Home Cosmetic Science Talk Formulating Charcoal Mask

  • Charcoal Mask

    Posted by Anonymous on June 4, 2015 at 2:18 am

    Hi there. Im working on a charcoal mask formula. It contains 20% Kaolin, 15% Bentonite and activated carbon.

    Used citric acid to neutralized to pH5-6.
    After sometime i noticed orange spot appearing and i suppose has microbial issues.
    Preservative system is Phenostat.
    Is there something wrong with the preservative used?
    Chemist77 replied 9 years ago 2 Members · 2 Replies
  • 2 Replies
  • Christopher

    June 4, 2015 at 9:36 am

    A quick google search resulted in this:

    “Phenostat™ is compatible with most cosmetic ingredients. However, it can
    interact with residual iron found in some clay-type compounds (e.g.,
    bentonite, silicates, etc). This interaction with iron may produce a
    very mild orange color or color shift that is barely perceivable to the
    eye in most formulations. In cases where the clays are high in iron, the
    colored compounds may be more perceivable Contains caprylhydroxamic
    acid (CHA), phenoxyethonal and methylpropendiol.”


  • Chemist77

    June 4, 2015 at 10:15 am

    Try changing the preservative and see where it takes you; as Christopher pointed out, it might be that case and I guess we had a discussion about in the past as well where salicylic acid in a mask was giving purple coloration. 

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