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HLB in emulsions
Hi everyone.
Usually when calculating HLB, we match the HLB of our mixture of emulsifiers to the required HLB of the oils we have.
My question is: would it still be ok if the emulsifiers’ HLB is higher than that required for the oils? We all know you can’t 100% depend on HLB , but you still need to try, so if i go higher with emulsifiers, would this make it a better start point, or theoretically, you have to have both HLBs equal?
Thanks In Advance -
3 Replies
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HLB is a stupid and obsolete system which too often doesn’t even work in real life. It was okay back in the day but is utter nonsense these days.It’s only useful for theoretical systems involving water, a PEG-based emulsifier system and an oil. No one produces cosmetics just based on these.A better approach would be HLD; oil industries use it instead of HLB because HLB doesn’t work and one failure in oil drilling easily costs months of work and millions of dollars. Sadly, we from the cosmetic sector don’t have the numbers for most of our ingredients because we are so addicted to HLB that HLD never got a chance. With both systems, the instant you add co-emulsifiers, ‘actives’, rheology-modifiers, and what not, the whole system changes. In that moment, HLB is toast, HLD can still be applied but you’d have to run a small series of tests to re-adjust.Hence, calculating HLB will give you an approximation on where to start but it’s neither a must not ultimate truth. For an o/w emulsion, being above theoretical HLB is by trend better than being below though energy input for emulsification may be higher.I do calculate HLB because I have the values and to see whether or not it matches results. So far, more failures than success. Just looking at the emulsifier’s chemical structure is as accurate and then it’s always trial and error… that’s the weird world of cosmetic product development. -
Thanks Pharma,Totally agree, HLB never comes out correctly in reality. I just use it as a start. Will definetly look into HLD more
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Best HLD page to start: https://www.stevenabbott.co.uk/practical-surfactants/
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