Session 8: Waterborne Systems
Chair: Dr. Jurgen Scheerder, DSM NeoResins+, NLThanks to its VOC-free or VOC-reduced character, waterborne coating is a fast developing technology. In many applications, waterborne coating systems have become the standard solution, replacing their solventborne counterparts. The first session on waterborne systems picks up new materials-based developments like polymer dispersions for metal coatings, fluoropolymer latex hybrids for ultra-low water sensitivity coatings and environmentally friendly fluoropolymer dispersions for coatings.
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Tuesday Morning 9.00 – 12.30 h
Room Shanghai
8.1 9.00 – 9.30 h New polymer dispersions for metal coatings Dr. Robin Harrison, Synthomer, GB New types of polymer dispersion have been developed to give exceptionally high levels of corrosion resistance in a range of water borne metal coatings. The use of new monomer compositions and novel water phases to achieve high levels of adhesion and corrosion resistance is discussed. Subsequent polymer development, using appropriate polymerisation techniques and functional polymers to control particle size, shear stability and cross-linking properties is described. Formulation parameters for paints based on the new polymer types are also described. The requirements for high performance primers, topcoats and direct to metal coatings are considered. Optimum choice of dispersants, coalescing aids, viscosity control agents and, in particular, active pigments is discussed. Prototype paint formulations based on these considerations are shown generically. Salt spray testing is presented, indicating what can be achieved with paints based on the new technology compared with existing water borne systems.  | ||
| 8.2 9.30 – 10.00 h Designing fluoropolymer latex hybrids for ultra-low water sensitivity coatings Dr. Kurt Wood, Arkema, US In order to capitalize on the inherent hydrophobicity of fluoropolymers to make highly water resistant latex coatings, careful attention must be paid to the optimization of hydrophilic stabilizing materials in the latex manufacturing process, to factors which control the latex morphology, and to formulation details. We discuss new results for experimental PVDF-acrylic hybrid systems which identify particular critical factors for reducing water sensitivity. One surprising result is that lower Tg, lower VOC coatings can have better water resistance than higher Tg coatings, despite the expectation that they should have higher water diffusivity. | ||
| 8.3 10.00 – 10.30 h Environmentally friendly fluoropolymer dispersions for coatings Dr. Marco Malvasi, Solvay Solexis, IT Aqueous dispersions of fluoropolymers used in water based coatings are obtained via emulsion polymerization in the presence of a non-telogenic perfluorinated anionic emulsifier, leading to 150-300 nm particles. Recent developments in fluoropolymers dispersions include matching knowledge on polymer chain design and fluorosurfactant content reduction in the dispersions with use of new fluorinated anionic surfactant molecules. Results of these investigations combined with appropriately selected phenol-free non-ionic surfactant allows to obtain environmentally friendlier fluoropolymer dispersions that even improve the processing performance compared to standard products. Starting from the colloidal properties of the initial system, this presentation discusses basic features (shear and settling stability, rheology) and applicative characteristics (film formation, wettability) of environmentally friendly fluoropolymer dispersions obtained by substituting APE surfactants with green ethoxylated alcohols and by extracting perfluorinated surfactants. 10.30 – 11.00 h Networking: Refreshments & Coffee Break | ||
| 8.4 11.00 –11.30 h Phase separation in alkyd/acrylic hybrids and blends for waterborne binders Prof. Diethelm Johannsmann, Clausthal University of Technology, DE Our aim is to determine the effect of alkyd hydrophobicity on the phase distribution and structure of waterborne blend films containing acrylic latex and either alkyd/acrylic hybrid particles or alkyd emulsion droplets. In our experiments, the acrylic particles are labelled with a fluorescent dye, which is not prone to photo-bleaching. Confocal microscopy and confocal Raman spectroscopy are used to determine the distribution of the phases within the resulting films. Hybrid particles polymerised with the hydrophilic alkyd were found to create clusters when blended with acrylic particles to make films. On the other hand, hybrid particles containing the hydrophobic alkyd were much more homogeneously distributed in the films. Furthermore, in blends of alkyd emulsion droplets and fluorescent acrylic latex particles, there is evidence for flocculation of the alkyd phase and coalescence into droplets, some as large as 10 ?m. A finer phase distribution is found with the hydrophilic alkyd. | ||
| 8.5 11.30 - 12.00 h Modifying the effects of water on aqueous-based coatings of exterior wood surfaces and enhancing secondary properties in OEM wood coatings Luc Vanderstappen, Michelman, LU To protect exterior wood surfaces, coating formulators face a number of problems such as UV degradation, color fading, dirt pick-up, water absorption, cracking, mold and mildew growth, swelling and splintering. Wax emulsions are an important tool to reduce the deleterious effects of many of these issues, especially those associated with the presence of water. Wax emulsions are a cost effective aid to protect wood from water. Water based wax emulsions are low in VOC’s and can provide water beading to protect the coating and prevent grain raising. Michem®Wood Coating emulsions provide beading plus resistance to swelling, cracking and warping. Mold, mildew growth and tannin staining are also reduced. This discussion provides pictorial and graphical test data supporting performance of wax containing coatings to modify water repellency. Emulsion selection criteria are also discussed with a focus on stability in low VOC coatings. Water repellant wax emulsions contribute to a number of secondary functions in aqueous coatings by improving mar and scratch resistance, modifying coefficient of friction, controlling gloss and providing block resistance. | ||
| 8.6 12.00 - 12.30 h Easy-to-disperse pigment preparations in granule form for waterborne coating application Dr. Christian Götz, Evonik Degussa, DE Evonik Industries offers first grades of a new easy-to-disperse pigment preparation series for water-borne coating systems. The new preparations allow the user to lower costs by significantly reducing dispersion time, increasing throughput, minimizing the cleaning process and utilizing raw materials more efficiently. Furthermore this new pigment preparation system allows for greater flexibility to meet market needs and provide consistent coloristic results. Using an innovative proprietary process, the preparations are prepared by combining a novel acrylic resin, additive compound and high quality pigments. Conventional milling is no longer necessary. The dust-free preparations can be solubilized in water or a waterborne binder within 15 to 45 minutes using a dissolver and small amounts of ammonia/amine resulting in a paste with broad compatibility with most of the waterborne raw materials. The presentation is presenting this innovative technology showing evaluation results and application examples. | ||
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