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Home Cosmetic Science Talk General Crystals and this weird white thing in a solution product.

  • Crystals and this weird white thing in a solution product.

    Posted by Abdullah on December 31, 2022 at 7:27 am

    This is a solution from 7 month ago. It was crystal clear then with no problem.

    Tetra sodium EDTA 0.3% 
    Allantoin 0.4% 
    Salicylic acid 0.1% 
    Xanthan gum 0.04% 
    Phenoxyethanol 0.6% 
    Caprylhydroxamic acid 0.15% 
    Glycerin 0.75% 
    pH 5.1 
    Packaging was in 120ml bottles with flip top cap. 
    The weather is cold now and at night up to -10°c so i checked some samples and saw they have some crystals in them as of picture
    Then i mixed and heated the contents of 60 bottles to 40°c but the crystala didn’t dissolve. 
    There was also this white weird thing in two bottles as of photos. It remains on top of water and didn’t mix. 


    My questions are 

    1. What are these crystals?
    2. Why they didn’t dissolve again when heated to 40°c and mixed?
    3. What is this weird white thing that has formed in two bottles? Yeast or mold or something else? 
    Abdullah replied 4 months, 4 weeks ago 3 Members · 3 Replies
  • 3 Replies
  • majibo

    January 2, 2023 at 2:56 pm

    Hi Abdullah
    I’m sure crystals are Salicylic acid. Salicylic acid is not soluble in water. You should use fair amount of solvents like Ethanol, Propylene Glycol, Propanediol… Glycols should be at least 1:10 ratio. You can search in the forum there are lots of information about this ingredient. You may choose to dissolve it in oils, too. 
    They can’t dissolve even if you heat them, so don’t bother. 

  • chemicalmatt

    January 3, 2023 at 3:02 pm

    @Abdullah this might be allantoin too. It has a water solubility threshold of 0.50%, lower than even salicylic acid. They both solvate better in presence of urea, or as @majbo points out, a lot of glycols, not glycerin, or ethanol if you can handle it. 

  • Abdullah

    January 4, 2023 at 2:39 am

    @chemicalmatt @majibo thanks 

    I will check them one by one and see which one is the problem. 

    I thought it may be EDTA because i usually make a 20% EDTA solution and use that in products but now it solidifies too.