This work evaluates the effects of accelerated aging on the discolouration of surface-treated spruce wood and oak wood coated with solvent-based polyurethane lacquers, and surface-treated spruce wood coated with water-based transparent coating systems. All concerned coating materials were intended for indoor use. It was also explored how the colour stability of spruce wood and oak wood surfaces treated with solvent-based polyurethane lacquers was affected by wood surface layer modifications with pigment or stain mordants applied before these lacquers. Another issue studied was how the lignin stabilizer admixed into the primer and pigments admixed into the top coating layers affected the stability of water-based coating systems on spruce. The experimental results showed that the accelerated aging process with a simulation of indoor conditions induced significant discolouration of wood surfaces coated with solvent-based polyurethane lacquers and water-based coating systems. There were also confirmed significant impacts of all the studied factors (wood species, lacquer/coating system type, lacquer modification, wood pre-treatment with pigment and stain mordants). The spruce wood surfaces coated with solvent-based polyurethane lacquers were less stable (ΔE = 10-19, dependent on the lacquer type) than the oak surfaces treated in the same ways (ΔE = 4-11). There were also confirmed significant impacts of the particular surface treatment on the colour stability as well as significant impacts of wood surface pre-treatment with pigment and stain mordants (ΔE = 4-17-for spruce wood, and ΔE = 5.5-13-for oak wood). In the case of water-based lacquers, the ΔE values ranged between 3 and 11 (according to the coating system type). The results show that an appropriate UV absorbent combined with an appropriate lignin stabilizer and pigment mordant may enable attaining the required colour stability for a given surface treatment applied on a given wood species.

Department of Wood Processing and Biomaterials Faculty of Forestry and Wood Sciences Czech University of Life Sciences Prague Kamýcká 129 165 00 Prague Czech Republic

Department of Wood Science Faculty of Wood Sciences and Technology Technical University in Zvolen T G Masaryka 24 96001 Zvolen Slovakia

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De Meijer M. Review on the durability of exterior wood coatings with reduced VOC-content. Prog. Org. Coat. 2001;43:217–225. doi: 10.1016/S0300-9440(01)00170-9. DOI

Cogulet A., Blanchet P., Landry V. The multifactorial aspect of wood eathering: A review based on a Holistic approach of wood degradation protected by clear coating. BioResources. 2018;13:2116–2138. doi: 10.15376/BIORES.13.1.COGULET. DOI

Tolvaj L., Faix O. Proceedings of the 2nd International Conference on the Development of Wood Science/Technology and Forestry. University of Sopron; Sopron, Hungary,: 1996. Modification of colour by steaming.

Williams R.S., Knaebe M.T., Evans J., Feist W.C. Erosion rates of wood during natural weathering: Part III. Effect of exposure angle on erosion rate. Wood Fiber Sci. 2001;33:50–57.

Kishino M., Nakano T. Artificial weathering of tropical woods. Part 1: Changes in wettability. Holzforschung. 2004;58:552–557. doi: 10.1515/HF.2004.084. DOI

Pandey K.K., Vuorinen T. Comparative study of photodegradation of wood by a UV laser and a xenon light source. Polym. Degrad. Stab. 2008;93:2138–2146. doi: 10.1016/j.polymdegradstab.2008.08.013. DOI

Fan Y., Gao J., Chen Y. Colour responses of black locust (Robinia pseudoacacia L.) to solvent extraction and heat treatment. Wood Sci. Technol. 2010;44:667–678. doi: 10.1007/s00226-009-0289-7. DOI

Chang T.C., Chang H.T., Wu C.L., Chang S.T. Influences of extractives on the photodegradation of wood. Polym. Degrad. Stab. 2010;95:516–521. doi: 10.1016/j.polymdegradstab.2009.12.024. DOI

Chen Y., Gao J., Fan Y., Tschabalala M.A., Stark N.M. Heat–induced chemical and color changes of extractive–free black locust (Robinia pseudoacacia) wood. BioResources. 2012;7:2236–2248. doi: 10.15376/biores.7.2.2236-2248. DOI

Persze L., Tolvaj L. Photodegradation of wood at elevated temperature: Colour change. J. Photochem. Photobiol. B Biol. 2012;108:44–47. doi: 10.1016/j.jphotobiol.2011.12.008. PubMed DOI

Huang X., Kocoege D., Kocaefe Y., Boluk Y., Pichette A. A spectrocolorimetric and chemical study on color modification of heat–treated wood during artificial weathering. Appl. Surf. Sci. 2012;258:5360–5369. doi: 10.1016/j.apsusc.2012.02.005. DOI

Liu Y., Shao L., Gao J., Guo H., Chen Y., Cheng Q., Via B.K. Surface photo-discoloration and degradation of dyed wood veneer exposed to different wavelengths of artificial light. Appl. Surf. Sci. 2015;331:353–361. doi: 10.1016/j.apsusc.2015.01.091. DOI

