Foundation (w/si) viscosity issue

Hello All,

I am struggling with a W/Si foundation. My main problem with it is that if I add pigment to the oil phase and then process the emulsion, the viscosity is very low (almost water thin). If I add the pigment to the ready emulsion (it’s smooth and very thick which is what I want) it looks great, applies great but shows signs of separation the very next day.

I process the emulsion as W/O: heat both phases to 70C, add water by drops under low shear (overhead stirrer) and then homogenize the emulsion after the temperature drops below 40C. If no pigment is added the emulsion is thick after I homogenize it. The pigment is TiO2 and Iron Oxides suspended in Octyldodecanol. Pure pigment concentration is 50%

INCI

%

Aqua

38.20%

Phenonip

1.00%

Betaine (trimethylglycine)

2.00%

Glycerin

3.00%

Sodium lactate

1.00%

Sodium PCA

2.00%

Dimethicone 5

10.00%

Isodedecane

4.00%

Hydrogenated Polyisobutene

5.00%

PEG-30 Dipolyhydroxystearate

2.00%

Cetyl PEG / PPG-10/1 Dimethicone

0.70%

Polyglyceryl-3 Triolivate

1.00%

Polyglyceryl-3 Beeswax

1.00%

Sericite Mica

1.00%

Dimethicone / Vinyl Dimethicone Crosspolymer, Silica (powder)

0.60%

Boron nitride

1.00%

Magnesium Stearate

0.50%

Dimethicone / Vinyl Dimethicone Crosspolymer (gel)

3.00%

Trimethylsiloxysilicate (and) cyclopentasyloxane (film former)

3.00%

Custom blend of TiO2 and iron oxides in octyldodecanol

20.00%

 Any advice is appreciated.


Comments

  • I understand that pigments broke the emulsion. I wonder if that can be fixed by adding some emusifier to the pigment mix..
  • gld010gld010 Member

    Color cosmetics are a pain, speaking from experience!

    Boost up levels of existing emulsifiers -- your PEGS/PPGs. If you are calculating with HLB make sure to factor in the oil your pigments are dispersed in (it's easy to forget).

    If you have access to other pigment dispersions, I'd give those a try as well - sometimes what the pigments are dispersed in can make or break a fussy emulsion like w/si.

