W/Si emulsion concealer changing color as it dries — Cosmetic Science Talk

W/Si emulsion concealer changing color as it dries

Hey all. I'm running into some issues trying to colormatch a certain formula because the color changes. I apply a little bit on the hand and leave it to dry and it gets more red and a bit darker. This happens whether I blend the concealer into my skin before letting it dry or if I just let it dry undisturbed. Is this a pigment wetting issue? I hoped the Bentone gel and GB20 would help with that. I tend to colormatch in the continuous phase before emulsification but the color changes while drying then, too.
I know there's been some discussion on this forum about D5 but the client is a US only company so it's not an issue. 

Here is the formula (with rounded percentage, real formula has messy numbers unpleasant to look at)
Water - 20%
Butylene Glycol - 5%
Glycerin+peptide blends - 0.3% (3 different ones at 0.1% each)
Botanisil L-23 - 16%
Botanisil GB20 - 6%
DC fluid 556 - 3%
Gransurf 90 - 1.25%
Gransurf 67 - 2.5%
Bentone gel in D5 - 7%
Euxyl PE 9010 - 1%
Gransil PSQ - 3%
The rest is hydrophobic pigments treated with dimethicone and triethoxycaprylylsilane. A giant amount of pigments but the client kept asking for more coverage *shrug* 

I combine the silicon based ingredients, DC fluid, and Euxyl in a beaker under a small Ika homogenizer at 4-5k RPM. Homogenize until texture is even. Add pigments, homogenize until pigments are fully dispersed. Add D5 bentone and homogenize until even. Then I mix together the water soluble ingredients separately and add them, bit by bit, into the solution, waiting until the prior batch of water has fully incorporated into the product before adding more. A lot of mixing and scraping happens.

Comments

  • Just a guess here, but could there be micro-encapsulation of your pigments happening? Once this breaks, those pigments would be looking a lot stronger if that were the case. Either that, or insufficient dispersion as you are suspecting.  As for GB20, I would not count on that material as a pigment wetter. Likewise Bentone Gel, both of which have D5.  I never considered D5 cyclomethicone to be a pigment wetter.  Try good old C12-15 Alkyl Benzoate here for that. Totally miscible with all that D5 too.
  • Thanks chemicalmatt, I'll give the C12-15 Alkyl Benzoate a try and see what happens.
  • edited December 2017
    Ok, I tried between 3-5% c12-15 alkyl benzoate in the formula and the color is more stable. It'll still change a bit on the borders while it dries and when you blend it, but the color is much more stable than it was. Very frustrating problem. Before your reply I thought it might be oxidation as it's turning a bit darker and a bit more red, but I thought about it a bit more and there isn't anything in there that can oxidize as far as I know. 

    If there is microencapsulation, how do you prevent that? I was thinking of switching to Lecithin coated pigments instead but they want a vegan formula and our lecithin coating is from eggs. if I used just regular non coated iron oxides that takes away from the waterproof and transfer resistant claims.
  • Try other pigment coatings? There are quite a few.
    Robert Zonis, Sr. Formulation Chemist, Beaumont Products "All opinions and comments expressed are my own, have no relation to Beaumont Products, are fully copyrighted, and may not be used without written permission."
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