Lightfastness and Lamination Temperature Stability of Decorative Paper Coloured with Inorganic Pigments, 1995 European Polymers, Laminations and Coatings Proceedings

R.Greifzu

Bayer AG

Among the key quality criteria for pigments used in the manufacture of decorative paper for laminates are light-fastness and lamination temperature stability. These properties are tested in two ways. First, the finished laminates are exposed to highenergy W radiation in accelerated testing units and then assessed against a lightfastness standard (wool scale). Second, the colour stability is tested at various lamination temperatures. This paper shows that, in the case of white laminates pigmented with titanium dioxide, the method for testing lightfastness yields results which do not occur under normal conditions of use and that the lightfastness requirements made of such laminates are therefore unrealistic. Likewise, the colour differences produced by the accelerated testing of laminates pigmented with iron oxide yellow do not occur under normal conditions of use exposure to light behind glass or outdoor weathering).

Moreover, it was found that the greying and colour differences observed after exposure under normal conditions can be reversed.