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Can O/W Emulsifier produce a W/O product?
Dear Sir,
I would like to get some advise as the subject. Recently I try to formulate a mineral sunscreen cream SPF 50 using a cold process O/W emulsifier. However, after finished, I try to make 10% solution to test pH and found out that the cream doesn’t dissolved in water as O/W cream behaviour.
My formula ingredients as below:
Water 50%; Glycerin 2%;
Cold process emulsifier (Sodium Acrylate/sodium Acryloyl Dimethyl Taurate Copolymer, Cetyl Alcohol, Glycol Stearate, Glyceryl Stearate, Caprylic/capric Triglyceride) 4%
TIO2 Dispersion (C13-15 Alkane based) 20%
ZnO Dispersion (C13-15 Alkane based) 15%
Natural oil (Argan Oil + Tocopherol) 5%
Sorbitan Oleate 1%
Phenyethanol Blend 1%
Water-based film former (Acrylates/Ethylhexyl Acrylate Copolymer (And) Water (And) Aminomethyl Propanol) - 1%
Silica - 1%
Appreciated if can giving advise on this and what is the mechanism on this shift.
Thank you
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4 Replies
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Could you be a bit more specific about the solubility test? Keep in mind that ZnO, TiO2 and silica are not water soluble.
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Dear Ketchito,
Previous practice when I make a O/W emulsion, I would check the product pH. Then, I will take 10% of the product and mix in 90% DH20 to check for product pH. The solution purpose is check for the product pH. My concern is, it is possible that I use O/W emulsifier, and the product come out with W/O emulsion.
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it will probably separate as stability accelerates
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@HenryLee With all those anionic acrylic polymers used there I do not foresee this ever being anything but an o/w emulsion. This is basically a Pickering emulsion. Test your pH directly and get on with your day.
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