# Development of Effective Infrared Reflective Coatings
## 2 Materials and Methods
### Characterization of Coatings with Infrared Transparent Pigments  
Refractive index: this is an important parameter of pigments. It measures the reflectivity of coatings, either at a given wavelength or in a range of wavelengths. The reflection of all coated samples was measured in the 335 to 2500 nm wavelength range (Surface Optics SOC410). The total solar reflection (TSR) and the infrared solar reflection (IR-SR: 700-2500 nm) vales are summarized in tables and demonstrated in figures.  
Characterization of chromatic properties: For the chromatic characterization of all the coatings, a RAL7016 color card was used. The brightness was measured using a Konica Minolta CM-25 cG instrument.  
\begin{table}
\begin{tabular}{p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt}} \hline \hline \multirow{2}{*}{**Name of the Coating**} & \multirow{2}{*}{**Short Name of Coatings**} & \multirow{2}{*}{**Pigment**} & \multicolumn{2}{c}{**Concentration of Pigments in Coatings**} & \multirow{2}{*}{**Characteristics of the Coating**} \\ \cline{3-4}  & & & & \\ \hline Metallux Aqua 2k SZ & \multirow{2}{*}{L95/CR28} & - & Inorganic metal-oxide & \multirow{2}{*}{20\%} & infrared reflective covering coating \\ RAL7016 L95/CR28 & & black pigment—rutile titanium dioxide pigment & & & \\ \hline Metallux Aqua 2k SZ & \multirow{2}{*}{S84/CR28} & - & Perylene black pigment & \multirow{2}{*}{17\%} & infrared transparent covering coating \\ RAL7016 S84/CR28 & & - & rutile titanium dioxide pigment & & \\ \hline Metallux Aqua 2k SZ & \multirow{2}{*}{TSR4/CR28/Lacquer} & - & Perylene black pigment & \multirow{2}{*}{6\%} & infrared transparent covering coating \\ RAL7016 TR RU/ZD & & - & Purylene black pigment & & \\ \hline Metallux Aqua 2k SZ & \multirow{2}{*}{TR RU/ZD} & - & Dyrele black pigment (CI.264)—Cut- & \multirow{2}{*}{20\%} & infrared transparent opaque coating \\ RAL7016 TR RU/ZD & & - & (IR transparent, opaque) & & \\ \cline{3-4}  & & - & rutile titanium dioxide & & \\ \hline Metallux Aqua 2k SZ & \multirow{2}{*}{PS/ZD} & - & Diketo-Pyrrolo-Pyrrole & \multirow{2}{*}{21\%} & infrared transparent opaque covering \\ RAL7016 PS/ZD & & - & Cu-Phtalocyanine- & & \\ \cline{3-4}  & & - & pigment & \\ \cline{3-4}  & & - & rutile titanium dioxide & & \\ \hline Metallux Aqua 2k SZ & \multirow{2}{*}{S84/A80} & - & Perylene black pigment & \multirow{2}{*}{10\%} & infrared transparent opaque coating \\ RAL7016 S84/A80 & & - & special titanium dioxide pigment & & \\ \hline Metallux Aqua 2k SZ & \multirow{2}{*}{Traditional} & - & carbon black pigment (IR absorber, covering) & \multirow{2}{*}{19\%} & Generally used in the paint industry, not infrared reflective \\ RAL7016 & & - & rutile titanium dioxide pigment & & \\ \hline Metallux Aqua 2k SZ & \multirow{2}{*}{Methlux Aqua 2k: OH-acrylate-isocyanate resin, two-component coating material. RAL7016: One of the most popular shades, also known as Anthracite Grey.} & \multirow{2}{*}{10\%} & \multirow{2}{*}{19\%} & \multirow{2}{*}{14\%} \\ RAL7016 & & - & rutile titanium dioxide pigment & & \\ \hline \hline \end{tabular}
\end{table}
Table 2: Compositions of coating samples under investigation.  
The colors of samples were determined according to the CIE, as shown in Figure 1 (Commission Intenationale de l'Eclairage).  
The color differences (\(\Delta\)E*) between two color points are calculated according to the distance between their locations in the three-dimensional space (Table 3).  
Heat camera: This instrument can evaluate temperature and show the change in temperature caused by infrared reflection. It can display a thermal image over and under the coated surfaces, and it compares the measured values to the ambient temperature. The instrument is a GUIDE PS610.