Stabilising Oil only scrub

cossci21cossci21 Member
edited May 2014 in Formulating
Hello I am working on trying to stabilise a body scrub. It has no water and consists of oils only, GTCC, etc. Feels great on the skin!

To thicken it I use Aerosil and it produces a nice 'gel like' scrub however its not stable.Oil starts separating from the Aerosil over time.
Are there any ingredients that I could add, oil soluble which will help stabilising it?
I was thinking of some silicone that emulsifies oils etc?
Any ideas?

Many thanks

Comments

  • vitalysvitalys Member
    You may try COVASILIC from Sensient. We produce the simmilar scrab formulation for years and we have never come across with separation of the oils.
  • Bill_TogeBill_Toge Member, Professional Chemist
    which Aerosil are you using, there are several different grades
    UK based cosmetic chemist with 13 years' experience at the bench. I've worked with pretty much everything apart from pressed powders, soap, solid lipstick and aerosols.
  • Hello ok its Aerosil 200 will have to check if its hydrophobic or hydrophilic...
  • BobzchemistBobzchemist Member, PCF student
    First thing - are you sure that you are dispersing the Aerosil enough? I know that it doesn't look like it, but it is very agglomerated in it's dry powder form. It gets more efficient the better dispersed it is.

    There are grades of waxes that gel oil. Some are natural, some not.
    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."
  • Bill_TogeBill_Toge Member, Professional Chemist
    200 is a hydrophilic grade - try 812, 972 or 974
    UK based cosmetic chemist with 13 years' experience at the bench. I've worked with pretty much everything apart from pressed powders, soap, solid lipstick and aerosols.
  • you can try to add some lecithin, stabilize the oils, improve feel, and conditions the hair
  • I heard Dr Straetsmann has a natural oil thickener. You might be interested.
  • Hello bobzchemist will try better dispersion just hand mixing in the lab so a bigger batch may work better.
    Crisbaysauli have used the dr straetmans before but too expensive unfortunately!
  • BobzchemistBobzchemist Member, PCF student
    Much, much better dispersion is required. Kitchen blender might work. Homogenizer may work, ball mill or 3-roll mill will definitely work.

    On a small scale, a muller or a flexible spatula against a glass plate will eventually work. 

    The general rule is to start with as stiff/thick a dispersion as you can get to move through your grinding/milling system, and to slowly add liquid as needed. As the dispersion improves, the batch will get thicker - eventually, you will reach the limits of what your grinding/milling system can disperse, and the thickness will stop increasing.

    Oil-based products thickened only with silica have a tendency to separate over time, particularly if the oil is thin - can you increase the oil/surfactant viscosity?
    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."
  • Hi Bobzchemist,

    thanks for that, the most helpful answer as yes it does separate over time. I think will be able to control the homogenising in manufacturing a bit more, dont have any mills though. Have a blender in the lab i can try as well. 
    Actually might be able to add a different surfactant to assist with the viscosity.
    Thanks for that!
  • BobzchemistBobzchemist Member, PCF student
    In a kitchen blender, you might want to try starting with the dry Aerosil first, adding a few drops of liquid, COVER THE BLENDER,  blending, and then repeat until the silica stops blending freely. Then, homogenize the mixture into the rest of your oil. (Trying to blend Aerosil or Cabosil without covering the blender, even on low speed, will get silica all over the lab. Don't ask how I know this - I just do, OK. I am an experienced chemist - I would never make a mistake like that. That's my story and I'm sticking to it)

    If you had stronger dispersing equipment, I would suggest Aerosil 300 instead of 200, because it's a stronger oil absorber. I'm not sure that you'll be able to disperse it well enough to take advantage of that difference, though.
    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."
  • BobzchemistBobzchemist Member, PCF student
    Bill_Toge also makes a good point - you might want to look at using a grade of silica where the coating on the silica assists oil 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."
  • Hi Bobzchemist
    ok thanks for that hehe thanks for the tip on the blender!
    Just have the one client for this so havent thought of getting in different grades of the Aerosil as its only a small client. Will keep it in mind though if we have other clients after a similar product...
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