Home Cosmetic Science Talk Formulating Stearic acid based shave cream that is thicker when hot?

  • Stearic acid based shave cream that is thicker when hot?

    Posted by Bati on October 16, 2014 at 5:11 pm

    I am working on a stearic acid based shave cream that becomes so thick it’s almost solid at 55-60C, but when it gets to room temp the viscosity significantly decreases to ~50,000 cPs.

    Notes:
    ~70% Water
    ~5% Sodium Lauroyl Methyl Isethionate
    ~15% Stearic Acid
    ~.5% Potassium Hydroxide
    Water phase and oil phase are heated to ~75C (surfactant in water phase) and combined hot via 3 blade prop. Neutralized with potassium hydroxide shortly after combining.
    Final product pH is 6.5-7
    Right now my concern is scale up, but I was curious if anyone had seen or knew why this phenomena existed (as I have never seen it before).
    aqeel4uk replied 9 years, 12 months ago 3 Members · 3 Replies
  • 3 Replies
  • Chemist79

    Member
    October 20, 2014 at 6:02 pm

    Yes I have seen this before, try finishing it with an excess of Stearic and neutralise it further when cooler

  • Bati

    Member
    October 23, 2014 at 10:03 am

    I ended up neutralizing with more Potassium Hydroxide as the viscosity got too thick during cool down. Worked out better from a processing perspective but I did have to homogenize at the end to make the product uniform (turned out pretty lumpy). I kept track of the total amount of potassium hydroxide added, so I’m going to try to add it all right away and see what happens.

  • aqeel4uk

    Member
    November 20, 2014 at 10:52 am

    Don’t use 3 blade prop. to mix your batch. use a Silverson Homogenizer.

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