Polymer-based pigmented coatings on flexible substrates with spectrally selective characteristics to improve the thermal properties

Functional textiles and membranes can create impressive optical effects and are being applied increasingly in the field of textile architecture. Lowering the thermal emittance of the textiles and membranes by a low-e coating leads to an improvement of the thermal properties. Therefore, the thermal insulation of such constructions rises as well as the thermal comfort in the building which finally results in a reduction of the energy consumption of the building.The spectrally selective coatings on flexible substrates considered in this work combine a customized color (or visual appearance) with a low emittance in the infrared spectral range. To realize the desired properties, polymer-based pigmented coatings were developed, optimized and characterized.Investigations were therefore carried out on the matrix material, the particle sizes and the dispersion of the colored pigments and the metal pigments concerning the infrared-optical properties and their optimization. As a result, the spectral emittance of the improved coating is presented from the ultraviolet over the visible up to the far infrared wavelength region. The thermal emittance of a polyester fabric was reduced from above 0.9 to below 0.3 by applying a colored low-e coating.