Home Cosmetic Science Talk Formulating Colour stability problem

  • Colour stability problem

    Posted by Anonymous on August 11, 2014 at 8:59 am

    Hi everyone!!

    I have a problem with the stability of colour in cold process soap, melt & pour and in transparent body shampoo. 
    In CP & MP, the colour fade after a week. Our supplier suggest to put benzophenone 4 to solve this problem but then the colour change.
    Example:
    Process: Melt & Pour
    Colour put in soap: Red
    Result: Colour change to orange
    I wonder, why the colour fade at first (CP & MP) and when put benzophenone 4, the colour change.
    While in transparent body shampoo, the colour not stable.
    Looking forward for everyone respond!
    Bill_Toge replied 9 years, 11 months ago 1 Member · 1 Reply
  • 1 Reply
  • Bill_Toge

    Member
    August 11, 2014 at 4:24 pm

    what red dye are you using? some dyes are notoriously unstable towards daylight

    also, benzophenone-4 goes bright yellow in alkaline formulas (e.g. bar soaps), hence the colour change

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