Trying to thicken a Glyceryl Stearate (and) PEG 100 Stearate lotion w/o Stearic Acid

GraillotionGraillotion Member
edited May 19 in Formulating
I am trying to make a reasonably natural lotion, and it is just a touch thinner than I wanted.  I am trying to avoid stearic....for the sensories it brings...and I blame it for soaping as well... :) 

I realize...some of my natural oils and butters contain stearic acid, and that will be part of my line of questioning.

From a sensory and soaping perspective.... let's use one of my ingredients by name for the sake of the conversation.... will there by any difference in the end result if I add just pure stearic acid vs increasing my Cupuacu butter, which is high in stearic?  (I realize I would have to use at a 2 to 1 ratio for a similar effect.)

I realize that from an economic and efficacy point of view...the purchased stearic will have the most dramatic influence for the lowest price.  But if I create the same result with more Cupuacu (as the example), will I get the same soaping and drag....that I will get from a comparable viscosity, using pure manufactured stearic?

So right now....the two primary thickeners I am using is cetyl esters (3%) and Xanthan gum (.3%).  This result...is just a touch too thin.  So my other question is...at what level....do these two ingredients become....'too much of a good thing'?  I don't really view X-gum as an efficient thickener...(but am open to being wrong)…. And at least one of the vendors listed cetyl esters at a max use rate of 3%....however several other vendors listed it MUCH higher.... So a little confused on that.

So bottom line....should I just keep bumping the cetyl ester....to say 4 or 5% to achieve the desired viscosity?  I don't have that far to go.

Note:  I am waiting at least 48 hours after producing the product....before I evaluate the viscosity.

Current product has ZERO soaping....and I want to keep it that way.  Found the: Hydrogenated Ethylhexyl Olivate, Hydrogenated Olive Oil Unsaponifiables, really helped with this, as well as the 165 emulsifier.


Comments

  • PharmaPharma Member, Pharmacist
    Not much time, doggies need to do what doggies do... More tomorrow?
    In short: Cupuacu is triglycerides = chemically reacted fatty acids whereas stearic acid is free acid. Both increase melting point but stearic acid tends to form more/better crystals which thicken the oil even better.
    Beeswax? Gellant combo instead of pure xanthan? Different emulsifier... meh... maybe don't change that. Try different shear force, droplet size matters, although... if it's at the cost of stability... (I like ... too, especially when in a hurry :D )
  • Pharma said:
    Not much time, doggies need to do what doggies do... More tomorrow?
    In short: Cupuacu is triglycerides = chemically reacted fatty acids whereas stearic acid is free acid. Both increase melting point but stearic acid tends to form more/better crystals which thicken the oil even better.
    Beeswax? Gellant combo instead of pure xanthan? Different emulsifier... meh... maybe don't change that. Try different shear force, droplet size matters, although... if it's at the cost of stability... (I like ... too, especially when in a hurry :D )
    Thank you for your feedback!

    I have been ALL the way around the block with different emulsifiers....and the 165 just seems to fit the bill....in everyway....and can be used in each of my 3 formulas + it makes the whitest product in my situations...with colored oils.

    I suspected that the natural stearic...would NOT perform the same way as the purchased.  Thankyou for the scientific answer.

    If I can't get there with an extra percent of cetyl ester....I will explore a small amount of stearic....hehehe....How bad can it be?  But if I can get there without adding another ingredient to the INCI....all the better.
  • @Graillotion Since you're not too far from the right consistency, you could just up the cetyl esters by 1% and Xanthan by another 0.4%, even a bit more of the Glyceryl (and) PEG-100 Stearate. Just upping any or all of these three should provide more thickness but different skin feels.

    To  avoid the lotion feeling slimy due to too much Xanthan Gum, maybe upping cetyl esters and 165 would be the better choice.

  • GraillotionGraillotion Member
    edited May 19
    @Graillotion Since you're not too far from the right consistency, you could just up the cetyl esters by 1% and Xanthan by another 0.4%, even a bit more of the Glyceryl (and) PEG-100 Stearate. Just upping any or all of these three should provide more thickness but different skin feels.

    To  avoid the lotion feeling slimy due to too much Xanthan Gum, maybe upping cetyl esters and 165 would be the better choice.


