Homogenizer, or simple mixer?

I want to currently formulating a facial cleanser with with oils. The concentration of oils i am currently using is 5.5%, so polysorbate is not the best option to simply solubize. Rather, I want to create an emulsion, kind of like a cream with 5.5% oils, and mix that into the surfactant phase. My question is, should I create the emulsion first with half the water, and mix this with a simple overhead mixer into the surfactant (with other 1/2 water) phase, or should I emulsify the oils into the water surfactant fase all-in-one using a homogenizer?

Comments

  • BobzchemistBobzchemist Member, PCF student
    That's way too much oil for a face cleanser. What are you trying to achieve? 

    And, why don't you try both production methods and see which works best?
    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."
  • Ihaven't use the homogenizer yet so I don't know how it works, I've been using an overhead mixer, and the mixture stays together for several weeks, but it starts to separate. I'm not sure if this is due to the fact that the pH is low, salicylic acid adjusted to around 4.0, or because a proper suspension was not formed. I was looking for more of a general suggestion as to which method is preferable. Is there any inherent problem with homogenizing foaming surfactants (mixture of SCI, betaine and decyl glucoside)?

    I agree that this is slightly too oily, but this is in line with what my former students mother, who owns a spa for which I formulate some simple products, requested -- she wants something which is low foaming, and re-fattening for extremely dry skin types.
  • what I really need to do is remove the salicylic acid, and try again. Like I said I was just hoping to get a general answer to the question of whether using a Hi-Shear homogenizer with foaming surfactants is "okay", or not recommended.
  • ozgirlozgirl Member, PCF student
    Perhaps you should look at something like Lamesoft PO65 (Coco Glucoside (and) Glyceryl Oleate) instead of oils. It will be much easier to incorporate.
  • BobzchemistBobzchemist Member, PCF student
    You're suspicions are correct, using a high-shear homogenizer with foaming surfactants is NOT recommended, due to the foam you will generate. Unless...you can get a hold of a homogenizer that runs in a vacuum kettle. (expensive, but very cool equipment) http://www.ika.com/Products-Lab-Eq/Laboratory-Reactors-csp-232/ 

    You can make the formula more stable by making the emulsion first with a homogenizer, and then adding it to your surfactant mix with an overhead mixer, but this isn't critically necessary if you design the formula properly.

    You should be able to get your formula stable - this type of system isn't unheard of, it's just not common, because that much oil will inhibit 80 - 90% of the foaming. Keep in mind that foaming surfactants are Very Bad Emulsifiers(tm), which may be the cause of your instability - try making the emulsion first with a strong emulsifier, then adding the other surfactants.
    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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