Two-component (2K) urethane and epoxy coatings have long been the standard for protecting steel and concrete structures. However, both of these systems have drawbacks. 2K urethanes pose handling issues, such as limited pot life and worker exposure to isocyanates, while epoxies are restricted to primer applications and also can contain hazardous ingredients, such as aromatic amines. Most urethanes and epoxies also contain higher than acceptable volatile organic compound (VOC) levels.
Scientists at Rohm and Haas Co. have developed a new waterborne industrial coating technology that can replace these 2K coating products without compromising performance.
Rohm and Haas has traditionally supported the architectural markets with advances in water-based acrylic technology. The company’s recent developments, dubbed Avanse Technology Platform, not only meet the physical and durability requirements of rigorous steel and concrete applications, but also offer VOC compliance in demanding regions such as California and Western Europe.
A 100,000x image showing the formation of latex polymer-pigment composites, in which Avanse latex particles are adsorbed onto the surface of a titanium dioxide particle.
Advantages
The Avanse Platform is based on a single-component, air-dry waterborne acrylic resin technology. Unlike 2K systems, pot life is not an issue. As a result, the coatings are easy to apply, and spray equipment is easy to clean. In addition, the material is benign to applicators because solvents are not used, and exposure to amines or isocyanates is eliminated.Corrosion resistance is one of the hallmark features of this new technology. Single coats over properly cleaned steel have passed more than 800 hours of salt fog testing (ASTM B-117). The technology’s versatility is underscored by its ability to be used as a primer, midcoat or topcoat. As a topcoat, the system is highly weatherable, being able to surpass 2500 hours of QUV A testing with minimal gloss loss or chalking.
In 2006, the California South Coast Air Quality Management District (SCAQMD) lowered acceptable VOC levels for industrial coatings to 100 grams per liter (g/L). Coatings based on Avanse contain less than 100 g/L, making them the lowest VOC alternative for civil engineering applications, such as bridges, water tanks and utility transmission structures.
Another unexpected advantage is that the resin’s crosslinking properties allow formulators to use lower levels of pigments, such as titanium dioxide, without compromising hiding power.
The Future
The Avanse Technology Platform is registered globally and is being further developed to meet the needs of specific regions through the efforts of Rohm and Haas scientists worldwide. The direct-to-metal formulation Avanse MV-100 has recently been specified by CALTRAN as a technology approved for use on bridges in California. The Avanse technology also meets the industry push by the European Union for APEO-free coating materials - that is, products that do not contain alkyl phenol/nonyl phenol ethoxylates. (APEOs are surfactants that can improve a substance’s miscibility with water, but they are being phased out due to their potential environmental effects.)As this technology advances from the architectural market into the industrial arena, Rohm and Haas expects further expansion into more traditional OEM applications.
For more information about the new technology, contact Shruti Singhal, marketing manager for Avanse Technology, at 215.619.5890 or ssinghal@rohmhaas.com. The company’s website is at www.rohmhaas.com.
Do you know of an innovative new product that should be featured in our Innovation Spotlight? If so, contact Technical Editor Kevin Biller at 614.286.2148 or editor@finishingtodaymag.com. Products will be covered in this department at the editors’ discretion.
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