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European Coatings Conference
Extra
Pre-Conference Tutorial
28 November 2007
Berlin, Germany
Main conference
"Easy-to-Clean /
Self-Cleaning Coatings"
29/30 November 2007
Berlin, Germany
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 Welcome
At a Glance
Tutorial
Abstracts
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| Events > Easy-to-Clean / Self-Cleaning Coatings > Abstracts |
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MAIN CONFERENCE: Abstracts
| THURSDAY, 29 November 2007 |
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Session I: Clean Cars
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Investigations of the dirt pick-up on wheel rims and consequences
for the coatings formulation
Prof. Wolfgang Bremser, University of Paderborn, Germany |
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Photocatalytic coatings for automotive application
Melanie Mönkemeyer, Nano-X GmbH, Saarbrücken, Germany |
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In times of constantly rising mobility and the vehicle density involved, an increase of the safety of cars and other automobiles is necessary. The project "Nanosafe", financed by the German government, has the goal to enhance the active and passive safety of vehicles by multi-functional nano-coatings in the interior and exterior. The developed coatings are predominantly based on nano-scaled titania (TiO2), which shows photo-activation with UV light in order to prevent or reduce the soiling of surfaces. Also hydrophobic coatings have been examined regarding their effectiveness to dirt avoidance. The target substrates vary from glass, plastic (polycarbonate, PMMA) up to painted surfaces. Potential applications go from headlight interior coating over windscreen, dash panel up to the outer skin of the automobile. The results of selected coating systems are presented regarding mechanical and chemical stability as well as concerning photocatalytic activity.
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Promotion and assessment of photocatalytic self-cleaning films
using intelligent inks and other methods
Prof. Andrew Mills, University of Strathclyde, Great Britain |
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Industrial use of polysilazane polymers in Easy-to-clean applications
Dr. Can Vu, Clariant, France |
Polysilazanes are a new class of industrial polymers consisting of silicon, nitrogen, hydrogen and, in the case of “organopolysilazanes”, carbon. Such polymers can be considered either “inorganic” in nature (perhydropolysilazanes), or “organic” in nature (organopolysilazanes or polycarbosilazanes) and have both silicon and nitrogen atoms in their backbone.
The polymers self condense in ambient conditions to give dense clearcoats which strongly adhere to most surfaces from metal to glass, wood and plastics. Applications are traditional techniques such as spraying, dipping or roll coating or just simply by wiping.
Controlling the chemistry and the formulation of polysilazanes allows the obtention of clear and pigmented hybrid coatings with multifunctional properties such as antigraffiti, easy-to-clean, UV and Temperature stability.
We will in this presentation give a broad spectra of industrially validated applications insisting particularly on railways and automotive applications.
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Session II: From architecture to appliances
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Anti-aging for facades with a silica / acrylate nanocomposite binder
Dr. Harm Wiese, BASF AG, Ludwigshafen, Germany |
Silica/acrylate nanocomposite dispersions are a new class of binders for waterbased coatings.
Film formation of these nanocomposite dispersions takes place at the same temperatures as for acrylate dispersions having the same polymer composition, whereas film hardness and strength are strongly improved. The films are highly transparent, provide an excellent hardness/elasticity compromise, do not swell in water and show very low water whitening.
Further film properties are high heat resistance, water vapour permeability, solvent resistance, adhesion to mineral substrates and a favourable burning behaviour.
Silica/acrylate nanocomposite dispersions therefore are a highly promising approach for solvent-free coatings. Special application features for paints are low dirt pick-up and high blocking resistance.
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Oleophobic, hydrophilic coatings: the optimum system for exterior
dirt pick up resistance
Dr. Andrew Edward Moody, DuPont Surface Solutions, Paris, France |
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Fluorosurfactants can enable the development of coatings which offer repellency to oily soils while allowing uniform rinsing of the surface: a combination of effects which gives paints excellent dirt pickup resistance. This paper will discuss how we can draw on the multi-functional properties provided by fluorosurfactants, including anti-crater, improved levelling, reduced foaming, decreased block, open-time extension and oil repellency to deliver an optimum formulation to counteract Dirt Pickup Resistance. Applications and formulation considerations will be presented from actual case studies, based on seven years of research of architectural coating applications.
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Clean surfaces on glass, ceramic, wood and metal - the possibilities of
silane treatment
Dr. Philipp Albert, Degussa GmbH, Rheinfelden, Germany |
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Organofunctional alkoxysilanes are well known for their broad range of applications. Easy-to-Clean formulations based on fluoroalkylsilanes can be used on diverse smooth substrates like glass and enamel. There are already several systems available e.g. for usage on shower cabins and windscreens. More sophisticated systems are based on sol-gel technology and are water-based and VOC-free. These novel coatings show excellent properties and are applicable on glass, enamel, as well as metal or wood.
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Long-term effectiveness of surface protection systems on construction
materials
Dr. Manuel Friedel, Degussa GmbH, Rheinfelden, Germany |
Banks, train and underground stations as well as shopping malls – all of these buildings have to be considered in terms of functionality and representative purpose. Therefore, function as well as appearance has to be protected and maintained.
