Emulsion seperation because too much wax?

ultraduyultraduy Member
in Formulating
Can having too much wax in relation to liquid oil cause emulsion instability even if the HLB of the oil phase fits that of the emulsifiers? I just made an emulsion very high in wax,  around 2/3 of the oil phase contained wax, and the other 1/3 oil. swapping in some of the wax for oil fixed the problem. Does anybody know why emulsions seperate if there is too much wax?

Comments

  • GuntherGunther Member
    Hard to answer without knowing the actual ingredients and % in the formula.
  • PharmaPharma Member, Pharmacist
    What are the melting points of the two oil phases?
    High amounts of wax are sometimes used to stabilise emulsions which contain no or "not enough" emulsifiers. On the other hand, the following scenario is possible: too much wax = high viscosity upon cool-down = not enough time for the emulsifiers to diffuse to the droplet-surface.
    But then again, it depends on a lot of things, for example what kind of emulsion you have.
    Posting your ingredients wouldn't hurt ;) .
  • ultraduyultraduy Member
    edited July 8
    waterphase:
    water 
    glycerin

    oil phase:
    rice bran wax
    cetylalcohol
    hydrogenated castor oil
    castor oil
    apricot kernel oil

    essential oil
    preservative 12

    emulsifiers:
    polysorabte 80 and glyceryl stearate

    the hlb matches the oil phase, if I go above 16% rice bran wax my emulsion does weird things. Also consider that this is a o/w emulsion with the oil phase being around 25% of the whole formula. But I should also note that during mixing somehow it wouldnt mix either, I saw no even white color even some yellowing.
  • MarkBroussardMarkBroussard Member, Professional Chemist
    edited July 8
    @ultraduy

    If you want to keep that high level of wax, you might try adding 0.2% Sodium Hydroxide to the water phase prior to emulsification.  I don't know if this will work with Rice Bran Wax, but if you are using Organic Emulsifying Wax (beeswax, lecithin, carnauba wax) this is how you get it to emulsify.

    Perhaps you could sub Rice Bran Oil for some of the Rice Bran Wax to enhance your emulsion stability.
    Chemist/Microbiologist formulating in the Organic & Naturals arena under ECOCert/Natural Products Assn/Whole Foods/National Organic Program guidelines focused skincare & haircare products. 

    Provides Formulation Development and Lab-Scale Contract Manufacturing Services.  See website for details www.desertinbloomcosmeticslab.com

  • PharmaPharma Member, Pharmacist
    Rice bran wax contains only small amounts of free fatty acids. Adding sodium hydroxide might still work but be careful adding not too much (control pH).
  • FekherFekher Member, Professional Chemist
    @Pharma @Markbroussard what about adding TEA in place of NaOh , it is for sure more secure about Ph but not sure about stability.
  • PharmaPharma Member, Pharmacist
    Might work as well, it's a base. Hydration radii are different and the % of neutralised free fatty acid will affect emulsion type but, as I said, it's just a base like NaOH or KOH.
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