What is an HLB Value?
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HLB stands for the hydrophilic-lipophilic value, which William Griffin created in 1949. He created this value to classify nonionic surfactants, such as an emulsifier, based on their hydrophilic or lipophilic characteristics. The HLB value is used to measure the balance between the hydrophilic and lipophilic properties. This value is important when formulating products that mix water and oils.
HLB Value & Surfactants
A surfactant is a “surface active agent’” and is special due to the shape of the molecule. It has a hydrophilic or water-loving head and a hydrophobic or water-hating tail. This makes the tail lipophilic. The HLB value is related to the solubility of a surfactant. It refers to how much the surfactant is hydrophilic or lipophilic. These features will influence how the surfactant will behave when forming and stabilizing emulsions.
How HLB is determined
HLB is determined by using a scale that ranges from 1 to 20. They are determined using calculated or experimental methods and are often provided by the manufacturer. The hydrophilic-lipophilic balance value is based on the chemical structure and performance in forming stable emulsions. These calculations can be done by:
- Experimental determination– Surfactants can be tested in experiments to calculate their HLB value. This involves different ways to test an emulsion’s stability.
- Theoretical calculation– the HLB value can be calculated using the chemical structure of the surfactant, focusing on the different groups that make up the surfactant
- Reference data– many surfactants already have established HLB values documented in scientific literature or from the manufacturer.
The Scale
The HLB value is based on a 1 to 20 value scale. A lower HLB value, ranging from 4 to 6, indicates a surfactant that is more lipophilic. This means the surfactant is better suited for water-in-oil (W/O) emulsions. A higher HLB value, 8 to 12, indicates a surfactant that is more hydrophilic. This value means the surfactant is suitable for oil-in-water (O/W) emulsions.
What Does the Scale Mean?
The scale will help to identify the behavior of the surfactant and the oil. Lower HLB surfactants on the 1 to 9 scale are required for water in oil (W/O) emulsions. This emulsion is when the water is dispersed into an oil phase. These emulsions are heavier. The higher HLB Surfactant on the 10 to 20 scale is for oil-in-water (O/W) emulsions. To achieve this, the oil is dispersed into a continuous water phase.
HLB Value in Lubricants
HLB values are important in water-based lubricants to help you form a stable emulsion. Lubricants and the HLB value work closely together to help ensure the lubricant formulation is stable and compatible. This value also plays a role in the lubricant’s performance during the oil and water phases in the formulation.
The HLB value is important to ensure performance and stability in water-based metalworking fluids. Depending on the HLB, the emulsion size will vary, changing the balance between cooling and lubrication of the metalworking fluid.
HLB Value in Cleaners
When formulating a cleaner, the HLB value plays a role in selecting the correct surfactant for your formula. HLB can influence emulsion stability and the application of your formula.
Depending on the cleaner’s application, the different HLB values help the formulator alter the emulsification.
HLB values play a role in the formula emulsifying such as fragrances or other hydrophobic components typically added in applications such as car washes for polishes and shine.
The HLB value helps formulators quickly choose the right surfactant based on their formula application. A high HLB value is a more hydrophilic surfactant, while a low HLB value is a more lipophilic surfactant. Choosing the right surfactant will help your formulation’s performance, emulsion, and stability.
