Formulating

aggregation when adding cetearyl alcohol

Posted by jeremien on March 8, 2017 at 4:11 pm

Hello, I have tried to prepare this formula

Water Deionized (Aqua)	85,7
Carbopol 940	0,3
Glycerine	3
Cetearyl Olivate, Sorbitan Olivate	2
(Olivem 1000)
ceteary alcool	1
CAPRYLIC/CAPRIC TRIGLYCERIDE	2
Octyldodecyl Myristate	2
Active	3
Preservative	1
NaOH10% adjust pH

I prepare the water phase with glycerin and carbopol,
I heat at 75ºC and add under agitation the oil phase (Olivem1000, cetearyl
alcohol carpylic and octyldodecyl myristate) at 75ºC.

There is a phase separation and i observe many aggregates in my formula.

I have try the same formula without cetearyl alcohol and no precipitation was
observed. Someone has an explanation why cetearyl alcohol causes aggregation of
the oil phase?

jeremien replied 7 years, 11 months ago 7 Members · 14 Replies

14 Replies

johnb

Member
March 9, 2017 at 2:50 pm

Not a direct answer to your problem, merely an observation, but I would never use Carbopol in a formulation like that - especially Carbopol 940 which is designed for “sparkling clear” gels.
jeremien

Member
March 9, 2017 at 3:03 pm

@johnb thanks for the recommendation. I use the carbopol 940
only for the viscosity building effect with limited concentration that gives
this very nice aqueous gel aspect (white because of the emulsion but I don’t
care in this case to obtain a transparent gel)
Interestingly, i have repeat the formulation changing the cetearyl
alcohol by the cetyl alcohol, and in this case, i obtain a stable homogeneous
formula.
Bill_Toge

Professional Chemist / Formulator
March 9, 2017 at 3:16 pm

there is no logical reason why using cetyl (C16) alcohol instead of cetearyl (C16/C18) alcohol would change the product’s ability to form an emulsion - or even why the emulsion failed to form in the first instance

to my mind, this suggests one or both of the following:

1. the emulsion cannot be consistently formed using this particular combination of method and materials

2. the ‘cetearyl alcohol’ you used before is actually a different material
johnb

Member
March 9, 2017 at 3:24 pm

Completely agree with Bill.

Regarding the grade of Carbopol, 940 is specifically designed to give very transparent gels and to do this it sacrifices some other properties -like tolerance to electrolytes. If you want to continue to use the original Carbopol types, 934 is the one to use in emulsions although I should point you in the direction of the more modern versions which are much more versatile.
jeremien

Member
March 9, 2017 at 3:45 pm

@Bill_Toge yes , i cannot understand the different behaviors, I
guess that it is your second answer, that the material i m using is not really
cetearyl alcohol. I’m using a sample that I received from KAO, the Kalcol
6850.

Another scientific explanation, is that with the cetearyl alcohol decreases
more the phase inversion temperature than the cetyl alcohol, and I start to
invert the emulsion at 75ºC with the cetearyl alcohol, but in my case I’m not
using ethoxilated surfactants so it sound highly unlikely.

@ johnb, thanks, i will try the Carbopol 934 or new versions of carbopol (carbopol smart?)
Bobzchemist

Member
March 9, 2017 at 7:45 pm

You might want to consider using one of the Pemulens to boost your emulsification also.
jeremien

Member
March 10, 2017 at 9:04 am

@Bobzchemist, i have also a sample of permulen, i will try. With only 5% oil, do you really think i need to boost the emulsification?
johnb

Member
March 10, 2017 at 9:26 am

My choice of viscosity modifier and stabiliser for a formulation such as yours would be xanthan gum, a guar derivative or hydroxyethylcellulose.
jeremien

Member
March 10, 2017 at 9:56 am

I try with Xanthan Gum, but final formulation look more heavy (more dense) compare with carbomer one. I’m looking for a very light effect of the final product
Bobzchemist

Member
March 10, 2017 at 2:57 pm

I don’t think that Olivem 1000 can produce a long-term stable emulsion at 2% without a co-emulsifier, so the amount of oil you have isn’t the issue, really.

Pemulen is synergistic with Carbopol, so you’d probably only need to use 0.05 - 0.1 percent of Ultrez 30 together with 0.2% of TR-1.

I’m not sure how the cetearyl alcohol would help you to get a light effect on skin, though.
MarkBroussard

Professional Chemist / Formulator
March 12, 2017 at 11:39 pm

You’ll get the best results with Olivem 1000 if you pair it with Glyceryl Stearate, Xanthan Gum and Cetyl Alcohol. I think your major problem is that you just are not using enough Olivem 1000 … try bumping up to 4%.

If you want to use Carbomer … Carpool Ultrez 21 is much simpler to work with.
belassi

Member
March 13, 2017 at 12:46 am

I agree with Mark that Ultrez 21 is way easier to use than 940. When I’m using 940 I like to allow hours for it to wet. However, I still use 940 in the carbomer creams because I prefer its sensorials.
David

Professional Chemist / Formulator
March 13, 2017 at 3:00 pm

Why use olivem unless you want an ecocert formula? There are plenty of alternatives, e.g. ethoxylated fatty alcohols
jeremien

Member
March 14, 2017 at 10:51 am

Thanks to all of you for your comments. @Bobzchemist when you say: Pemulen is synergistic with Carbopol,
you mean in term of viscosity? I will try it.

@ David i use olivem 1000 because i like the
sensorial feeling it gives to the formula. And I would like to jump to tottaly
ecocert formula. By the way, is there any ecocert thickener polymers?