ir reflective pigments and colorants david white heucotech, ltd. 99 newbold road fairless hills, pa...
TRANSCRIPT
IR REFLECTIVE PIGMENTS AND COLORANTS
David White
Heucotech, Ltd.
99 Newbold Road Fairless Hills, PA 19030-4307
215-736-0712
Western Coatings ShowOctober 25-28, 2015Las Vegas, NV
Agenda
• Introduction• Challenge & Principle• Current main Application: Coil Coating / Roofing• Wood Coating• IR-reflecting Pigments in Multilayer Systems• Smart formulating of a Car Refinish System• Enhanced life-time of a composite Thermal Insulation System• Benefits
IR REFLECTIVE PIGMENTS
Introduction / Principle
IR REFLECTIVE PIGMENTS
IR REFLECTIVE PIGMENTS
cities with IR-absorbing surfaces (streets, pavements, dark roofs etc.)
temperature in the city center is 2°- 5°C higher compared to suburb
IR REFLECTIVE PIGMENTS
Solar emission spectrum of the sun
~50% of total energy in NIR (near infrared radiation)
NIR-radiationNIR-radiationUVUV
0 m N.N. (sea level) wavelength [nm]
slide 7 / 38
(NIR)-Radiation
Absorption
Reflection
Emission(Radiation und convection)
Heat flux
Interaction of (pigmented) surfaces with (NIR)-Radiation
IR REFLECTIVE PIGMENTS
slide 8 / 38
1. Reflectivity is the fraction of the solarenergy that is reflected by the surface (roof,wall) back to the sky. White color has thehighest solar reflectance, while black has thelowest.2. Emissivity is the emission of the absorbedheat as IR radiation. High infrared emissivityhelps to keep surfaces cool. Metallic surfacesfor example have a low infrared emissivity.3. Roof insulation
All 3 effects combined offer a system that significantly reduces heat build-up in buildings
IR REFLECTIVE PIGMENTS
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IR REFLECTIVE PIGMENTS
The surface temperature coated with an IR reflecting pigment increases less during the day time. High solar reflectance reflects the radiation before it effects the energy balance of the roof (building)!
It is mainly seen from sunset tomorning, where a surface with a high emissivity cools down faster.High infrared emittance gives the roof (building) the ability to radiate some of the absorbed solar energy!
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IR REFLECTIVE PIGMENTS
TSR means Total Solar Reflectance
TSR is the total amount of solar energy that is immediately rejected by the surface material (e.g. coating). This term is a key figure to describe the heat build-up of surfaces.A high TSR indicates efficient reflection – a low TSR value indicates a strong tendency to absorb NIR light and hence a significant heat build-up!It is useful to interpret the TSR value in relation to the matrix used and/or a reference pigment (e.g. titanium dioxide)IR-
slide 11 / 38
heat build-up of different pigments until equilibrium stage(20% Pigmentation in Alkyd/Melamine) according to ASTM D4803
max. DT20 °C
Paint characteristic: heat build-up
25,0
30,0
35,0
40,0
45,0
50,0
55,0
60,0
65,0
0 10 20 30 40 50 60
Irradiation time [min]
Tem
pera
ture
[°C
]
Titaniumdioxide; max 43°C
P.Br. 29 (1); max 49°C
P.Bk. 30; max 55 °C
Carbon Black; max 63°C
IR REFLECTIVE PIGMENTS
IR REFLECTIVE PIGMENTS
0
10
20
30
40
50
60
70
80
90
100
300 800 1300 1800 2300
Wavelength [nm]
Re
fle
cta
nc
e [
%]
Titaniumdioxide; TSR 85%
Chromium Iron Oxide P.Br. 29 (1); TSR 21%
Chrome Iron Nickel Black Spinel P.Bk.30;TSR 9%
Carbon Black; TSR 5%
Pigment Characteristic: Total Solar Reflectance
TSR – Spectra of different Pigments (20% Pigmentation in Alkyd/Melamine)
slide 13 / 38
Dry film thickness / NIR-Opacity / Influence of Substrate
TSR-value of a P.Br.29 as function of the dry film thickness at a constant
Pigment/Binder ratio over black (absorbing) substrate:
the influence of the substrate is decreasing with increasing dry film thickness
IR REFLECTIVE PIGMENTS
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TSR-value / temperature difference
IR REFLECTIVE PIGMENTS
slide 15 / 38
NIR-Reflective Pigments for Roof Coating
Did you know white-painted metal roofing has the highest solar reflectance value of any roofing product available and can save you up to 40% of your annual energy bills?
