Session 19: Waterborne Protective Coatings
Chair: Prof. Joe Keddie, University of Surrey, GBWithin the years water-based anticorrosion resins have gone through different stages of evolution. Nevertheless, there is still enough space for further improvements, e.g. in barrier properties, increasing their potential and widening their application spectrum. This session is dedicated to the latest developments in waterborne resin presenting epoxy as well as hybrid systems. Performance of waterborne systems is discussed as well as the use of nanoscaled materials.
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Wednesday Morning 9.00 – 12.30 h
Room Kopenhagen
19.1 9.00 – 9.30 h Corrosion resistant properties of waterborne coatings Dr. Rolf Nothhelfer-Richter, Research Institute for Pigments and Coatings (FPL), DE Increasing demands on environmental protection and legislative regulations are the driving forces to develop waterborne coatings for corrosion protection of steel. The performance of waterborne primers based on epoxy dispersions and styrene acrylate dispersions were compared to a conventional solvent borne epoxy primer. The influence of anticorrosion pigments - two zinc phosphate pigments and two zinc-free pigments - were investigated in various primer formulations. Coatings formed from the investigated waterborne epoxy primers showed an improved durability against salt spray exposure (DIN EN ISO 9227) than coatings with waterborne styrene acrylate primers. On the other hand the wet adhesion of the coatings tested after exposure to condensation-water test atmospheres (DIN EN ISO 6270-1) in general performed better with the styrene acrylate primers. In order to understand the reasons of cathodic delamination and to develop means to improve the performance of the coatings the transportation paths of ions were investigated using semi-transparent coatings. With different setups including the Leidheiser cylinder the propagation of the delaminating front was observed. The propagation is controlled by lateral diffusion processes along the steel-coating interface combined with vertical transfer.  | ||
| 19.2 9.30 – 10.00 h Performance properties of anticorrosive pigments in waterborne primer systems Dr. Lars Kirmaier, Heubach, DE There has been a lot of progress and increasing interest in waterbased coatings technology during the last two decades. There most important reason why waterbased coatings have become commercially important in the last few years is environmental concern regarding solvents and other volatile organic compounds (VOC) being emitted in to the atmosphere and causing ozone depletion, and possibly a chemical imbalance of the earth's ecosphere. Corrosion inhibitors are significantly influenced by the desired application performance as well as the resin used. As a leading producer of anticorrosive pigments Heubach has concentrated much effort in the development of corresponding anti-corrosive pigments inline with the constantly changing requirements such as environmental, application, testing parameters and performance. The further development of active anticorrosive pigments and combinations with organic inhibitors, as well as suitable binders, are essential for the protection of metals with waterborne coatings. Waterborne coatings can cause corrosion to substrates which they are applied to in form of flash/ early-rusting. Liquid flash-rust and early-rust inhibitors like sodium and ammonium nitrites, nitrates, phosphates and benzoates are used in small amounts for the paint formulation to control flash- and early-rusting. Levels of these materials must be controlled, however due to their high solubility which tends to cause osmotic blistering in very humid or fresh water environments. The lecture will also introduce a new powder organic corrosion inhibitor which combines the properties of a high performance organic corrosion and highly effective flash/early rust inhibitor especially for water borne but also of solventborne protective coatings on a variety of substrates. This ?2 IN 1 SOLUTION? is a major advantage over a lot of other available inhibitors providing only flash/early rust inhibition or temporary protection. Furthermore talk demonstrates the performance of assorted inorganic and organic anticorrosive pigments in waterborne resin systems. In the end, the lecture might help to overcome prejudice against ?water? in corrosion protection. | ||
| 19.3 10.00 – 10.30 h Waterborne epoxy coatings in the marine industry: An option? Françoise Heine, Hexion Specialty Chemicals, BE Due to more stringent regulations and increasing environmental concerns, waterborne paints are replacing solvent-borne paints. Recently developed new waterborne epoxy and amine curing agent technology provides excellent corrosion resistance under controlled cure conditions with the use of the appropriate formulations. This technology is being used in a growing range of applications. An example is in the transportation industry where this technology is increasingly accepted and used. The marine industry requires uncontrolled cure conditions as well as multi-layered coatings capable to resist water, aggressive chemicals, biological attacks and heavy mechanical loads. One such type of coating used in the marine industry is the Zinc-rich formulations as anticorrosive primer. One of the obstacles is that Zinc can react with water. How to formulate around such challenges will be discussed and this presentation will explain the various options available to address the marine industry needs with waterborne epoxy systems. 10.30 – 11.00 h Networking: Refreshments & Coffee Break | ||
| 19.4 11.00 – 11.30 h Waterborne Zero VOC HDP Primer for Outdoor Applications Martin Gerlitz, Huntsman, US A recently developed novel waterborne amine curing agent (= ACA 1) has been found to give excellent anticorrosion protection performance in industrial applications. Based on these findings we have focused on developing a waterborne system, that can be formulated without usage of any organic co-solvent (VOC-free) and that can be applied under non-ideal outdoor conditions (low temperatures, high humidity) for heavy duty protection (HDP), marine or repair applications and still featuring excellent anticorrosion performance. | ||
| 19.5 11.30 – 12.00 h New concepts for water-based anticorrosion resins: A step closer towards replacing solvent-borne systems Oihana Elizalde, BASF SE, DE Within the last decades, water-based anticorrosion resins have gone through different stages of evolution. Nevertheless, there is still enough space for further improvements, e.g. in barrier properties, increasing their potential and widening their application spectrum. Recent innovations in the area of polymer colloids and hybrids offer new opportunities to develop novel coatings for metal corrosion. At BASF two hybrid binders were developed, which provide protective coatings with improved barrier properties, extremely low water uptake and improved anticorrosion properties, even at low dry-film thickness. Additionally, a new technology was developed which goes beyond mere barrier function. This was achieved via a built-in enhanced corrosion protection mechanism resulting in outstanding performance in salt-spray testing and good early-rain resistance. The binders produced following these novel technologies provided superior performance and have a higher potential to replace established solvent-borne systems. | ||
| 19.6 12.00 - 12.30 h A Novel Low-Temperature Sol-Gel System for Environmental Friendly Metal Pre-Treatment Dr. Philipp Albert, Evonik Degussa GmbH, DE Traditional metal pre-treatment solutions face increasing skepticism as they contain ingredients that pose environmental as well occupational health hazards, resulting in tightening regulations. Replacements products are already available but suffer from different drawbacks compared to the conventional systems. Sol-gel chemistry is a technology that has the potential to overcome the challenges that the industry faces today. A new water-based sol-gel system for metal surfaces will be presented. The product can be used advantageously on steel, zinc, aluminum, and magnesium. As it derives from silanes it is an environmental friendly solution for today´s metal pre-treatment problems. As it neither contains heavy metals (e.g. chromium) nor inorganic fluorides, cost intensive waste management as well as occupational health measures become obsolete. The curing temperature of the new product is extraordinary low requiring reducing energy costs. These advantages are achieved without compromising on organic emissions as the material is essentially VOC-free. As the product is based on bifunctional organosilanes it features both excellent binding to the metal substrate and therefore passivation to the metallic surface, as well as improving adhesion to subsequent organic coating layers. The silanes are condensed in a special sol-gel process resulting in a water-borne oligomeric silanes system that is virtually VOC-free. The sol-gel system has been shown to be especially resistant to corrosion in combination with a further coating system. | ||
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