Notes
Slide Show
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The Quest for Cyclomethicone  Replacements
  • Tony O’Lenick
  • July 2008
  • © 2008 Siltech LLC
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        1. Cosmetic products are used at ambient  
     temperatures.

2. Flammable materials are highly 
    undesirable in cosmetic formulations.

3. Dry feel is a consumer perceptible rather
    than a laboratory metric.
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        1. Cosmetic products are used at ambient  
     temperatures.

Evaporation at high temperature is meaningless!
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        2. Flammable materials are highly 
    undesirable in cosmetic formulations.

Eliminate flammables (hydrocarbons, MM and others)!
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        3. Dry feel is a consumer perceptible rather
    than a laboratory metric.

Be open to new approaches and let the consumer decide.
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Volatility for PC should be measured at ambient.
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D4 is both cyclic and  volatile.


MM (0.65 visc) and 1 cps silicone are volatile but not cyclic.


D5 and 2 cps silicone are non-volatile.
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Dryness is related to volatility, but also and more importantly to surface tension.


D5 is an example.
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Silicones have low surface: responsible for spreadbility and dry feel.
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Silicone Properties
  • Reduce Surface Tension
  • Oil  - Reduction from 32 dynes/cm2 to 20 dynes/cm2
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"At the interface these materials..."


  • At the interface these materials lower surface tension.
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"The importance of surface tension..."

  • The importance of surface tension reduction cannot be overstated in providing a dry feel.
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"The through and efficient spreading..."


  • The through and efficient spreading requires a lowering of surface tension.
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CMC
  • What is the CMC of cetyl dimethicone in Mineral oil?


  • What is the CMC of cetyl dimethicone in Soybean oil?
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CMC
  • Unlike CMC graph in water, the CMC of an alkyl silicone in an oil phase has no clear “break point”.


  • Need to create a new term to evaluate efficiency.
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Dimethicone / Methicone
Problem
  • Dimethicones are made using D4 as a reactant. They have two methyl groups:


  •              CH3
  •                  |
  •                -Si-O-
  •                  |
  •                  CH3
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Dimethicone / Methicone
Problem
  • Methicones are not made using D4 as a reactant. They have one methyl group:


  •              CH3
  •                  |
  •                -Si-O-
  •                  |
  •                  R
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Dimethicone / Methicone
Problem
  • D4 is:


  •                CH3
  •                    |
  •               -[-Si-O-]4-
  •                    |
  •                   CH3


  • It requires 2 methyl groups.
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Dimethicone / Methicone
Problem

  • Dimethicones can degrade into D4
  •             (Article O’Lenick et al 2003)
  •                   http://www.siliconespectator.com/articles/Silicone_Spectator_Equilibration_Reaction_Revised.pdf


  • Methicones cannot degrade into D4
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Implications to low MW silicone fluids:


  • Even if fractionated to low % D4, dimethicone can give D4 back under conditions of high or low pH.
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Approaches
 for D5 Replacement

  • Modify oils ( triglycerides and esters) to feel dry (like silicone), using methicones.


  • Use methicone to replace dimethicones.
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Target Products
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