The document discusses infrared (IR)-reflective coatings and pigments. It explains that 49% of sunlight that reaches Earth is infrared, which causes heat buildup. IR-reflective pigments can reflect infrared light and reduce heat absorption through their nanoparticle size and composition. An experiment showed that applying IR-reflective paint to panels reduced their surface temperature by 35°C compared to standard black paint. The document concludes that IR-reflective coatings can lower temperatures regardless of color.

1. Invisible but Functional
IR-reflective coatings
Smart Coating Application Lab
27/10/2016 1© sirris | www.sirris.be | info@sirris.be |

2. It all starts with the sun…
Electromagnetic radiation
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 5% UV (300-450nm)
 Skin damage
 Degradation of paint and
polymers
 46% VIS (450-750 nm)
 Colors our world
 49% (N-)IR (750-2500 nm)
 Mostly heat
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Source: heubachcolor

3. Heat: Absorption of VIS and IR radiation
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Degradation of
 Colors (mostly due to UV)
 Gloss
 Elasticity
Thermal expansion, stress
Air conditioning
 increase of energy consumption
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4. Mechanisms of heating
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5. What do you need to keep (it) cool?
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 High solar reflectance
 Ability to reflect sunlight
 High thermal emittance
 Ability to radiate heat (ease of
loosing heat to the environment)
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6. Quantification of heat buildup
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 TSR (Total Solar Reflectance) (in %)
Def: TSR is the percentage of irradiated energy that is reflected by an object
 High TSR = high reflection = lower heat buildup
 IR reflective pigments
 Provide means to get the TSR as high as possible
without color changes
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7. TSR is influenced by pigmentation
27/10/2016 7© sirris | www.sirris.be | info@sirris.be |
Source: BASF

8. What are IR-reflective pigments?
27/10/2016 8© sirris | www.sirris.be | info@sirris.be |
Organic based Inorganic based Ceramic (MMO* and CICP**)
Moderate durable Long term durability Unparalleled resistance to
heat, light chemicals,
Low cost Higher cost High cost
<molted metals, high temp
*Mixed Metal Oxides, **Complex inorganic colored pigments
Conventional pigments IR reflecitive pigments

9. What makes the pigments IR-reflective?
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 Most important for NIR reflectivity
 Mean particle size
 Nanoparticles significantly enhance reflective properties
The particle size should be more than half the
wavelength of the light to be reflected
Reflecting IR in the range of 800-1200 nm you needs
pigment particle sizes of at least 400 to 600 nm
© sirris | www.sirris.be | info@sirris.be |Source: http://rhopoint.co.kr/bbs/board.php?bo_table=rho_faq&wr_id=4

10. For example: IR black pigment
27/10/2016 10© sirris | www.sirris.be | info@sirris.be |
Source: BASF
TSR black:42%

11. Comparison between regular and IR pigment
27/10/2016 11© sirris | www.sirris.be | info@sirris.be |
Source: BASF

12. Other important parameters
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 Colour of the substrate/using white primer
 TSR over white substrate is higher
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Pigment IR brown
Source: CPSColor

13. Other important parameters
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 Thickness of the coating
 Thicker coating gives higher TSR: needs optimalisation
© sirris | www.sirris.be | info@sirris.be |Source: CPSColor

14. Other important parameters
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 High enough concentration of the IR pigment
 Contamination
 Small amounts of non IR reflecting colorants can
have drastic effects
© sirris | www.sirris.be | info@sirris.be |
Source: CPSColor

15. Other important parameters
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 Binder system
© sirris | www.sirris.be | info@sirris.be |
Source: CPSColor

16. 27/10/2016 16© sirris | www.sirris.be | info@sirris.be |
 Panels used for outdoor application
 Exposure to direct sunlight resulted in
deformation of the panels
 IR reflective paints were used to
investigate the use of IR-reflective
pigments on the surface temperature
IR reflective paint on PVC panels

17. 27/10/2016 17
Setup
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IR reflective paint on PVC panels
Measurements
pigment TSR 150µ Temperature
Black 35,4 107°C
IR Black 54,12 72°C
Temperature reduction of 35°C

18. Conclusions
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 Keeping it cool is possible with heat reflective
paints, regardless the colors used.
 The system needs optimalisation to ensure
maximum TSR
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19. 27/10/2016© sirris | www.sirris.be | info@sirris.be |
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