Light Stability Testing of Home
and Personal Care Products
Jeffrey Quill
Director of Technical Applications
Q-Lab Corporation
Light Stability Testing of Home & Personal Care Products
Q-Lab Corporation
• Founded in 1956
• Specialize in material durability testing equipment and
services
Cleveland,Ohio
Headquarters &
Instrument Division
Bolton, England
Q-Lab Europe
Saarbrücken Germany
Shanghai, China
Q-Lab China
Q-Lab Outdoor Weathering Sites
Miami, Florida
Cleveland, Ohio
Phoenix, Arizona
Topics 1
•
•
•
•
•
Weathering Testing vs. Light Stability
Sunlight
Interior Lighting
Natural Exposures
Xenon Arc Testing
– Daylight and Window Spectra
– Irradiance Control
– Temperature & RH Control
Light Stability Testing of Home & Personal Care Products
Topics 2
• Fluorescent UV & Cool White Testing
• Testing Best Practices & Practical
Considerations
Light Stability Testing of Home & Personal Care Products
Forces of Weathering
Sunlight
Temperature
Moisture
Light Stability Testing of Home & Personal Care Products
Weathering Testing
• Simulation of sunlight—direct or through
window glass
• Moisture (water spray) usually included
• Temperatures simulate realistic hot
outdoor conditions
Light Stability Testing of Home & Personal Care Products
Light Stability
Sunlight
Artificial Light
Light Stability Testing of Home & Personal Care Products
Light Stability Testing
•
•
•
•
Simulation of sunlight or indoor lighting
No moisture
May have RH control
Test temperatures often simulate typical
indoor environment
Light Stability Testing of Home & Personal Care Products
Definitions
Irradiance: The rate at which light energy falls on
a
2
surface, per unit area; usually given as W/m
Spectral Power Distribution (SPD):
irradiance vs. wavelength
Graph of
Radiant Dosage: Irradiance x Time; accumulated
light energy exposure per unit area over a period
of time
Light Stability Testing of Home & Personal Care Products
Sunlight
Sunlight
• Direct
• Filtered through
window glass
Sunlight--Direct and Through Window Glass
2.0
Direct Sunlight
1.8
Sunlight through
Window Glass
1.6
Irradiance (W/m2)
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
280
320
360
400
440
480
520
560
Wavelength (nm)
Light Stability Testing of Home & Personal Care Products
600
640
680
720
760
800
Direct Sunlight
Noon Summer Sunlight/Air Mass 1
– ASTM G177
– CIE 85 Table 4
– D65 (CIE & ISO)
Air Mass 1.5
– ASTM G173
– IEC 60904-3
Light Stability Testing of Home & Personal Care Products
Standard Sunlight Spectral Power
Distributions
2.0
CIE 85 Table 4
1.8
Irradiance (W/m2/nm)
SMARTS2 ASTM G177
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
250
300
350
400
450
500
550
600
Wavelength (nm)
Light Stability Testing of Home & Personal Care Products
650
700
750
800
Summer Sunlight Spectrum
2.0
1.8
UVA
UVB
2
Irradiance (W/m )
1.4
UVC
1.6
1.2
1.0
Visible Light
0.8
0.6
0.4
0.2
0.0
250
300
350
400
450
500
550
Wavelength (nm)
Light Stability Testing of Home & Personal Care Products
600
650
700
750
800
Even Though It Is Only
5% of Sunlight...
UV Causes Most Photodegradation
Light Stability Testing of Home & Personal Care Products
Wavelength Regions of UV
UV - C
Found in outer space
100 – 280 nm
UV – B
280 – 315 nm
UV – A
315 – 400 nm
Light Stability Testing of Home & Personal Care Products
Includes shortest
wavelengths at earth’s
surface: severe polymer
damage; absorbed by
window glass
Causes polymer damage
Sunlight Spectrum – UV Region
Light Stability Testing of Home & Personal Care Products
Sunlight through Window Glass
2.0
CIE 85 Table 4
1.8
1.6
Irradiance (W/m2)
1.4
1.2
1.0
CIE 85 Table 4,
3 mm Glass
0.8
0.6
0.4
CIE ID65
6 mm glass
0.2
0.0
250
300
350
400
450
500
550
600
Wavelength (nm)
Light Stability Testing of Home & Personal Care Products
650
700
750
800
Sunlight Through Window Glass
1.4
Direct Sunlight
CIE 85 Table 4
1.2
Irradiance (W/m2)
1.0
0.8
0.6
CIE 85 Table 4,
3 mm glass
0.4
CIE ID65
6 mm glass
0.2
0.0
280
300
320
340
Wavelength (nm)
Light Stability Testing of Home & Personal Care Products
360
380
400
Interior Lighting
Light Stability Testing of Home & Personal Care Products
Commercial Indoor Lighting
Light Stability Testing of Home & Personal Care Products
Typical Indoor Lighting (4x normal illuminance)
