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How long do you mix your emulsions?
Generally, how many minutes do you high shear mix your lotion emulsions?
Let’s say a 50 gallon batch.
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9 Replies
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Shear is very emulsion dependent.
I only do lab-scale….so I shear for 2 minutes at elevated temps, before lamellar structures are formed.
I stir the entire time until pouring below 35 C.
Some emulsifiers greatly benefit from one last kiss of shear below 40C. I know PCP is one that likes a late kiss of shear.
So, question is essentially impossible to answer…without more details.
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The emulsifyers are 4.5% GMS SE, cetyl alcohol, stearic acid, xanthan gum with a 14% additional oils. Medium lotion thickness.
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i don’t think that GMS SE alone can give a stable emulsion .
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Really? Tests batches are stable. I thought GMS SE is self-emulsifying as it contains a small amount 1-3% of sodium stearate.
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may @ketchito @Abdullah @Graillotion can help
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Sure it can be stable. With that emulsifier…pH is everything! Needs to be a bit higher than most….or you will ‘un-make’ the soap. 😅
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This would not need high shear mixing so any amount is enough.
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As @graillotion said, the amount of energy (time and speed) is formula and reactor-size dependent. Formally, when you go from lab to plant, you’d need to calculate different parameters like BTO, power number, heat gradient, etc.
As a general rule, for a regular O/W emulsion with waxy emulsifiers and structuring agents, and a decent amount of oil phase, for a 50gal batch and one high-shear homogenizer, I’d emulsify close to 80C and with high shear for close to 10 min (it should be a bit less when increasing the diameter of your homogenizer compared to the diameter of your reactor), then I’d switch to a helical mixer. If the product is lighter (like a lotion with few and soft waxes), I’d cut the emulsion time to 5 min under high shear.
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Ive made every mistake you can, experiment on a test batch. There’s information on what a typical test batch size is and then extrapolate. I’ve used too high of a sheer, not long enough, too long, too little, and the final product will be vastly different from one another. Chemical, mechanical and temperature tend to be the trifecta of how to properly mix an emulsion. For my small one gallon emulsions, 3 minutes is the max I need however, I slowly incorporate ingredients. I use kitchen supplies so industrial equipment will be different. You don’t need to mix long or use high sheer. 5 minutes or less is average for me.
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