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European Coatings Conference
Extra
Pre-Conference Tutorial
13 February 2008
Berlin, Germany
Main conference
"Polyurethanes for High Performance Coatings V"
14/15 February 2008
Berlin, Germany
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 Welcome
At a Glance
Tutorial
Abstracts
Delegates Section
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| Events > European Coatings Conferences > PUR Coatings V > Abstracts |
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MAIN CONFERENCE: Abstracts
| THURSDAY, 14 February 2008 |
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| SESSION I: Improved isocyanates or no isocyanates? |
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Possibilities with high functional aliphatic polyisocyanates
Markus Mechtel, Bayer MaterialScience AG , GERMANY
Since the introduction of light fast aliphatic polyisocyanates based on HDI-biurets and HDI-isocyanurates polyurethane coatings have set a standard for high end coatings applications. 2K-polyurethane coatings offer a broad variety in adjusting the coatings performance according to the individual market requirements. The most recent development in polyisocyanate research are high functional HDI trimer/allophanates with a NCO-functionality of more than 4. The benefits of the new polyisocyanate in highly cross-linked 2K-polyurethane coatings will be demonstrated in various application areas, e.g. scratch resistant clearcoats for metal, plastics and wood.
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Isocyanate- and formaldehyde-free crosslinking of polymer dispersions
Maria Hechavarria-Fonsera, BASF AG , GERMANY
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Developing polyurethane coatings with low or no free isocyanate
Richard Jones, Baxenden Chemicals Ltd. , GREAT BRITAIN
Isocyanates are one of the fundamental building blocks for polyurethanes. However the hazards associated with handling monomeric isocyanate make them unacceptable for some potential users.
Methods of producing polyurethane prepolymers and with low free monomer and new developments preparing urethanes without using isocyanate are presented. Not only do these newer materials provide access to urethanes which are "isocyanate free", but they allow chemists to access new raw materials for coating formulation.
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| SESSION II: Waterworld |
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Waterborne 2K polyurethane clear coats - from property to function
Christoph Irle, Bayer MaterialScience AG , GERMANY
Waterborne 2K polyurethane clearcoats are currently substituting solventborne coatings systems in many applications. In particular in European, but also north American and Asian market places, legislation and increasingly critical end users are driving the change from solventborne to high end waterborne systems. Both A- and B-component of a waterborne 2K formulation can trigger the performance and application behavior of the coating. The chemical nature of the polyisocyanate - hydrophobic, standard types and diferent generations of hydrophilic polyisocyanates - but also choice and quantity of the cosolvent have a significant influence on the coatings process, appearance and durability.
State-of-the-art waterborne 2K systems
- in near-zero VOC formulations for floor coatings,
- for highly chemical resistant and fast drying clearcoats for commercial vehicles and car refinish and
- as wet look clear coats on furniture surfaces
are described in detail, giving proof to the broad diversity of the waterborne PU approach.
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Improving polyurethane dispersions using biobased technology
Erwin Honcoop, Uniqema bv/Croda International plc, THE NETHERLANDS
Polyurethanes have been used for many years to produce high performance materials such as solvent-borne coatings. However, though possible to formulate water-borne polyurethane systems, the widely used adipate polyester backbones often cause problems, such as reduction in storage stability and hydrolytic resistance. Additionally the water evaporation rate of polyurethane dispersions is seen as a drawback in certain applications. These deficits have been countered with a new range of hydrolytically stable polyester polyols using biobased technology. The reduced number of ester bonds, and the hydrophobic environment make these polyols practically immune for water, while keeping the resistance against UV characteristic for polyesters.
