THE HLB SYSTEM Done by: Abdykadyrkyzy A., Nurkair A.

What do we mean by HLB All surfactants must have an oil loving portion and a water loving portion or they would not have surface activity The ratio of the oil loving portion to the water loving portion is what we call its balance We measure this balance based on molecular weight HLB stands for – HYDROPHILE / LIPOPHILE / BALANCE

What is the HLB system story The system was created as a tool to make it easier to use nonionic surfactants In general it applies to nonionic surfactants only The basic principle of the system is: –Surfactants have an HLB value –Applications for surfactants have an HLB requirement –Matching the requirement with the value saves time and money

The desired HLB numbers can also be achieved by mixing lipophilic and hydrophilic surfactants. William Griffin devised HLB System to calculated amount of emulsifier to get the desired HLB. Advantage of HLB system: Gives stable emulsion. Works best with nonionic surfactants. Disadvantage: HLB is only a good approximation. Doesnt always work. Hydrophilic-Lipophilic Balance (HLB) System.

Why use the HLB System It tells us something about the chemistry of the surfactant when you know about the chemistry of the surfactant you can predict how it will behave being able to predict how a surfactant will behave will save you time ( $$$$$ )

What is the chemistry of a nonionic surfactant ? Each surfactant has a hydrophilic group and a lipophilic group –must have both or it would not be surface active the hydrophilic group is usually a polyhydric* alcohol or ethylene oxide the lipophilic group is usually a fatty acid or a fatty alcohol –* polyhydric- an alcohol with OHs attached

How do we determine the HLB value of a surfactant ? We calculate the water loving portion of the surfactant on a molecular weight basis and then divide that number by 5 this keeps the HLB scale smaller and more manageable –the working scale is from 0.5 to 19.5 this number is then assigned to the nonionic surfactant

Important to remember ! The HLB value is an indication of the solubility of the surfactant the lower the HLB value the more lipophilic or oil soluble the surfactant is the higher the HLB value the more water soluble or hydrophilic the surfactant is this surfactant solubility property is an indicator of its likely end use

Important to remember, cont. HLB values are calculated for nonionic surfactants only the HLB value is the molecular weight percent of the water loving portion of the nonionic surfactant - divided by five What does it mean when you hear of an anionic with an HLB for 40 or so? –This number is a relative or comparative number and not a mathematical calculation

Examples of matching HLB values to application needs mixing unlike oils together –use surfactants with HLBs of 1 to 3 making water-in-oil emulsions –use surfactants with HLBs of 4 to 6 wetting powders into oils –use surfactants with HLBs of 7 to 9 making self emulsifying oils –use surfactants with HLBs of 7 to 10 making oil-in-water emulsions –use surfactant blends with HLBs of 8 to16 making detergent solutions –use surfactants with HLBs of 13 to 15 for solubilizing oils ( micro-emulsifying ) into water – use surfactant blends with HLBs of 13 to 18

For example A simple O/W lotion formula –mineral oil8 % –caprylic/capric triglyceride2 % –isopropyl isostearate2 % –cetyl alcohol4 % –emulsifiers4 % –polyols5 % –water soluble active1 % –water74 %

Some general required HLB rules for O/W emulsions

Directions for using the HLB system to select surfactants for an O/W emulsion Look at your formula determine which are the oil soluble ingredients –this does not include the emulsifiers weigh each of the weight percents of the oil phase ingredients together and divide each by the total multiply these answers times the required HLB of the individual oils add these together to get the required HLB of your unique blend

Calculations: add up the oil phase ingredients –mineral oil8 % –caprylic/capric triglyceride2 % –isopropyl isostearate2 % –cetyl alcohol4 % » 16 –emulsifiers4 % –polyols5 % –water soluble active1 % –water74 % –perfumeq.s. –preservativeq.s.

Calculations: divide each by the total to get the contribution to the oil phase Mineral oil8 / 16 = 50% caprylic/cap. trig.2 / 16 = 12.5% isopropyl isostearate2 / 16 = 12.5% cetyl alcohol4 / 16 = 25%

Summary HLB is a number system that lets you know how oils and surfactants will likely interact Surfactants have an HLB value –the higher the number the more hydrophilic –the lower the number the more lipophilic Oils and applications have an HLB requirement Matching the HLB value with the requirement will give good performance It is not rocket science – just a very useful time saving general guide