CoolSun: organic paints for cool buildings

Chemistry for the Future - 2019

CoolSun: organic paints for cool buildings

P. MINEI

_{, A. Pucci}

_{, G. Ruggeri}

_{, M. Lessi, F. Bellina}

_{, B. Maraviglia}

_{, A. Pallesi}

_{, L.}

Contiero

1

_{Dipartimento di Chimica e Chimica Industriale, Università di Pisa, via Moruzzi 13, 56124}

Pisa, Italy

2

_{IEXI SRL, Piazza Paolo Uccello 5, 50142 Firenze, Italy}

3

_{TECNOCHIMICA S.P.A Via Del Salice 16/18 56022 Castelfranco Di Sotto, Pisa, Italy}

4

_{CROMOLOGY ITALIA S.P.A. Via 4 Novembre 4, 55016 Porcari, Lucca, Italy}

pierminei@gmail.com

Poor attention has been paid so far to the 50% of NIR radiation flux (750-2500 nm), coming from direct, diffused and reflected sun radiation, which contributes to increase the temperature in urban areas. To reduce the increasing demand for energy consumption for air conditioning or to produce cool fabrics, there is a need for NIR reflective pigments and coatings formulation since reflecting the sun’s radiation minimizes the amount of energy absorbed by the surface1_{. NIR reflective}

property is useful in applications where solar heating must be attenuated, such as leather goods, greenhouse coverings, roofing and transporting of heat-sensitive materials2 _{Today, NIR reflectivity}

is obtained with the use of inorganic pigments (TiO2, metal oxides and complexes) that are

expensive and, in some cases, toxic2_{. The challenge is the development of a fully organic NIR}

reflective coating. This can be possible by mixing NIR non-absorbing pigments with polymeric NIR-reflective additives in the formulation of coatings.

This work aims at the preparation of paints starting from waterborne-dispersion of resin and NIR reflective organic pigments and additives. As pigment we used different perylene bis-imide derivatives, already known for their NIR reflective properties4_{. Aswell, we studied the synergic cool}

effect adding thermoplastic hollow microspheres (Expancel®₎5 _{and their comparison with a}

standard black dye.

Acknowledgements

This work was supported by the Tuscany region POR FESR 2014-2020 COOLSUN - New NIR-reflective “cool” organic pigments

References:

[1]. I. Hernández-Pérez, G. Álvarez, J. Xamán, I. Zavala-Guillén, J. Arce and E. Simá, Energy and Buildings, 80, 81-105 (2014).

[2] A. Muscio, Climate, 6, 12 GNS (2018). [3] V. Fang et alt. Science Report 2013/39.

[4] M. Mazhara, M. Abdoussa, K. Gharanjig, R. Teimuri-Mofrad Progress in Organic Coatings 101, 297–304 (2016).