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blending liquid/oil-based foundation
Aloha,
I have become pretty good at formulating different shades of powder-based and pressed make-ups for daily wear foundations. However, I’d like to incorporate my shades into a liquid-based concealer. I have done this using octyldodecanol for the majority of the liquid component. However, I can still feel the small particles from the titanium oxides. I “homogenized” with the simplest of tools, a battery-operated mini paint-mixer.
My question is: how would an ultrasonic homogenizer do with this? Would it be overkill or God’s gift to creaminess? Is it possible that this kind of tool would help in creating a creamy foundation? I would homogenize the oil-base and powder-based ingredients prior to adding hyaluronic acid, as I’ve read that HA would be destroyed.
I know it’s an expensive option, but with a less than 50 ml batch I feel like it would be a fun tool to buy for a home-lab.
Also, my pigments are not silicone-ized (if that’s the term). Perhaps buying pigments that are already soluble is the best answer?
Thank you for this forum, I learn something each time I visit.
Jennifer (Oahu, Hawaii)
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1 Reply
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Hi Jennifer. As you surmised, a paint mixer won’t really “homogenize” much. The disaggregation that you get from any overhead stirrer type of device is much less than you would get from an actual homogenizer. Here’s a decent rule of thumb:
- An overhead stirrer will break down immiscible particles (things that don’t naturally dissolve into the solvent) to around 100 micrometers (aka “microns” - in other words 0.1 mm) depending on the stirring conditions, what you’re stirring, etc.
- A rotor-stator homogenizer, depending on the probe used, can get particle sizes down to about 5 microns (0.005 mm)
- A high-pressure homogenizer, which are what are used in many industrial processes, can get the particle size down to around 100 nanometers (i.e. 0.1 microns, or 0.0001 mm) depending on the instrument, pressure, and what you’re homogenizing
- An ultrasonic homogenizer with sufficient processing can sometimes achieve particle sizes around 50 nm (0.05 microns).
YMMV based on the chemistry of your mixture, but ultimately a homogenizer will provide you with far greater disaggregation of your titanium particles than a mixer. A mixer is really a tool for blending miscible substances - things that will naturally dissolve in each other. A homogenizer is for the tough jobs when you really need to force substances to blend by reducing the particle sizes of the solutes.
The downside is capacity. Stirrers are much better equipped to handle large volumes, and ultrasonics in particular can be a PITA to scale up. They also don’t handle higher viscosity mixtures very well. You might be better off with a rotor stator, depending on what ultimate particle size you need. Rotor stators are easier to scale up, handle larger volumes at any given price point than an ultrasonic, and can process higher viscosity liquids (although not as high viscosity as overhead stirrers can handle).
Hope that helps!
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