Titre : |
Water-based system to prevent the yellowing of opaque coatings on knotted pine wood |
Type de document : |
texte imprimé |
Auteurs : |
Rodrigo Coniglio, Auteur ; Wolfgang Gaschler, Auteur ; Leonardo Clavijo, Auteur |
Année de publication : |
2023 |
Article en page(s) : |
p. 781-788 |
Note générale : |
Bibliogr. |
Langues : |
Américain (ame) |
Catégories : |
Bois -- Revêtements protecteurs Décoloration Essais accélérés (technologie) Liants Mesure Opacité (optique) Primaire (revêtement) Résistance au jaunissement Revêtements -- Finition
|
Index. décimale : |
667.9 Revêtements et enduits |
Résumé : |
Water-based opaque coatings used on pine wood show undesired discolorations related to the presence of knots which have an outstanding high concentration of extractives. These compounds, of both polar and nonpolar nature, migrate through the polymeric structure resulting in a yellow–brown spot over the knot. A water-based coating system comprising a polar primer and a nonpolar topcoat proved to have remarkable performance preventing the migration of the extractives and the discoloration of the painted surface. The knot bleeding resistance was tested following EN 927–7. The color of the coating over the knot was measured using CIELab coordinates, and the resulting color difference in comparison with the surrounding paint was in all cases less than the accepted limit for discoloration of opaque coatings. The need to have the combined system to successfully block the whole spectrum of extractives was proved by the evaluation of the individual coatings as well as the utilization of polar dispersions as topcoats. The system presented in this work constitutes a solution to the discoloration of water-based coatings over knotted pine wood. |
Note de contenu : |
- MATERIALS AND METHODS : Wood material - Coatings - Coating procedure - Artificial weathering procedure - Discoloration measurement
- RESULTS AND DISCUSSION : Performance of a nonpolar binder - Performance of a polar binder - Performance of a system of a polar primer and nonpolar topcoat - Performance of a system of a polar primer and polar topcoats
- Table 1 : Hansch parameter for the binders used in this work
- Table 2 : Exposure parameters according to EN ISO 4892–2:2006
- Table 3 : Discoloration results of the staining test on 20 boards painted with the binder A
- Table 4 : Maximum discoloration measured for boards painted with the binder B as pigmented coating
- Table 5 : Discoloration results of the staining test on 20 boards painted with the binder A as primer and the binder B as topcoat
- Table 6 : Detail of the systems used to test the performance of a polar primer and polar topcoat
- Table 7 : Maximum discoloration measured for boards painted with the systems with polar primer and polar topcoats |
DOI : |
https://doi.org/10.1007/s11998-022-00723-w |
En ligne : |
https://link.springer.com/content/pdf/10.1007/s11998-022-00723-w.pdf?pdf=button% [...] |
Format de la ressource électronique : |
Pdf |
Permalink : |
https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=39318 |
in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 20, N° 2 (03/2023) . - p. 781-788