Each type of emulgator has a price equilibrium is not the same magnitude. Equilibrium price is known as HLB (Hydrophyl Lipophyl Balance) is a number that indicates the ratio between lipophilic groups with hydrophilic groups.
The HLB value is an indication of the solubility of the surfactant. This surfactant solubility property is an indicator of its likely end use. 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
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
HLB VALUE BASED ON THE FUNCTION
• mixing unlike oils together/Antifoaming agent : use surfactants with HLB’s of 1 to 3
• making water-in-oil emulsions/ Emulgator type w/o : use surfactants with HLB’s of 4 to 6
• wetting powders into oils/Wetting agent : use surfactants with HLB’s of 7 to 9
• making self emulsifying oils : use surfactants with HLB’s of 7 to 10
• making oil-in-water emulsions/Emulgator type o/w : use surfactant blends with HLB’s of 8 to16
• making detergent solutions : use surfactants with HLB’s of 13 to 15
• for solubilizing oils ( micro-emulsifying ) into water/Solubilizing agent : use surfactant blends with HLB’s of 13 to 18 Some general required HLB rules for O/W emulsions
| Class | Required HLB |
|---|---|
| Vegetable oil family | 6 |
| Silicone oils | 8-12 |
| Petroleum oils | 10 |
| Typical ester emollients | 12 |
| Fatty acids and alcohol | 14-15 |
To determine the composition of the mixture emulgator in accordance with the desired HLB value, can be done by following the example calculations.
Formula I
A % b = ((x - HLB b)/ HLB a - HLB b) x 100 %
B % a = ( 100% - A%)
Note:
x = requested HLB (HLB Need)
A = high HLB value
B = low HLB value
Formula II
(B1 x HLB1) + (B2 x HLB2) = (B compound x HLB compound)
Aligasi Method
Tween 80 (15) (X – 4,5)
X
Span 80 (4.5) (15 – X)
(X – 4,5) : (15 – X) = 70 : 30 = 7 : 3
(X – 4,5) 3 = 7 (15 – X)
3X – 13,5 = 105 – 7X
10X = 118,5
X = 11,85
HLB compound = 11,85
EXAMPLE
A simple O/W lotion formula| Ingredients | % Weight |
|---|---|
| Mineral oil | 8 |
| Caprylic/Capric triglyceride | 2 |
| Isopropyl isostearate | 2 |
| Cetyl alcohol | 4 |
| Emulsifier | 4 |
| Polyols | 5 |
| Water soluble active | 1 |
| Water | 74 |
| Perfume | q.s |
| Presevative | q.s |
Calculations:
add up the oil phase ingredients:
- mineral oil 8 %
- caprylic/capric triglyceride 2 %
- isopropyl isostearate 2 %
- cetyl alcohol 4 %
TOTAL 16
Calculations:
divide each by the total to get the contribution to the oil phase
- Mineral oil 8 / 16 = 50%
- caprylic/cap. trig. 2 / 16 = 12.5%
- isopropyl isostearate 2 / 16 = 12.5%
- cetyl alcohol 4 / 16 = 25%
CALCULATION FOR HLB OF THIS UNIQUE BLEND
| Oil Phase Ingredients | Contribution | X Required HLB of ingredient | Equals |
|---|---|---|---|
| Mineral oil | 50% | 10.5 | 5.250 |
| Caprylic cap. Trig. | 12.5% | 5 | 0.625 |
| Isopropyl isostearate | 12.5% | 11.5 | 1.437 |
| Caetyl alcohol | 25% | 11.5 | 3.875 |
| TOTAL | 11.2 |
- as a starting point, select a surfactant system with an HLB value of ~11.2
- For the surfactant system, you should use a blend of at least two surfactants, why?
- experience has shown the benefit
- mixtures of a low HLB and a high HLB surfactant give better coverage at the interface
- a blend of two surfactants is typical
- The correct HLB value usually translates to superior stability at a lower use level. For example: our unique formula with a surfactant blend at HLB 11.2 at a 4% use level will most likely give longer stability at elevated temperatures than 5% of a blend at either HLB 10.2 or 13.2
