Hair Shampoo Separation

edited October 11 in Formulating
Hi, I'm new to cosmetics and desperately need some help from you guys.
I'm doing my shampoo stability test at RT and 45°C. It is separated into 2 layers where the upper layer is a bit cloudy/milky at 45°C after 2 weeks. Any ideas on why my shampoo is separating?

Below is my formulation:

Carbopol Ultrez 20                                            0.45%
SLES                                                                 10.00%
Decyl Glucoside                                                 4.00%
Cocamidopropyl Betaine                                    5.50%  
Disodium Cocoamphodiacetate                          3.00%
Palm Kernelamide DEA                                       3.00%
Polyquaternium-10                                            0.40%
Xiameter MEM-1784 Emulsion
(Dimethiconol, TEA-dodecylbenzenesulfonate)   5.50%
Menthol                                                              0.70%
Menthyl Lactate                                                   0.30%
C12-15 Pareth-12                                              0.70%
PPG-20 Methyl Glucose Ether                              1.00%
PEG-12 Dimethicone                                           2.50%
DMDM Hydantoin                                                0.70%
Fragrance                                                            1.50% 
Glycerin                                                               3.00%


  • @PassionFruit95 There are few things to adjust in your formula (like excessive menthol -irritant to some people at high levels-, fragrance and glycerin), but if we want to focus on the issue, I'd think it's your MEM-1784 (5.5% is also a bit too high) the issue. How much is your viscosity? This silicone tends to cream on top of the product in stability testing, especially when the viscosity is not too high. Now, if the layer on top of the product is not thin, but rather thick, then you might have some instability with your lamellar system (the one formed by your surfactants/polymers). 
  • PerryPerry Administrator, Professional Chemist
    I'd guess that you have too much silicone for the amount of surfactant in the system. Typically, a 2-in-1 shampoo will have about 1% silicone at most.
  • @ketchito ; I don't feel any cooling effect when the dosage of menthol and menthyl lactate is low. Thus, I increase the menthol dosage until I get the desired coolness. My viscosity is 38,960 cPs using Brookfield RV2/1rpm. But there's a strange thing, I've tried to add in 1.50% of Cutina AGS in the same formulation but there's no separation. The viscosity is 18,640 cps using the same speed and spindle.  :/
  • @Perry But my other formulation using 5.50% of silicone is ok and has no separation. My hair is still frizzy when using a low dosage of silicone. Will increase the percentage of surfactants can prevent the separation? Or is there any method to increase the conditioning effect without using a high dosage of silicone?
  • PerryPerry Administrator, Professional Chemist
    What's the difference between this formula and your other formula that doesn't separate?
    Yes, increasing surfactant may prevent separation...or it may not.
  • @Perry The formula that doesn't separate has Cutina AGS, the percentage of menthol is lower, and also the ratio of surfactants is slightly different.
    Below is the formulation percentage FYR just in case.

    Carbopol ultrez 20                                             0.45%
    SLES                                                                 12.00%
    Decyl Glucoside                                                 3.00%
    Cocamidopropyl Betaine                                    5.50%  
    Disodium Cocoamphodiacetate                          2.50%
    Palm Kernelamide DEA                                       3.50%
    Polyquaternium-10                                            0.40%
    Xiameter MEM-1784 Emulsion
    (Dimethiconol, TEA-dodecylbenzenesulfonate)   5.50%
    Menthol                                                              0.25%
    C12-15 Pareth-12                                              0.70%
    PPG-20 Methyl Glucose Ether                              0.30%
    PEG-12 Dimethicone                                           2.50%
    DMDM Hydantoin                                                0.70%
    Fragrance                                                            1.20% 
    Glycerin                                                               4.50%
    Styrene/Acrylates Copolymer                               0.20%
    Could it be the high percentage of menthol and menthyl lactate causing the separation also? 
  • AbdullahAbdullah Member
    edited October 12
    Are you selling this product or for your own use? 