    Thank you for your thoughts.

    I am already using the 165 @ 4%.  (Formula is basically 14% natural oils and 3% butters)  It is my understanding.... 165 does not do much thickening (like other emulsifiers....)  So I will make again today...with Cetyl Esters bumped....another percent.
    Hehehe....I am already maxed on humectants....as I am using what I imagine to be a synergistic blend... :) 

    Expecting some feedback from my Arizona testers...today.

    Aloha.
  • It’s not w/o it’s o/w. Just add a little of cetyl alcohol or some polymeric emulsifier such as Aristoflex AVC.
  • PharmaPharma Member, Pharmacist
    Looking at the facts I know about your product (also from other posts and if memory serves me right):
    Very white, pearlising/whitening agents don't seem to work, product requires thickener, colour of inner phase (oils) is not visible, lotions not cream, low % emulsifier 165 with low % oil and no fatty alcohol or fatty acids added: You have a pure w/o emulsion in the traditional sense (tiny oil droplets, no lamellar phase).
    Adding cetyl ester or other high melting wax will only increase viscosity of those droplets. Although cetyl esters can increase lamellar phase, they aren't sufficient alone. Ever played that game where you try to grab apples out of a basket full of water with your mouth? How hard the apples are isn't important, only how liquid water is. What you need is a more viscous outer phase. You've got three options (longer version of exactly the same as @ngarayeva001 said).
    A: Change emulsifier which changes your emulsion type. A hard decision at a late stage of development.
    B: Add more xanthan or use a synergistic thickener combo. I wouldn't opt for particle based gelling (e.g. bentonite). This won't affect the overall appearance of your lotion but might change sensorial profile. IMHO this is your best choice.
    C: Create a lamellar network which is easy because emulsifier 165 responds well to that. However, cetyl esters alone might not suffice because of the very large hydrophilic groups of 165. You will have to add cetyl alcohol or stearic acid to make it work (it's just a matter of how much you add), if glycerol palmitate or cosmetic grade glycerol stearate (a mix of mono- and distearate) work, I don't know, 165 already contains a lot glycerol stearate. Pros/cons for stearic acid: likely stronger effect but likely electrolyte sensitive. But then again, you change the type of emulsion and it may well be that you'll start to see the inherent colour of your oils. One option might be octyldodecanol which supposedly forms a unique type of lamellar network and affects the oil phase less... Unlike fatty alcohols/acids, octyldodecanol is liquid and less draggy/greasy. My personal (unsubstantiated) impression is that it plays nicer in thicker creams than low viscosity lotions, it doesn't up viscosity as much as solid thickeners and has to be added at higher amounts (up to 20% are possible).
    BTW lamellar networks have become very frequent in cosmetics and the ready to use DIY emulsifiers and emulsifier blends are usually building lamellar networks. Such emulsions are less susceptible to creaming and coalescence and allow for a larger playground (just a rule of thumbs). Imagine you add plastic foil sheets to your apple water bucket, the game goes from waterboarding to cakewalk. On the other hand, 'true' emulsions of tiny oil droplets in water are what you learn first when hearing about emulsions. These become more liquid the smaller droplets get and the narrower size distribution is (imagine cherries instead of apples). They usually require a gellant in the outer phase (like picking apples out of a JellyO). Another option would be worm-like micelles (like fishing for bananas, also quite easy)... but such formulations are not simple to predict and somewhat susceptible to many things such as ingredient type, amount of oil phase, ratio emulsifier/oil etc.
    Questions? :D
  • If you analyse many commercial products, you will notice a common pattern:
    Water, Glycerin, some sort of oil, GMS+PEG-100 Stearate, Cetyl or Cetearyl Alcohol or both, Dimethicone, some sort of polymeric emulsifier (Sepinov EMT 10, Aristoflex AVC, Sepigel 305 etc) for stability and improved texture. This is your bulletproof formula of success. Add a good preservation system and you have a minimalistic yet decent product.
    You can always make it better by combining different fatty alcohols and esters, you can replace glycerin to glycols, you can add silicone elastomers and more than one polymeric emulsifier for even more fancy feel. You can replace veg oil to a light ester with high spreadability or a blend of oils and esters. But what I listed above is your "it will always work" base.
  • Pharma said:
    Looking at the facts I know about your product 
    A: Change emulsifier which changes your emulsion type. A hard decision at a late stage of development.

