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Cationic emulsion system questions for lotion
I am using BTMS 50 to create a cationic emulsion. As I understand it, this means that the positive charge will adsorb to our negatively-charged skin, and create a more lasting conditioning effect. Assuming this is correct, I want to add a salt to aid in emulsion stability (I read this somewhere) and for metals sequestration. I also want to lower the ph a bit for stability and for skin compatibility. I have chosen disodium EDTA (at .2%) in hopes that it will help meet these objectives. Can anyone confirm? Deny? Point me in the right direction?
Also, I understand that EDTA carries a negative charge. Might this cancel the positive charge of the emulsion-and consequently, the benefit I am seeking? I I have been unable to successfully google answers to this line of questioning.
Thanks, in advance, for any thoughts!
Leslie -
10 Replies
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First of all EDTA’s primary function is to act as a chelate and whatever charge it is carrying would be used up to form those metal complexes. Supposedly, still if there is some charge left it would be much smaller than that of cationic BTMS and won’t affect the conditioning efficacy of BTMS.
I might be wrong in my assumption so discretion advised. -
I can buy that-thanks!
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When I read the first two lines of you question, I thought you were referring to hair as it makes sense what you are saying for the hair. I can see BTMS-50 being of use in a conditioner but cationic emulsifiers for the skin have traditionally been viewed as a bit irritating. They are also have a dry, matt feel.
Yes you can add edta to the heated water phase - 0.1-0.2%. However if you are aiming for the natural market you might wish to look at chelators such as Dissolvine GL 47-S and Dermofeel
PA-3. -
Thanks for the feedback, MakingSkincare- I am actually looking to make a matte-feeling lotion with lots of film-formers for my own use (for now, at least) while riding my motorcycle. Added protection, and no slip…
I’ll look around for your chelator suggestions. I don’t know that I’ve run across them at the usual hobbyist-suppliers. If you know of a company that sells small quantities, please let me know!
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The BTMS 50 will actually feel good on the skin, try it. Try 2 to 4%
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I’ve been using BTMS 50 in my formulas for nearly a year now, along with 1 to 2% Cetyl Alcohol (usually). I prefer the feel to other emulsion systems I’ve used (Polawax, E Wax, Ritamulse)-especially on face and hands. I haven’t noticed any irritation on my own skin, but it’s always good to be alerted to the potential that it might bother others.
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According to Croda BTMS-50 is “non-irritating on the skin”
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I like BTMS as well. The only problem I found is the smell. In some formulations, especially anhydrous ones, I can smell ammonia.I haven’t had that problem with emulsions, though.
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Inolex Emulsense cationics are worth a look:
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Thank you Bobzchemist. I’ll ask for a sample and give it a try
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