Silicone-based thickness insensitive spectrally selective (TISS) paints as selective paint coatings for coloured solar absorbers (Part I)

The objective of this study was to make paints having a variety of colours and whose spectral selectivity would be independent of the thickness of the deposited layer of paint (thickness insensitive spectrally selective (TISS) paint coatings). TISS paint coatings combine the advantages of paints (longevity and chemical resistance achieved by a high thickness of the applied layer, variety of colours and simple application) with spectral selectivity. Low emittance is attained by the addition of bare aluminium, coloured aluminium flake pigments or copper flake pigments, while other inorganic pigments impart various colours to the paints. Pigments were dispersed in silicone resin binder imparting the TISS paint coatings high-temperature tolerance, excellent adhesion, uv resistance, flexibility and weather-durability, which make them suitable coatings for coloured glazed or unglazed solar absorbers.