The document discusses particle characterization of pigments using laser diffraction and dynamic light scattering. It examines the analysis of particle size for organic pigments, inorganic pigments like titanium dioxide, and ink pigments. The effects of particle size on properties like hue, hiding power, and stability are described. Methods for measuring the dry and wet dispersion of samples are provided for both laser diffraction and dynamic light scattering. The importance of controlling particle size for applications is emphasized.

1. Particle Characterization of Pigments
Mark Bumiller
Mark.bumiller@horiba.com
© 2012 HORIBA, Ltd. All rights reserved.

2. Outline
Why is particle size important?
Organic pigments using laser diffraction
Inorganic pigments using laser diffraction
Ink pigments
TiO2 study using laser diffraction
TiO2 particle size and zeta potential using
dynamic light scattering
Conclusions
© 2012 HORIBA, Ltd. All rights reserved.

3. Pigments
A pigment is a material that changes the color of reflected or
transmitted light as the result of wavelength-selective absorption
red and green absorb
blue reflects
© 2012 HORIBA, Ltd. All rights reserved.

4. Properties Dependent on Particle Size
 Hue/Tint Strength
 Hiding/Transparency
 Gloss/Flatting and Film Appearance
 Flocculation
Gloss vs. % > 1 µm
 Viscosity
 Stability
 Weather resistance
© 2012 HORIBA, Ltd. All rights reserved.

5. Organic Pigments
Commonly powder form
Dry milling procedures monitored by dry
laser diffraction method
Particle size effects dispersibility of
pigment in application media
Wet laser diffraction method to monitor
dispersion of organic pigments in low
viscosity liquid media
© 2012 HORIBA, Ltd. All rights reserved.

6. Organic Pigments Study
Samples*:
•2583 Diarylide Yellow 83
•1274 Hansa Yellow 74
•2574 Hansa Yellow 74
•5576 Phthalo Blue 15:3
1. Select the small, high-dispersion nozzle for the fine particle sizes expected.
2. Set the automatic measurement conditions to proper testing range (96-94%T for the laser).
3. Set dispersion air pressure to Low.
4. To prevent nozzle clogging, remove large agglomerates from sample using 1mm sieve
5. Load enough filtered sample onto feeder chute to perform multiple measurements.
6. Take 3 consecutive measurements using the Auto Measurement function.
*Thank-you to Lansco Colors, Warwick, RI for supplying the samples for this study. www.pigments.com
© 2012 HORIBA, Ltd. All rights reserved.

7. Dry Organic Pigment Results
2583 Diarylide Yellow 83
Sample ID
Results
Run 1
18.386
Run 2
18.082
Run 3
18.032
Mean
18.17
COV %
1.05
1274 Hansa Yellow 74
Sample ID
Results
Run 1
50.125
Run 2
50.096
Run 3
50.442
Mean
50.220
COV %
0.38
© 2012 HORIBA, Ltd. All rights reserved.
2583 Diarylide Yellow 83
1274 Hansa Yellow 74

8. Dry Organic Pigment Results
2574 Hansa Yellow 74
Sample ID
Results
Run 1
36.490
Run 2
36.618
Run 3
36.603
Mean
36.570
COV%
0.19
5576 Phthalo Blue 15:3
Sample ID
Results
Run 1
25.114
Run 2
25.546
Run 3
25.531
Mean
25.397
COV %
0.97
© 2012 HORIBA, Ltd. All rights reserved.
2574 Hansa Yellow 74
5576 Phthalo Blue 15:3

9. Inorganic: Iron Oxide, LA-950 Wet
© 2012 HORIBA, Ltd. All rights reserved.

10. Inorganic: Chromium Oxide Green
 Micro 90 surfactant to wet powder
 0.1% sodium pyrophosphate
© 2012 HORIBA, Ltd. All rights reserved.

11. Inorganic: Alumina Al2O3
© 2012 HORIBA, Ltd. All rights reserved.

12. Ink Pigment
© 2012 HORIBA, Ltd. All rights reserved.

13. TiO2 Commercial Data Sheet
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14. TiO2 : Effect of Size
Opacity of TiO2
mean 0.25 and 10 µm
0.0
0.25
Relative scattering power
0.50 0.75 1.00 1.25 1.50
1.75
Relative scattering power
rutile TiO2 vs. size
0.05
0.1
0.15 0.20
0.3
Size (diameter) in µm
© 2012 HORIBA, Ltd. All rights reserved.
0.5
0.8

15. TiO2 Measurement Procedure
Step 1: Buy a HORIBA LA-950
Decide wet or dry analysis
Wet: disperse sample using surfactant and
ultrasound
Method development using Method Expert
RI, concentration, ultrasound
Dry: Use smallest nozzle and highest air
pressure
© 2012 HORIBA, Ltd. All rights reserved.

16. TiO2: Effect of Refractive Index
Measure sample once
Fix real RI, vary imaginary
Minimize R parameter (error calculation)
Use 1.0 for imaginary RI
© 2012 HORIBA, Ltd. All rights reserved.

17. TiO2 for Cosmetics
% under 100 nm
“nanoparticles”
© 2012 HORIBA, Ltd. All rights reserved.

18. TiO2: Wet vs. Dry
Only 8 nm difference!
Dry dispersion below 350 nm median
Wet
Dry
© 2012 HORIBA, Ltd. All rights reserved.

19. TiO2: Dry Analysis of 2 Samples
Able to reproducibly distinguish
2 samlpes with 12 nm difference
@ D(v,0.5)
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20. Nano TiO2*
Data from HORIBA LB-500
*
© 2012 HORIBA, Ltd. All rights reserved.

21. TiO2 Size & Zeta Potential on SZ-100
Size, note: Intensity distribution
Zeta potential @ pH = 7
© 2012 HORIBA, Ltd. All rights reserved.

22. Conclusions
Particle size important physical
parameter requiring analysis for control
Laser diffraction excellent tool down to
30 nm
Dynamic light scattering for sub micron
particle size + zeta potential
HORIBA has products and support for
your application requirements
© 2012 HORIBA, Ltd. All rights reserved.

23. To Learn More: www.horiba.com/particle
Talk to us, ask questions
Receive news of updates
View application/technical
notes (>130), webinars (>40),
white papers.
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24. ありがとうございました
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Tacka dig
감사합니다
© 2012 HORIBA, Ltd. All rights reserved.
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Danke
Большое спасибо
Obrigado