Silane systems are particularly suited to protect the surface of various construction materials such as concrete, sand limestone or marble from environmental influences like water staining, moss, algae as well as soot and oil stains. Silane systems are also used as corrosion inhibitors for reinforced steel. Furthermore, silanes are available that create a low energy facing thus rendering a building surface highly hydro- and oleophobic. Silanes thereby help to prolong maintenance cycles and to ease cleaning. The latest silane systems are oligomeric and are essentially VOC free – adding an element of increasing environmental friendliness.
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New concepts for waterborne easy-to-clean coatings
Hartmut Ottensmann, Alberdingk Boley GmbH, Krefeld, Germany |
For many years the world of paints & varnishes is no more imaginable without waterborne polyurethane coatings.
Nowadays they are not only used in the field of plastic and wood coatings, but as well in almost any other application field such as easy-to-clean coatings, industrial flooring,…
Waterborne, 2-pack Polyurethanes have been proving their performance and reliability in everyday life for more than a decade and can therefore be considered as a state-of-the-art technology with a constantly growing market-share.
Due to the upcoming new EU-regulations regarding the solvent content, it is necessary to develop new solvent-free easy-to-clean coatings in order to fulfil the future demands in this market.
Alberdingk Boley has started this development already in 2005 and is now able to offer solventfree, high-end products for the easy-to-clean market.
The paper will show a comparison of solvent-containing easy-to-clean-coatings versus solvent-free 2-pack Polyurethanes. This essay will also disclose a comparison of different chemical basics of the Polyurethanes (e.g. fluorine-modification).
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Durable easy-to-clean coating for home appliance application
Dr. Inka Henze, Schott AG, Mainz, Germany |
New functionalities for surfaces of all kinds have developed into an important trend. Because they simplify daily routines, they fit in well with today's life styles, where saving time is often an objective. This trend has reached kitchens and, more specifically, ovens.
It is essential that the "Easy to Clean" coated full glass pane made out of SCHOTT flat glass needs to be transparent and capable of meeting high demands. In addition to being easy to clean, and capable of withstanding heat and mechanical wear, indoor oven panes as well as soda lime hop tops must also satisfy food safety regulations.
With its "Easy to Clean" coating, SCHOTT has succeeded in becoming the first vendor to offer a stable coating that satisfies market requirements and appeals to the eye. This coating fits in perfectly with the trend towards modern convenience products.
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| FRIDAY, 30 November 2007 |
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Session III: Novel polymer technology
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Self-replenishing low adherence coatings
Tamara Dikic, Eindhoven University of Technology,
The Netherlands |
Low surface tension coatings are widely used today since their water/oil repellency makes them easily cleanable. The low surface tension is provided by fluorine or silica containing polymers/species that are present on the surface of a film. Difficult processing and price of films with a large amount of fluorine in the bulk makes them not suitable for a wide range of applications. Therefore, the self-stratification of low amount of fluorine rich species upon film formation has been of the increasing research interest as the strategy for obtaining coatings with low surface energy and desired bulk properties. The low surface tension of these films is provided by a thin fluorine-rich layer on the surface of a coating. A drawback of these materials is that the fluorine enriched layer is rather thin (~ 20 nm) and therefore will not sustain low surface tension upon damage or wearing off of the material.
Herewith self-replenishing low adherence films are defined as those able to retain low surface energy even upon damage by providing the sufficient amount of low surface energy species on newly created surfaces.
The approach we have taken is to relatively homogeneously distribute fluorinated species that contain long polymer spacer throughout the bulk of a film. These species will be able to reorient or even move from sub-layers driven by the surface tension of the new film/air interface. The process will start spontaneously after the damage on sufficient temperature as the prerequisite for mobility of the chains. Once on the new interface, they will lower the surface tension of the complete film.
Miscibility, mobility and spacer length of network precursors (dangling chains that are fluorine end-capped) as well as the mobility of the bulk polymer largely influence the possibility of self-replenishing. The possibility of making self-replenishing low surface films and using force displacement measurements and XPS for characterizing the change in surface energy of a film before and after the damage will be represented.
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Superhydrophobic and self-cleaning cellulose surfaces by controlled
polymerisation
Prof. Eva Malmström, Royal Institute of Technology - KTH Fibre and Polymer Technology, Stockholm, Sweden |
Controlled polymerizations have attracted considerable interest over the last 10-15 years. One interesting feature with is that it allows for covalent surface modification where the initiating group is chemically attached to the substrate where after the substrate is subjected to the polymerization conditions. If successful, the polymer chains will grow from the surface providing a tool to control surface properties. By utilizing a combination of surface roughness, high grafting density and suitable monomers it is possible to obtain superhydrophobic surfaces exhibiting very high contact angles (< 165°) with low hysteresis towards water droplets.
The aim of the present paper is to discuss how superhydrophobic and self-cleaning biobased substrates can be accomplished by the use of controlled radical polymerization.
