# Hlb System

Topics: Emulsion, Surfactant, Water Pages: 4 (759 words) Published: February 3, 2013
The HLB System
hydrophilic-lipophilic balance value “A numerical representative of the hydrophilic and lipophilic tendencies of the material” - used most in the rational selection of combinations of nonionic emulsifiers - stable o/w emulsion can be prepared by utilizing HLB method

HLB Value
• Depends on the ratio of hydrophilic and lipophilic portion - low HLB values soluble/ disperse in oil - high HLB value soluble/ disperse in water • Determined by the chemical composition and degree of ionization or hydration of the emulsifier molecule

HLB = ? hydrophilic gr. + ? hydrophobic gr.+7 CH3-(CH2)10-CH2-O-S-O3-Na+ HLB = 38.7 + 12(-0.475) + 7 = 40

Rational Between HLB range and Surfactant Application
HLB Range 0-3 4-6 7-9 8-18 13-15 10-18 Use Antifoaming agents w/o emulsifying agent Wetting agent o/w emulsifying agent Detergents Solubilizing agents

Required HLB
• For calculating the relative quantities of emulsifying agents necessary to produce the most physically stable emulsion (o/w) o/w 5 4 4 8 w/o 12 15 12 12 10

Beeswax Cetyl alcohol Mineral oil Soft paraffin Wool fat

Rx

Mineral oil Wool fat Cetyl alcohol Emulsifier system Water to

35%

1 1 5 100

HLB 12 10 15

Proportion of each: Mineral oil Wool fat Cetyl alcohol

35/37 x 100 = 94.6% 1/37 x 100 = 2.7% 1/37 x 100 = 2.7%

Total required HLB number Mineral oil 94.6/100 x 12 = 11.4 Wool fat 2.7/100 x 10 = 0.3 Cetyl alcohol 2.7/100 x 15 = 0.4 Total required HLB 12.1 This formulation requires an emulsifying agent blend of HLB 12.1 sorbitan monooleate (4.3) polyoxyethylene sorbitan monooleate (15)

A = 100 (x-HLB of B) (HLB of A – HLB of B) A = the % conc. of the hydrophilic B = the % conc. of the hydrophobic (100-A) x = required HLB A = 100 (12.1-4.3) = 72.9 (15-4.3) B = 100-72.9 = 27.1 Total % of emulsifying blend = 5, then the % of each:

Sorbitan monooleate = 5 x 27.1/100 = 1.36 Polyoxyethylene sorbitan monooleate = 5-1.36 = 3.64

Have to be Remebered
• Degree...