    SLES, CAPB, amphodiacetate preservative with some sodium chloride makes stable formula. Add ingredients one by one and see which one cause separation
  • @Abdullah Hi, I'm formulating for selling the product. Thanks for the advice. Btw, how do you mean by adding the ingredients one by one? The formulation looked stable during RT, only separated at 45C after 2-3 weeks.
  • I mean from base shampoo formula, make several samples. Add these extra ingredients one in each sample. Then evaluate which one is not stable. 
  • @PassionFruit95 I had a similar issue back in the day. On one hand, you could have creaming due to your silicone, and that's solved by increasing viscosity, especially increasing your suspending agent (in your case, your Carbopol Ultrez 20). The addition of Cutina AGS might help with the increase in viscosity (but not on the suspending part). By the way, what are you neutralizing your Carbopol with? Keep in mind that most carbopols come in an acid form, and needs to be neutralized to develops all its viscosity/stabilizing features.

    But, consider also that your system SLES-CAPB-PQ-DEA, which is very sensitive to low pH and electrolytes. What's your final pH? is there any chance you're adding sodium chloride or related inorganic salts?
  • @ketchito I didn't neutralize my Carbopol as the final pH of my shampoo fell around 6 to 6.50. For now, the viscosity of the shampoo is a little bit too thick for me because it's difficult to lather at the beginning. The texture of the shampoo seems too thick and clumping together. I need more water to make it lather. I didn't add any sodium chloride or inorganic salt too. Maybe I can redo the shampoo by neutralizing the Carbopol with some TEOA or adding in some sodium chloride to see how it works.
  • @PassionFruit95 Yes, and if your final viscosity is too high, that means you need to reduce some of the viscosifying agents (I'd go for reducing Carbopol a bit -not less than 0.35%, to help suspend silicones-, Palm Kernelamide DEA -2.0-2.5% would be a good level-, and PQ-10 -you might not need more than 0.3%, since that PQ actually builds up more than others on hair-). 
  • @ketchito, thanks for the advice. I'll try it out later to see how it work. As you previously stated that if the separation layer on top of the product is thick, it means instability with my lamellar system. Could you please explain a little bit more? Or the way to solve this problem? Really appreciate your help on this. :)
  • @PassionFruit95 No worries, I know how frustrating that is. The lamellar gel is just the way surfactants arrange in a water solution at certain concentration. Imagine a bus, if a couple of people travel in it, they can stretch their legs and wander around freely, but the more people come inside, the less mobility they'll have and they might to find ways to organize themselves so more people can get inside. That also explains the increase in viscosity in these systems. Well, the problem is when certain types of surfactants are all together, like a system with SLES-CAPB-DEA. This system is very common, but CAPB can be very picky (especially at high doses). So, if a PQ wants to join the party, CAPB might not be so pleased since PQ likes to stand with the eldows bent. This is even worse in the presence of NaCl, which can make your SLES-CAPB-DEA-PQ very unstable. The way this systems separates is from the bottom (like the courtains in a nice theater), you'll see how it'll slowly go up, leaving water phase at the bottom; gradually, the water phase will increase while the lamellar system that is separating will decrease, till a thick phase at the top remains. 
  • @ketchito I had/still having exact same prob as you mention above using the same surfactants but with xanthan gum instead of ultrez. It looks great then days then weeks later I presume what is water starts rising from the bottom. I didn't realise this for ages as I put the shampoo on white non see through bottles. Was so annoying.
    I thought it was method, tried mixing, faster, slower, longer, tried letting the xantham slurry longer.
    Are you saying using less capb and maybe a slightly higher pH could help?

  • @crillz Higher pH will help for sure. I would also try things:

    1) remove the styrene acrylates (if that works, replace it by a glycol distearate dispersion)
    2) increase SLES (this will help solubilize any hard phase that tries to separate, close to 14-16%)
    3) replace decyl glucoside by coco-glucoside (decyl glucoside might be reducing your viscosity, and that's why you need things to ncrease)
    4) decrease PQ-10 (not more than 0.2-0.25%)
    5) decrease your DEA (no more than 2-2.5%)
    6) decrease CAPB (no more than 4%)
  • Thanks ketchito, will give these things a whirl. I don't have styrenee acrylates, dea or PQ so will simply do the other tasks.
  • @ketchito Thanks for the explanation, understand better now. ;) 
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