Home Cosmetic Science Talk Formulating Low pH Gel Cleanser

  • Low pH Gel Cleanser

    Posted by geepee on April 18, 2023 at 1:49 am

    Help please!
    Reverse engineer formula issues

    Info I have been told:
    - 12% Glycolic Acid
    - Clear, gel

    -pH 3.75

    - Contains Cocamidopropyl Betaine, Sodium Methyl Cocoyl Taurate, Decyl Glucoside

    - Potassium Sorbate

    - Glycerin extracts

    - Fragrance, Vit E

    1. I have tried Pureact WS-70 @15% and CAPB30 @20% and Decyl (solubilise fragrance) @0.8% - did not thicken, adding salt = no change

    2. I have tried Pureact WS-70 @20% and CAPB30 @15% and Decyl (solubilise fragrance) @1.5% - did not thicken, adding salt = no change

    3. I have tried Pureact WS-70 @25% and CAPB30 @20% and Decyl (solubilise fragrance) @1.5% - did not thicken, adding salt = no change

    4. I have tried Pureact WS-70 @15% and CAPB30 @6% - did not thicken, adding salt = no change

    Nothing seems to be working but I have been told this is the ingredients list??
    Any insights would be great!
    I feel like they are missing some critical ingredients as they don’t have any pH adjusters listed and with 12% glycolic I don’t think there’s any chance of getting to pH 3.75.
    I’m wondering if I change it up a bit and try some Sepimax Zen to see if i can get a gel and just hope that I can get the foaming right.

    geepee replied 1 year, 6 months ago 3 Members · 8 Replies
  • 8 Replies
  • Richard

    Member
    April 18, 2023 at 2:17 am

    I have always found the Innospec surfactants more tricky to work with than the information would indicate and have never really found that salt works particularly well to thicken them. In theory it does appear to be possible. When working with the Iselux and Taurates I have always found that slowly reducing the pH at the end has turned out to be the best way to thicken the end product.

  • ketchito

    Member
    April 18, 2023 at 1:41 pm

    I think the active level of the taurate in your formula is a bit low. Usually, a synergy between and anionic and amphoteric surfactant occurs at an excess of anionic compared to the amphoteric. Try a mixture of taurate/betaine with a ratio of 3:1 (active level). Once you find dose in which you see a viscosity response, you can start adding salt. I would’t use Decyl glucoside at the start, since it could impact your viscosity negatively.

  • geepee

    Member
    April 18, 2023 at 6:19 pm

    Great thank you!
    So from what you are both saying…
    - Potentially try another SCMT supplier
    - Add glycolic acid last and slowly once i have made viscosity and then adjust with KOH to be in spec
    - Increase SCMT active percentage to 3x that of betaine - my SCMT is 20% active, CAPB is 30%, so try 30% pureact and 6.5% CAPB30?
    - Add my Decyl glucoside with fragrance and oils at the end?

  • ketchito

    Member
    April 18, 2023 at 9:01 pm

    As a first trial, I wouldn’t add Decyl glucoside.

  • geepee

    Member
    April 24, 2023 at 12:56 am

    So! I tried the above (excluding changing the SCMT, i still used the pureact), added everything excl. salt, glycolic and caustic and started off adding salt - no change to viscosity. So then i added glycolic and it THICKENED!! but then when i added caustic it thinned 🙁 so I think the formula doesn’t like too much pH change down and then back up.
    Should I try adding caustic first, then glycolic and salt last and making viscosity?
    I just worry when scaling up the pH will be harder to predict as to how much caustic to add etc.
    Thoughts?

    • geepee

      Member
      April 25, 2023 at 11:06 pm

      So, I tried adding caustic first (not ideal for manufacturing :/ ), remainder of my ingredients, then glycolic and salt last and making viscosity, salt had no effect on viscosity but pH was exactly where I wanted it at around 3.75.
      I honesty don’t know where to go from here… I can get pH right but can’t get it to gel!!!

  • ketchito

    Member
    April 24, 2023 at 6:51 am

    Can you measure the pH of your product when it got thick? If it’s a little bit lower than 5, then my guess is that CAPB is being protonated, and you have a better interaction between your CAPB and your taurate. If you’re not to low in pH, you don’t need to bring it up.

  • geepee

    Member
    April 25, 2023 at 6:58 pm

    pH needs to be around 3.75 and final pH when adding all of my glycolic acid was around 2.8 before adjustment with caustic, it got thicker at a higher pH than 2.8 (I did not measure) but I need to add 12% glycolic acid so cannot just stop adding acid when it is thick…

Log in to reply.

Chemists Corner