Verfahren zur Herstellung eines Holzbeschichtungsmittels

Die Erfindung betrifft ein Verfahren zur Herstellung eines transparenten Ueberzugsmittels fuer die Beschichtung von Holz, bei dem ein Bindemittel aus der Gruppe der physikalisch trocknenden Acrylatharze oder strahlenvernetzenden Acrylatharze ausgewaehlt und dann mit zumindest einem hocheffizienten und lichtstabilen Laserfarbstoff dotiert wird, der in Form von 0,1-5,0 Gew.-% bezogen auf die Gesamtzusammensetzung in dem Bindemittelmolekular dispers geloest wird und den UV-Anteil des UV-Lichtes sowie spektrale Lichtanteile im Wellenlaengenbereich zwischen 280 nm und 500 nm vollstaendig oder selektiv absorbiert und mit einer Konversionseffizienz von L 30% in laengerwellige, die Holzsubstrate und das Bindemittel nicht schaedigende Strahlung umwandelt, wobei zumindest ein Photoinitiator, Hilfsstoffe und gegebenenfalls Loesemittel beigemischt werden.

DE 19942993 A UPAB: 20010704 NOVELTY - Transparent wood-coating material is obtained by doping a physically drying or radiation-crosslinkable acrylate resin binder with a light-stable laser dye which completely or selectively absorbs light in the range 280-500 nm and converts this with an efficiency of at least 30% into longer-wavelength radiation which does not damage the substrate or the binder. DETAILED DESCRIPTION - A process for the production of a transparent wood-coating material involves doping a physically drying or radiation-crosslinkable acrylate resin binder with highly efficient, light-stable laser dye(s) in the form of a 0.1-5.0 wt% (based on total composition) molecular dispersion in the binder and then adding photoinitiator(s), auxiliary substance(s) and optionally solvents. The dyes used show complete or selective absorption of light in the wavelength range between 280 and 500 nm, converting this with an efficiency of at least 30% into longer-wavelength radiation which does not damage the wood substrate or the binder. An INDEPENDENT CLAIM is also included for similar materials in which the binder is a medium- to long-oil alkyd resin based on drying fatty acids and/or drying oils (in this case without photoinitiators). USE - For the production of weather-resistant transparent coatings on wood, e.g. cladding, windows, doors and panelling etc. ADVANTAGE - Enables the production of transparent coatings which provide a high level of protection from light (even in the blue part of the spectrum), by converting this into longer-wavelength light which does not damage the wood (by degradation of lignin) or the coating material itself. This protection is achieved without using pigments, thus retaining the grain of the wood, and the thickness of the coating is matched with the concentration of the dye, resulting in a cost-effective coating process (especially with economical UV-curing systems).