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Badila M.,Carinthian Competence Center | Jocham C.,Carinthian Competence Center | Zhang W.,Zhejiang Agriculture And forestry University | Schmidt T.,TIGER Coatings GmbH and Co. KG | And 4 more authors.
Progress in Organic Coatings | Year: 2014

The powder coating of veneered particle boards by the sequence electrostatic powder application - powder curing via hot pressing is studied in order to create high gloss surfaces. To obtain an appealing aspect, veneer sheets were glued by heat and pressure on top of particle boards and the resulting surfaces were used as carrier substrates for powder coat finishing. Prior to the powder coating, the veneered particle board surfaces were pre-treated by sanding to obtain good uniformity and the boards were stored in a climate chamber at controlled temperature and humidity conditions to adjust an appropriate electrical surface resistance. Characterization of surface texture was done by 3D microscopy. The surface electrical resistance was measured for the six veneers before and after their application on the particle board surface. A transparent powder top-coat was applied electrostatically onto the veneered particle board surface. Curing of the powder was done using a heated press at 130 °C for 8 min and a smooth, glossy coating was obtained on the veneered surfaces. By applying different amounts of powder the coating thickness could be varied and the optimum amount of powder was determined for each veneer type. © 2014 Elsevier B.V. Source

Jocham C.,Kompetenzzentrum Holz GmbH | Schmidt T.W.,TIGER Coatings GmbH and Co. KG | Wuzella G.,Kompetenzzentrum Holz GmbH | Teischinger A.,University of Natural Resources and Life Sciences, Vienna | And 2 more authors.
Journal of Adhesion Science and Technology | Year: 2011

In the powder coating of non-conventional substrates such as engineered wood, natural fibre composites or synthetic polymers, several technological problems must be resolved which result from the substantial differences between such coating substrates and metallic ones. Unlike metals, non-conventional carrier materials show low temperature stability, much rougher and more irregular surface texture, large dependence of their dimensional stability on the moisture content of the surrounding environment and significantly less electrical conductivity. Hence, when powder technology is transferred from coating metals to coating fiberboards, for example, the surfaces of the boards need to be engineered in order to provide ideal adhesion for the coating layer. One major problem is the lack of electrical conductivity. Since the powder coatings are preferably applied using electrostatic spraying equipment, sufficient electrical conductivity of the surface is a major requirement and the correct moisture content plays an important role as well. In the present study, a pre-heating process was used to improve the powder application during powder coating of medium density fibreboards (MDFs). Electrical resistance, treatment temperature and moisture content were systematically studied to better understand the complex physical mechanisms leading to an improvement in powder application by such a pre-heating process. To this end, a new sophisticated procedure was developed to measure the electrical resistance (surface and core resistance) during pre-heating. The results show, that the electrical resistance of MDF is influenced by board temperature and moisture content. Moreover, it is confirmed that pre-heating proves to be an efficient method to improve the powder application onto non-conventional substrates. © Koninklijke Brill NV, Leiden, 2011. Source

Holzmann D.,Johannes Kepler University | Holzmann D.,TIGER Coatings GmbH and Co. KG | Holzinger D.,TIGER Coatings GmbH and Co. KG | Hesser G.,Johannes Kepler University | And 2 more authors.
Current Nanoscience | Year: 2013

The properties of nanoscale titanium dioxide particles generated in-situ during a polycondensation process are explored and the compounds obtained are investigated as UV-stabilizing additives for the formation of ultradurable powder coatings. Beneficial effects of TiO2 nanoparticles for the long-term photoprotection of polyester composite materials under accelerated weathering conditions could be clearly demonstrated. These results are of considerable interest for the development of new hybrid organic-inorganic systems to be used as transparent coatings for outdoor applications such as UV-resistant protection layers stabilized with functional nanoparticles based on cheap, environmentally benign and abundant compounds. © 2013 Bentham Science Publishers. Source

Svehla J.,Vienna University of Technology | Feichtenschlager B.,Vienna University of Technology | Schmidt T.,TIGER Coatings GmbH and Co. KG | Holzinger D.,TIGER Coatings GmbH and Co. KG | Kickelbick G.,Saarland University
Journal of Sol-Gel Science and Technology | Year: 2011

Polyester nanocomposites were prepared using sol-gel precursors, prehydrolyzed sols, or nanoparticles in polyester formulations. The different inorganic components were introduced in the early stages of the esterification reaction and a typical polymerization temperature program was applied leading to temperatures up to 240 °C at low pressures. The structural and physical properties of the final materials depend on the applied method for the introduction of the sol-gel materials. Silicon atoms were incorporated into the polyester chain if silicon tetraalkoxide was used as precursor. The silicon atoms represent branching points in the polymer structure. Prehydrolyzed sols that were prepared under acidic conditions were another source of silicon and formed larger inorganic aggregates in the polymer matrix. Nanoparticles prepared via the Stöber process were the third inorganic species in polyester formation. All three processing pathways produced different kinds of materials depending on the type of silica incorporated in the polyester networks but also with regard to the nanoscale structure of the materials. Both, composition and structure have a major influence on the final polyester nanocomposite properties. Model reactions between silicon tetraalkoxides and diols or diacids using the temperature program for the polyester formation showed that exchange reactions of the alkoxides and the alcohols or acids can occur and the obtained products can carry out side reactions in the polyester formation. The final materials show a homogeneous distribution of the silicon containing moieties in the polyester matrix. The viscosities and the branching degrees of the polymers changed dramatically compared to the pristine polymers by incorporation of the sol-gel precursors. © 2010 Springer Science+Business Media, LLC. Source

Holzmann D.,Johannes Kepler University | Holzmann D.,TIGER Coatings GmbH and Co. KG | Schofberger W.,Johannes Kepler University | Holzinger D.,TIGER Coatings GmbH and Co. KG | And 2 more authors.
Monatshefte fur Chemie | Year: 2011

Surface-modified titania nanoparticles were prepared and their suitability as additives for the long-term UV-photoprotection of polymer materials was investigated. It was demonstrated that the functionalization of nano-TiO 2 with different fatty acid and phosphonate-based grafting reagents has a beneficial effect on the long-term stability of polyester composites under accelerated weathering conditions. These results are of considerable interest for the development of robust organic-inorganic hybrid systems that can be utilized as transparent but UV-resistant protective layers for outdoor applications. © Springer-Verlag 2011. Source

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