Liu R., Zhu H.W., Li K., Yang Z. Comparison on the aging of woods exposed to natural sunlight and artificial xenon light. Polymers. 2019;11:709. doi: 10.3390/polym11040709. PubMed DOI PMC

Reinprecht L., Mamoňová M., Pánek M., Kačik F. The impact of natural and artificial weathering on the visual, colour and structural changes of seven tropical woods. Eur. J. Wood Wood Prod. 2018;76:175–190. doi: 10.1007/s00107-017-1228-1. DOI

Kropat M., Hubbe M.A., Laleicke F. Natural, accelerated and simulated weathering of wood: A review. BioResources. 2020;15:9998–10062. doi: 10.15376/biores.15.4.Kropat. DOI

Landry V., Blanchett P. Weathering resistance of opaque PVDF-acrylic coatings applied on wood substrates. Prog. Org. Coat. 2012;75:494–501. doi: 10.1016/j.porgcoat.2012.06.004. DOI

Kocaefe D., Saha S. Comparison of the protection effectiveness of acrylic polyurethane coatings containing bark extracts on three heat-treated North American wood species: Surface degradation. Appl. Surf. Sci. 2012;258:5283–5290. doi: 10.1016/j.apsusc.2012.02.017. DOI

Saha S., Kocaefe D., Boluk Y., Pichette A. Surface degradation of CeO2 stabilized acrylic polyurethane coated thermally treated jack pine during accelerated weathering. Appl. Surf. Sci. 2013;276:86–94. doi: 10.1016/j.apsusc.2013.03.031. DOI

Saha S., Kocaefe D., Krause C., Krause C., Boluk Y., Pichette A. Enhancing exterior durability of heat-treated jack pine by photo-stabilization by acrylic polyurethane coating using bark extract. Part 2: Wetting characteristics and fluorescence microscopy analysis. Prog. Org. Coat. 2013;76:504–512. doi: 10.1016/j.porgcoat.2012.11.008. DOI

Wan C., Lu Y., Sun Q., Li J. Hydrothermal synthesis of zirconium dioxide coating on the surface of wood with improved UV resistance. Appl. Surf. Sci. 2014;321:38–42. doi: 10.1016/j.apsusc.2014.09.135. DOI

Girardi F., Cappellettoa E., Sandak J., Bochichio G., Tessadri B., Palanti S., Feci E., Di Maggio R. Hybrid organic–inorganic materials as coatings for protecting wood. Prog. Org. Coat. 2014;77:449–457. doi: 10.1016/j.porgcoat.2013.11.010. DOI

Reinprecht L., Šomšák M. Effect of plasma and UV-additives in transparent coatings on the colour stability of spruce (Picea abies) wood at its weathering in xenotest. Acta Fac. Xylologiae Zvolen. 2015;57:49–59. doi: 10.17423/afx.2015.57.2.05. DOI

Liu X.Y., Liu M., Lv M.Q., Lv J.F. Photodegradation of Three Hardwood Species by Sunlight and Xenon Light Sources. BioResources. 2019;14:6909–6922. doi: 10.15376/biores.14.3.6909-6922. DOI

Novák I., Sedliačik J., Krystofiak T., Lis B., Popelka A., Kleinová A., Myatyašovský J., Jurkovič P., Bekhta P. Study of wood surface pre-treatment by radio-frequency discharge plasma. Drewno. 2019;62:81–91. doi: 10.12841/wood.1644-3985.D14.06. DOI

Kržišnik D., Lesar B., Thaler N., Planinšič J., Humar M. A study on the moisture performance of wood determined in laboratory and field trials. Eur. J. Wood Wood Prod. 2020;78:219–235. doi: 10.1007/s00107-020-01506-z. DOI

Slabejová G., Šmidriaková M., Svocák J. Interlayer with microcapsules and its influence on the surface finish quality of wood. Acta Fac. Xylologiae Zvolen. 2020;62:61–74. doi: 10.17423/afx.2020.62.2.06. DOI

Nowrouzi Z., Mohebby B., Petrič M., Ebrahimi M. Influence of nanoparticles and olive leaf extract in polyacrylate coating on the weathering performance of thermally modified wood. Eur. J. Wood Wood Prod. 2021;80:301–311. doi: 10.1007/s00107-021-01761-8. DOI

Kúdela J., Gondáš L. Stability testing of coating materials proposed for renovation of surface finish windows. Acta Fac. Xylologiae Zvolen. 2022;64:25–37. doi: 10.17423/afx.2022.64.1.03. DOI

Forsthuber B., Schaller C., Grull G. Evaluation of the photo stabilizing efficiency of acrylic clear topcoats and wooden surfaces. Polym. Degrad. Stab. 2013;95:746–755. doi: 10.1016/j.polymdegradstab.2010.02.016. DOI

Olsson S.K., Johansson M., Westin M., Östmark E. Reactive UV-absorber and epoxy functionalized soybean oil for enhanced UV-protection of clear coated wood. Polym. Degrad. Stab. 2014;110:405–414. doi: 10.1016/j.polymdegradstab.2014.09.017. DOI

Reinprecht L., Pánek M. Effect of pigments in paints on the natural and accelerated ageing of spruce wood surfaces. Acta Fac. Xylologiae Zvolen. 2013;55:71–84.

