Home Cosmetic Science Talk Formulating Can’t get solution into proper ph range for thickening with Carbomer.

  • Can’t get solution into proper ph range for thickening with Carbomer.

    Posted by Xenk on August 26, 2023 at 4:30 pm

    I am working on a trying to keep a serum as light as possible. Maybe my process is just wrong and someone can spot my rookie problem. I am combining everything on medium heat. I can get a good looking solution, but once everything is combined, I am unable to get the ph back up into a workable range for Carbomer hydration.

    I found Carbomer 940 at about 0.175-0.2% with water and witch hazel gives me the feel I am targeting. I can repeat this without issue, using a few drops of TEA to bring the mix up to 6-7ph before adding Carbomer. Works every time with a resulting ph in the 4-5 range hydrated.

    When I attempt to add other ingredients like glycolic acid, a touch of pearl, and a drop of lavender to cut the smell…the formula seems to lock in at 4.5ish ph, and no amount of TEA gets it up into the activation range for Carbomer.

    My current process is:

    75% distilled water heated to about 35c < 20% witch hazel < 4% glycolic acid < 0.08 % pearl powder < 0.25ml lavender oil into a solution.

    TEA has no effect on getting the ph in the 6-7 range to attempt carbomer gelling. Thoughts?

    Xenk replied 9 months, 3 weeks ago 3 Members · 4 Replies
  • 4 Replies
  • Paprik

    August 27, 2023 at 1:56 pm

    Glycolic acid is never let you to thicken the Carbomer 940. Also bringing the pH to high level will neutralise the acid anyway.

    You need something electrolytes resistant. I had success with Sepimax Zen. And keep the pH low so the acid can stay bioavailable.

    • Xenk

      August 27, 2023 at 2:19 pm

      Thanks for the reply! I started poking around and felt like it was just incompatible. I would need to use something else, I just happened to have carbomer 940 on hand. I figured it had to be something like that…Everything worked up to the point I tried tinkering with actives.

      I have some Xanthum gum coming to the door at any moment, I just need something to help with absorption or drying it up faster. once applied. Thoughts?

      • evchem2

        August 28, 2023 at 7:35 am

        Xanthan should work in presence of 4% glycolic, just slurry it with glycerin and add it in after water (and chelator if using). Whether you like the sensory/appearance or not is another question, but to speed up ‘absorption’ you could add small amount of ethanol, or try adding some starch or silica- but those options will also modify feel

        • Xenk

          August 28, 2023 at 9:10 pm

          Thanks @evchem2 , that helps me down the right track. The Xanthan is working much better. Next on the list is to work on the skin feel. I have some butylene glycol that should be here in a few days.

          With a water base, I am getting a lot of separation when rubbing the gel on skin. The water is beading up and being left behind on the surface.

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