Novel Surface Treatment For Hydrophobicizing Pigments

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Novel Surface Treatment For Hydrophobicizing
Pigments
Frank Mazzella, David Schlossman, and Yun Shao,
Ph.D. Kobo Products, Inc.
PCITX - New York September 28-30, 2004
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Overview

• What is needed to make a good surface treatment
  ?
• Common used substrates.
• Common Treatments.
• Specialty Treatments.
• Summary.

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Surface Treatments Why ?

• Improve performance
• Make the product Hydrophobic.
• Make the product Lipophobic.
• Improve the products ability to disperse in
  various media.
• Change the oil absorption of the product.
• Improve wear, adhesion, or other desirable
  attribute.

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Requirements for Good Surface Treatment

• The surface has free hydroxyl groups or available
  surface moisture.
• This allows the treatment to react and attach.
• Surface area to mass is low.
• The smaller the particle the more treatment
  required due to the larger surface area
  available.
• The substrate is compatible with the process.

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Requirements for Good Surface Treatment

• Examples of good surface to coat
• Most metal oxides such as iron oxide and titanium
  dioxide.
• Starch.
• Examples of Hard to Coat surfaces
• Organic Pigments and Lakes
• Polymers
• Minerals such as Mica

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Popular Hydrophobic Organic Treatments
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Treatments Studied

• Crosspolymer treatments (TTS, TTB TTM)
  promote the
  wetting of pigments in multimedia.
• Branched Alkyl Silane treatment (BAS)
  enhance wetting in non-polar media.
• Aminosilane / Silane Treatment for Hard to Treat
  Surfaces (HTT)
  super hydrophobic
  prevents bleed.

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Crosspolymer Treatments
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Crosspolymer Treatments - Structure
Kobo codes TTS ITT / Silane ( R
Caprylyl) TTM ITT / Methicone ( R
Methyl) TTB ITT / Dimethicone (R Branched
Dimethicone)
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Crosspolymer Treatments - Structure

• INCI Names
• TTS Isopropyl Titanium Triisostearate/
  Triethoxycaprylylsilane Crosspolymer
• TTM Isopropyl Titanium Triisostearate /
  Methicone Crosspolymer
• TTB Isopropyl Titanium Triisostearate /
  Dimethicone Crosspolymer

US patent No. 60,472,527
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Hydrophobicity of Crosspolymer vs Its Components
2 gr. of Treated Pigment in 50 mL Water Shaken 10
times - Picture taken after 10 minutes
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Dispersions with 10 nm TiO2
Formulas
Test Results
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Branched Alkyl Silane Treatment
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Branched Alkyl Silane

• Very low Hydrogen potential.
• Better affinity in many organic non polar systems
• More hydrophobic than the straight chained alkyl
  Silanes.

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Branched Alkyl Silane - Structure
Schematic Representation of the Branched Alkyl
Silane used to Coat
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Comparison of Methicone vs BAS treatments
60 nm TiO2 Dispersions in Silicone
40 - Methicone Treated
50 - BAS Treated
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Comparison of Methicone vs BAS treatments
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Branched Alkyl Silane - Summary

• Benefits of the Branched Alkyl Silane in a
  Dispersion
• Higher pigment levels in the dispersion with,
• Lower viscosity dispersion (pourable)
• Very good dispersion stability
• No gelling, or settling
• No vehicle separation

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Treatment for Hard to Treat Surfaces
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Hard to Treat Surfaces

• A process for treating and coating materials that
  traditionally do not coat well.
  (Patent WO 03/043567).
• These include such materials as
• - Organic pigments and lakes (example Red 7 Ca
  Lake)
• - Mineral Silicates such as Mica and Sericite
• - Porous Silicates.

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Hard to Treat Surfaces

• Treatment type
• - Amino Silane or Amino Alkoxy Silane treatment
• Advantages to this treatment type
• - No residual Silane reactions.
• - Surfaces that could not be effectively
  treated to make
• them hydrophobic can now be treated.

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Stability of Organic Lakes in Water
FDC Blue 1 Aluminum Lake
FDC Red 40 Aluminum Lake
NT
MS
HTT
NT
MS
HTT
NT non-treated lake - after 1 day _at_ room
temperature MS methicone-treated lake - after 7
day _at_ room temperature HTT Hard to treat
treatment on lake - after 30 day _at_ room
temperature
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Stability of Organic Lakes in Water
Non-treated - 1 day _at_ room temp HTT-treated -
30 day _at_ room temp HTT-treated - 30 day _at_ 50C
Comparison of percent bleed between HTT-treated
and non-treated lakes in 2 aqueous suspensions.
Measurements by spectrophotometry, results
expressed in percent of the original lake content.
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Effect of pH on Stability in Water
pH 11 Organic Base
pH 2 Mineral Acid
pH 12 Mineral Base
pH 3 Organic Acid
FDC Red 40 Aluminum Lake
1 Day test 2 Lake in water
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Effect of Surfactant on Stability in Water
Methicone treated in 2 SLS
HTT treated in 2 SLS
FDC Blue 1 Aluminum Lake
7 Days test 2 lake in water
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Stability on Mineral Surface
Methicone treated Sericite
HTT treated Sericite
1 Day test 2 Sericite in water
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Hard to Treat Surfaces - Summary

• Much improved hydrophobic properties.
• Outperforms Methicone with no Hydrogen potential.
• Coat very well to mineral surfaces that normally
  dont coat well.
• Prevent water bleed at various pHs and in salts.

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Summary

• Surface treatments can be made and modified to
  achieve a specific performance criteria
• Improved Dispersability
• Improved Hydrophobicity.
• Reduce or eliminate synerisis
• Increase or Reduce Gloss

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Acknowledgements
I wish to thank the following for their efforts
in making this presentation possible Shirley
Wang, Eric Smith, David Cornelio, Scott
Holzapfel, Uyen Nguyen, and Pascal Delrieu.