  • ngarayeva001ngarayeva001 Member
    edited June 10
    It is a pain indeed. Unfortunately I only managed to find pigments in octyldodecanol. I didn’t apply HLB system (should it be applied for w/si?). It works fine when I add pigments to the oil phase. It emulsifies and stays together at a room temperature (I didn’t stability test it). But the texture isn’t even close to what I want. I will increase level of emulsifiers, I think it’s always a good idea.
  • PharmaPharma Member, Pharmacist
    Did you try pure octyldodecanol to see if it's this or really the pigments?
  • I played with these emulsifiers for a quite a bit before I added pigments. I tested these with several esters including octyldodecanol, no problem at all. It’s clearly about pigments. Oh I forgot to mention the emulsion is thickish with 10% of pigment blend (which translates to 5% pigment and 5% of octyldodecanol), but the coverage is too light.
  • gld010gld010 Member
    Are your pigments coated with anything or are they plain oxides? Coated pigments tend to play nicer with w/si emulsions (emulsions in general, really) in my experience
  • Bill_TogeBill_Toge Member, Professional Chemist
    how fine is the screen on your homogeniser, and what speed are you running it at?
    UK based formulation chemist. Strongest subjects: hair styling, hair bleaches, hair dyes (oxidative and non-oxidative) I know some stuff about: EU regulations, emulsions (O/W and W/O), toothpaste, mouthwash, shampoos, other toiletries
  • Ready dispersion (for makeup) in octyldodecanol. Emulsion without pigment gets viscous after application of high shear. So I guess it’s not easy to get viscous w/si with pigments. Anyone tried?
  • Just a guess... Could there be a problem with polarity of my oil phase? I use dimethicone which is non-polar with polar esters. Could that be the reason?
  • DoreenDoreen Member
    @Bill_Toge
    I think ngarayeva001 uses a stick blender.
  • SpongeSponge Member
    I’m sorry, not to hijack your thread... can anyone explain/elaborate on why cetyl PEG/PPG-10/1 dimethicone is ubiquitous in complexion products? 
  • Unfortunately I do. It’s possible to find not expensive overhead stirrer but not homogenizer. Also homogenizers are pain to clean and it’s impossible to make 100 g batces. Materials for foundation aren’t cheap.
  • @Sponge, the reason I bought this material is that I saw it in every foundation I like. My observation it creates  a nice texture but it’s hard to stabilize on its own (w/si made with this alone separates quickly).So, I use three emulsifiers and stabilisers.
  • chemicalmattchemicalmatt Member, Professional Chemist
    Sponge, that emulsifier from Evonik is perhaps the most commonly used for w/o inverse phase emulsions, always with a co-emulsifier like the polyhydroxystearate. That's why you see it so often. 
  • Bill_TogeBill_Toge Member, Professional Chemist
    @ngarayeva001 for W/O products you definitely need a homogeniser with a very fine screen, or an extremely high-speed mixer (10,000+ rpm) like an Ultra Turrax
    also, it helps to form the emulsion at as low a temperature as practically possible, so any solubility variations during cooldown are kept to a minimum
    speaking from experience, the easiest way to clean homogenisers once they've been in products like this is to run them in a mixture of very hot water and alkaline detergent; this will shift a lot of the product and reduce the amount of elbow work required to get the rest of it off
    UK based formulation chemist. Strongest subjects: hair styling, hair bleaches, hair dyes (oxidative and non-oxidative) I know some stuff about: EU regulations, emulsions (O/W and W/O), toothpaste, mouthwash, shampoos, other toiletries
  • I know that homogenizer is important and I hope to buy it one day. Thank you @Bill_Toge for an idea. Ultra Turex looks small (and I guess allows making small batches) and I found a couple of used models on ebay within $500. 
  • SpongeSponge Member
    @ngarayeva001 @chemicalmatt Interesting. Thanks. 
  • An update: I tried to emulsify pigment blend separately with Polyglyceryl-3 Triolivate and 5% of water and added to the main batch after emulsification (So I basically made one concentrated W/O emulsion with pigments and one W/Si emulsion without pigments). Separated again....

    What is really annoying is that the same formula works perfectly with 20% of mineral pigment blend. I am referring to untreated TiO2 and iron oxides, that are not good for a foundation for obvious reasons. My first prototype that I made in late March is still stable..
    Regarding the stick blender, although I undertand that it's not very professional to use it, I don't think it's the cause of the separation. I made several W/O and W/Si using it and they don't separate (at least at the room temperature). Everthing is ok until I add those pigments wetted in octyldodecanol...
  • PharmaPharma Member, Pharmacist
    Do I understand you right: You can add other pigments at 20% and it's fine, you can add octyldodecanol and it's fine, you add that mysterious blend and it's not fine, correct?
    Is it possible that they add something else to those pigments?
    Did you calculate HLB and HLB requirement (with and without octyldodecanol)?
  • @Pharma, the concentration of my pigment blend is 10% (50% pigments, 50% octyldodecanol). The same formula (all other inputs are the same) where I added 10% octyldodecanol to the oilphase and 10% of dry pigments didn't break. But those dry pigments were for soap making (uncoated and poor quality). I did that as an experiment to see what happens. 
    I didn't calculate HLB as I was hoping that since I use a blend of 3 emulsifiers I should be covered.

    I made another batch on Friday and added pigments in octyldodecanol to the oil phase. Didn't separate so far, but it's water thin.

