[mehrzadkia]

Gunther said:

You could use a w/o emulsifier like Span 20/60/80 but it’s better to stick to the approved ones as @Perry just said.

It’s all about curiosity. I will stick to the safe side.
Thank you and happy new year to you.

[mehrzadkia]

Bill_Toge said:

legality aside, the fundamental problem is that water-soluble dyes are the wrong type of colourant for colour cosmetics; what you need is a pigment

Thank you so much.
What if I use beetroot powder, not its water extract?

[mehrzadkia]

Perry said:

@mehrzadkia - very good question. The unsatisfying answer is because that’s what the regulations are. 

The FDA even specifically says “Approval of a color additive for one intended use does not mean approval for other uses.”  Therefore, even if a colorant is approved for food, that does not mean it is approved for cosmetics.

The cosmetic industry in the US is not highly regulated except in a couple areas. Colorants is one of those areas. Formulators (who follow the law) are limited to the colors listed in the FDA approved colorants. The safety or origin the ingredient does not matter. If it’s not on the list, it’s illegal to use as a colorant. 

Thank you Dr. Perry for the clarification.

I guess it has something to do with the stability and subsequent changes of natural colorants in the formulas. As far as I’m concerned, beetroot powder and all other food/fruit/vegetable powders do not work in color cosmetics as they are. They either don’t work at all (they color the product but not the skin) or they stain the skin irreversibly (like turmeric or henna).

[mehrzadkia]

Perry said:

It is illegal to use beetroot powder as a colorant in your cosmetic formulas. If the ingredients are not listed here (FDA approved colorants) it is illegal to do what you are requesting and not recommended.

Thank you Perry.
May I ask why? The colorant agent is anthocyanin which is edible and apparently is a good antioxidant.

[mehrzadkia]

Pharma said:

They can get cloudy at lower temps . Bring them to 25-30°C and if they become clear again, they’re okay. Polysorbates are very stable: Tween 60 is visually stable for years but might get cloudy at higher temps when getting old whilst polysorbate 80 starts smelling rancid before you see any degradation. I found some long forgotten bottles in our cellar which were over 20 years old and they only showed minor visual signs of ageing. Smell wasn’t okay but still far from rancid.

Thank you very much
So, I’m going to bring some 25-30°C. I have just these two bottles handy! 🙂 Hope they are OK. 

[mehrzadkia]

ngarayeva001 said:

PEG-8 dimethicone works well in skincare but although it’s water soluble it’s a bad idea for shampoos: reduces viscosity and foam.

I love this corner. You guys are awesome.

[mehrzadkia]

Gunther said:

You can either 
A. buy a premade, water-soluble silicone emulsion.
Those from DOW are great, but they usually only sell by 18 or 200 Kg drums.
You can buy small amodimethicone amounts from shops like
https://www.makingcosmetics.com/Amodimethicone_p_975.html
But I don’t know how this one works in skin products. It works great for hair products tough. (I’m not affiliated with makingcosmetics in any way).

B. emulsify silicone yourself
For shampoos you can neutralize LABSA with TEA and use it to emulsify silicones, but that’s only suitable for shampoos, not for skincare.
Emulsiying silicones with nonionic emulsifiers is tricky.

C. buy a water soluble modified silicone
Water soluble ones don’t work well for shampoos, but are probably OK for skincare.

Tricky stuff
Thank you so much for your answer. I need a lot more research.

[mehrzadkia]

ngarayeva001 said:

For emulsions dimethicone is added to reduce soaping. You don’t need much and 1.5-2% shouldn’t cause issues if you add it to the oil phase (even when you use polar oils).

You can add silicone emulsifier such as ViscOptima SE by croda or Abil EM 90
 to stabilise higher amount of silicone.

For shampoos, watersoluble forms are usually used (Amodimenticone for example).

Thank you so much for your detailed answer.

[mehrzadkia]

Thank you for sharing your formulation. 
I found a relatively similar mask formulation:
Polyvinyl alcohol, Ethyl alcohol, glycerin, propylene glycol, menthol, d-panthenol, methyl chloro isothiazolinone, methyl isothiazolinone, deionized water, fragrance, colorant

What does the surfactant do in your formulation? How do you see this formulation?
Thank you.

[mehrzadkia]

em88 said:

mehrzadkia said:

Hello everyone,
Is this statement correct?
The type of an emulsion (w/o or o/w) is determined by the type of the emulsifier (and its solubility in a certain phase), not the ratio of the hydrophile and lipophile compounds in the emulsion. 
Thank you.

Well, it is correct. The type of an emulsifier indicates its solubility, so I would remove the “and” in the parentheses.
Regarding the ratio of hydrophile and lipophile in the emulsion, technically it isn’t a criteria to determine the type of emulsion, but in most of cases it suggests the type of emulsion. 

Thank you so much for the clarification.

