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What makes emulsion loose viscosity?
I made 100g glycerin cream in laboratory scale with :<div>
Water Qsp
Edta 0.1%
Citric 0.05%
Cetearyl alcohol 3%
Emulsifier wax 5%
Glycerin 3%
Parfum 0.5%
Paraffin oil 10%
Preservative 0.8%
Process heating oil phase and water phase separately to 70 °C, start cooling and add oil phase to water phase mixing with 600 rpm
So the emulsion get thick then it loose viscosity.
I want to know the reason of loosing viscosity.
My doubts are :
1)The fast cooling where I take my emulsion far from the heating source just before adding oil to water phase then the 100 grams cream was cooling fast.
2)Reason of mixing after cream getting thick (but I did with other emulsion and they didn’t loose viscosity)
3)there is needed mixing time in hot temperature to get stable thick cream that will not get thinner after thickening.
Also by making after shampoo( hair conditioner )I get very strange curve of viscosity with temperature variation so supposed u is the viscosity, I had as viscosity u(75°C)>u(70°c)>u(49°C)>u(53°C)>u(60°C)
Any explanation from experts please I really thought a lot without reaching convincing answer.
@Perry44 @chemicalmatt @Cafe33 @Abdullah @Pharma @Graillotion @Paprik @ngarayeva001 @ketchito
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7 Replies
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I am having a little trouble following the timeline. But it sounds a little like a phase inversion (for lack of details). This occurs when an emulsion tries to first become a W/O instead of O/W. They manifest as being very thick at first. Typically once you reach a certain point that breaks…and tries to return to O/W which is typically far less viscous.
Again… without a detailed description of what is happening at what point in time… I could be way off.
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Thanks.
For making cream the order is :
1)heating separately oil and water phase to 70°C(Except perfume and preservative)
2)take both oil and water phase far from heat source(cooling start very fast it needs near to 30 min to reach 40°C)
3)start stiring with 600 rpm speed
4) between 50° C and 40 °C emulsion became thick as usual(stiring 600 rpm) .
5)from 40° C or lower emulsion became thinner( stiring 600 rpm without adding preservative and perfume)
For conditioning hair : the chronology of viscosity is in cooling phase.
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You should add the oil nto the water phase while keeping the heat during the entre emulsification process. Only after that, you start cooling (not before). This prevents crystal formation of your high melting point waxes so they can properly mix.
Also, the amount of mineral oil might also be to blame for the viscosity loss. Non polar oils are hard to emulsify. Are you making a massage cream? If that’s the case, then build a more robust interfase to support the mineral oil. If not, then just drop it to 2-3%.
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Actually I have very close formulation with preolatum instead paraffin oil and I did not face a problem actually I got with petrolatum viscous cream. About recristalisation all solids have fusion temperature far from 70 °C then it can not happen. ( today I just do same process described just increasing the speed of stiring and I got better results.)
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It’s either preservative or the emulsifier because the formula os straightforward otherwise. Can you post INCIs, please?
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I did not add preservative and perfume.
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If you keep everything unchanged and use Glyceryl Stearate + PEG100 Stearate (goes under many different trade names) as an emulsifier it will work. It handles non polar oils pretty well. I used it with petrolatum and mineral oil many times.
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