    To summarise my problem: I want to achieve a high viscosity foundation. The base has high viscosity without pigments. When pigments added after emulsification, the viscosity stays high but the product separates (within an hour!) when pigments are added to the oil phase, it stays together but it's water thin.
  • PharmaPharma Member, Pharmacist
    ...The same formula (all other inputs are the same) where I added 10% octyldodecanol to the oilphase and 10% of dry pigments didn't break. ...
    I didn't calculate HLB as I was hoping that since I use a blend of 3 emulsifiers I should be covered.
    ...
    To summarise my problem: I want to achieve a high viscosity foundation. The base has high viscosity without pigments. When pigments added after emulsification, the viscosity stays high but the product separates (within an hour!) when pigments are added to the oil phase, it stays together but it's water thin.
    Weird... any chance of finding out with what the custom pigments are coated?
    You actually have 5 emulsifiers in your formula ;) .
    Do you have a microscope? You probably don't have a w/si emulsion but something like a so called liquid crystal aka alpha-gel emulsion which is just on the brink of either breaking or turning into a real water drops in continuous silicon phase emulsion (something like Table 1 on PAGE 4: Lalpha, V2, or H2 turning into I2)... You don't happen to have a good microscope or a polarised light source (which could either come with the microscope or be self-made using sunglasses).
    Something you could try: Lower HLB, generally increase surfactants, remove/reduce electrolytes (betaine, glycerin, sodium lactate, and sodium PCA).
    Gotta go sleepy-sleepy







  • PharmaPharma Member, Pharmacist
    Corrigendum: Glycerol is not an electrolyte, don't remove that one ;) .
  • ngarayeva001ngarayeva001 Member
    edited July 2
    @Pharma, you got me thinking... I can only see three emulsifiers in the formula (at least that was my intention): PEG-30 Dipolyhydroxystearate, Cetyl PEG / PPG-10/1 Dimethicone and Polyglyceryl-3 Triolivate, what are the other two? Are you referring to the cera bellina because it's a PEG?

    Regarding electrolytes, the supplier recommends adding electrolytes to stabilise PEG-30 Dipolyhydroxystearate. I don't like magnesium sulfate, so replaced it with bunch of others. I will try to reduce them. Regarding a microscope, may I ask you to advice what do I need? If something small and not too pricey is suffient for seing droplets shape I will get it. Apologies for my ignorance but I don't even know what zoom do I need..

