Preserving Clay Masks

Hi all, had a clay mask fail and go moldy, even after using Optiphen Plus. PH was 6, and it was added after cool down at room temperature, so it should have held up. I know clay is notoriously hard to preserve, so I want to get this right. Any thoughts on why this would go bad and what I can do to ensure it doesn't happen again? Full ingredient list:  distilled water, unrefined shea butter, bentonite clay, kaolin clay, cetyl alcohol, castor oil, glycerin, citric acid, dead sea salt, charcoal, peppermint oil, tea tree oil, fragrance, and grapeseed oil. Thank you in advance!

Comments

  • DoreenDoreen Member
    edited December 2018
    pH 6 is too high for Optiphen plus. The sorbic acid in Optiphen Plus is inactivated at a pH that high. And it's the sorbic acid that is active against mold.
    Do you use clay that is sterilized (by radiation)? Remember, clay is dirt!
  • Thanks for your help! Ah I thought it could go up to a PH 6. Just started using Optiphen plus, so I see that's where I made the mistake. Going to add a bit of citric acid. And yes, clay is sterilized.  
  • MarkBroussardMarkBroussard Member, Professional Chemist
    Clay products are notoriously difficult to preserve.  I would recommend that you consider adding Tetrasodium Glutamate Diacetate (chelating agent), Phenethyl Alcohol and either p-Anisic Acid or Naticide (Parfum) to bolster your preservative system and bring your pH down to 5.0.
    Chemist/Microbiologist formulating in the Organic & Naturals arena under ECOCert/Natural Products Assn/Whole Foods/National Organic Program guidelines focused skincare & haircare products. 

    Provides Formulation Development and Lab-Scale Contract Manufacturing Services.  See website for details www.desertinbloomcosmeticslab.com

  • Obviously I yield to your years of industry experience @MarkBroussard, but I read that chelating agents are overwhelmed and rendered ineffective in most clay based products. Does this effect vary depending on the variety of clay used? e.g kaolin v bentonite v rhassoul.
  • MarkBroussardMarkBroussard Member, Professional Chemist
    I've never seen anything substantiating that chleators are rendered ineffective in clay products, but if you have some credible evidence of that, by all means post it up.  
    Chemist/Microbiologist formulating in the Organic & Naturals arena under ECOCert/Natural Products Assn/Whole Foods/National Organic Program guidelines focused skincare & haircare products. 

    Provides Formulation Development and Lab-Scale Contract Manufacturing Services.  See website for details www.desertinbloomcosmeticslab.com

  • I believe I read it on this Forum at some point, I believe posited by @Belassi, I just joined the industry about 8 months ago so my specific cosmetic knowledge is limited. I found this article,

    https://oaktrust.library.tamu.edu/bitstream/handle/1969.1/153620/ANDOTRA-THESIS-2014.pdf?sequence=1

    In the abstract it stated that in their test, 1% citric performed the best but when compared to their sample without citric acid, and factoring in the cost, it became an unfavorable option. Also, clays are mostly made of aluminous minerals.
  • ngarayeva001ngarayeva001 Member
    edited December 2018
    @Bubbles this is a discussion you are referring to https://chemistscorner.com/cosmeticsciencetalk/discussion/4817/raw-material-first-cosmetic-product-assurance-for-industry-novice-to-not-go-wrong-way

    If I understand it right, clay contain so much of metal ions that EDTA will be overwhelmed by it. Too much of EDTA would be required to bind all these ions.
  • Dirtnap1Dirtnap1 Member
    edited December 2018
    If you don't mind the preservative to be a formaldehyde releaser, DMDM Hydantoin should work in your formulation. 

    Any way to make the formula anhydrous by chance? 
  • Need to add multiple preservatives for the clay mask like phenoxyethnaol, ethylhexyl glyceirn, if possible you can add parabens.
  • Thank you all. Tried again with a ph of 4 and added .5% alcohol and 1% citric acid in addition to the Optiphen Plus. Within less than 24 hours Mask looked like this. Is it possible this reaction is something other than fungi? 

  • DoreenDoreen Member
    edited January 16
    Fungi usually need more time to grow, less than 24 hours is very quick. What happened in the last week?
    And what was the reason for adding the 0.5% alcohol?
  • I found Germall Plus very active even at 0,2% working with clay. Its upper limit is at 0,5%, so make a try. About chelating agents and clay: depending from clay specifications they can be completely useless because the clay itself acts as chelating or exchanger. It can depend from mineralogic composition, site, and even from preconditioning process before the market.
  • ChemistCradleChemistCradle Member
    edited January 16
    The white points could be Salt efflorescence. Try to isolate, and put in few drops of distillated water. If you have cristallization again, no fungi.
  • MarkBroussardMarkBroussard Member, Professional Chemist
    Why don't you just test it with either a microbial dipstick or send it to a lab for a plate test.
    Chemist/Microbiologist formulating in the Organic & Naturals arena under ECOCert/Natural Products Assn/Whole Foods/National Organic Program guidelines focused skincare & haircare products. 

    Provides Formulation Development and Lab-Scale Contract Manufacturing Services.  See website for details www.desertinbloomcosmeticslab.com

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