vs Xenon, QUV, Sunlight
2.0
Irradiance (W/m2)
1.6
Sunlight through Window Glass
Q-SUN with
Window-Q
1.2
0.8
QUV with
UVA-351
QUV with cool white lamps
20 klx (40x typical office)
0.4
4x Typical Indoor
Light Level
0.0
300
350
400
450
500
550
600
Wavelength (nm)
Light Stability Testing of Home & Personal Care Products
650
700
750
800
Average Home Lighting
Light Stability Testing of Home & Personal Care Products
Natural Exposures
Light Stability Testing of Home & Personal Care Products
Natural Exposures
• Benchmark Commercial Sites
– South Florida
– Arizona Desert
– Inexpensive
– Reliable
– Extreme environments create acceleration
– “Scientific Window Sill Testing”
– Convenient
Light Stability Testing of Home & Personal Care Products
Florida Site
Latitude
25° 27’
North
Elevation
8 feet
TUV
280
MJ/m2
Total
6,588
MJ/m2
Under Glass
193
MJ/m2
5,416
MJ/m2
Summertime
Average Max
Air Temp:
32°C
90°F
Annual Solar
Energy:
Light Stability Testing of Home & Personal Care Products
%Sun
69%
Arizona Site
Latitude Elevation
1055 feet
33° 23’
North
Annual Solar
Energy:
TUV
334
MJ/m2
Total
8,004
MJ/m2
Under Glass
230
MJ/m2
6,563
MJ/m2
Summertime
Average Max
Air Temp:
40°C
105°F
Light Stability Testing of Home & Personal Care Products
%Sun
85%
DIY Natural Exposures
Light Stability Testing of Home & Personal Care Products
Xenon Arc
Light Stability Testing of Home & Personal Care Products
Q-Sun Xenon Test Chamber
Light Stability Testing of Home & Personal Care Products
Optical Filters
Daylight Filters
(exterior exposures)
Window Glass
(indoor exposures, textiles, inks, etc.)
Extended UV
(automotive, aerospace, etc.)
Light Stability Testing of Home & Personal Care Products
Light Spectrum
• Critical Factor
• UV “cut-on” or “cut-off”
• Not all “Window” or “Daylight” filters are
the same
• Commercial filter names create confusion
Light Stability Testing of Home & Personal Care Products
Xenon with Daylight Filters
Light Stability Testing of Home & Personal Care Products
Daylight Filters – UV Region
2.00
1.80
1.60
2
Irradiance (W/m )
1.40
Daylight - Q
1.20
1.00
0.80
0.60
Daylight - B/B
0.40
Daylight - F
Direct Sunlight
0.20
0.00
260
270
280
290
300
310
320
330
340
Wavelength (nm)
Light Stability Testing of Home & Personal Care Products
350
360
370
380
390
400
Xenon with Window Filters
vs. CIE85 through 3mm Glass
3.0
Window-B/SL
2.5
Window-IR
Window-Q
Irradiance (W/m2)
2.0
1.5
1.0
CIE 85 Table 4,
3 mm Glass
0.5
0.0
250
300
350
400
450
500
550
600
Wavelength (nm)
Light Stability Testing of Home & Personal Care Products
650
700
750
800
Xenon with Window Filters
vs. CIE85 through 3mm Glass
1.4
1.2
Irradiance (W/m2)
1.0
0.8
Window-Q
0.6
0.4
CIE 85 Table
4, 3 mm
Glass
Window-B/SL
Window-IR
0.2
0.0
280
300
320
340
360
Wavelength (nm)
Light Stability Testing of Home & Personal Care Products
380
400
420
Xenon with Window Filters
vs. ID65 (6mm glass)
2.5
Irradiance (W/m2)
2.0
1.5
Window-SF5
1.0
CIE ID65
6 mm glass
0.5
Window-IR
0.0
250
300
350
400
450
500
550
600
Wavelength (nm)
Light Stability Testing of Home & Personal Care Products
650
700
750
800
Xenon with Window Filters
vs. ID65 (6mm glass)
1.6
1.4
Window-IR
1.2
Irradiance (W/m2)
1.0
Window-SF5
0.8
0.6
0.4
CIE ID65
6 mm glass
0.2
0.0
280
300
320
340
360
Wavelength (nm)
Light Stability Testing of Home & Personal Care Products
380
400
420
Irradiance Control
• Narrow Band
– 340 nm
– 420 nm
• Total UV (300-400 nm) Wide Band
• Global (300-800 nm) – not recommended
– Shorter wavelengths cause more
photodegradation
– Fails to account for xenon lamp aging
Light Stability Testing of Home & Personal Care Products
Narrow Band Control
3.5
3.0
Irradiance (W/m2/nm)
2.5
Sensor detects single
wavelength and maintains
constant irradiance at that
wavelength
420 nm
Control
2.0
340 nm
Control
1.5
1.0
Q-Sun Window - Q
0.5
Sunlight thru glass
0.0
250
300
350
400
450
500
550
Wavelength (nm)
Light Stability Testing of Home & Personal Care Products
600
650
700
750
800
Wide Band Control -- TUV
3.5
3.0
Sensor
detects
energy
from 300 to
400 nm and
maintains
constant
irradiance
2.5
Irradiance (W/m2/nm)
2.0
1.5
1.0
Q-Sun Window - Q
0.5
Sunlight thru glass
0.0
250
300
350
400
450
500
550
Wavelength (nm)
Light Stability Testing of Home & Personal Care Products
600