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Non-ionic diols for internal stabilisation of polyurethane dispersions
Petra Winberg, Perstorp Specialty Chemicals AB, SWEDEN
A non-ionic diol, which can be built into lateral position in a polyurethane backbone in order to achieve internal stabilisation of polyurethane dispersions, is presented. The benefits to be gained from using non-ionic segments in lateral positions along the polyurethane backbone in terms of tolerance of the resulting dispersion against electrolytes, cold temperatures and shear forces have been investigated and compared to other means of internal stabilisation. In addition, the tolerance of the resulting polyurethane coating against polar solvents has been studied. The non-ionic diol was observed to be an efficient dispersant functioning well together with anionic stabilisation in the form of dimethylolpropionic acid. The polyurethane dispersions stabilised with non-ionics and anionics displayed excellent stability towards electrolytes and cold temperatures and improved resistance towards shear forces. Furthermore the resulting flexible polyurethane coatings displayed improved resistance towards polar solvents.
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Multiphase acrylic/polyurethanehybrids - impact of morphology on
properties
Matthias Hölderle, Alberdingk Boley GmbH , GERMANY
Originally, polyurethane / acrylate hybrid systems have mainly been developed for cost reasons. There are, however, some unique combinations of properties which can be achieved neither with pure polyurethane nor with pure acrylic systems. For example, the combination of hardness and elasticity of some of PUR/acrylid hybrid materials makes it possible to formulate coatings with very good abrasion resistance.
To achieve the desired properties, the morphology of the polymer particles turns out to be as important as the overall composition. Systems with the same composition but different morphology can have completely different properties concerning blocking resistance, elongation at break or water resistance. In this presentation, structure property relationships and possibilities to produce new materials with new properties, based on well known raw materials, are discussed.
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New fast drying waterborne acrylic polyols for industrial two pack
urethane coatings
Jaap Akkerman, Nuplex Resins BV , THE NETHERLANDS
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| FRIDAY, 15 February 2008 |
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| SESSION III: Speeding up |
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Fluidized bed sintering with novel low temperature curable polyurethane powder coatings
Emmanouil Spyrou, Evonik Degussa GmbH , GERMANY
Low temperature curable powder coatings in fluidized bed applications offer the opportunity to combine application, melting and crosslinking in one step.
Uretdione (blocking agent free) based polyurethane powder coating formulations release no emission at all and thus comply with the highest environmental requirements. With the help of recently found catalysts the reactivity of these innovative coatings systems can be enhanced tremendously from 180 down to 130°C.
Metallic grids have been preheated to temperatures of about 140-200 degree centigrade and then dipped into the fluidized powder. The heat capacity of the metal is used both for melting and crosslinking of the powder. In case of substrates with lower heat capacity the cure can be completed in a post curing step.
Reactive polyurethane powder coatings might offer some additional opportunities compared to conventional thermoplastic coatings. Enhanced weather stability, better adhesion due to lower shrinkage and the possibility to apply both glossy and hard finishes at the same time are some of the special properties of these systems.
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Alternatives to DBTL catalysts in polyurethanes - a comparative study
Dr. Dieter Guhl, TIB Chemicals, Germany
Since many years organotin compounds are excellent and well established catalysts for polyurethane systems. Nevertheless, the continuing discussion regarding toxicological estimation especially of dibutyl tin compounds sparks the interest in alternatives.
Additionally to amines, zinc- and zirconium compounds basically bismuth based catalysts are tested and offered.
The present study shows, which compounds are in discussion as alternatives to DBTL. Furthermore possible results and the operating range are shown in different model- and end-user formulations. Restrictions and special characteristics are discussed.
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| SESSION IV: Nanoworld |
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Surfactant-based antimicrobial coating formulation
Prof. Dr. John Texter, Eastern Michigan University College of Technology,
USA
Anionic surfactants have been developed as vectors for easily incorporating antimicrobial silver ion into hydrophobic and hydrophilic coatings. While efficacy varies with the physical properties of the dominant binder, long acting activity is demonstrated at quite low levels of silver ion incorporation into the coating bulk. A new class of anionic surfactants lethal to Gram positive bacteria has been discovered, and the incorporation of such surfactants into practical industrial and consumer coatings is facile. These surfactants also offer means for making bulk polyurethanes and silicones intrinsically antimicrobial with anticipated applications in footwear, catheters, and other advanced materials. Ionic liquid reactive surfactants have been developed to make new quaternary copolymers as antimicrobial surface additives for advanced materials, and ionic liquid surface modifiers have been used to produce solvent-free nanofluids for making transparent and antimicrobial clear coats. Together these surfactant-based technologies provide formulation friendly means for making extant coatings antimicrobial.
