How CTAC contribute to the viscosity?

ZivBAZivBA Member
edited August 2018 in Formulating

Hello,

I have a formula for hair cream according to the following raw materials:

Phase 1, Heating to 70:

  1. Water- 80%
  2. Polyquaternium7- 2%

Phase 2, Heating to 70:

  1. Mineral Oil- 5%
  2. Cetyl Alcohol- 4%
  3. GMS SE- 2%
  4. Dimethicone 350cp- 1%
  5. Vaseline- 1%
Homogenize and stirring.

Then the liquid product is liquid at 50-60 temp,
But immediately with the addition of CTAC-4%, the substance becomes a viscous cream.

why?
Chief Chemist/ R&D Manager at SASA Cosmetics

Comments

  • ozgirlozgirl Member, PCF student
    It is most likely that the CTAC (cationic) is incompatible with the anionic potassium stearate that is present in the GMS SE.
  • Usually CETAC reduces viscosity
    But you can try mixing some bare K-stearate with CETAC to see if they form a thick slime = sign of uncompatibility.
  • Also, this effect would likely be pH dependent, where it would be less significant below the pKa of the potassium stearate (i.e., where it becomes neutral).
  • Thank you for the comments,

    I want to say that this change to thick cream is welcome! I want and need this change, I just still don't understand how and why it is happening, and what I should do if I want to duplicate it to another formula :)

    you all say that the small amount of K-Stearate that is present in the GMS SE is responsible for this change?

    Chief Chemist/ R&D Manager at SASA Cosmetics
  • DASDAS Member
    It's how an ewax is made. Cetyl + surfactant, in this case the CTAC. 
  • DAS - sorry for the dam question-

    What is EWAX, and how it is made?


    Chief Chemist/ R&D Manager at SASA Cosmetics
  • DASDAS Member
    Self emulsifying waxes are a blend of a fatty alcohol and a surfactant. The result is usually a solid, for example BTMS is an ewax. It becomes pasty even at low percentage. Considering you are using 4% of each the result will be creamy on cool down. The reticulate formed by the cetyl alcohol + CTAC is what holds the rest of the ingredients. You do have an important quantity of oils, the GMS SE wouldn't hold by itself. 
  • DAS- Thank You Very Much!!!!!

    In your opinion- Should I add the CTAC at the END of the procedure at cool down, Or should I add it with the water phase at the first stage?

    Chief Chemist/ R&D Manager at SASA Cosmetics
  • DASDAS Member
    First stage. Better homogenization with less torque, and to prevent air bubbles.
  • Interesting
    I always wondered if you can make an emulsifier out of CETAC + fatty alcohol.

    @DAS Do you know why Croda used cetyl alcohol in their BTMS and not cetearyl alcohol instead?
  • DASDAS Member
    It IS an emulsion. Think of you hair conditioners, what would happen if you remove the surfactant?. 

    You would have to ask croda, perhaps if you mail R&D they answer. They do perform differently, those 2 carbons make a huge difference. Cetearyl is used to avoid recrystallization (being 16 and 18 they don't align the same). Perhaps the microstructure with BTMS shows no significant difference.
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