used on everything from automobiles to bridges and tunnels, anti-corrosion coatings protect structures in some of the harshest environments.

Today there are a number of growth areas for anti-corrosive coatings. Key markets include oil and gas, power, industrial and infrastructure, according to Anders Braekke, category group manager, topcoats at Jotun Coatings. “The oil and gas industry still show good growth and we have good insight in the industry. The Norwegian oil industry is located on Jotun’s doorstep and this is an industry that we understand quite well,” he said. “We also see the alternative power industry as very interesting. Windmill production is one area that has potential. This is an industry where we may see innovative solutions for the future. New alternative power will hopefully try to be environmentally friendly throughout the whole value chain and we can expect that waterborne technology will be preferred in this type of business.” The reason is that customers will not sacrifice any anti-corrosion properties since maintenance here can be difficult and expensive, for example windmills located at sea.

Another important area for anti-corrosion coatings is transportation infrastructure. “We are addressing the requirements of repairing/rebuilding the transportation infrastructure including highways and bridges,” said John Steele, president, Substrate, Inc. “We also see significant opportunities within the Armed Forces. Above ground storage tanks and off-shore oil platforms are also high on our priority list.”

Development Hurdles

Developing anti-corrosion coatings for a wide variety of applications is no easy task. Coatings must meet specific performance requirements, as well as meet increasingly strict environmental regulations.� �

“The constantly increasing requirements on the performance of anti-corrosion coatings combined with cost and environmental awareness make all-important areas such as OEM, car refinish, heavy duty, industrial and specialty coatings the key areas of the corrosion protection coating makers,” said Lars Kirmaier, business development manager, anticorrosives, Heubach GmbH.

One important trend is the growth of the water-based paint area and the decreased use of solventborne coatings. “It looks like a rise of water-based industrial protective coatings will occur in the future, because of the increased regulations to produce low VOC,” said Kirmaier. “These coatings are more convenient to use due to their low odor and are safer for the environment.”

“VOCs are a necessary component of all organic surface coatings,” Kirmaier continued. “Of the available low VOC content paint technologies to date, only high solids or waterborne formulations are currently practical propositions for protective coatings. Alternatives include radiation curing coatings and powder coatings. Also, thin ceramic or sol-free coatings have become a popular material in recent times in the protective coatings world.”

Other trends in the market, according to Kirmaier, are surface tolerant protective coatings systems or coatings providing universal adhesion. They use less coatings�up to single coat application-and are combined with high film thickness and high gloss.

Despite all the innovations, a coating can only perform at its best when it is applied correctly. Proper substrate preparation is vital.

“Substrate preparation is the most important step of the coating process,” said Mehrooz Zamanzadeh a NACE (National Association of Corrosion Engineers) certified materials protection specialist at Matco Associations. “Adequate substrate surface preparation will result in long life and high performance with minimum maintenance.”

One way to improve anti-corrosive properties of a protective coating is to achieve the best adhesion on the substrate. “Accordingly, the pre-treatment is a very important factor and strongly influences the development of the protective coating,” said Kirmaier. “High-energy costs and environmental legislation have driven research and development of alternative pre-treatment technologies. Among them are new trends like nanotechnology, silane technology or phosphorus-free pre-treatment.”

Follansbee TCS II Roofs top the two main residential buildings at Stonnington Commons, an historic restoration project that shaped a mixed-use development from a 19th century foundry in Stonnington, CT.

Zirconium, vanadium, titanium or silicon-based compounds are often used in combination or without organic or inorganic polymerization, according to Kirmaier. “The combination with an organic polymeric component has led to significant new opportunities in pre-treatment,” he said. “Some automotive producers have already replaced part of their conventional zinc-phosphating pre-treatment with a so-called ‘nano-ceramic’ method by using nano-scale particles such as zirconium compounds and special organic substances, which generate less sludge and are less harmful to the environment.”

Nanotechnology continues to offer some exciting possibilities for the anti-corrosion� market.

“Nanotechnology will most likely include some interesting future perspectives for anti-corrosion applications, but the feasibility of that technology for industrial use especially in respect to the handling and costs has not yet been fully proven,” said Kirmaier. “Heubach is in close contact and forming cooperation with different universities and institutes, who are engaged with nanotechnology and is currently focusing much effort in research work regarding the use of this technology for modern anti-corrosive pigment development.”

For Substrate, Inc., nanotechnology is and has been the backbone of its anti-corrosion products. “This ‘new’ technology causes our anti-corrosion products to covalently bond to substrates-eliminating the need for costly surface profiles,” said Steele.

Latest Product Offerings

There are a number of new products utilizing the latest technology available for anti-corrosion coatings. On the supplier side Heubach has developed an innovative anti-corrosion pigment.

“After the successful marketing of our wide spectrum anti-corrosive pigments, based on modified phosphates for universal applications, Heubach has recently developed a zinc-free anti-corrosive pigment based on silica, which is designed for use in thin-film applications, especially coil coatings and will be introduced to the market in the second quarter of 2008,” said Kirmaier.

Substrate, Inc. has developed TegaTeknology products, a range of chemical-graft coatings, primarily focused on anti-corrosion coatings for steel and aluminum. “Our products contain a carefully chosen selection of certain monomers, combined with a proprietary graft/catalyst system, achieving permanent substrate modification,” said Steele. “The primary application of our products is as a primer. Our products require minimal surface preparation-scale free, hydrocarbon free-and can be applied over tightly bonded rust. Top coats can be applied directly over our primers and no intermediate coats are required.”

According to Zamanzadeh, chromate, which is used in galvanized roofing and sidings, and lead containing coatings for roofing materials are prone to corrosion and water wash out due to rain, which may result in contamination of underground water. “Therefore, these coatings should be replaced ASAP,” he said. Follansbee Steel offers roofing products, such as TCD II, which are environmentally friendly panels that provide a pleasant appearance, as well as corrosion protection. Follansbee’s high performance corrosion resistant tin-zinc coatings for coppers, stainless steel and carbon steel roofing panels have passed over 17,750 hours of salt spray testing.

Jotun has recently launched Hardtop Flexi, a flexible polyurethane and Hardtop XP, a traditional high solid polyurethane. In addition the company will continue to develop environmentally friendly products. “Waterborne products will be more important and we will increase focus on this,” said Braekke. “In the future traditional technologies will have higher volume solids and contain less harmful solvents.”