The HLB System

Systematic method for selecting the most effective nonionic emulsifier(s) for any given

application

The number, the system, the concept

Presentation Outline• System history• HLB definition• Emulsion types • Three-step surfactant selection method• HLB requirement determination• System flexibility • Summary

History of the HLB System• HLB stands for

• System invented 60 years ago – William C. Griffin – Atlas Powder Company

• Developed for use with nonionic surfactants

Hydrophile Lipophile Balancewater compatibility oil compatibility Ratio

Defining the HLB System

• All nonionic surfactants have an HLB Value– the higher the number, the more hydrophilic– the lower the number, the more lipophilic

• Emulsified oils and emulsion applications have very specific HLB Requirements

• Matching HLB requirement with surfactant HLB value yields optimum performance

Determining HLB Values• Molecular weight percent of hydrophilic portion

in a given nonionic surfactant, divided by 5– HLB range between 1 and 20

• 60% hydrophilic– HLB = 60/5 = 12

OO

O

OO

OO

OO

HO

Hydrophilic groupMW = 600

Hydrophobic groupMW = 400

HLB ValuesHow can surfactants have such a wide range of HLB values?

HLB values of nonionic surfactants range from 1 to 20.

water-loving end of molecule oil-loving

end of molecule

water-loving end of molecule oil-loving end of molecule

High HLB (10-20) surfactants have a larger water loving end, and smaller oil-loving end

Low HLB (1-10) surfactants have a larger oil-loving end, and smaller water-loving end

HLB Values And Blending• HLB value for surfactant blend

– Weighted average of the HLBs of blended surfactants– 50 / 50 blend of HLB 4 and HLB 16 = HLB 10

• The HLB requirement of oil blend– Weighted average of the HLB requirements of blend

components – 50 / 50 blend of Requirement 10 oil and Requirement

14 ester yields Requirement 12 ester

Emulsion Types• Oil-in-water (o/w)

– the continuous phase is water

– dispersed oil droplets– med / high HLB

requirement

• Water-in-oil (w/o) invert– the continuous phase is oil– dispersed water droplets– low HLB requirement

MILK

HAND CREAM

How to Choose an Emulsifier• Literally thousands of choices for the formulator• Usual choice is the “favorite”• Narrow choice and expedite selection using the HLB

system• Saves time and money• Leads to best emulsifiers for the application

The Three Step System1. HLB requirement of oil2. Most effective surfactant chemistry3. Surfactant concentration required to achieve

desired stability or rheology

Required HLB’s are accurate to ±0.5 HLB units

How to Determine a Required HLB• Prepare seven simple emulsions, using

– the same amount of oil and surfactant concentration– an HLB value progression– the same amount of water and mixing

• Observe which emulsion appears to be the most stable• The HLB value of the surfactant used in the most stable emulsion

is the required HLB for the system

Determining HLB RequirementHLB Span 80 Tween 80

4 100%

6 83% 17%

8 65% 35%

10 46% 54%

12 28% 72%

14 9% 91%

15 100%

Determine the Required HLB

6 148 10 12

Use applicable water hardness, pH and temp.

4

Determine the Required HLB

HLB 11 HLB 12 HLB 13

Select the Chemistry Determine the Concentration

All surfactants: HLB = 12

----

---

----

Surf A15%

Surf B15%

Surf C15%

Surf C8%

Surf C4%

Optimizing Your EmulsionHow Stability of Your Emulsion Is Affected by

HLB and Concentration of Emulsifier

0

1

2

3

4

5

6

7

8

9

10

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

% Concentration of Emulsifier

Stab

ility

HLB 12Surf C HLB 12

Surf A

Invert Emulsion Experiment±0.5 HLB Unit Accuracy

HLB 6 HLB 5

4% surfactant 9% surfactant

Matching HLB Values to Application Requirements

Surfactant HLB Requirements

Compatibilizing Dissimilar Oils 1 – 3

Water-in-oil emulsions (Inverts) 4 – 6

Wetting Powders into Oils 7 – 9

Oil-in-Water Emulsions 8 – 12

Detergent Solutions 13 - 15

Examples of HLB Requirements for O/W Emulsions

Class Required HLBVegetable oil family 6Silicone oils 8 - 12Petroleum oils & waxes 9 - 11Fatty acids and alcohols 14 - 15Resins 16 - 18

A Personal Experience

• Morning– Taking a “shortcut”– 3 hours of work, 100% failure

• Afternoon– Utilizing HLB system– 1 hour of work, 100% success

HLB System Flexibility – The Concept

• All components must be added to the oil before the HLB requirement can be determined– Biocide package– Anionic emulsifiers– Functional additives

HLB System Flexibility – The Concept

• Surfactant Pivot Pair– Identify the high HLB surfactant and low HLB

surfactant– Adjust blend ratios to establish stability

Anionic HLB Values

• Apparent anionic HLB values• When used in combination with nonionics,

they function as if

TEA Oleate HLB 12 Sodium Oleate HLB 18Potassium Oleate HLB 20Petroleum Sulfonates HLB 4 / 7

HLB & Water Dispersibility Relationships

HLB Dispersibility1 – 4 No dispersibility3 – 6 Poor dispersibility6 – 8 Milky after shake8 – 10 Stable, milky dispersion10 – 13 Translucent to clear13+ Clear solution

Summary• HLB System predicts how oils and surfactants will likely

interact• Surfactants have HLB values• Oils and systems have HLB requirements• Matching surfactant HLB value with HLB requirement will

yield optimum cost and performance• Two opportunities to optimize performance and cost

Required HLB’s are accurate to ± 0.5 HLB units

In Conclusion

Many formulators don’t think too much about the science behind the HLB System, they just use it because it works.

HLB Book & Kit

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