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IR-Reflecting Pigments – Main Application Coil Coating
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IR-Reflecting Pigments – Main Application „Cool Roofs“
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NIR-Reflective Pigments for Roof Coating
IR REFLECTIVE PIGMENTS
ecological contribution of NIR-reflecting Pigments
Interior Heat management by reduced heat flux
(reduced energy consumption for cooling)
Increased lifetime by reduced thermal binder degradation
(Arrhenius-Equation k = A * exp (-Ea/RT) )
(exponential increase of degradation rate in relation to temperature)
Increased lifetime by reduced thermomechanical stress
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Applications-
NIR REFLECTIVE COATINGS
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NIR-Reflecting Coatings
IR Reflective pigments- reflecting CICPs – Complex Inorganic Colored Pigments
Offer a wide range of color shades from yellow to black! They provide an outstanding performance profile: for optimum NIR-reflection superior weather- and light fastness opacity, dispersibility high TSR values highest outdoor durability excellent cost efficiency
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PRODUCT TSR in %PY 53 Nickel Antimony Titanium Yellow 63PBr 24 Chrome Antimony Titanium Yellow 54PBr 24 Chrome Antimony Titanium Yellow 58PG 50 Cobalt Titanate Green 23PBl 28 Cobalt Aluminate Blue 27PBl 28 Cobalt Aluminate Blue 34PBl 36 Cobalt Chromite Blue 24PBr 29 Iron Chromite Brown 22PG 17 Chromium Green-Black 21PBr 35 Iron Chromite Spinel 24PBk 30 Chrome Iron Nickel Black 10
slide 23 / 38
Applications-
Wood Coatings
slide 24 / 38
craters- and blisterscraters- and blisters
Tmax= 60°C Tmax= 90°C
NIR-reflecting pigmentation Conventional pigmentation
Colour difference after 7h irradiation DE = 0,5 DE = 2,2
Wood panels under max. temperature impact
IR-reflecting Colorants – Wood Coating
slide 25 / 38
cyclic impact on coated spruce panels
4 cycles: 48h conditioning (50% humidity at room temperature)6h IR-Irradiation48h conditioning (50% humidity at room temperature)
NIR-reflecting Pigmentation Conventional Pigmentation
Loss of adhesionand blistering
Loss of adhesionand blistering
DE = 0,2 DE = 1,7
IR-reflecting Colorants – Wood Coating
slide 26 / 38
Applications-
Composite Thermal Insulation
slide 27 / 38
Using IR reflecting pigments, the heat build-up on the composite thermal
insulation is reduced, with positive impact on prevention of premature failure
Bri
ck
Pla
ster
Insu
lati
on
≥20°C
80°C
Increased thermal/thermo-
mechanical stress due to higher surface temperatures
Bri
ck
Pla
ster
Insu
lati
on
20°C
60°C
IR-Reflecting Colorants – Composite Thermal Insulation
Exterior coating with IR-reflecting pigment
Exterior coating without IR-reflecting pigment
Composite Thermal Insulation
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Heat-build-up*, Composite thermal insulation, 1/3 STD
25
35
45
55
65
75
85
95
0 5 10 15 20 25 30 35 40 45
Irradiation time [min.]