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Easy-to-clean properties for crosslinking coatings, based on silicone additives
Christoph Buchmann , BYK Chemie GmbH, Germany |
Paint does not only provide protection, but also a decorative finish. Most coatings, however, are exposed to the normal weathering process, which includes dirt pick-up. Over time the appearance deteriorates. Accordingly, there is a high interest in the industry for coatings with self-cleaning or easy-cleaning properties. In nature, there are perfect examples for self-cleaning effects, where rain water easily removes dirt from surfaces. Scientific studies have identified the three major properties for this self-cleaning effect, namely: Low surface tension, a permanent hydrophobic surface and a surface micro structure.
One can reproduce this effect in a coating, but a micro structure will result in a matt coating. However, additives can provide a long term self-cleaning effect without the necessity of a structured surface, so that high gloss systems with easy-to-clean surfaces can be achieved. This concept is available for solvent-borne as well as for water-borne systems.
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Development of smart surfaces: from responsive copolymers to an
easy clean coating
Dr. Gaelle Baquey, Chamelic Limited, Leeds, Great Britain |
Over the last few years, adsorption of polyelectrolytes at solid/liquid interfaces has gained in popularity due to their potential applications (drug delivery, preparation of nanosized materials, and smart surface coatings).
To develop such a smart surface coating, a series of new stimulus responsive copolymers has been synthesized by controlled radical polymerization. Such polymers are able to self assemble into micelles and have a reversible morphology once upon adsorbed onto a surface. The adsorbed micelles seen at high pH are observed to "open" at low pH; and, the original core-shell adsorbed micelles appear to be reformed on returning to high pH.
This approach enables us to prepare a pH-responsive surface coating film via an easy and straight forward process, without a use of organic solvents, drying and/or annealing procedures. These coatings are currently used for the fabrication of an easy-clean coating.
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Oil repellency on superhydrophobic surfaces
Dr. Weihua (Marshall) Ming, Eindhoven University of Technology, Eindhoven, The Netherlands |
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There have been enormous renewed interests in the past decade on superhydrophobic surfaces in both academia and industry, partly inspired by the elegant examples from our Mother Nature. It is also highly desirable for the superhydrophobic surface to be oil repellent to maintain its self-cleaning property related to water; otherwise, the superhydrophobicity can be easily comprised by oily substances in both household and industrial applications. We have successfully obtained superhydrophobic films by incorporating raspberry-like silica particles to conventional polymer films, in a way mimicking the dual-size structure of the lotus leaf. We further examined the feasibility to achieve oil repellency on dual-sized-structured surfaces. By modifying the dual-size-structured surfaces with perfluoroalkyl chains, we successfully obtained (super) oil-repellent films as well as superlipophobic cotton textiles.
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Session IV: Beyond dirt-repellence
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Biomimetic ice nucleating coatings
Stefan Holberg, Teknologisk Institut, Aarhus, Denmark |
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Ice repellent surfaces are of great interest for a wide variety of applications including the continuous production of ice cream or the use of ice slurries as environmental friendly coolants as well as the protection of many outdoor surfaces. When covered with ice, airplane wings and wind turbine blades loose efficiency and optical sensors loose sight. Based on organisms living in polar or mountainous regions, a biomimetical model for ice nucleating surfaces will be presented and the difference between ice nucleating and freezing point depressing surfaces, both strategies applied by nature to survive cold environments, will be outlined. The active principle of combining a hydrophobic surface with nanoscaled hydrophilic nucleation points could be converted to novel coatings, where the formation of ice crystals is encouraged, but then these crystals are easily removed by an air or water stream.
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Developing effective, verifiably safe and environmentally compatible
marine coatings
Dr. Christof Baum, Alfred Wegener Institute for polar and marine research, Bremerhafen, Germany |
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Marine coatings are in service to protect structures such as ships and platforms or sensors. The break-down of the desired protective performance occurs during the process of biofouling and corrosion, causing damage to the underlying materials. It is difficult to predict the performance of marine coatings, when relying solely on field trials. In order to enhance the reproducibility and significance of results new in-vitro testings are available such as bioassays based on settling stages of barnacles and a permanent culture of barnacles, high precision force measurements, a flow channel for analytical studies of the dehesion of hydrodynamic obstacles and shear inducing biolayers. Using these tools, new foul-release greases and pastes inspired by the skin of dolphins were adapted for the aquaculture market very quickly.
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Development of a novel kind of nanocoating showing anti-fingerprint (afp) properties
Dr. Christoph Dölle, Fraunhofer Institute for Manufacturing Technology and Applied Materials Research (IFAM), Bremen, Germany |
There is a high demand for clean surfaces presenting a perfect, hygienic optical appearance insensitive to fingerprints. Surfaces with antifingerprint-coatings are desirable for the household as well as for the automotive area for example or to be more general for noble surfaces.
The Fraunhofer Institute in Bremen has developed a novel kind of nanocoating showing an antifingerprint-property (afp). This means that although a fingerprint might be present on the surface it is optically invisible to a viewer. The effect is based upon the reduction of the optical contrast caused by a fingerprint. Therefore, a robust »island like« coating is generated by applying either a hybrid wet-chemical/plasma process or by a wet-chemical/UV-light process. A fingerprint characterization as well as details concerning the coating process will be presented.
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