Home Cosmetic Science Talk Formulating Adding the bulk of the water during cool down phase of emulsion

  • Adding the bulk of the water during cool down phase of emulsion

    Posted by Joshlin on April 9, 2023 at 1:12 pm

    Can someone verify that this method of adding a heat sensitive water phase would be effective/possible?

    Ingredients: Distilled water 60g, emulsifying wax 40g(various options, rice bran wax, soy wax, olivem, palm oil esters/fatty acids), 300g heat sensitive water solution

    - 60g water, 40g emulsifying wax (60:40 water:wax content to establish the o/w emulsion

    - Both phases heated to melting point of wax (example, 170F), blended at 170F until emulsion forms

    - Emulsion allowed to cool to 120F, occasion stirring. I read somewhere that when adding liquids during cool down you still need to keep the temperature well above room temp and 120 was suggested.

    - 300g heat sensitive water phase heated to 120F (same as cooled emulsion), slowly added while blending

    - Cooled to room temp with occasional stirring

    The final product results in a 10% total usage of emu wax (a very thick, but useable cream).

    I’m just wondering about the logic of the process. Is that destined to result in leaking/stability issues? Graininess? Will the added water phase truly go towards the emulsion and disperse properly or is it a kind of low stability pseudo emulsion situation? Or is this totally fine way of doing things.

    I think I read somewhere online this process has to do with the critical micelle concentration and/or the critical micelle temperature. Does anyone know? Ty!!

    Unknown Member replied 1 year, 8 months ago 2 Members · 1 Reply
  • 1 Reply
  • Unknown Member

    Deleted User
    April 28, 2023 at 5:27 am

    I think the easiest way to look at its success is to compare the melting point of your waxes to the point at which you are introducing the heat-sensitive phase. Your waxes will distribute best if they are still molten at this point, or if not molten, then completely solubilised in either the water or oil phase.

    Once they have firmed up and created their micelles, they can be distributed evenly throughout the formulation but can no longer form more micelles to help to stabilise the emulsion. Hopefully you can visualise what I am trying to describe!

    To reassure you, a similar method is often used in manufacturing of emulsions where a paste is formed with the surfactants/emulsifiers and a little water, oils are added very slowly to achieve particle size, and then the mixture is very slowly diluted to the required concentration with remaining water. However, the surfactants used are completely soluble in the water phase, so are free to move through the solution and create more micelles.

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