    C: Create a lamellar network which is easy because emulsifier 165 responds well to that. However, cetyl esters alone might not suffice because of the very large hydrophilic groups of 165. You will have to add cetyl alcohol or stearic acid to make it work (it's just a matter of how much you add),
    Questions? :D
    Regarding emulsifier....when it was down to two.... It was Glyceryl Stearate (and) PEG 100 Stearate, and a Sodium Stearoyl Lactylate type.  I chose the 165, because I thought I could use it across 3 products.... including a mosquito formula with lots of fun and difficult ingredients.
    The 165 also whitened the final products better than the Lactylate types, and even seemed to retard oxidation in the mosquito formula?  And I thought that 165 was the easiest to work with, and might be the most forgiving?  And last but not least....the 165 seemed to 'soap' less!  (but I never gave the lactylate a shot with the Hydrogenated Ethylhexyl Olivate, Hydrogenated Olive Oil Unsaponifiables.

    So in choosing the 165....I knew the challege would then be in the thickening.  Or should I say...thickening while avoiding soaping and losing sensories, all while trying not to use any silicones.  From the comments of Pharma, ngarayeva001, and ChemicalMatt, sounds like I need to blend my C Esters with C Alcohol.  I will say....I made the formula with exclusively C Esters and again with exclusively C Alcohol, and certainly preferred the final product that was made with the C Esters.  

    In trying to achieve the viscosity...I have taken C Esters to 4%.... I think I will try a blend... maybe 2% C esters and 1% C Alcohol.  Or....would you recommend a different ratio?  Did I understand you ….that the fix might be as simple as that?
  •  Dimethicone, some sort of polymeric emulsifier (Sepinov EMT 10, Aristoflex AVC, Sepigel 305 etc) for stability and improved texture. This is your bulletproof formula of success. Add a good preservation system and you have a minimalistic yet decent product.
     you can add silicone elastomers and more than one polymeric emulsifier for even more fancy feel. 
    My greatest weakness as a amateur formulator....I am addicted to label appeal. :(   Therefore trying to keep the synthetics to a minimum....and the hard to pronounce things...

    I sell in Hawaii....where more natural....is a good thing... almost a religion. :) 

    So If I can create a sound emulsion, with the fewest possible ingredients....with some of my other pet peeves...and keep a tidy label....I am happy guy.

    I have been doing this just long enough..... that I have already discovered....a beautiful label, and story.... make the product sell. :( 

    I truly appreciate your comments.
  • PharmaPharma Member, Pharmacist
    Sounds like you'd be better off with version B then ;) .
    Add locust bean gum aka carob, guar gum, or tara gum. These three show synergism with xanthan gum. Hardness/stiffness/viscosity of a xanthan gum blend decreases in the following order LBG>guar>tara whilst smoothness/softness/slip increases. Typical ratios are 1:1 - 1:2.
    Someone here on board said that mixing xanthan with sclerotium gum (1:1 - 1:4) reduces soaping/whitening sometimes seen with pure xanthan.
  • Pharma said:
    Sounds like you'd be better off with version B then ;) .
    Add locust bean gum aka carob, guar gum, or tara gum. These three show synergism with xanthan gum. Hardness/stiffness/viscosity of a xanthan gum blend decreases in the following order LBG>guar>tara whilst smoothness/softness/slip increases. Typical ratios are 1:1 - 1:2.
    Someone here on board said that mixing xanthan with sclerotium gum (1:1 - 1:4) reduces soaping/whitening sometimes seen with pure xanthan.
    So you are saying...don't bother with blending C esters and C alcohol?  Just go for Plan B?
  • PharmaPharma Member, Pharmacist
    edited May 21
    Yes. The reason why is hidden in the long post on May 20... I know, I write too long interlocking phrases, adding too many parentheses (you can simply skip them if you like it simple), and touching too many subjects within those phrases (not to mention that English is not my mothers tongue and my phrasing might be somewhat off). So, re-read first paragraph in said post. It says: small chance to win with the other options without turning your lotion less white.
    BTW test gums or synthetic gelling agent in plain water to get a rough approximation of the required % and ratio.
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