Pigment Suspension

hishine1hishine1 Member
edited November 2014 in Formulating
Hi

Can anyone give me a couple of ideas for pigment suspension in a volatile liquid? Ethyl Alcohol, Cyclopentasiloxane base.  Currently using a predispersed pigment in Isododecane.

Thanks

Comments

  • BobzchemistBobzchemist Member, PCF student
    Robert Zonis, Sr. Formulation Chemist, Beaumont Products "All opinions and comments expressed are my own, have no relation to Beaumont Products, are fully copyrighted, and may not be used without written permission."
  • Thanks for those links Bobzchemist :-)

    Would these colours still not precipitate to the bottom of my bottle?  I need to keep the formula super simple for cost. Quick dry hence the Ethanol (50%), Cyclo with 3% Dimethiconol/Cyclo for a little gloss.  Ideal would be to package into clear bottles.  Any other additives I should be using?
  • BelassiBelassi Member, PCF student
    I don't see why a water-soluble pigment should settle? It doesn't settle in shampoo, for instance!
    Cosmetic Brand Creation. Concept to name to IMPI search to logo and brand registration. In-house graphic design inc. Pantone specs. Cosmetic label and box design & graphics.
  • @ Belassi ... I made the base mix as above, I used (Sensient) a pigment dispersion in Isododecane (Carbon Black/oxide) and it settles within 6 hrs.
    no water here other than in the Ethanol (97.5%).

    do you have any ideas?


  • BelassiBelassi Member, PCF student
    It's not a water soluble pigment, is why.
    Cosmetic Brand Creation. Concept to name to IMPI search to logo and brand registration. In-house graphic design inc. Pantone specs. Cosmetic label and box design & graphics.
  • BobzchemistBobzchemist Member, PCF student
    There is no such thing as a water soluble pigment. By definition, any soluble colorant is called a dye. Pigments are always insoluble particles - without a suspending agent, the particles will settle out.
    Robert Zonis, Sr. Formulation Chemist, Beaumont Products "All opinions and comments expressed are my own, have no relation to Beaumont Products, are fully copyrighted, and may not be used without written permission."
  • BelassiBelassi Member, PCF student
    Then why, can I add some blue pigment to water, and it will never settle out? Such as fluorescein I should think... 
    Cosmetic Brand Creation. Concept to name to IMPI search to logo and brand registration. In-house graphic design inc. Pantone specs. Cosmetic label and box design & graphics.
  • yours is a difficult question to answer depending on the use of your formulation. If it's a normal dye the pigment should readily dissolve in water, otherwise you need to check you need to check your HLB (hydrophili-lipophile balance) of the surfactant if it's a suspension or emulsion. Depending on whether it's a nonionic or ionic surfactant, you'll be able to choose which to use for your formulation. Secondly the viscosity of your formulation will affect migration of your pigment (be it settling or creaming). In this case then your vehicle must be something viscous depending on the intention of your formulation. 
  • @ Belassi Probably because fluorecin has a small solubility in water
  • I have successfully dispersed FDC colorants in Castor Oil. 1:1 ratio... my understanding is that the liquid can be viscous.enough to suspend the color. example you can use. iron oxide dispersed in castor etc. you can disperse in silicones. you can disperse in glycerin.
    but remember that the amount of castor or item you disperse may change your formulas outcome.

    I am a Nurse not a Chemist.. 
  • Thanks everyone :-)  Im not at all familiar with dyes etc, but obviously what I need is a dye instead of a pigment.  I have since tried several direct dyes and they will suffice with some formula modification. 

  • Cali SCC just had David Steinberg do a presentation on colors - go to www.caliscc.org/education and look for the blog article about color. There is also a presentation to download. May give you a good insight into pigments, lakes, dyes, etc.
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