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Carbonic acid stabilisation of nano-SiO2 particles in 2K polyurethane
containing clearcoats
Volkmar Stenzel, IFAM Fraunhofer Institut für Fertigungstechnik & angewandte Materialforschung, GERMANY
Formulations of 2K nano-particle-rich clearcoats often suffer from flocculation when the isocyanate component is added, which leads to slight turbidity, that is not acceptable for "class A"- surfaces. To avoid that, a new method for the stabilization of SiO2 nanoparticles in high-gloss polyurethane based clearcoats has been developed.
The stabilization depends on a treatment of the nano-particles with carboxylic acids, which cover the surface of the nano-particles and can be anchor-groups to the organic paint matrix. The new stabilisation method allows concentrations up to 40% SiO2 particles without flocculation.
The resulted clearcoats, in particular dual-cure systems, show excellent scratch- and abrasion resistance as well as high transparency and gloss.
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Design of low surface energy polyurethanes for underwater marine
coatings
Prof. Dean Webster, North Dakota State University Polymers And Coatings,
USA
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Mechanical properties and UV resistance of acrylic polyurethane coatings
containing unmodified and NCO-functionalized carbon nanofillers
Dr. Tinh Nguyen, NIST - National Institute of Standard and Technology, USA
Carbon nanofillers (CNFs), such as carbon nanotubes and carbon nanofibers, have a wide range of potential applications due to their unique mechanical properties, high aspect ratios, high conductivities, and low density. Many of these applications require good dispersion and chemical reactivity of CNFs in polymer matrices. However, CNFs are chemically inert and hard to be dispersed in polymeric materials. For effective stress transfer in nanocomposite coatings, chemical functionalization so that covalent bonds are formed between the nanofiller and the polymer matrix is desired. This talk will present mechanical properties and UV resistance of a polyurethane coating containing unmodified and NCO-functionalized carbon nanofillers (NCO-fCNFs). The first step of the functionalization was to generate COOH groups on the CNF surface. The COOH-terminated CNFs were then reacted with a diisocyanate monomer in which one NCO group has a higher reactivity than the other. By controlling the catalyst concentration and reaction time, the higher reactive NCO groups were consumed while the less reactive NCO groups were left for further reactions.
NCO-functionalized (multiple-walled carbon nanotube, single-walled carbon nanotube, and carbon nanofibers) have been prepared. FTIR, XPS and TGA results clearly showed that the functionalized CNFs contained a substantial amount of organic molecules and free NCO groups, indicating that this method of functionalization is effective. The NCO-fCNFs have been found to react readily with amines and polyols. Nanocomposites using a model automobile acrylic urethane formulation containing 1% unmodified and 1 % NCO-fCNFs (multi-walled carbon nanotubes and carbon nanofibers) have been fabricated for mechanical property and UV-resistance studies. Field emission SEM images of fractured surfaces revealed that the NCO-fCNFs were strongly imbedded in the PU matrix while unmodified CNFs were not. Tensile strength and tensile modulus of PU films containing NCO-fCNFs were much higher than films having no or with unmodified CNFs. Further, the UV resistance of PU films containing NCO-fCNF was greatly improved as compared to films without carbon nanofillers. However, NCO-fCNFs appear to be less effective than unmodified CNFs in preventing the photodegradation of PU. The results indicated that NCO-functionalized and unmodified carbon nanofillers can be potentially used to enhance the mechanical properties and UV resistance of PU coatings.
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Core/Shell nanoparticles for improving mechanical resistance of PUR
coatings
Gerhard Jonschker, Merck KGaA , GERMANY
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