650
700
750
800
Global Control (300-800 nm)
3.5
3.0
Sensor detects energy
from 300 to 800 nm and
maintains constant
global irradiance
2.5
Irradiance (W/m2/nm)
2.0
1.5
1.0
Q-Sun Window - Q
0.5
Sunlight thru glass
0.0
250
300
350
400
450
500
550
Wavelength (nm)
Light Stability Testing of Home & Personal Care Products
600
650
700
750
800
Irradiance Control Points
Example: Window B/SL Filter
These represent the same intensity:
Control Point
Irradiance
340 nm
0.35 W/m2
420 nm
0.95 W/m2
TUV (300-400 nm)
43 W/m2
Global (300-800 nm)
442 W/m2
Light Stability Testing of Home & Personal Care Products
Temperature Control
• Black panel
– Hotter than ambient in sunlight
– Not necessarily same as specimen temperature
– Exists for test repeatability and reproducibility
• Chamber air
– Controlled somewhat independently
– More relevant for some applications
• Chiller System
– Removes heat to allow normal indoor temperatures
inside xenon arc test chamber
Light Stability Testing of Home & Personal Care Products
Black Panel Temperature
Black Panel
(uninsulated)
Insulated
Black Panel
Black
Standard
Two types of black panels!
Light Stability Testing of Home & Personal Care Products
QUV Fluorescent UV Weathering Tester
and Cool White Light Stability Tester
Light Stability Testing of Home & Personal Care Products
QUV Specimen Holders
Light Stability Testing of Home & Personal Care Products
QUV Spectra vs. ASTM G177 Sunlight
2.00
ASTM G177
Sunlight
1.80
1.60
Irradiance (W/m2)
1.40
1.20
QUV with
UVA-340
1.00
0.80
QUV with
UVA-351
0.60
QUV with
Cool White,
20 kLux
0.40
0.20
0.00
300
380
460
540
Wavelength (nm)
Light Stability Testing of Home & Personal Care Products
620
700
780
UVA-340 Lamps
1.60
1.40
Sunlight (ASTM G177)
2
Irradiance (W/m )
1.20
1.00
UVA-340
0.80
0.60
0.40
0.20
0.00
260
280
300
320
340
Wavelength
Light Stability Testing of Home & Personal Care Products
360
380
400
420
Cool White Lamps
1.10
1.00
0.90
QUV/cw Spectral
Power
Distribution
Irradiance (W/m2/nm)
0.80
0.70
0.60
0.50
0.40
0.30
0.20
0.10
0.00
250 275 300 325 350 375 400 425 450 475 500 525 550 575 600 625 650 675 700 725 750 775 800
Wavelength (nm)
Light Stability Testing of Home & Personal Care Products
Best Practices for Light Stability Testing
1. Perform natural exposures
– Necessary for understanding accelerated
results
– Does lab test correctly rank material
performance?
Miami
Light Stability Testing of Home & Personal Care Products
Best Practices for Light Stability Testing
2. Test until failure (forced degradation)
– Required for drug products
• Identify impurities resulting from photodegradation
• Determine degradation pathways
– Necessary for developing rank order
performance
Light Stability Testing of Home & Personal Care Products
Best Practices for Light Stability Testing
3. Expose a control with your test
specimen
• Use Control Material of Known Durability
– Outdoor performance
– Lab performance
• Similar Composition to Test Material
• Similar Degradation Mode to Test Material
Light Stability Testing of Home & Personal Care Products
Benefits of a Control
• Compare performance of control to a
known material
• Allows confidence in lab exposure
• Assure that lab tester is operating
properly
Light Stability Testing of Home & Personal Care Products
Example:
Correlation using Control Material
• Background
– New products must
be lightfast
– Ingredients to make
it lightfast are
expensive
Light Stability Testing of Home & Personal Care Products
Correlation with Control Material
• Selected a control
product
• Included control with
all new product
testing
• Test 36 hours
• If new product fails,
add lightfastness
ingredients
• Retest
Light Stability Testing of Home & Personal Care Products
Best Practices for Light Stability Testing
4. Test your product “In the package” in order to
simulate the actual service environment.
Light Stability Testing of Home & Personal Care Products
Conclusions
• Understand and define the service
environment
• Define what constitutes product failure
• Obtain real world results
• Define evaluation method and understand the
variability
• Test both constituent parts, finished product
and product in packaging
Questions?
Light Stability Testing of Home & Personal Care Products