[mehrzadkia]

Doreen said:

The most valuable information I’ve found on emulsions, written by @Bill_Toge , you can read it in this link:
https://chemistscorner.com/cosmeticsciencetalk/discussion/3005/emulsions-setting-the-record-straight
It will answer your question and more!

I’m glad I asked this question. A very informative click!  🙂
Thank you so much for sharing this.

[mehrzadkia]

em88 said:

https://www.theherbarie.com/files/resource-center/formulating/Emulsifiers_HLB_Values.pdf

Thank you very much.

[mehrzadkia]

ngarayeva001 said:

Option for lazy: makingcosmetics.com => sections W/O emulsifiers and O/W emulsifiers 

Thank you so much.

[mehrzadkia]

Belassi said:

Use one of the many online books, it is far too much to relate here.

Sorry for bothering you. 

[mehrzadkia]

Loud and clear, I got the point.
Thank you.

[mehrzadkia]

ngarayeva001 said:

I listed two very good emulsifiers above. Beeswax isn’t an emulsifier. If you want to make it cheap to show students how to make a cream get emulsifiying wax with cetearyl alcohol and PEG-20 stearate for 6 pounds from Amazon. 

The combination of Beeswax+Borax, not beeswax alone, is effective in emulsifying. In this case, I am going to try the two options you suggested.
I really appreciate your responses. Very helpful.

Sorry I am bothering you with too many questions
Regarding HLB value, after calculating the required HLB of the oil phase, which option do you recommend?
1- Choosing emulsifier(s) with HLB value close to this calculation

2- Choosing 2 or more emulsifiers which cover two ranges, below and above of this value.

[mehrzadkia]

Belassi said:

For emulsifier, what about this combination?
Beeswax 7.8%+0.2% Borax & Lecithin 1%
NO! It’s out of the dark ages. Use something modern.

You are right. It’s an old-fashioned option! But I just trying to show students what an emulsion is and how it works. I’m trying to keep it as simple as possible.
Thank you for your point.

[mehrzadkia]

ngarayeva001 said:

Don’t forget preservative and tocopherol. Natthinking has both in section preservatives. And glycerin. 

Thank you for your detailed response. This is very thoughtful of you.
Actually, the students are trying to make a moisturizing cream. Something with around 55% of aqueous phase (glycerin 2%+deionized water 43%+aloe vera gel 10%) and 33% of oil phase (5% castor oil+13% avocado oil+7% olive oil+8% cacao butter).
Emulsifier: 9%
Additives including herbal extract, preservative, antioxidant, essential oil: 3%

For emulsifier, what about this combination?
Beeswax 7.8%+0.2% Borax & Lecithin 1%

Thank you.

[mehrzadkia]

Perry said:

Well, that depends on what else is in your formula.  See this discussion.

https://chemistscorner.com/cosmeticsciencetalk/discussion/417/stearate-base-emulsion

and this one…

https://chemistscorner.com/cosmeticsciencetalk/discussion/1605/stearic-acid-neutralization-in-emulsions

Thank you Dr. Perry for your response.
They are a group of beginners trying to make something like cream or lotion in the lab. So, they are going to keep it very simple:
Oil phase: olive oil, sweet almond oil, jojoba oil, cocoa butter
Aqueous phase: water and hydrosol, or aloe vera gel.

What kind of emulsifier would do the trick? Is stearic acid an option here?

[mehrzadkia]

ngarayeva001 said:

No. Stearic acid is not an emulsifier.

Thank you for your response.
So strange! I came across a couple of ingredient sellers that introduce stearic acid as an emulsifier! See the picture below.

[mehrzadkia]

amitvedakar said:

Cream Base is unstablet for Salicylic Acid.

Suitable base is Ointment.

White soft Paraffin Base. Dissolve In hot Paraffin with continuous Stirring.

Thank you so much.
It’s true for sure, but we the point is we want salicylic acid to make creams, not ointment. Great point though! Thank you.

[mehrzadkia]

em88 said:

That formula must be a state secret.  There are some ways to dissolve it without (partially) neutralizing it, but again the formula is needed. 
Assuming the concentration of SA is up to 2% you should not have too much issues dissolving it.

Thank you so much for your response.
Yes the concentration is 2%. As one of the chemists here sugessted, the problem is probably with pH.

[mehrzadkia]

MarkBroussard said:

It’s really a function of you total formula pH … try to keep it around 4.0.  Again, without knowing you have in your formula it is not possible to tell what may be causing the SA to precipitate out.  Check your pH would be the first recommendation.

I’m going to check the pH then. Hope it works out.
Thank you very much. 

[mehrzadkia]

Fekher said:

@mehrzadkia  may you need better  quality of salicylic acid , ”    smaller granulation powder” 

Thank you so much.

[mehrzadkia]

Chemist77 said:

As Mark said, the acid should be solubilized and with the aid to keep it soluble. Else precipitation won’t be stopped. 

Thank you so much.
Sorry, my question may sound stupid, but how can I keep the acid soluble? I mean, is there a special compound for this?