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Sharing any knowledge about emulsion
I will share some information about emulsion and I want to know more and more about it so please share any information :
1) making the same formulation of cream : just changing (cetearyl alcohol to cetyl palmitate to stearic acid) “with same level”
*As result, the formulation with cetearyl alcohol is the best for viscosity and texture.
*Stearic Acid gives very near viscosity but with lower texture (lower smoothing)
*Cetyl palmitate gives too thin emulsion.
I guess may a combination will give better results? Any one try to make some combinations and compare with cetearyl alcohol alone (it needs a lot of work the combination and synergy. I will do it when I collect more information and find time…)
2) For required hlb, i find always two groups, one says it is not important and another says it is . Personally I’am with the group who says it is not important because with same oils and level changing the hlb of my emulsfiers I did not get really important challenges. Or maybe I get better result when decreasing the hlb of emulsfiers comparing to required one, any add or comment?
3) when using cetearyl alcohol in emulsion, its level will be calculated as emulsfier, oil or no one?
As exemple if we have 5% cetearyl alcohol, 10 % oils, 5% emulsfier so
* the total amount of emulsfier is 10% and 10% oils
* the total amount of emulsfier is 5% and 15% oils
* the total amount of emulsfier is 5% and 10% oils.
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5) Always we talk about noewax 165 as from best emulsfier, however my experience shows that it has not good resistance versus Sensicare c1060 because adding this preservative makes an important drop in viscosity to emulsion . Anyone have similar experience?
@Abdullah @Aniela @Perry44 @Paprik @chemicalmatt @Cafe33 @ozgirl @ketchito @Graillotion @PhilGeis @Pharma @ngarayeva001
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2 Replies
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Cetearyl alcohol is a popular fatty alcohol because it provides excellent stabilisation and viscosity enhancement, it’s also cheap. Stearic acid provides good viscosity but less smoothness because it tends to form a different type of gel structure and can sometimes feel slightly draggy or waxy.
Cetyl palmitate is an ester rather than a fatty alcohol or fatty acid, which explains the thinner consistency, esters typically provide minimal structural support to emulsions. They are classed as emollients and contribute to your total oil phase.
Regarding combinations, yep, synergistic effects can produce superior results. You can mix a few different acids and alcohols to form a more robust system. Cetearyl alcohol is an example of a synergistic blend of fatty alcohols (It’s a mixture of cetyl and stearyl alcohols).
If you want to make a stable emulsion using stearic acid as an emulsifier you would need to use TEA, NaOH, KOH etc to form a soap emulsifier. This is how older emulsions were made. I believe Lush use this type of system in a few of their creams and lotions, the issue with this type of emulsifier is the higher pH and very inelegant skin feel. But I also think every formulator should learn how to react fatty acids to form emulsifiers. Maybe then people would stop referring to stearic acid as a “strong anionic emulsifier.” On its own, it’s not an emulsifier.
Honestly the HLB system remains controversial among formulators. While it provides a useful starting point, it has some big limitations in my opinion. It doesn’t account for formula complexity and ingredient interactions. It doesn’t take into account that things like temperature, pH, and electrolyte concentration affect emulsifier performance. Most modern emulsifier systems often work through multiple mechanisms beyond traditional HLB theory. Use HLB as a guide and rely on more practical testing and observation
Cetearyl alcohol functions as both an emulsion stabiliser (or structuring agent) and a rheology modifier. In your example with 5% cetearyl alcohol it should not be calculated as part of your primary emulsifier system (the 5% emulsifier you mentioned). However it does contribute to stabilisation and helps the emulsifier at the oil/water interface. It is better classified as a co-emulsifier or structural component. It does contribute to the oil phase % in practice.
So (again, in your example, as seems too much emulsifier for 10% oil) the most accurate interpretation would be, 5% primary emulsifier, 10% oils, and 5% structural agent (or co-emulsifier).If you used 5% cetearyl with 5% GS+ PEG100S (165 bland) the result would be quite waxy/draggy/soapy and quite viscous. If you used stearic acid it would be thicker again, more draggy, more waxy.
Your experience with GS + PEG100S and Sensicare C1060 compatibility issues is interesting. Do you have a polymer in your water phase (0.2% Xanthan gum would help stability,) ? While I have not used sensicare C1060 (Piroctone Olamine (and) Phenoxyethanol (and) Glyceryl Laurate) as a preservative system myself, I do know that phenoxyethanol can sometimes affect viscosity.
I do wonder if presence of glyceryl Iaurate, which is a shorter-chain fatty acid ester (C12), could disrupt the formation or integrity of the lamellar gel network because it’s primarily built by the longer-chain stearyl components (C18). I wonder this because i know that systems combining fatty alcohols or esters with different chain lengths can affect packing and phase behaviour. Maybe this could potentially lead to less stable or lower-viscosity structures? I’m guessing here as not used this preservative.
Do you know what is the ionic change of the preservative is? Olamine usually refers to an anime salf. Could this potentially interact with the polar components of the lamellar gel network? or other ingredients in your formulation (as we don’t know the formula or process)? Ionic interactions can destabilise emulsifier structures or polymers, which can result in a viscosity drop or formama instability.
Maybe there’s another culprit? I’m not sure, as it could be other things in your system, and without a full formula and full process, it’s hard to give an answer or direction to follow. Others might have a better answer. Have you tried using another preservative ? Does it still happen? Have you done knockout experiments to work out actually cause the viscosity drop? Have you use this preservative in other formulae?
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Thanks a lot for your valuables answers.
For emulsion of Neowax165 no i did not use gelling agent . for sensicare c1060 phenoxyethanol effect the viscosity almost but with differents intensity depend on formulation . For shampoo formulation i find piroctone olamine effect also the viscosity of product the point of glyceryl laurate i really i did not get it …
I haven’t time till now to make other samples with neowax 165 just the same formulation using sabowax AE gives higher viscosity.
About the used level of emulsifier you have right however it is not just to stabilise oil but to reach a desired viscosity and texture .
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