What is the HLB index ~ Archie Paint

What is the HLB index?

The empirical "hydrophilic-lipophilic balance value" (HLB value) tells us something about the polarity of emulsifiers. These are often either fatty acid esters or ethoxylated compounds of fatty acids, alcohols, amines, amides, alkyl phenols etc. The HLB value is calculated by different methods, according to the type of compound. For fatty acid esters, for example, the calculation is as follows:

(HLB)_F= 20 (1 — S:A)
where
S(mg/g) saponification number of the ester
A(mg/g) acid value of the fatty acid

For ethoxylated products:
(HLB)_E= E+P:5
where
E(% by weight) oxyethylene content in the molecule
P(% by weight) polyhydric alcohol content

The higher the HLB value, the more hydrophilic is the emulsifier,
Values vary between 1 (completely hydrophobic, not dispersible in water) to about 20 (completely hydrophilic, forms clear solution in water). Higher values can occasionally be encountered. McCutcheon‘s "Emulsifiers and Detergents" (published by MC Publishing Company, 175 Rock Road, Glen Rock, NJ 07452, USA) a standard reference work for industrial wetting agents and emulsifiers, gives the HLB values for a number of products. These help the experienced user to select the emulsifier most suited for his particular application. The HLB values of mixtures behave additively.