A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
A number of searchers have shown that the UV fraction of the solar radiation is causing most of the chemical modification and mechanical breakdown on exposed wood surface layers, thus explaining the origin of clear or transparent coating adhesion failures. Full exposure to light, heat and humidity make coatings themselves degrade and lose their esthetical and protective functions. The coating alteration process is the result of phenomena such as photo- and thermoxidations, hydrolysis and effects of chemical pollutants (i.e. acid rain) and of natural biological factors such as bacteria, fungi and algae. Durable systems for outdoor applications therefore require improvements not only in the top coat service life time performance but also and essentially in the adhesion retention properties of primers and substrate/coating interface layers. Improvements are therefore necessarily related to reinforced lignin stabilization. A new and simple stabilization concept is described which provides long term wood colour stability in indoor applications and improved durability to clear and light transparent pigmented coatings on wood in exterior applications. Best protection effects are obtained using a process which consists of an aqueous wood pretreatment with a new type of HALS radical scavenger, subsequently top coated with finishes containing a new UV absorber specially designed for wood and wood coatings protection.
A number of searchers have shown that the UV fraction of the solar radiation is causing most of the chemical modification and mechanical breakdown on exposed wood surface layers, thus explaining the origin of clear or transparent coating adhesion failures. Full exposure to light, heat and humidity make coatings themselves degrade and lose their esthetical and protective functions. The coating alteration process is the result of phenomena such as photo- and thermoxidations, hydrolysis and effects of chemical pollutants (i.e. acid rain) and of natural biological factors such as bacteria, fungi and algae. Durable systems for outdoor applications therefore require improvements not only in the top coat service life time performance but also and essentially in the adhesion retention properties of primers and substrate/coating interface layers. Improvements are therefore necessarily related to reinforced lignin stabilization. A new and simple stabilization concept is described which provides long term wood colour stability in indoor applications and improved durability to clear and light transparent pigmented coatings on wood in exterior applications. Best protection effects are obtained using a process which consists of an aqueous wood pretreatment with a new type of HALS radical scavenger, subsequently top coated with finishes containing a new UV absorber specially designed for wood and wood coatings protection.
Improved photoprotection of wood and durability improvement of wood coatings
Verbesserung des Lichtschutzes für Holz und der Haltbarkeit von Holzbeschichtungen
2002
20 Seiten, 16 Bilder, 2 Tabellen, 25 Quellen
(+ 8 S. Anh.)
Conference paper
English
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