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, 11 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.