    By the way thank you very much for your input in my threads as well as in others. It's great to have a pharmacist who is willing to share their knowledge. You motivated me to dive deeper into a couple of important topics (pH buffers) which clearly made me a little less of a dilettante.
  • PharmaPharma Member, Pharmacist
    Yes, cera bellina is an emulsifier and so is magnesium stearate. They may not be used primarily as such but they are (co-)emulsifiers. Magnesium stearate is of special interest because it imparts a negative (inner) surface charge to the inverse micelles.
    Your supplier is correct ;) . I'm not telling you to reduce them to solve the problem but I'm proposing to completely remove them in a small batch in order to help you finding a solution. In your case, I was a bit short-worded in this regard yesterday evening, sorry! I'm expecting your base emulsion (w/o pigments) to become less viscous and not your liquid endproduct to become viscous again! This experiment would simple help you understand what's going on with your formula and point towards a worm- or net-like structure which turns into inverse micelles. Then it would be a closer guess assuming that adding your custom blend is destroying your emulsion by changing emulsion type in a certain way. Once you know what causes the issue, finding a cure becomes way more simple.
    Can't help you today with the microscope. Have neither tried my old binocular nor the USB microscope to visualise emulsions ;( . It's on my to do list but... but not today. It needs to be "see-through", not just a "look on top" (lacking the sciency terms for this :) ). Maybe @Perry knows which magnification is needed for the everyday life of a cosmetic chemist?
    Any you're welcome! Glad I could kick-start your curiosity!
  • DoreenDoreen Member
    @Pharma (...) By the way thank you very much for your input in my threads as well as in others. It's great to have a pharmacist who is willing to share their knowledge (...)
    I second this!
  • PharmaPharma Member, Pharmacist
    I did some thinking, some reading, some more thinking and reading...
    It looks like a tough nut to crack and that's what intrigues me though it's hard work. See, what we learn in galenics is o/w emulsions and their laws. Hence, these come natural to me which is quite the nuisance when thinking about inverse emulsions such as w/o or w/si. That's because half the laws don't apply and the other half, though still following the same rules, results in completely different effects. In addition to that, you get the same effects with different approaches in the two emulsion types. On the other hand, most w/o emulsions aren't of the droplet-type but lamellar or 3D-networks.
    That said, there might be some misconceptions in my first brain churning approach, who knows? For example, removing electrolytes might shift the droplet-type emulsion to a worm-like structure which can as well result in an emulsion of higher viscosity, not the other way round.
    I've been thinking about triple ratio of non-ionic surfactant/anionic surfactant/fatty alcohol, surface shape of these molecules, surface charge aka zeta potential etc. The one thing all comes down to seems to be charge related. Somehow the custom pigments annihilate negative surface charge although in a w/si emulsion, there is only a charged inner surface, not an outer one. Hmmm....
    It might be advisable to re-start from the beginning, figuring out a simple, easy, and cheap solution:
    - "Your supplier said..." does that mean you have a basic formulation you improved over time? What would the most reductionistic formula (w/o pigments) which is still stable and viscous be?
    - Did you find out what's in that custom blend? Do they use quats?
    - What's the highest amount of custom blend you can add before emulsion tips over?
    - The below 40°C homogenisation, is that also low shear?
    - Do you know for sure it's a w/si emulsion?
    - Don't throw your failures away! Try for example adding an anionic high HLB emulsifier at 0,2% (guessing here), just something on your shelf such as glyceryl stearate citrate. Even an anionic detergent like SLS, SLES, an isethionate, or a lactylate might work. If they work: your issue is most likely charge related and hence solvable.
    Gotta go for now (it's getting less hot and the doggies need their party).
  • Thank you @Pharma. I will try to add glyceryl stearate SE for the anionic. Regarding your questions, I think it should be w/si because I use w/si emulsifier but I know chemistry doest always work this way.
     I can add up to 10% of the custom blend before it breaks. The blend is iron oxides and TiO2 in octyldodecanol. The below 40 homogenisation is a stick blender (I process the emulsion on the overhead stirrer). Without pigments the emulsion is liquid and gets the viscosity ones I apply stick blender.
     I continue working on it and ordered more ingredients for making foundations recently. Hopefully I will get there at some point :smile:
    I wonder if there are any more or less simplified materials about making w/si emulsions except for ulprospector.
  • PharmaPharma Member, Pharmacist
    edited July 7
    Better to take a pure anionic emulsifier and not glyceryl stearate SE which contains only about 1/10 anionics.
    Assuming it really were charge related and by extrapolating from the 10% pigment which work fine: either up magnesium stearate to about 1% or add roughly 0,5% anionics because you might require more than just the 0,2% I mentioned above. On the other hand, a "permanent" anionic emulsifier (magnesium stearate is pH dependent and hence not always 100% anionic) such as a sulphate might actually work with less...
    BTW did I already ask: What's the pH before and after you add the custom blend?
    If high speed increases viscosity it usually means that it's a "real" water in silicone emulsion (high shear/speed = small droplet size). As a rule of thumbs, lamellar emulsions can be made with a lower shear force.

  • Pharma said:

    If high speed increases viscosity it usually means that it's a "real" water in silicone emulsion (high shear/speed = small droplet size). As a rule of thumbs, lamellar emulsions can be made with a lower shear force.

    Thank you! It's very good to know this.
  • Hello All!

