The Phase B is the “oily phase” or the “heated oily phase”.
It contains the emulsifier or the emulsifiers if they are two, the thickeners (if needed) and all the oils and fats which do not get negatively affected by heat (this because 90% of the times the Phase B is heated up to 70°C).
There are many kinds of emulsifiers. I will create a dedicated post about them. The main difference regard to the formulation of a lotion/cream is that some need to be heated up to 70°C and others don’t need it. The highest number, however, need to be heated to create a stable emulsion; this is why the Phase B is called also the “heated oily phase”: because most of the time it is heated.
Thickeners are those ingredients which give consistency to the cream and also help keeping the emulsion stable; the most common are cetyl alcohol, stearic acid, cetylstearic acid). Some are even slight emulsifiers themselves (for example cetyl alcohol which is a lipophilic emulsifier: it means that it is “fat-loving” emulsifier which can emulsify a small small quantity of water into a large quantity of fat).
Thickeners are solid (usually they are in pearls) and need to be heated in order to melt with the other ingredients.
In a formula you should add around 1% of thickeners and you can choose to add only one kind or two kinds. I personally like the combination of 0.5% cetyl alcohol and 0.5% cetearyl palmitate. You should do experiments to find out which consistency each thickener gives to a cream, in order to be able to choose what you like the most. 🙂
Pay attention, however, that while most of the emulsifiers do not contain thickeners in their formula, some do. It is the case, for example, of Montanov 68 (this is one of its commercial names) which is: “cetearyl alcohol, cetearyl glucoside”, where the cetearyl alcohol is our co-emulsifier and thickener, the cetearyl glucoside is the emulsifier. In this case you should not add any extra thickener to your cream-formula or it would result in a very lumpy cream difficult to spread.
– THE FAT (finally) 🙂 :
Before you start formulating a lotion you obviously need to know what is going to be its purpose: is it a cream for body, face or feet/hands? And, if it is for face, is it for normal skin, dry skin or oily skin?
Once you know what kind of cream you are planning to do, then you can start formulating.
Here is a short guideline on the percentage of fats you should add to your cream according to its purpose.
Keeping in mind that in any cream the fats should never go over the 25% fats (I am talking about O/W creams, about W/O it’s a different story but that will require another post) these are the values:
0-2% – it is obviously not a lotion but it is a gel: good for oily skin in summer days.
2-4.5% – this could be considered a oil-free lotion because the percentage of fats is so low. Good for oily skin.
4.5-7.5% – good for a cream for oily skin in winter days or normal skin in summer.
8-12% – good for normal skin
12-15% – good for dry skin
15% – light body cream
20% – medium weight body cream
25% – good for a rather thick body cream, hand cream and foot cream!
All these values can be changed a bit, according to what is your purpose: they are not fixed values but they give the idea 🙂
How to decide which oils and butters should go in your lotion?
On the market there are tons and tons of oils and buttes, some are natural, nowadays it is fashionable to use exotic oils 🙂 and some are synthetic.
Probably the first thing you would do is to add any kind of oil which sounds good to you: “Oh I read somewhere that the oil of khtululu (I invented this plant 🙂 I am just trying to make a point) is very good against skin-aging, it has miraculous antioxidant properties and, if used everyday, it will also prepare the breakfast for you in the morning!!! I will make a cream with 7% fats using 5% this oil and 2% turururu oil, which is a very rare, I will just sell my kidney to have it but you see it is found only on the Everest peak in 100 ml jars and it is said to be marvelous for firming the skin…”
Let me say NO NO NO NO NO and NOOO 😀
There is one thing that you will happily or sadly learn while learning to make lotion-creams: nothing is miraculous and it is not true that the more one thing costs, the more it is effective. That is just what market wants us to believe. 🙂 And, if you study well enough (even on your own, doing some research), you will realize that most of the times we are just being fooled 🙂 .
There are some rules which need your attention when deciding which fats to add in your formula and these rules concern the density, viscosity, spreading ability of your oil more than the so-called miraculous properties. I will never repeat this too many times.
So the new post will be only about the oils and how to formulate a group of oils in the cream, how to choose them, what to look for and so on 😀