Red #40 Al Lake is very transparent. How to opacify?

Hi all,

I made a dispersion of FD&C Red #40 aluminum lake pigment in castor oil, with a 33% strength, on a three roll mill. Dye load for this pigment is 21-24%. The resulting dye is very transparent and I'm having a very hard time making an opaque red lipstick with it, always getting a sheer red tint. I'm using the dispersion at 20% of my formula.

My question is, is FD&C Red #40 just really transparent or did I make the dispersion too weak? I'm using it at a rate consistent with what I've seen in formulas from ingredient manufacturers.

Since I want a strong red, I'm avoiding the use of titanium dioxide because it'll wash the color out to pink. Does anyone have any ideas on how to get strong color performance out of lake pigments?

My current lipstick formulation is a fairly standard blend of plant waxes and oils, with no particularly advanced ingredients. The most interesting things in there are Olivem 900 and high viscosity hydrogenated polyisobutene.

Comments

  • BobzchemistBobzchemist Member, PCF student
    Is your dispersion a buttery texture? Are you below a 4 on the hegman gauge? How many times did you mill the dispersion?
    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."
  • It's fairly thick, yeah. Regrettably I don't have a hegman gauge yet (the ones on eBay look a bit banged up). It went through the mill three times.
  • BobzchemistBobzchemist Member, PCF student
    Color performance in pigments is directly correlated to particle size and concentration (as opposed to dyes where concentration is the only factor). To increase color intensity, you have to either increase the concentration of your lake, or decrease the particle size, or both.

    Even if you take that route, lakes are inherently transparent. To make this less obvious, you need an opacifier. But, all opacifiers have a color of their own. Using TiO2 will tint you towards the pink side. Using red iron oxide will tint you towards the brown side. Using yellow iron oxide will tint you towards the orange/brown side.Using Manganese Violet will move towards the blue/purple side, as will black iron oxide.

    The other way to add opacity is to use colored pearlescent mica. You'll have a similar issue with color movement, but your color choices will be greatly expanded.
    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."
  • Thank you so much!

    Pearlescent micas sound like the way forward. I'll be experimenting with those.

    You are a lifesaver! Thank you so much for your help!
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