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oxidation in w/o makeup foundation and white cast
<div>Hi,</div>
I have a huge problem with a W/O foundation formula that we developed for a client. We used Daito Kasei’s OTS pigments that have a TRIETHOXYCAPRYLYLSILANE coating. We are using EASYNOV emulsifier. I find that as soon as the formula is applied on skin it has a color, 2 minutes later tends to oxidize hugely (towards a red color) and when dried is a completely different color. Besides, once dry, if you rub the finger across the surface you see a white patina appear that is quite visible. We have been trying to adjust the color of the different productions to the master sample’s tone and it seems impossible as the color changes constantly.
I was thinking it might be something related to lack of affinity from the emulsifier toward the silicone coating, as we aren’t using any other siliconic substance appart from the one on the pigments. I haven’t seen any market formula with PEG or natural W/O emulsifiers that contains that coating, all I find is those pigments are usually paired with ABIL EM-90 or other W/Si emulsifiers.
Another idea I came across was also that with time W/O formulas tend to become unstable and when freshly produced the formula seems quite thick but over time it becomes more fluid, so I’m guessing the micelles might be becoming bigger and not so homogeneous and that might be affecting the color perception as well?
I also considered that maybe the titanium dioxide might be migrating towards the water phase…? This particular pigment has also ALUMINIUM HYDROXIDE apart from the silicone and I don’t know what impact that might have on its water solubility.
Any solution or explanation regarding what might be happening would be so welcome, as I am not a chemist myself but a molecular biologist that changed career paths and I find that I lack some basic knowledge regarding chemical structures and reactions. I also find there is so little published data regarding cosmetic formulation and would love if someone could give me some references on more science-based formulation books as all I seem to find are “cookbooks” with no profound explanations.
Thanks so much!
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1 Reply
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It sounds like you want to learn advanced cosmetic chemistry techniques. You should take Perrys course on Beginning Cosmetic Formulation. I would suggest you also enroll at the Institute of Personal Care Science. I have finished the program here but Belinda courses and chemistry degree program will give you the foundational skills to competently formulate from scratch for companies and always get good results.
From the information you have provided it sounds like you should be using a build with more lipids with more spread (emollient esters, silicones). If you have a lot of powders you need to also look at your stabilizers (gums, polymers).
Since you are a beginner, I would contact the pigment supplier and see if they have any sample formulas to begin your foundational work if you do not want to take courses.
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