HLB scale.pptx
- 1. BRIEF PRESENTATION ON HLB PRESENTED BY : MR. Pankaj Sharma
- 3. INTRODUCTION In past fifty years, there has been a tremendous growth in the field of surfactants. The term surfactants include emulsifiers, wetting agents, suspending agents, detergents, anti-foam compounds and many others. Therefore, there classification is very important to choose suitable surfactant to give maximum effect. William Griffin, in the late 1940s, introduced the Hydrophilic-Lipophilic Balance system (HLB) as a way of figuring out which emulsifier would work best with the oil phase of an emulsified product
- 4. DEFINITION : It is the relative efficiency of the hydrophilic portion of the surfactant molecule to its lipophilic portion of the same molecule . Emulsifiers / Surfactants are characterized according to the "balance" between the hydrophilic ("water-loving") and lipophilic ("oil-loving") portions of their molecules. An emulsifier that is lipophilic in character is assigned a low HLB number and an emulsifier that is hydrophilic in character is assigned a high number.
- 5. The midpoint is approximately ten and the assigned values have ranged from one to forty. The hydrophilic-lipophilic balance (HLB) number indicates the polarity of the molecules in a range of 1-40, with the most commonly used emulsifiers having a value between 1 and 20. The HLB number increases with increasing hydrophilicity. Lipophilic tails align with oil Hydrophilic heads align with water
- 6. Lipophilic Tail & Hydrophilic Head The theory behind HLB is that emulsifier having low HLB value tend to be oil soluble and materials having high values tend to be water soluble. However, this doesn’t always be right, e.g., two emulsifiers may have the same HLB and exhibit different solubility characteristics. Further, one should take a point into consideration that chemical type alone doesn’t establish hydrophilic- lipophilic balance. Thus, soaps may range from strongly hydrophilic for sodium laurate to strongly lipophilic for aluminium oleate; esters, ether-esters, and ethers may range from low to high HLB’s, sulphates and sulfonates may range from medium to high.
- 7. DeterminationofH L B For most polyhydric alcohol fatty acid esters approximate values may be calculated with the formula: Where, • S= saponification number of the ester • A= acid number of the acid
- 8. DeterminationofH L B“ R e q u i r e m e n t ” 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.
- 9. hlbscale:
- 10. Applications of Surfactants depending on H L B The HLB system is very useful to distinguish the surfactants according to their applications. Generally, the applications for nonionic surfactants within the following HLB ranges are as follows: HLB range Application 4-6 w/o emulsifiers 7-9 wetting agents 8-18 o/w emulsifiers 13-15 Detergents 10-18 Solubilizers
- 11. Advantages: Gives stable emulsion. Works best with nonionic surfactants. Disadvantages: HLB is only a good approximation. Doesn’t always work.
- 13. Let’sc o n c l u d eb y: The HLB system, though it does not indicate the overall efficiency of the surfactant, it does tell “what it will do” i.e. what kind of an emulsion or product to expect. By so doing, it enables us to compare various chemical types of surfactants at their optimum balance. The HLB system appears to be suitable for all types of problems employing surface active agents.