    An update for those who are also struggling with a foundation. As I suspected, it's all about pigments. I found ready foundation blend consisting of: Titanium Dioxide (CI 77891), Hydorgenated Polydecene, Iron Oxides (CI 77492), Polyhydrixystearic Acid, Iron Oxides (CI 77491), Disteardimonium Hectorite, Iron Oxides (CI 77499), Propylene Carbonate (for those who are ingterested: https://www.glamourcosmetics.it/it/gc-base-bb-cream-warm-beige)

    I got two colors (light and dark) and mixed to achieve desired shade. The downside is that you can't play with shades. Bases are neutral and you can't make them more pinkish or more yellowish. However, all my problems are resolved. I made two foundations with different emulsifiers and slightly different silicones/emollients and added pigments blend into a formed emulsion after  cool down. Both have been stable for two weeks. I understand it's not a "stability" test but provided that before they were separating right away it's a success. These pigments do not break emulsions and I actually needed less to achieve medium coverage.
  • Version with Cithrol DPHS:

    Aqua 47.80%
    Betaine 3.00%
    Magnesium Sulfate 1.00%
    Sodium lactate 2.00%
    Euxyl PE 9010 1.00%
    PG 3.00%
    Dimethicone 5 10.00%
    Caprylic/Capric triglycerides 13.00%
    Magnesium Stearate 0.50%
    PEG-30 Dipolyhydroxystearate (Croda's) 2.00%
    Cetyl PEG / PPG-10/1 Dimethicone (Abil EM 90) 0.70%
    Polyglyceryl-3 Triolivate 0.50%
    Hydrogenated Castor Oil 0.50%
    Pigments blend 15%

    Lighter feel. Spiky and bouncy emulsion that is melting and super spreadable on skin.

    The HCO above is not PEG-40 HCO it's castor wax.
  • Version with Dowsil 5225 Formulation Aid

    Aqua
    61.00%
    Betaine 3.00%
    Magnesium Sulfate 1.00%
    Sodium lactate 2.00%
    Euxyl PE 9010 1.00%
    PG 3.00%
    Phenyl trimethicone 3.00%
    Caprylic/Capric triglycerides 1.00%
    Magnesium Stearate 0.50%
    Cyclopentasiloxane (and) PEG/PPG-18/18 Dimethicone (Dow) 8.00%
    Cetyl PEG / PPG-10/1 Dimethicone (Abil EM 90) 0.70%
    Polyglyceryl-3 Triolivate 0.50%
    Hydrogenated Castor Oil 0.30%
    Pigments blend 15.00%

    Very viscous easier applied with a sponge (not a brush). It is so thick that could work for cushion packaging with a net (such as https://www.chanel.com/en_GB/fragrance-beauty/makeup/p/complexion/healthy-glow-makeup/les-beiges-healthy-glow-gel-touch-foundation-spf-25--pa--p184610.html#skuid-0184610)

    I understand it's a bit early to talk about shelf stability, but the fact they both withstood 38C in London last week is very promising.

    The main difficulty of making a foundation is not making w/si emulsion. It takes some trial and error but doable. The main difficulty is to source good pigments. They must be coated and pre-disperced. Neither mineral makeup pigments, nor uncoated oxides, TiO2 pre-disperced in oil would work. Methicone coated TiO2 kinda works but still, when it's not pre-disperced it makes a thin and poor quality foundation. I tried it all and I hope my experience is useful.
  • PharmaPharma Member, Pharmacist
    Good to hear that you found a solution for your problem!
  • Thank you @Pharma
  • DoreenDoreen Member
    @ngarayeva001
    Well done! I hope you can achieve exactly the right hue for your skin!
    It's a pain to find the exact right colour, regardless of the brand. It's almost always too dark for me, or even too light so I look either ill or like Morticia from the Addam's Family (if I wore a black wig too). Or it has too much of a yellow undertone so I look like an alcoholic with liver cirrhosis. :confused:
    And I'm done with buying several hues and mix them. What a hassle.

    I've recently bought Lancôme Teint Idole Ultra Wear (Beige Porcelaine) and this is one of the best so far.
    (And I won't even try something like La Prairie as I'm not willing to spend more than 200 euros per 30 ml :dizzy: )
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