Hello. Lately, I am interested to learn how the HLB system works. The reason for that is I want to learn how to combine the different emulsifiers, and also how to define the emulsifiers amount more precisely. I was reading a lot of information about that, also I have found a calculator in Excel which makes the calculations faster, but I am still confused.
Here is my current lipid phase :
* Cetearyl alcohol - 2.5%
* Decyl oleate - 3%
* Octyl palmitate - 2%
* Mineral oil - 2%
* Dimethicone 350 - 2%
The HLB value of this combination is : 11,1
To be honest I am not sure if the all HLB values are correct. For example I have found that the HLB of the Dimethicone can vary in a wide range. But still ...
And now the interesting moment. With this lipid phase I am using two emulsifiers :
Glyceryl Stearate SE - 3%
Methyl Glucose Sesquistearate - 1%
Total HLB - 6
As I understand the HLB values of the emulsifiers and the oil phase are totaly unmatched. But, the emulsion is perfectly fine, stable with a great sensorials. The question is why?
The second combination :
Ceteareth - 25 - 0.5%
GMS - 3%
Total HLB - 5.6 ( This combination is borrowed from the Evonik's Teginacid's formulation giude)
Again, stable emulsion and a great sensorial profile - easy spreading, fast absorbing, no gloss, no stickiness. Again too far from the desired HLB.
The third combination : (according to HLB)
Ceteareth - 25 - 1.4%
GMS - 3%
Total HLB - 11.1
The emulsion offcourse is a bit more liquid because of the redused amount of the GMS. But the sensorial is totally different. It feels a bit "heavy" than the previous, also it tends to be more sticky and shiny. It also have a fast absorbtion time, but the overal feeling to the skin isn't the best.
The questions here are two in general :
1. How is it possible to get a stable and fully working emulsions which are totaly out of the HLB system?
2. Does the sensorial properties related with the HLB of the emulsifier system? High HLB gives heavy and more upleasant sensorial, low HLB more pleasant.
The same situation I got with the Lotionpro 165. Used alone it gives light, but unpleasant emulsions which tend to be sticky and glossy.
To be honest I don't understand why's that.