Dioxide Pigments Glenn R. Evers, IS2 LLC (M: 302-379-1265 - PowerPoint PPT Presentation

How to Achieve One-Coat, High Hiding Power Paints by Optimizing Titanium Dioxide Pigments Glenn R. Evers, IS2 LLC (M: 302-379-1265 eversgr@gmail.com)

Basic Paint : Water, Resin & TiO 2

TiO 2 Optimization in Low VOC Paints, Promises Better:  TiO2 Grades / Extenders  Dispersion  Zeta Potential  Particle Size – Instrument Pay Back in 3 months!  Gold Standard Glenn R. Evers, IS2 LLC (eversgr@gmail.com)

TiO2 Quality Certificate of Analysis (If you don’t’ ask, you don’t get) Particle Size Distribution (PSD) 1. GSD (Geometric Standard 2. Distribution) % Greater than 0.5 um 3. Compare to Gold Standard (GS) 4. Nibs or Scatts and distribution 5. Slurry Solids (76%)/pH 6. Rheology 7. Grit (wt.%) 8.

Effect of % TiO 2 (alumina treated) on Hiding 20 o Oil Average Average Relative Use % Abs. Enamel Hiding Hiding Chalk Min. (lb/ Gloss Low PVC High PVC Resistance TiO 2 100 lb) General – 12 70 90 Good 95 100 High gloss 13 67 100 Very Good Universal 91 95 Interior/ Exterior 17 60 95 Excellent Exterior 89 90 Durable 32 45 115 Good Flat 80 85

High Opacity & Whiteness by Spacing TiO2 w/ poor b*

Green Glass Loses Color and Becomes Whiter by Grinding & Sieving to 2mm 850 m 177 m Beer Bottle Glass

Basic Paint : Water, Resin & TiO 2

Ideal Dispersion is Better than Random (Ref: Diebold (2005))

NEED Dispersion Dispersion Dispersion  BEST Dispersiple & Durable R706 type coating alumina/silica better than SuperDurable – eg Roof Coatings  BEST Gloss  Effects Tint Strength, Contrast Ratio, Hiding Power, Whiteness

CHALKING Light Degrades Resin Binder 1. Works with water, acid rain, 2. environmental deposits and UV Worst case Oxygen Free in the film 3. TiO 2 Ti (+4)O 2 + Ti 2 (+3) O 3 + O 2 a) Particle size CONTROLLED Sulfate = Hydrolysis Chloride = Oxidation/ Pressure b) Grind: Steam /Pigment control c) High density TiO 2 spacing

TiO 2 for Low VOC Paint TiO 2 Slurry Particle Median Draw Down Resin & Gloss Optical: Viscosity % > Particle Particle HEUR Con. Ratio, Grade @ 80 wt. 0.5 um Size & Size & Comp. Color Comp. # % GSD # Particles & Tint S (low Cp) (low %) (low #) (high) (high) #3 ++ + ++ + ++ ++ + GS #3 - - 0 -- 0 - -

Lab Equipment Need For TiO 2 Optimization  Zeta Potential / pH Meter  Rheometer  Particle Size Analyzer

Zeta for TiO2 : - In Paint: Avoid Dangerous pH Zones - In Pigment Grind: Shift IEP w/ Dispersants - Disperse Near IEP -

Universal Grade TiO 2 Slurry Zeta Potential as a Function of pH 30 20 TiO2 Only 10 Zeta Potential, mv 0 4 4.5 5 5.5 6 6.5 7 7.5 8 8.5 9 -10 pH -20 -30 TiO2 + Dispersant -40 -50 -60

Lab Equipment Need For TiO 2 Optimization  Zeta Potential / pH Meter  Rheometer  Particle Size Analyzer

Horiba PSD Plots: iPhone Video Tracking TiO2 Spacer Composite Agglomeration Effect of mixing TiO2 slurry with CaCO3 coated TiO2 Demonstrate - Real Time Particle Growth - GSD Peak Broadening - Final Finger Print GSD 4.5 @45 min. GSD 1.7 @ 0 min. GSD 2.2 @11 min.

Two Types of Flocculation 1. Bridging: Polymer Molecules Connect TiO 2 Particles. 2. Depletion: TiO 2 get squeezed out of the thickener solution a) Lower Gloss & CR b) Poorer Film Strength c) Poorer Adhesion

Rheology Modifier / TiO2 Dispersant Phase Diagram

Great GSD needs a hydrophobic micro- codispersant (Helps Rheology Chemicals) JCT Research, Vol. 3, No.3, July 2006

Effect of pH on TiO 2 Median Particle Size (Better is < 0.4um, AMP-95 pH adjusted) 0.60 0.55 Median Particle Size (um) 0.50 0.45 TiO2 A TiO2 B TiO2 A GS 0.40 0.35 Gold Standard (GS): Ideal Particle Size 0.30 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 pH

Effect of pH on TiO 2 Particle Size GSD (Lower numbers are better, AMP- 95 pH adjusted) 2.20 2.00 Geometric Standard Deviation (GSD) 1.80 1.60 TiO2 B TiO2 A TiO2 A GS 1.40 Gold Standard: Narrow Particle Size Over all pH’s 1.20 1.00 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 pH

High Opacity VOC Paints Requirements  Minimize Thickeners & Surfactants  High Solids Filler Slurries  Target : 70 wt. % solids (min.)  TiO 2 Slurry Properties 1) Small Particle Size vs. pH 2) Narrow – GSD vs. pH 3) Zeta Potential vs. pH 4) High Solids / Low Viscosity: 380-480 Cp @ 79% Solids (Brookfield : #3 spindle, 100 rpm) 5) Compatibility Tests & Phase Diagrams