Tem
per
atu
re [
°C]
PBk 7 - 1/3 STD
PBk 11 - 1/3 STD
PBk 30 - 1/3 STD
PBr 29 - 1/3 STD
measured at the surface w ith IR thermometer
A comparison of IR-reflecting black pigments (PBk 30,PBr 29) with IR absorbing
pigments (PBk 7, PBk 11) shows dramatic differences in heat build-up
D = 15°C
* Measured in a closed box, interior walls Al-foil covered, 150W IR-bulb, electronically dimmed to 60W, 32 cm distance lamp-sample, contactless temperature measurement by IR thermometer, sample 100x200x22 mm
IR-Reflecting Colorants – Composite Thermal Insulation
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Heat-build-up*, Composite thermal insulation, 1/9 STD
25
35
45
55
65
75
85
95
0 5 10 15 20 25 30 35 40 45
Irradiation time [min]
Tem
per
atu
re [
°C]
PBk 7 - 1/9 STD
PBk 11 - 1/9 STD
PBk 30 - 1/9 STD
PBr 29 - 1/9 STD
measured at the surface w ith IR thermometer
At lower proportions of black pigment in 1/9 STD formulations, the heat
build-up of non IR-reflecting pigments still is drastically higher
D = 13°C
IR-Reflecting Colorants – Composite Thermal Insulation
* Measured in a closed box, interior walls Al-foil covered, 150W IR-bulb, electronically dimmed to 60W, 32 cm distance lamp-sample, contactless temperature measurement by IR thermometer, sample 100x200x22 mm
slide 30 / 38
Heat-build-up*, Composite thermal insulation, 1/25 STD
25
35
45
55
65
75
85
95
0 5 10 15 20 25 30 35 40 45
Irradiation time [min]
Tem
per
atu
re [
°C]
PBk 7 - 1/25 STD
PBk 11 - 1/25 STD
PBk 30 - 1/25 STD
PBr 29 - 1/25 STD
measured at the surface w ith IR thermometer
D = 7°C
Even small amounts of non IR-reflecting pigments in a very light 1/25 STD
colour „poison“ the system regarding heat build-up:
PBk 7 and PBk 11 need to be avoided when formulating cool dark and light
colors
IR-Reflecting Colorants – Composite Thermal Insulation
* Measured in a closed box, interior walls Al-foil covered, 150W IR-bulb, electronically dimmed to 60W, 32 cm distance lamp-sample, contactless temperature measurement by IR thermometer, sample 100x200x22 mm
slide 31 / 38
PBk7 PBk30 PBk7 PBk30
Composite thermal insulation with plaster colored with PBk7 and an IR-
reflecting pigment were irradiated with Red/IR-light in a closed box
The surface of the carbon black plaster reached temperatures of >105°C,
causing the insulation layer to degrade in the zone of highest irradiance
IR-Reflecting Colorants – Composite Thermal Insulation
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Measurement of maximum temperatures under realistic conditions
Experimental parameters
Langelsheim, Germany (51.93°N, 10.34°E); sample facing south
9.7.2010; 14:00 o‘clock
38°C maximum air temperature
Thin insulation(20 mm)~15°, south
Thick insulation(110 mm)~45°, south
PBk301/3 STD
PBk71/3 STD
PBr 29 1/9 STD PBk7, 1/9 STD
IR-Reflecting Colorants – Composite Thermal Insulation
slide 33 / 38
PBk7 PBk30PBk7 PBk30
Composite thermal insulation with plaster colored with PBk 7 and IR-reflecting
PBk 30 on professional composite thermal insulation were irradiated with
Red/IR-light in a closed box
The surface of the plaster colored with PBk 7 reached temperatures of max.
102°C, with visibile effects on the structural integrity of the insulation layer in
the zone of highest irradiance, even in this professional set-up
after 5hirradiation !
IR-Reflecting Colorants – Composite Thermal Insulation
slide 34 / 38October 2012
Temperature build-up of composite thermal insulation can be reduced by using IR-
reflecting Pigments
especially PBk7 (Carbon black) and PBk11 (black ironoxide) have to be
avoided, even in low concentrations
Positive effect on heat management expected
Less heat transfer into buildings => less energy consumption for cooling
Longer life-time of composite thermal insulation can be expected with the use of
IR-reflecting pigments in the top coat (coloured plaster, painted plaster)
Less thermal stress/degradation on binder
Less ageing of the insulation layer
Less thermomechanical stress on the interface plaster/insulation layer
Application of darker colours with lower luminosity values becomes possible
IR-Reflecting Colorants – Composite Thermal Insulation
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Thank You for your Attention !!!
David White
Heucotech, Ltd.
99 Newbold Road Fairless Hills, PA 19030-4307
215-736-0712 ext. 142
[email protected] QUESTIONS?