how to change o/w to w/o? - Chemists Corner

Formulating

how to change o/w to w/o?

Posted by cherri on March 28, 2014 at 1:15 pm

happy Friday everyone!
quick question.. how do I change my o/w formula to w/o?
I have water phase, oil phase, actives, and preservative.
the original comes out as gel type white cream and I want to try w/o… any help?
I used kappa, cetyl oh, wheat germ oil, ptc, stearyl oh, and my water phase is with xanthan gum.

any help will be appreciated. thank you!

Chemist77 replied 10 years, 9 months ago 5 Members · 13 Replies
13 Replies

Chemist77

Member
March 28, 2014 at 1:23 pm

kappa???? Carrageenan grade you mean???
Bobzchemist

Member
March 28, 2014 at 3:19 pm

A complete formula with percentages would be needed before we could help you. INCI names would be useful too.
MakingSkincare

Member
March 28, 2014 at 7:34 pm

cherri, here’s an article from a supplier - MakingCosmetics.com:-

http://www.makingcosmetics.com/articles/27-how-to-make-water-in-oil-emulsions.pdf

You will want to make quite a few changes to your formula incl using a low HLB emulsifier and add epsom salt to stabilize etc
cherri

Member
March 31, 2014 at 9:18 am

WATER QS
GLYCERIN @ 3%
XANTHAN GUM @ 0.3%
CETEARYL GLUCOSIDE AND CETEARYL OH @4 %
GLYERYL STEARATE, PEG 100 @ 1%
SHEA BUTTER @ 3%
SOY BEAN OIL @ 5%
WHEAT GERM OIL @ 3%
CETYL ALCOHOL @1 %
BEHENYL ALCOHOL @ 1%
HYDROGENATED POLYISOBUTENE @ 0.5%
PRESERVATIVE 1%

I switched from emulium kappa to montanov 68… so how do I change o/w to w/o? any help will be appreciated thanks so much!
chemicalmatt

Member
March 31, 2014 at 10:09 am

Before you get too far using that article linked from makingcosmetics.com, cherri, be advised there are glaring misrepresentations in that article about inverse-phase emulsions. Do not add polymeric thickeners to the internal (water) phase - ever - unless you really want to drive yourself crazy. I don’t know where they came up with that one, but it is categorically wrong. (Who writes this stuff?) Also, magnesium sulfate works better than NaCl in stabilizing W/O emulsions about 90% of the time, so start with epsom salt always. That article also fails to mention the best W/O emulsifiers in existence, the silicone-based ones. See Evonik, Siltech and Dow-Corning product guidelines for these. In case you haven’t deduced this yet: you have to begin from scratch here; you cannot simply “change” from O/W to W/O.
Chemist77

Member
March 31, 2014 at 11:32 am

@Cherri I agree with chemicalmatt, totally clueless how to change this one to w/o but yeah if you start from scratch and wanna some help on w/Si emulsion then let me know DC have some very good w/Si emulsifiers though I have used NaCl to thicken my formula. As per the crazy request of customer I had to incorporate 3% perfume oil as well into this formula and it came out wonderful.
Bobzchemist

Member
March 31, 2014 at 11:38 am

You may not have to start “completely from scratch - but you can’t keep all that much of your original formula either:

Phase A

ABIL® EM 90 2.0 %

Behenyl Alcohol 0.5 %

Cetyl Alcohol 0.5 %

Shea Butter 3.0%

Soybean Oil 10.5 %

Wheat Germ Oil 5.0 %

Cyclomethicone 6.0 %

Tocopheryl Acetate 0.5 %

Phase B

Magnesium Sulfate 0.5 %

Glycerin 3.0 %

Water 63.5 %

Phase C

Alcohol 5.00 %

Preservative, Parfum q.s.

-Heat Phase A and B to at least 70C

-Homogenize A and B for 20 minutes

-Cool to 50C

-Add Phase C and then anchor mix to RT

You could say that you “changed” from a o/w to a w/o - or you could say that you started over.

Either way, what you had to do was:

1. Remove all water phase thickeners

2. Remove all o/w emulsifiers and emulsion stabilizers

3. Use a w/o emulsifier

4. Increase oil phase

5. Add magnesium sulfate
MakingSkincare

Member
March 31, 2014 at 1:51 pm

Some great advice here.

Bob - I see you added 5% alcohol??
Bobzchemist

Member
March 31, 2014 at 2:24 pm

It was in Evoniks starting formula…

But it’s not needed for the formula, it’s just in there for skin feel and possibly to assist the preservative, as far as I can tell.

And I left out that you have to start out homogenizing Phase A and slowly add the water.
MakingSkincare

Member
March 31, 2014 at 2:45 pm

Ah, that explains it, I was wondering where the 5% alcohol had appeared from!!

If only homogenizers were cheap - I know w/o really needs it. cherri do you have access to one??
Bobzchemist

Member
March 31, 2014 at 4:27 pm

How cheap do homogenizers need to be?
cherri

Member
March 31, 2014 at 6:18 pm

@Bobzchemist, chemicalmatt, milliachemist , MakingSkincare thanks all for your help.
Chemist77

Member
March 31, 2014 at 9:59 pm

@Bobz does the addition of water need to be slow and in parts as needed for W/Si emulsion? Because you mentioned homogenization so I am guessing all at once.