Reinprecht L., Tino R. Effect of plasma and UV-absorbers in transparent acrylic coatings on photostability of spruce wood in exterior. Acta Fac. Xylologiae Zvolen. 2015;57:63–73.

Kúdela J., Štrbová M., Jaš F. Influence of accelerated ageing on colour and gloss changes in tree of heaven surface treated with an iruxil coating system. Acta Fac. Xylologiae Zvolen. 2016;58:25–34. doi: 10.17423/afx.2016.58.1.03. DOI

Oberhofnerová E., Panek M., Böhm M. Effect of surface pretreatment with natural essential oils on the weathering performance of spruce wood. BioResources. 2018;13:7053–7070. doi: 10.15376/biores.13.3.7053-7070. DOI

Lagaňa R., Svocák J., Kúdela J. Proceedings of the 9th Hardwood Proceedings Pt. II. An Underutilized Resource: Hardwood Oriented Research, Sopron 2021. University of Sopron Press; Sopron, Hungary: 2021. A study of the surface properties of a solid wood coating system with self-healing microcapsules; pp. 61–67.

Huang N., Yan X., Han Y. Preparation of Melamine-Formaldehyde Resin/Rice Husk Powder Coated Epoxy Resin Microcapsules and Effects of Different Microcapsule Contents on the Properties of Waterborne Coatings on Tilia europaea Surface. Coatings. 2022;12:1213. doi: 10.3390/coatings12081213. DOI

Kúdela J., Kubovský I. Accelerated-ageing-induced photodegradation of beech wood surface treated with selected coating materials. Acta Fac. Xylologiae Zvolen. 2016;58:27–36. doi: 10.17423/afx.2016.58.2.03. DOI

Salca E.A., Krystofiak T., Lis B., Hiziroglu S. Glossiness evaluation of coated wood surfaces as function of varnish type and exposure to different conditions. Coatings. 2021;11:558. doi: 10.3390/coatings11050558. DOI

Bekhta P., Krystofiak T., Lis B., Bekhta N. The Impact of Sanding and Thermal Compression of Wood, Varnish Type and Artificial Aging in Indoor Conditions on the Varnished Surface Color. Forests. 2022;13:300. doi: 10.3390/f13020300. DOI

Žigon J., Petrič M., Dahle S. Artificially aged spruce and beech wood surfaces reactivated using FE-DBD atmospheric plasma. Holzforschung. 2019;73:1069–1081. doi: 10.1515/hf-2019-0005. DOI

Žigon J., Zaplotnik R., Ayata Ü., Petrič M., Dahle S. The influence of artificial weathering and treatment with FE–DBD plasma in atmospheric conditions on wettability of wood surfaces. Niedersächsisches Symp. Mater. Clausthal. 2019;14:559.

Standard Practice for Operating Xenon Arc Light Exposure of Non-Metallic Materials. American Society of testing and Materials; West Conshohocken, PA, USA: 2005.

Allegretti O., Travan L., Cividini R. Drying techniques to obtain white Beech; Proceedings of the EDG Conference; Bled, Slovenia. 21–23 April 2009; pp. 7–13.

Pánek M., Oberhofnerová E., Hýsek Š., Šedivka P., Zeidler A. Colour Stabilization of Oak, Spruce, Larch and Douglas Fir Heartwood Treated with Mixtures of Nanoparticle Dispersions and UV-Stabilizers after Exposure to UV and VIS-Radiation. Materials. 2018;11:1653. doi: 10.3390/ma11091653. PubMed DOI PMC

Machová D., Baar J., Paschová Z., Pařil P., Křenková J., Kúdela J. Color changes and accelerated ageing in oak wood treated by ammonia gas and iron nanoparticles. Eur. J. Wood Wood Prod. 2019;77:705–716. doi: 10.1007/s00107-019-01406-x. DOI

Reinprecht L., Pánek M. Effects of Wood Roughness, Light Pigments, and Water Repellent on the Color Stability of Painted Spruce Subjected to Natural and Accelerated Weathering. BioResources. 2015;10:7203–7219. doi: 10.15376/biores.10.4.7203-7219. DOI

The Influence of the Initial Treatment of Oak Wood on Increasing the Durability of Exterior Transparent Coating Systems