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Dual phase questions
Hi all,
I’m looking to formulate a dual phase hair spray, with oil phase being milky.1. How can i make oil phase milky? I found this formulation from Dow Corning and I’m seeing they have added Polysorbate 20 @ 1% in the oil phase…the rest are silicones.What’s the function of polysorbate 20 in this formula?2. I’m seeing that sodium chloride is typically added in dual phase formulas. I understand that in W/O formulations, salt is added to stabilize emulsion, but don’t understand it’s function in a dual phase.Thanks in advance! -
1 Reply
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since the ES-5227 Formulation Aid is described as being “grey white to milky white” on the SDS, and all the others are “clear to slightly hazy”, I’m guessing it’s that
the polysorbate 20 is there to form a transient emulsion which lasts long enough for the product to be usable in its mixed form, but which also breaks down over time
sodium chloride increases the surface tension of the water phase, and ensures the two phases separate cleanly, so that any partitioning/leaching from one phase into the other is kept to a minimum
surface tension is also the reason why it’s used in W/O emulsions, though in that case it’s to stop the water droplets from coalescing rather than to promote separation
(I found out a lot of this stuff because the last place I worked was the UK-based contract manufacturer for a very well known brand of two-phase mouthwash)
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