hlb of essential oils

ultraduyultraduy Member
edited July 2019 in Formulating
Hello guys

I recently encountered emulsion seperation when I added the preservative and essential oil. The blend became yellowish so I think the essential oil may be causing this instability. I do not take the required hlb of lemon oil  into account when calculating the required hlb. Can this be the reason why I experience the seperation? Can I also have the required HLB of lemon oil for future formulations? 

My formula:

57% water 

2% glycerin 

8% polysorbate 


16% rice bran wax  

4% glyceryl stearate

2% hydrogenated castor oil

6.4% castor oil 

1.6% apricot kernel oil 


2% lemon oil  

1% preservative 12  


  • ngarayeva001ngarayeva001 Member
    edited July 2019
    Polysorbate what? (20, 60, 80?). The reason it separates, is that you add too much of EO to the ready emulsion. Usually fragrance is added at 0.5% or even lower. Have you tried mixing fragrance in Polysorbate 20 or any other solubilizer before adding it to your cool down phase?

    Also, you have quite a lot of oil and you made up your own emulsification system. It might not be as reliable as a commercial blend even if you calculated the HLB right.
  • I will try again using less essential oil, at 1%. I am using polysorbate 80. How much oil would have been apropiate? How do you see there is too much oil?
  • ngarayeva001ngarayeva001 Member
    edited July 2019
    Too much oil for a self made emulsification system. You can add 50% (or even more) if you are using commercial blends such as Arlacel 165. I am not sure that Poly 80 will hold 20%+ oil phase. Glyceryl Stearate is  a thickener and co-emulsifier if it's not SE version.

    Another question, isn't it soaping upon application?
  • I was trying the formula again, using less EO, but it did not work, I first added the preservative and that caused the seperation. Upon further reading I discovered that phenoxyethanol and ethylhexylglycerin is not compatible with a high amount of polysorbates, so that can cause the instability ->http://makingskincare.com/preservatives/. I may have to switch to another preservative. Do you have any suggestions?
  • It is the SE version btw
  • I might also use some peg-40 hydrogenated castor oil instead of polysorbate 80
  • I actually suggest finding Glyceryl Stearate and PEG-100 Stearate (aka Arlacel 165) and your problem will be gone.
    Regarding preservatives, I really like Germaben II. But it's comprised of parabens and formaldehyde releasers if that's ok with you.

    You see.. polysorbates, PEG-40 HCO, those all are solubilisers. Their function is to make clear microemulsions with tiny amount of oil, not being emulsifiers. Polysorbate 60 is relatively suitable for this. Again my suggestion is to go with a commercial blend.
  • I managed to make relatively stable custom emulsifier blend (calculating HLB):

    Phase INCI %
    A Aqua 74.45%
    A Tetrasodium EDTA 0.20%
    A Glycerine 1.00%
    A Butylene Glycol 2.00%
    A Ultrez 20 0.30%
    A Propanediol 1.00%
    B Jojoba 4.00%
    B Butyrospermum parkii butter 3.00%
    B Squalane 1.00%
    B Tocopherol 0.10%
    B Tocopheryl Acetate 0.75%
    B Sorbitan Oleate 1.00%
    B Glyceryl Oleate 4.00%
    B Polysorbate 60 2.00%
    C Retinol 2.00%
    C Bisabolol 0.20%
    C PEG-8 Dimethicone 2.00%
    C Germaben II 1.00%
    TEA to pH 6.5

    But you see, my total oil phase is 11% (with retinol). You have much higher oil phase.

    Keep that HCO, it acts as a stabiliser.
  • PharmaPharma Member, Pharmacist
    Every EO has, in theory, it's own HLB but since EOs are natural products and may come from different chemovars, their composition may be very different between batches. In addition to that, knowing their HLB would only help if you included the EO in the oil phase. Since EOs are volatile, one usually adds them last (unless you're cold processing) and that's where & why solubilisers come into play.
  • You recommend polysorbate 60?
  • Polysorbate 60 is a high HLB emulsifier, while Polysorbates 20 and 80 are solubilizers. Which makes me think it might be a better option.
  • Sorry if this has been covered, but I am a newbie.
    I have a mostly oil blend, and I want to add a small amount of liquid to the Oils.  Is this possible?  Do I use Poly 80?  
  • Yes, mix your essential oil with polysorbate 80 or 20. 80 tends to foam a little bit more than 20, so depending on your product you can choose one or another. Try 1:4 (one part of EO to 4 parts of solubilizer) for transparent product.
  • I tried using peg-40 hco instead of poly 80,
    6% peg-40 hydrogenated castor oil and 2% polyssrbate 80. The washability was not as good as it used to be, you have any tips on how to improve the wash? Maybe adding other emulsifiers?
  • MarkBroussardMarkBroussard Member, Professional Chemist

    You have a couple of issues with your formula: 

    (1) Lemon Oil is very photosensitizing and irritating to the skin ... you might consider something more on the order of 0.5% (max) or less

    (2)  You do not need hydrogenated castor oil and polysorbate 80 to get the Lemon oil to integrate into your cream.  You can eliminate both of these ingredients.  Simply add a higher HLB co-emulsifier to complement your Glyceryl Stearate SE and you're done.

    (3)  Your Rice Bran Wax is quite high ... you might cut that back to 6% to 8%.

    The reason for your separation is that you are only using one low HLB emulsifier and an inordinately high percentage of wax, so your total formula HLB balance is out of whack.
    Chemist/Microbiologist formulating in the Organic & Naturals arena under ECOCert/Natural Products Assn/Whole Foods/National Organic Program guidelines focused skincare & haircare products. 

    See website for details www.desertinbloomcosmeticslab.com
  • ultraduyultraduy Member
    edited July 2019
    Why does having What a lot of rice bran wax cause instability, what other high hlb emulsifiers do you prefer
    and isn't peg-40 and polysorbate 80 a emulsifier with a hlb of 15?
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