Home Cosmetic Science Talk Formulating Neutralisation of Carbopol - Order of Addition

  • Neutralisation of Carbopol - Order of Addition

    Posted by ozgirl on March 16, 2018 at 2:38 am

    I am looking to make a hand wash with suspended particles and according to the Lubrizol website, Carbopol ETD 2020 should meet my needs.

    I found a couple of shampoo formulas on their website to use as a starting formulation. In one formula the Carbopol is added to water and then neutralised before any thing else is added. In another very similar formula the Carbopol is partially neutralised,the surfactants are added and then the remaining neutralising agent is added.

    Does anyone know if there is any advantage to either method? Or can you disperse the carbopol and then add all the other raw materials and neutralise at the end.

    I am going to try all of these methods but I am waiting on a new Carbopol sample as my very old lab sample had turned into a rock. I was just hoping someone might be able to share an insight and save me reinventing the wheel.

    The basic formula from lubrizol was

    Water                        to 100 %
    Carbopol ETD 2020   0.80 %
    AMP                          0.10 %
    SLES (28%)                20.00 %
    Lauryl Glucoside       5.00 %
    CAPB (30%)               5.00 %
    AMP                          0.66 %
    Dow 1784 Emulsion  4.00 %
    Phenonip                   0.50 %

    Thanks for any assistance.

    doreen replied 6 years ago 7 Members · 12 Replies
  • 12 Replies
  • chemist77

    Member
    March 16, 2018 at 2:57 am

    @ozgirl I have used Ultrez 10 and had a similar formula expect the SLES. I made the gel first and then added the surfactants to it.
    In another formula when I tried adding SLES (70%) the aeration was terrible and it was so persistent that I had to dispose the trial. 

  • ozgirl

    Member
    March 16, 2018 at 3:12 am

    @Chemist77 I almost forgot about aeration. Thanks for the reminder. I am guessing that is why they don’t neutralise at the end.

  • em88

    Member
    March 16, 2018 at 8:33 am

    You are using SLES at 28% so you should not have issues in the preparation process. 
    I like the idea of partially neutralized first, this will make it easier for the other ingredients to be homogenized properly. 

  • JOJO91343

    Member
    March 18, 2018 at 12:28 pm

    I like the first technique: “In one formula the Carbopol is added to water and then neutralised before any thing else is added” because the anionic (SLES) and Amphoteric Surfactants (CAPB: Cocamidopropyl Betaine, if my guess is right) are mostly water so if you add them on carbopol while carbopol is only hydrated (without neutralization) the whole batch will be very watery, then, if you neutralize the batch after adding the surfactants, the thickening effect you can get from carbopol may not compensate the batch dilution by the water percentage of the batch firstly, and by the water in the anionic and amphoteric surfactants, secondly unless you will thicken the batch by adding salt (Sodium Chloride). You didn’t mention Sodium Chloride in your formula.  I think you don’t like to add Sodium Chloride, because you added 0.8% Carbopol ETD 2020.  That makes the formula very “Pricey” .  I think if you try 0.25-0.30% of carbopol and tried to thicken the batch by salt (Sodium Chloride) and/or Cocamide (If you are not working for a certain Natural Standard which prevents using cocamide) you may get a good viscosity in a significantly lower cost.

  • em88

    Member
    March 19, 2018 at 7:36 am

    CAPB has NaCl around 5% so you can not claim NaCl free. 

  • das

    Member
    March 19, 2018 at 3:29 pm

    Keep in mind glucosides have a high pH, you should consider the order or addition of surfactants too. Have you done any trials without the carbopol?. 

    Air bubbles are the enemy, working with surfactants and carbopol is painful, expensive and takes longer. And if you are suspending stuff airation is near impossible without a vacuum mixer. It might work if what you are suspending is lighter than air and you don’t need much viscosity.

  • ozgirl

    Member
    March 19, 2018 at 9:50 pm

    Thanks everyone for your thoughts.

    The formula I have given is the one from the Lubrizol website and I haven’t tried it yet. I was just wondering about the order of addition for the neutralisation.

  • doreen

    Member
    March 20, 2018 at 8:26 am

    I always neutralise at the end (when there’s no more need for high shear).
    This to avoid damage to the structure which can cause an irreversible viscosity drop.

  • JOJO91343

    Member
    March 20, 2018 at 9:59 am

    You can still do both techniques whether to neutralize before adding anything or to neutralize after adding the surfactants.  I did both techniques in the same formula and I didn’t have any problem.  For shampoo, I, always, do high shear in the hydration step of thickener only.  Once it’s completely hydrated without lumps,  I switch to medium - low shear. whether I neutralize before or after adding surfactants.  I never get any lumps, viscosity drops, or structural damage.  Of course, if you use high shear when the thickener is getting thick, you can get structural damage.

  • oldperry

    Member
    March 20, 2018 at 11:00 pm

    @Doreen - I’ve also found that you get less air trapped in the formula by neutralizing at the end.

  • ozgirl

    Member
    March 21, 2018 at 8:54 pm

    Thanks @Perry and @Doreen . I will give neutralising at the end a try as well. 

  • doreen

    Member
    March 22, 2018 at 8:38 am

    @Perry
    Agreed!

    @ozgirl
    You’re welcome, good luck!

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